Dissertations / Theses on the topic 'Collision avoidance systems'
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1
Melega, Marco. "Autonomous Collision avoidance for Unmanned aerial systems." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9251.
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Unmanned Aerial System (UAS) applications are growing day by day and this will lead Unmanned Aerial Vehicle (UAV) in the close future to share the same airspace of manned aircraft.This implies the need for UAS to define precise safety standards compatible with operations standards for manned aviation. Among these standards the need for a Sense And Avoid (S&A) system to support and, when necessary, sub¬stitute the pilot in the detection and avoidance of hazardous situations (e.g. midair collision, controlled flight into terrain, flight path obstacles, and clouds).
This thesis presents the work come out in the development of a S&A system taking into account collision risks scenarios with multiple moving and fixed threats. The conflict prediction is based on a straight projection of the threats state in the future. The approximations introduced by this approach have the advantage of high update frequency (1 Hz) of the estimated conflict geometry. This solution allows the algorithm to capture the trajectory changes of the threat or ownship. The resolution manoeuvre evaluation is based on a optimisation approach considering step command applied to the heading and altitude autopilots. The optimisation problem takes into account the UAV performances and aims to keep a predefined minimum separation distance between UAV and threats during the resolution manouvre. The Human-Machine Interface (HMI) of this algorithm is then embedded in a partial Ground Control Station (GCS) mock-up with some original concepts for the indication of the flight condition parameters and the indication of the resolution manoeuvre constraints.
Simulations of the S&A algorithm in different critical scenarios are moreover in-cluded to show the algorithm capabilities. Finally, methodology and results of the tests and interviews with pilots regarding the proposed GCS partial layout are covered.
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Blackwell, Grahame Kenneth. "An expert systems approach to collision avoidance." Thesis, University of Plymouth, 1992. http://hdl.handle.net/10026.1/1773.
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Barrios, Cesar. "Predicting Trajectory Paths For Collision Avoidance Systems." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/386.
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This work was motivated by the idea of developing a more encompassing collision avoidance system that supported vehicle to vehicle (V2V) and vehicle to infrastructure (V2I) communications. Current systems are mostly based on line of sight sensors that are used to prevent a collision, but these systems would prevent even more accidents if they could detect possible collisions before both vehicles were in line of sight.
For this research we concentrated mostly on the aspect of improving the prediction of a vehicle's future trajectory, particularly on non-straight paths. Having an accurate prediction of where the vehicle is heading is crucial for the system to reliably determine possible path intersections of more than one vehicle at the same time. We first evaluated the benefits of merging Global Positioning System (GPS) data with the Geographical Information System (GIS) data to correct improbable predicted positions. We then created a new algorithm called the Dead Reckoning with Dynamic Errors (DRWDE) sensor fusion, which can predict future positions at the rate of its fastest sensor, while improving the handling of accumulated error while some of the sensors are offline for a given period of time. The last part of out research consisted in the evaluation of the use of smartphones' built-in sensors to predict a vehicle's trajectory, as a possible intermediate solution for a vehicle to vehicle (V2V) and vehicle to infrastructure (V2I) communications, until all vehicles have all the necessary sensors and communication infrastructure to fully populate this new system.
For the first part of our research, the actual experimental results validated our proposed system, which reduced the position prediction errors during curves to around half of what it would be without the use of GIS data for prediction corrections. The next improvement we worked on was the ability to handle change in noise, depending on unavailable sensor measurements, permitting a flexibility to use any type of sensor and still have the system run at the fastest frequency available. Compared to a more common KF implementation that run at the rate of its slowest sensor (1Hz in our setup), our experimental results showed that our DRWDE (running at 10Hz) yielded more accurate predictions (25-50% improvement) during abrupt changes in the heading of the vehicle. The last part of our research showed that, comparing to results obtained with the vehicle-mounted sensors, some smartphones yield similar prediction errors and can be used to predict a future position.
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Degen, Shane C. "Reactive image-based collision avoidance system for unmanned aircraft systems." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/46969/1/Shane_Degen_Thesis.pdf.
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Approximately 20 years have passed now since the NTSB issued its original recommendation to expedite development, certification and production of low-cost proximity warning and conflict detection systems for general aviation [1]. While some systems are in place (TCAS [2]), ¡¨see-and-avoid¡¨ remains the primary means of separation between light aircrafts sharing the national airspace. The requirement for a collision avoidance or sense-and-avoid capability onboard unmanned aircraft has been identified by leading government, industry and regulatory bodies as one of the most significant challenges facing the routine operation of unmanned aerial systems (UAS) in the national airspace system (NAS) [3, 4]. In this thesis, we propose and develop a novel image-based collision avoidance system to detect and avoid an upcoming conflict scenario (with an intruder) without first estimating or filtering range. The proposed collision avoidance system (CAS) uses relative bearing ƒÛ and angular-area subtended ƒê , estimated from an image, to form a test statistic AS C . This test statistic is used in a thresholding technique to decide if a conflict scenario is imminent. If deemed necessary, the system will command the aircraft to perform a manoeuvre based on ƒÛ and constrained by the CAS sensor field-of-view. Through the use of a simulation environment where the UAS is mathematically modelled and a flight controller developed, we show that using Monte Carlo simulations a probability of a Mid Air Collision (MAC) MAC RR or a Near Mid Air Collision (NMAC) RiskRatio can be estimated. We also show the performance gain this system has over a simplified version (bearings-only ƒÛ ). This performance gain is demonstrated in the form of a standard operating characteristic curve. Finally, it is shown that the proposed CAS performs at a level comparable to current manned aviations equivalent level of safety (ELOS) expectations for Class E airspace. In some cases, the CAS may be oversensitive in manoeuvring the owncraft when not necessary, but this constitutes a more conservative and therefore safer, flying procedures in most instances.
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Mcfadyen, Aaron. "Visual control for automated aircraft collision avoidance systems." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/81418/1/Aaron_McFadyen_Thesis.pdf.
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This thesis presents a new vision-based decision and control strategy for automated aircraft collision avoidance that can be realistically applied to the See and Avoid problem. The effectiveness of the control strategy positions the research as a major contribution toward realising the simultaneous operation of manned and unmanned aircraft within civilian airspace.
Key developments include novel classical and visual predictive control frameworks, and a performance evaluation technique aligned with existing aviation practise and applicable to autonomous systems. The overall approach is demonstrated through experimental results on a small multirotor unmanned aircraft, and through high fidelity probabilistic simulation studies.
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Strömgren, Oliver. "Deep Learning for Autonomous Collision Avoidance." Thesis, Linköpings universitet, Datorseende, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-147693.
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Deep learning has been rapidly growing in recent years obtaining excellent results for many computer vision applications, such as image classification and object detection. One aspect for the increased popularity of deep learning is that it mitigates the need for hand-crafted features. This thesis work investigates deep learning as a methodology to solve the problem of autonomous collision avoidance for a small robotic car. To accomplish this, transfer learning is used with the VGG16 deep network pre-trained on ImageNet dataset. A dataset has been collected and then used to fine-tune and validate the network offline. The deep network has been used with the robotic car in a real-time manner. The robotic car sends images to an external computer, which is used for running the network. The predictions from the network is sent back to the robotic car which takes actions based on those predictions. The results show that deep learning has great potential in solving the collision avoidance problem.
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Alturbeh, Hamid. "Collision avoidance systems for UAS operating in civil airspace." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9295.
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Operation of Unmanned Aerial Vehicles (UAVs) in civil airspace is restricted by the aviation
authorities which require full compliance with regulations that apply for manned aircraft.
This thesis proposes control algorithms for a collision avoidance system that can be used
as an advisory system or a guidance system for UAVs that are flying in civil airspace under
visual flight rules. An effective collision avoidance system for the UAV should be able to
perform the different functionalities of the pilot in manned aircraft. Thus, it should be able
to determine, generate, and perform safe avoidance manoeuvres. However, the capability to
generate resolution advisories is crucial for the advisory systems. A decision making system
for collision avoidance is developed based on the rules of the air. The proposed architecture
of the decision making system is engineered to be implementable in both manned aircraft
and UAVs to perform different tasks ranging from collision detection to a safe avoidance
manoeuvre initiation. Avoidance manoeuvres that are compliant with the rules of the air are
proposed based on pilot suggestions for a subset of possible collision scenarios. The avoidance
manoeuvre generation algorithm is augmented with pilot experience by using fuzzy
logic technique to model pilot actions in generating the avoidance manoeuvres. Hence, the
generated avoidance manoeuvres mimic the avoidance manoeuvres of manned aircraft. The
proposed avoidance manoeuvres are parameterized using a geometric approach. An optimal
collision avoidance algorithm is developed for real-time local trajectory planning. Essentially,
a finite-horizon optimal control problem is periodically solved in real-time hence
updating the aircraft trajectory to avoid obstacles and track a predefined trajectory. The optimal
control problem is formulated in output space, and parameterised by using B-splines.
Then the optimal designed outputs are mapped into control inputs of the system by using
the inverse dynamics of a fixed wing aircraft.
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Yi, Boliang [Verfasser]. "Integrated Planning and Control for Collision Avoidance Systems / Boliang Yi." Karlsruhe : KIT Scientific Publishing, 2018. http://www.ksp.kit.edu.
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Yick, King-Yeung 1978. "Design and test of intersection collision avoidance systems for automobiles." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/82790.
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Gorman, Thomas Ian. "Prospects for the Collision-Free Car: The Effectiveness of Five Competing Forward Collision Avoidance Systems." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/24721.
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Rear-end collisions in which the leading vehicle was stationary prior to impact and at least one vehicle was towed from the crash site represent 18% of all yearly crashes in the United States. Forward Collision Avoidance Systems (FCASs) are becoming increasingly available in production vehicles and have a great potential for preventing or mitigating rear-end collisions. The objective of this study was to compare the effectiveness of five crash avoidance algorithms that are similar in design to systems found on production vehicles of model year 2011. To predict the effectiveness of each algorithm, this study simulated a representative sample of rear-end collisions as if the striking vehicle was equipped with each FCAS.
In 2011, the ADAC (Allgemeiner Deutscher Automobil-Club e.V) published a test report comparing advanced emergency braking systems. The ADAC tested production vehicles of model year 2011 made by Audi, BMW, Infiniti, Volvo, and VW. The ADAC test results were used in conjunction with video evidence and owner's manual information to develop mathematical models of five different FCASs. The systems had combinations of Forward Collision Warning (FCW), Assisted Braking (AB), and Autonomous Emergency Braking (AEB).
The effectiveness of each modeled system was measured by its ability to prevent collisions or reduce the collision severity of reconstructed crashes. In this study, 977 rear-end crashes that occurred from 1993 to 2008 were mathematically reconstructed. These crashes were investigated as part of NHTSA's National Automotive Sampling System, Crashworthiness Data System (NASS/CDS). These crashes represent almost 800,000 crashes during that time period in which the struck vehicle was stationary. Part of the NASS/CDS investigation was to reconstruct the vehicle change in velocity during impact, ∆V. Using energy and Newtonian based methods, the ∆V in each crash was calculated as if the vehicle was equipped with each modeled FCAS. Using the predicted reduction in crash ∆V, the expected reduction in the number of moderately-to-fatally injured (MAIS2+) drivers was predicted.
This study estimates that the most effective FCAS model was the Volvo algorithm which could potentially prevent between 79% and 92% of the crashes simulated in this study and between 76% and 94% of associated driver injuries. This study estimates that the BMW algorithm would prevent the fewest number of crashes (between 11% and 14%), but would provide admirable benefits to driver safety by preventing between 21% and 25% of driver injuries. The VW algorithm would be the least effective at preventing driver injuries if the system were to be implemented across the U.S. fleet. This algorithm offers a 19% reduction in crashes, but only prevents 15% of driver injuries.
This study introduces and demonstrates a unique method of comparing potential benefits of competing FCAS algorithms. This method could be particularly useful to system designers for comparing the expected effects of design decisions on safety performance. This method could also be useful to government officials who wish to evaluate the effectiveness of FCASs.Master of Science
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Farahmand, Ashil Sayyed. "Cooperative Decentralized Intersection Collision Avoidance Using Extended Kalman Filtering." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/36276.
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Automobile accidents are one of the leading causes of death and claim more than 40,000 lives annually in the US alone. A substantial portion of these accidents occur at road intersections. Stop signs and traffic signals are some of the intersection control devices used to increase safety and prevent collisions. However, these devices themselves can contribute to collisions, are costly, inefficient, and are prone to failure. This thesis proposes an adaptive, decentralized, cooperative collision avoidance (CCA) system that optimizes each vehicle's controls subject to the constraint that no collisions occur. Three major contributions to the field of collision avoidance have resulted from this research. First, a nonlinear 5-state variable vehicle model is expanded from an earlier model developed in [1]. The model accounts for internal engine characteristics and more realistically approximates vehicle behavior in comparison to idealized, linear models. Second, a set of constrained, coupled Extended Kalman Filters (EKF) are used to predict the trajectory of the vehicles approaching an intersection in real-time. The coupled filters support decentralized operation and ensure that the optimization algorithm bases its decisions on good, reliable estimates. Third, a vehicular network based on the new WAVE standard is presented that provides cooperative capabilities by enabling intervehicle communication. The system is simulated against today's common intersection control devices and is shown to be superior in minimizing average vehicle delay.Master of Science
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Jia, Yanbo. "An automated cyclist collision avoidance system for heavy goods vehicles." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708620.
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Doerzaph, Zachary R. "Development of a Threat Assessment Algorithm for Intersection Collision Avoidance Systems." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/30013.
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Relative to other roadway segments, intersections occupy a small portion of the overall infrastructure; however, they represent the location for nearly 41 % of the annual automotive crashes in the United States. Thus, intersections are an inherently dangerous roadway element and a prime location for vehicle conflicts. Traditional safety treatments are effective at addressing certain types of intersection safety deficiencies; however, cumulative traffic data suggests these treatments do not address a large portion of the crashes that occur each year.
Intersection Collision Avoidance Systems (ICAS) represent a new breed of countermeasures that focus on the types of crashes that have not been reduced with the application of traditional methods. Incursion systems, a subset of ICAS, are designed to specifically undertake crashes that are a result of the violation of a traffic control device. Intersection Collision Avoidance Systems to address Violations (ICAS-V) monitor traffic as it approaches the intersection through a network of in-vehicle sensors, infrastructure- mounted sensors, and communication equipment. A threat-assessment algorithm performs computations to predict the driver's intended intersection maneuver, based on these sensor inputs. If the system predicts a violation, it delivers a timely warning to the driver with the aim of compelling the driver to stop. This warning helps the driver to avoid a potential crash with adjacent traffic.
The following dissertation describes an investigation of intersection approach behavior aimed at developing a threat assessment algorithm for stop-sign intersections. Data were collected at live intersections to gather infrastructure-based naturalistic vehicle approach trajectories. This data were compiled and analyzed with the goal of understanding how drivers approach intersections under various speeds and environmental conditions. Six stop-controlled intersection approaches across five intersections in the New River Valley, Virginia area were selected as the test sites. Data were collected from each site for at least two months, resulting in over sixteen total months of data.
A series of statistical analysis techniques were applied to construct a set of threat assessment algorithms for stop-controlled intersections. These analyses identified characteristics of intersection approaches that suggested driver intent at the stop sign. Models were constructed to predict driver stopping intent based on measured vehicle kinematics. These models were thoroughly tested using simulation and evaluated with signal detection theory. The overall output of this work is a set of algorithms that may be integrated into an ICAS-V for on-road testing.Ph. D.
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Sahawneh, Laith Rasmi. "Airborne Collision Detection and Avoidance for Small UAS Sense and Avoid Systems." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5840.
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The increasing demand to integrate unmanned aircraft systems (UAS) into the national airspace is motivated by the rapid growth of the UAS industry, especially small UAS weighing less than 55 pounds. Their use however has been limited by the Federal Aviation Administration regulations due to collision risk they pose, safety and regulatory concerns. Therefore, before civil aviation authorities can approve routine UAS flight operations, UAS must be equipped with sense-and-avoid technology comparable to the see-and-avoid requirements for manned aircraft. The sense-and-avoid problem includes several important aspects including regulatory and system-level requirements, design specifications and performance standards, intruder detecting and tracking, collision risk assessment, and finally path planning and collision avoidance. In this dissertation, our primary focus is on developing an collision detection, risk assessment and avoidance framework that is computationally affordable and suitable to run on-board small UAS. To begin with, we address the minimum sensing range for the sense-and-avoid (SAA) system. We present an approximate close form analytical solution to compute the minimum sensing range to safely avoid an imminent collision. The approach is then demonstrated using a radar sensor prototype that achieves the required minimum sensing range. In the area of collision risk assessment and collision prediction, we present two approaches to estimate the collision risk of an encounter scenario. The first is a deterministic approach similar to those been developed for Traffic Alert and Collision Avoidance (TCAS) in manned aviation. We extend the approach to account for uncertainties of state estimates by deriving an analytic expression to propagate the error variance using Taylor series approximation. To address unanticipated intruders maneuvers, we propose an innovative probabilistic approach to quantify likely intruder trajectories and estimate the probability of collision risk using the uncorrelated encounter model (UEM) developed by MIT Lincoln Laboratory. We evaluate the proposed approach using Monte Carlo simulations and compare the performance with linearly extrapolated collision detection logic. For the path planning and collision avoidance part, we present multiple reactive path planning algorithms. We first propose a collision avoidance algorithm based on a simulated chain that responds to a virtual force field produced by encountering intruders. The key feature of the proposed approach is to model the future motion of both the intruder and the ownship using a chain of waypoints that are equally spaced in time. This timing information is used to continuously re-plan paths that minimize the probability of collision. Second, we present an innovative collision avoidance logic using an ownship centered coordinate system. The technique builds a graph in the local-level frame and uses the Dijkstra's algorithm to find the least cost path. An advantage of this approach is that collision avoidance is inherently a local phenomenon and can be more naturally represented in the local coordinates than the global coordinates. Finally, we propose a two step path planner for ground-based SAA systems. In the first step, an initial suboptimal path is generated using A* search. In the second step, using the A* solution as an initial condition, a chain of unit masses connected by springs and dampers evolves in a simulated force field. The chain is described by a set of ordinary differential equations that is driven by virtual forces to find the steady-state equilibrium. The simulation results show that the proposed approach produces collision-free plans while minimizing the path length. To move towards a deployable system, we apply collision detection and avoidance techniques to a variety of simulation and sensor modalities including camera, radar and ADS-B along with suitable tracking schemes.
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Moon, James Nicholas John. "An investigation into the use of multi-agent systems in marine simulator instructor stations." Thesis, University of South Wales, 1997. https://pure.southwales.ac.uk/en/studentthesis/an-investigation-into-the-use-of-multiagent-systems-in-marine-simulator-instructor-stations(a6ae516b-fda8-4be7-985e-3b3a10dee408).html.
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This thesis documents an investigation into the automatic provision of reasonably realistic motion for the computer generated target ships in a marine simulator. The thesis explores: automatic collision avoidance between the target ships; automatic track keeping for the target ships; the use of sea stabilised and land stabilised motion for the target ships; some issues of software fault tolerance in marine simulators; message frameworks for use in a Multi-Agent System (MAS) simulation; the opportunity to provide different manoeuvring characteristics for different target ships; and the use of autonomous agents to control the target ships. A software system has been developed to facilitate this research. Entitled "A Multi-Agent Realm for Investigating Navigators' Educational Simulators" (MARINES), the software is a MAS providing much of the functionality of a marine simulator instructor station; basic functions are encapsulated into the instructor environment and additional features are provided by processes that connect to the environment using Dynamic Data Exchange. The processes can also connect to each other and, in MARINES, co-operate to navigate the ships. These co-operative, autonomous processes are the agents that together form a MAS. A simple 3D view is also connected, enabling the view from the bridge of a specific target ship to be assessed. The MARINES software is written using C++ to run under Microsoft Windows v3.1. Therefore, the processes multi-task co-operatively. In MARINES each target ship can be made to perform in an individual manner; manoeuvring and performance characteristics can be customised to simulate a specific ship type. Additionally, the agents performing collision avoidance can be given rule sets that interpret the International Regulations for the Prevention of Collisions at Sea in subtly different ways, and the track-keeping agents can have different beliefs about the manoeuvring capabilities of the vessels they control. Automatic collision avoidance and track keeping is performed for two-ship situations even when the set and drift of a current is introduced. A comparison is made with the tracks of land stabilised targets. This shows how aspect, course and speed are affected by ignoring the effects of the current, and demonstrates the need for an accurate simulation.
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Wolfe, Sage M. "Heavy Truck Modeling and Estimation for Vehicle-to-Vehicle Collision Avoidance Systems." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405704063.
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Every, Joshua Lee. "Development of a Driver Behavior Based Active Collision Avoidance System." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429800895.
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Pai, Arun S. "Development of deterministic collision-avoidance algorithms for routing automated guided vehicles /." Online version of thesis, 2008. http://hdl.handle.net/1850/7289.
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Nowak, Jakub. "Robust Control of Coupled Multirobot Systems under Signal Temporal Logic Specifications with Collision Avoidance." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-240368.
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Multi-agent systems have been gaining attention among robotics researchersdue to their capabilities, in terms of which they surpass individualrobots. Such systems, however, entail an increase in complexity,especially to the task planning problem. Therefore, a more sophisticatedplanning approach is needed, one that is able to resolve conflictsbetween local tasks, in particular. These conflicts arise from couplingsbetween robots expressed in their task specifications.A computationally inexpensive collaborative control scheme is implementedin a setup consisting of three omni-directional robots. Therobots execute tasks encoded in Signal Temporal Logic, using PrescribedPerformance Control. They are guaranteed to satisfy the specificationsor, if that is not possible, reach a least violating solution, evenin the face of a task conflict. What is more, collision-free trajectoriesare produced.A series of simulations and experiments is carried out to verify theutility of the method. The approach is shown to be effective despiterestrictive assumptions imposed on the system. Finally, directions forfuture work, that would allow the method to perform well in moredemanding experimental scenarios, are suggested.Multiagentsystem har fått uppmärksamhet bland robotikforskare på grund av dess prestanda, där de kan prestera bättre än individuella robotar. Sådana system, däremot, bidrar till en ökning i komplexitet, i synnerhet för uppgiftsplaneringsproblemet. Därav behövs en mer so- fistikerad planeringsmetod, särskilt en som kan lösa konflikter mellan lokala uppgifter. Dessa konflikter uppstår från kopplingar mellan ro- botar uttryckta i deras uppgiftsspecifikationer. Ett beräkningsmässigt inexpensivt och kollaborativt kontrollschema är implementerat i ett system bestående av tre rundstrålande robotar. Robotarna utför upp- gifter som är kodade i Signal Temporal Logic, med användning av Prescribed Performance Control. De är garanterade att uppnå speci- kitationerna eller, om det inte är möjligt, uppnå den minst överträdan- de lösningen trots uppgiftskonflikter. Dessutom är kollisionsfria ba- nor producerade. En serie av simuleringar och experiment utförs för att verifiera metodens lönsamhet. Tillvägagångssättet visar sig vara ef- fektivt trots de restriktiva antaganden som ålagts på systemet. Till sist så föreslås direktiv för framtida arbeten så att metoden kan prestera bra i hårdare experimentella scenarier.
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Thedchanamoorthy, Sivaranjini. "Optimisation-based verification process of obstacle avoidance systems for unmanned vehicles." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/15106.
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This thesis deals with safety verification analysis of collision avoidance systems for unmanned vehicles. The safety of the vehicle is dependent on collision avoidance algorithms and associated control laws, and it must be proven that the collision avoidance algorithms and controllers are functioning correctly in all nominal conditions, various failure conditions and in the presence of possible variations in the vehicle and operational environment. The current widely used exhaustive search based approaches are not suitable for safety analysis of autonomous vehicles due to the large number of possible variations and the complexity of algorithms and the systems. To address this topic, a new optimisation-based verification method is developed to verify the safety of collision avoidance systems. The proposed verification method formulates the worst case analysis problem arising the verification of collision avoidance systems into an optimisation problem and employs optimisation algorithms to automatically search the worst cases. Minimum distance to the obstacle during the collision avoidance manoeuvre is defined as the objective function of the optimisation problem, and realistic simulation consisting of the detailed vehicle dynamics, the operational environment, the collision avoidance algorithm and low level control laws is embedded in the optimisation process. This enables the verification process to take into account the parameters variations in the vehicle, the change of the environment, the uncertainties in sensors, and in particular the mismatching between model used for developing the collision avoidance algorithms and the real vehicle. It is shown that the resultant simulation based optimisation problem is non-convex and there might be many local optima. To illustrate and investigate the proposed optimisation based verification process, the potential field method and decision making collision avoidance method are chosen as an obstacle avoidance candidate technique for verification study. Five benchmark case studies are investigated in this thesis: static obstacle avoidance system of a simple unicycle robot, moving obstacle avoidance system for a Pioneer 3DX robot, and a 6 Degrees of Freedom fixed wing Unmanned Aerial Vehicle with static and moving collision avoidance algorithms. It is proven that although a local optimisation method for nonlinear optimisation is quite efficient, it is not able to find the most dangerous situation. Results in this thesis show that, among all the global optimisation methods that have been investigated, the DIviding RECTangle method provides most promising performance for verification of collision avoidance functions in terms of guaranteed capability in searching worst scenarios.
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Kirven, Thomas C. "AUTONOMOUS QUADROTOR COLLISION AVOIDANCE AND DESTINATION SEEKING IN A GPS-DENIED ENVIRONMENT." UKnowledge, 2017. https://uknowledge.uky.edu/me_etds/105.
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This thesis presents a real-time autonomous guidance and control method for a quadrotor in a GPS-denied environment. The quadrotor autonomously seeks a destination while it avoids obstacles whose shape and position are initially unknown. We implement the obstacle avoidance and destination seeking methods using off-the-shelf sensors, including a vision-sensing camera. The vision-sensing camera detects the positions of points on the surface of obstacles. We use this obstacle position data and a potential-field method to generate velocity commands. We present a backstepping controller that uses the velocity commands to generate the quadrotor's control inputs. In indoor experiments, we demonstrate that the guidance and control methods provide the quadrotor with sufficient autonomy to fly point to point, while avoiding obstacles.
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Glynn, Patrick Joseph, and n/a. "Collision Avoidance Systems for Mine Haul Trucks and Unambiguous Dynamic Real Time Single Object Detection." Griffith University. Griffith Business School, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060809.163025.
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A suite of new collision avoidance systems (CAS) is presented for use in heavy vehicles whose structure and size necessarily impede driver visibility is introduced. The main goal of the project is to determine the appropriate use of each of the commercially available technologies and, where possible, produce a low cost variant suitable for use in proximity detection on large mining industry haul trucks. CAS variants produced were subjected to a field demonstration and, linked to the output from the earlier CAS 1 project, (a production high-definition in-cabin video monitor and r/f tagging system). The CAS 2 system used low cost Doppler continuous wave radar antennae coupled to the CAS 1 monitor to indicate the presence of an object moving at any speed above 3 Km/h relative to the antennae. The novelty of the CAS 3 system lies in the design of 3 interconnected, modules. The modules are 8 radar antennae (as used in CAS 2) modules located on the truck, software to interface with the end user (i.e. the drivers of the trucks) and a display unit. Modularisation enables the components to be independently tested, evaluated and replaced when in use. The radar antennae modules and the system as a whole are described together with the empirical tests conducted and results obtained. The tests, drawing on Monte-Carlo simulation techniques, demonstrate both the 'correctness' of the implementations and the effectiveness of the system. The results of the testing of the final prototype unit were highly successful both as a computer simulation level and in practical tests on light vehicles. A number of points, (as a consequence of the field test), are reviewed and their application to future projects discussed.
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Scofield, Jan W. (Jan William). "Benefit analysis and feasibility of ground collision avoidance systems on United States Air Force aircraft." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/41801.
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Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management, 1995.Includes bibliographical references (p. 91-92).
This thesis examines a specific type of USAF aircraft mishaps - Controlled Flight Into Terrain (CFIT) mishaps. The thesis presents data on CFIT mishaps, causes, and efforts to reduce CFIT mishaps through the development and adoption of Ground Collision Avoidance Systems (GCAS) or similar designs - Ground Proximity Warning Systems (GPWS). GPWS exist today on some USAF aircraft, but many times these systems are inadequate (as evidenced by the continued occurrence of CFIT mishaps). Both ongoing and future initiatives by the USAF to adopt and develop better GPWS/GCAS systems were studied. An analysis was performed which studied the cost to the USAF (and the U.S. taxpayer) as a result of CFIT mishaps, and compared with an analysis of the cost to develop and implement improved GPWS/GCAS systems. The results show conclusively that installing GCAS/GPWS on a majority of USAF aircraft is cost effective. Technology exist today which could improve existing GPWS performance, and although efforts to improve GPWS are moving forward, some resistance does exist. Possible reasons for resistance of GCAS/GPWS adoption were studied and several recommendations were made on how to improve the adoption of these systems within the USAF.
by Jan W. Scofield.
S.M.
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Berges, Paul Martin. "Exploring the Vulnerabilities of Traffic Collision Avoidance Systems (TCAS) Through Software Defined Radio (SDR) Exploitation." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90165.
Full textAbstract:
Traffic Collision Avoidance Systems (TCAS) are safety-critical systems that are deployed on most commercial aircraft in service today. However, TCAS transactions were not designed to account for malicious actors. While in the past it may have been infeasible for an attacker to craft arbitrary radio signals, attackers today have access to open-source digital signal processing software like GNU Radio and inexpensive Software Define Radios (SDR). Therefore, this thesis presents motivation through analytical and experimental means for more investigation into TCAS from a security perspective. Methods for analyzing TCAS both qualitatively and quantitatively from an adversarial perspective are presented, and an experimental attack is developed in GNU Radio to perform an attack in a well-defined threat model.Master of Science
Since 1993, the Federal Aviation Administration (FAA) requires that many commercial turbine-powered aircraft to be outfitted with an on-board mid-air collision mitigation system. This system is known as the Traffic Collision Avoidance System (TCAS) in the United States, and it is known as the Airborne Collision Avoidance System (ACAS) in other parts of the world. TCAS/ACAS is a type of safety-critical system, which means that implementations need to be highly tolerant to system failures because their operation directly affects the safety of the on-board passengers and crew. However, while safety-critical systems are tolerant to failures, the designers of these systems only account for failures that occur in a cooperative environment; these engineers fail to account for “bad actors” who want to attack the weaknesses of these systems, or they assume that attacking such a system is infeasible. Therefore, to demonstrate how safety-critical systems like TCAS/ACAS are vulnerable to such bad actors, this thesis presents a method for manipulating the TCAS/ACAS in the favor of a bad actor. To start, a method for qualitatively and quantitatively analyzing the system’s vulnerabilities is presented. Then, using Software Defined Radio (SDR), which is a free and open-source effort to combine the flexibility of software with the power of wireless communication, this thesis shows how an actor can craft wireless signals such that they appear to look like an aircraft on a collision course with a target.
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Glynn, Patrick Joseph. "Collision Avoidance Systems for Mine Haul Trucks and Unambiguous Dynamic Real Time Single Object Detection." Thesis, Griffith University, 2005. http://hdl.handle.net/10072/365488.
Full textAbstract:
A suite of new collision avoidance systems (CAS) is presented for use in heavy vehicles whose structure and size necessarily impede driver visibility is introduced. The main goal of the project is to determine the appropriate use of each of the commercially available technologies and, where possible, produce a low cost variant suitable for use in proximity detection on large mining industry haul trucks. CAS variants produced were subjected to a field demonstration and, linked to the output from the earlier CAS 1 project, (a production high-definition in-cabin video monitor and r/f tagging system). The CAS 2 system used low cost Doppler continuous wave radar antennae coupled to the CAS 1 monitor to indicate the presence of an object moving at any speed above 3 Km/h relative to the antennae. The novelty of the CAS 3 system lies in the design of 3 interconnected, modules. The modules are 8 radar antennae (as used in CAS 2) modules located on the truck, software to interface with the end user (i.e. the drivers of the trucks) and a display unit. Modularisation enables the components to be independently tested, evaluated and replaced when in use. The radar antennae modules and the system as a whole are described together with the empirical tests conducted and results obtained. The tests, drawing on Monte-Carlo simulation techniques, demonstrate both the 'correctness' of the implementations and the effectiveness of the system. The results of the testing of the final prototype unit were highly successful both as a computer simulation level and in practical tests on light vehicles. A number of points, (as a consequence of the field test), are reviewed and their application to future projects discussed.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith Business School
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Klaus, Robert Andrew. "Development of a Sense and Avoid System for Small Unmanned Aircraft Systems." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3761.
Full textAbstract:
Unmanned aircraft systems (UAS) represent the future of modern aviation. Over the past 10 years their use abroad by the military has become commonplace for surveillance and combat. Unfortunately, their use at home has been far more restrictive. Due to safety and regulatory concerns, UAS are prohibited from flying in the National Airspace System without special authorization from the FAA. One main reason for this is the lack of an on-board pilot to "see and avoid" other air traffic and thereby maintain the safety of the skies. Development of a comparable capability, known as "Sense and Avoid" (SAA), has therefore become a major area of focus. This research focuses on the SAA problem as it applies specifically to small UAS. Given the size, weight, and power constraints on these aircraft, current approaches fail to provide a viable option. To aid in the development of a SAA system for small UAS, various simulation and hardware tools are discussed. The modifications to the MAGICC Lab's simulation environment to provide support for multiple agents is outlined. The use of C-MEX s-Functions to improve simulation performance and code portability is also presented. For hardware tests, two RC airframes were constructed and retrofitted with autopilots to allow autonomous flight. The development of a program to interface with the ground control software and run the collision avoidance algorithms is discussed as well. Intruder sensing is accomplished using a low-power, low-resolution radar for detection and an Extended Kalman Filter (EKF) for tracking. The radar provides good measurements for range and closing speed, but bearing measurements are poor due to the low-resolution. A novel method for improving the bearing approximation using the raw radar returns is developed and tested. A four-state EKF used to track the intruder's position and trajectory is derived and used to provide estimates to the collision avoidance planner. Simulation results and results from flight tests using a simulated radar are both presented. To effectively plan collision avoidance paths a tree-branching path planner is developed. Techniques for predicting the intruder position and creating safe, collision-free paths using the estimates provided by the EKF are presented. A method for calculating the cost of flying each path is developed to allow the selection of the best candidate path. As multiple duplicate paths can be created using the branching planner, a strategy to remove these paths and greatly increase computation speed is discussed. Both simulation and hardware results are presented for validation.
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Hodota, Kenichi. "R&D and deployment valuation of intelligent transportation systems : a case example of the intersection collision avoidance systems." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35087.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.Includes bibliographical references (p. 147-154).
Compared with investments in the conventional infrastructure, those in Intelligent Transportation Technology (ITS) include various uncertainties. Because deployment of ITS requires close public-private partnership, projects concerning the R&D and deployment of ITS technology involve project risks and market risks induced by both the public and private sector. This characteristic makes it difficult to evaluate the value of the project through traditional valuation method such as the benefit cost analysis (BCA) or the discounted cash flow (DCF) method. To address the difficulty, this thesis proposes two appropriate valuation methodologies for R&D and deployment of ITS: decision analysis and "hybrid real options" analysis that combines decision analysis and real option analysis. This thesis applies the proposed methodologies to a case example of the ongoing R&D and deployment project to reduce the automobile crashes at intersection under public-private partnerships. The proposed systems in the project consist of two conflicting concepts; one depends on user acceptance of in-vehicle ITS technology employed, and the other one does not require user acceptance of this ITS technology.
(cont.) To evaluate the value of two concepts, this thesis identifies various uncertainties associated with the project and quantifies them by utilizing various quantitative techniques including the product diffusion model to formulate project risks and market risks. This thesis finally compares the financial value in two concepts and demonstrates that the concept without in-vehicle ITS technology is a more promising system for crash prevention at an intersection than that with this technology and recognizes the value of real option in case of the unfavorable outcome of the R&D stage. The results imply that developing attractive new product and obtaining user acceptance of ITS technology are the most crucial factors to influence the project value and future success of the countermeasures.
by Kenichi Hodota.
S.M.
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Lin, Yuan. "Bat swarming as an inspiration for multi-agent systems: predation success, active sensing, and collision avoidance." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/64858.
Full textAbstract:
Many species of bats primarily use echolocation, a type of active sensing wherein bats emit ultrasonic pulses and listen to echoes, for guidance and navigation. Swarms of such bats are a unique type of multi-agent systems that feature bats's echolocation and flight behaviors. In the work of this dissertation, we used bat swarming as an inspiration for multi-agent systems to study various topics which include predation success, active sensing, and collision avoidance. To investigate the predation success, we modeled a group of bats hunting a number of collectively behaving prey. The modeling results demonstrated the benefit of localized grouping of prey in avoiding predation by bats. In the topics regarding active sensing and collision avoidance, we studied individual behavior in swarms as bats could potentially benefit from information sharing while suffering from frequency jamming, i.e., bats having difficulty in distinguishing between self and peers's information. We conducted field experiments in a cave and found that individual bat increased biosonar output as swarm size increased. The experimental finding indicated that individual bat acquired more sensory information in larger swarms even though there could be frequency jamming risk. In a simulation wherein we modeled bats flying through a tunnel, we showed the increasing collision risk in larger swarms for bats either sharing information or flying independently. Thus, we hypothesized that individual bat increased pulse emissions for more sensory information for collision avoidance while possibly taking advantage of information sharing and coping with frequency jamming during swarming.Ph. D.
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Graziano, Timothy Michael. "Establishment of a Cyber-Physical Systems (CPS) Test Bed to Explore Traffic Collision Avoidance System (TCAS) Vulnerabilities to Cyber Attacks." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/104624.
Full textAbstract:
Traffic Collision Avoidance Systems (TCAS) are safety-critical, unauthenticated, ranging
systems required in commercial aircraft. Previous work has proposed TCAS vulnerabilities
to attacks from malicious actors with low cost software defined radios (SDR) and inexpensive
open-source software (GNU radio) where spoofing TCAS radio signals in now possible. This
paper outlines a proposed threat model for several TCAS vulnerabilities from an adversarial
perspective. Periodic and aperiodic attack models are explored as possible low latency solutions
to spoof TCAS range estimation. A TCAS test bed is established with commercial
avionics to demonstrate the efficacy of proposed vulnerabilities. SDRs and Vector Waveform
Generators (VWGs) are used to achieve desired latency. Sensor inputs to the TCAS system
are spoofed with micro-controllers. These include Radar Altimeter, Barometric Altimeter,
and Air Data Computer (ADC) heading and attitude information transmitted by Aeronautical
Radio INC (ARINC) 429 encoding protocol. TCAS spoofing is attempted against the
test bed and analysis conducted on the timing results and test bed performance indicators.
The threat model is analyzed qualitatively and quantitatively.Master of Science
Traffic Collision Avoidance Systems (TCAS), or Airborne Collision Avoidance Systems ACAS), are safety-critical systems required by the Federal Aviation Administration (FAA) in commercial aircraft. They work by sending queries to surrounding aircraft in the form of radio transmission. Aircraft in the who receive these transmissions send replies. Information in these replies allow the TCAS system to determine if a nearby aircraft may travel too close to itself. TCAS can then determine help both pilots avoid a mid-air collision. Information in the messages can be faked by a malicious actor. To explore these vulnerabilities a test bed is built with commercial grade TCAS equipment. Several types of attacks are evaluated.
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Brown, Glenn, and n/a. "Remote Intelligent Air Traffic Control Systems for Non-Controlled Airports." Griffith University. School of Engineering, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040225.084516.
Full textAbstract:
Non-controlled airports are literally that - uncontrolled. Safe separation is achieved by pilot vigilance. The consensus of reports on incidences at noncontrolled airports generally conclude that pilots cannot rely entirely on vision to avoid collision and attempts should be made to obtain all available traffic information to enable a directed traffic search. Ideally, a system is required which has the ability to provide advice to all parties to ensure separation minima is maintained. Provision of a such a system would remove a measure of pressure from the pilot to allow that person to devote their attention to their prime responsibility of flying the aircraft. To this end, research on use of intelligent remote advisory systems for non-controlled airports was undertaken with emphasis on those systems which could minimize human resources and associated recurring costs, to provide a measure of repeatability and to provide an acceptable level of safety. A rule based system was developed and evaluated. The evaluation showed that use of a rule based system as the basis of an intelligent remote air traffic control system for non-controlled airports is a viable proposition. In test scenarios, collision hazards were identified and evasion tactics generated. For a full operational system, the application of the rules and definition of the aircraft circuit area may need refining; however, the results are certainly encouraging.
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Brown, Glenn. "Remote Intelligent Air Traffic Control Systems for Non-Controlled Airports." Thesis, Griffith University, 2003. http://hdl.handle.net/10072/367276.
Full textAbstract:
Non-controlled airports are literally that - uncontrolled. Safe separation is achieved by pilot vigilance. The consensus of reports on incidences at noncontrolled airports generally conclude that pilots cannot rely entirely on vision to avoid collision and attempts should be made to obtain all available traffic information to enable a directed traffic search. Ideally, a system is required which has the ability to provide advice to all parties to ensure separation minima is maintained. Provision of a such a system would remove a measure of pressure from the pilot to allow that person to devote their attention to their prime responsibility of flying the aircraft To this end, research on use of intelligent remote advisory systems for non-controlled airports was undertaken with emphasis on those systems which could minimize human resources and associated recurring costs, to provide a measure of repeatability and to provide an acceptable level of safety. A rule based system was developed and evaluated. The evaluation showed that use of a rule based system as the basis of an intelligent remote air traffic control system for non-controlled airports is a viable proposition. In test scenarios, collision hazards were identified and evasion tactics generated. For a full operational system, the application of the rules and definition of the aircraft circuit area may need refining; however, the results are certainly encouraging.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Engineering
Faculty of Engineering and Information Technology
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McLaughlin, Shane Brendan. "Analytic Assessment of Collision Avoidance Systems and Driver Dynamic Performance in Rear-End Crashes and Near-Crashes." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/29561.
Full textAbstract:
Collision avoidance systems (CASs) are being developed and fielded to reduce the number and severity of rear-end crashes. Kinematic algorithms within CASs evaluate sensor input and apply assumptions describing human-response timing and deceleration to determine when an alert should be presented. This dissertation presents an analytic assessment of dynamic function and performance CASs and associated driver performance for preventing automotive rear-end crashes. A method for using naturalistic data in the evaluation of CAS algorithms is described and applied to three algorithms. Time-series parametric data collected during 13 rear-end crashes and 70 near-crashes are input into models of collision avoidance algorithms to determine when the alerts would have occurred. Algorithm performance is measured by estimating how much of the driving population would be able to respond in the time available between when an alert would occur and when braking was needed. A sensitivity analysis was performed to consider the effect of alternative inputs into the assessment method. The algorithms were found to warn in sufficient time to permit 50â 70% of the population to avoid collision in similar scenarios. However, the accuracy of this estimate was limited because the tested algorithms were found to alert too frequently to be feasible. The response of the assessment method was most sensitive to differences in assumed response-time distributions and assumed driver braking levels. Low-speed crashes were not addressed by two of the algorithms. Analysis of the events revealed that the necessary avoidance deceleration based on kinematics was generally less than 2 s in duration. At the time of driver response, the time remaining to avoid collision using a 0.5g average deceleration ranged from â 1.1 s to 2.1 s. In 10 of 13 crashes, no driver response deceleration was present. Mean deceleration for the 70 near-crashes was 0.37g and maximum was 0.72g. A set of the events was developed to measure driver response time. The mean driver response time was 0.7 s to begin braking and 1.1 s to reach maximum deceleration. Implications for collision countermeasures are considered, response-time results are compared to previous distributions and future work is discussed.Ph. D.
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Pant, Vivek. "Biomimetic Visual Navigation Architectures for Autonomous Intelligent Systems." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194273.
Full textAbstract:
Intelligent systems with even the bare minimum of sophistication require extensive computational power and complex processing units. At the same time, small insects like flies are adept at visual navigation, target pursuit, motionless hovering flight, and obstacle avoidance. Thus, biology provides engineers with an unconventional approach to solve complicated engineering design problems. Computational models of the neuronal architecture of the insect brain can provide algorithms for the development of software and hardware to accomplish sophisticated visual navigation tasks. In this research, we investigate biologically-inspired collision avoidance models primarily based on visual motion. We first present a comparative analysis of two leading collision avoidance models hypothesized in the insect brain. The models are simulated and mathematically analyzed for collision and non-collision scenarios. Based on this analysis it is proposed that along with the motion information, an estimate of distance from the obstacle is also required to reliably avoid collisions. We present models with tracking capability as solutions to this problem and show that tracking indirectly computes a measure of distance. We present a camera-based implementation of the collision avoidance models with tracking. The camera-based system was tested for collision and non-collision scenarios to verify our simulation claims that tracking improves collision avoidance. Next, we present a direct approach to estimate the distance from an obstacle by utilizing non-directional speed. We describe two simplified non-directional speed estimation models: the non-directional multiplication (ND-M) sensor, and the non-directional summation (ND-S) sensor. We also analyze the mathematical basis of their speed sensitivity. An analog VLSI chip was designed and fabricated to implement these models in silicon. The chip was fabricated in a 0.18 um process and its characterization results are reported here. As future work, the tracking algorithm and the collision avoidance models may be implemented as a sensor chip and used for autonomous navigation by intelligent systems.
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Kotte, Jens, Carsten Schmeichel, Adrian Zlocki, Hauke Gathmann, and Lutz Eckstein. "Concept of an enhanced V2X pedestrian collision avoidance system with a cost function–based pedestrian model." Taylor & Francis, 2017. https://publish.fid-move.qucosa.de/id/qucosa%3A72238.
Full textAbstract:
Objective: State-of-the-art collision avoidance and collision mitigation systems predict the behavior of pedestrians based on trivial models that assume a constant acceleration or velocity. New sources of sensor information—for example, smart devices such as smartphones, tablets, smartwatches, etc.—can support enhanced pedestrian behavior models. The objective of this article is the development and implementation of a V2Xpedestrian collision avoidance system that uses new information sources.
Methods: A literature review of existing state-of-the-art pedestrian collision avoidance systems, pedestrian behavior models in advanced driver assistance systems (ADAS), and traffic simulations is conducted together with an analysis of existing studies on typical pedestrian patterns in traffic. Based on this analysis, possible parameters for predicting pedestrian behavior were investigated. The results led to new requirements from which a concept was developed and implemented.
Results: The analysis of typical pedestrian behavior patterns in traffic situations showed the complexity of predicting pedestrian behavior. Requirements for an improved behavior prediction were derived. A concept for a V2X collision avoidance system, based on a cost function that predicts pedestrian near future presence, and its implementation is presented. The concept presented considers several challenges such as information privacy, inaccuracies of the localization, and inaccuracies of the prediction.
Conclusion: A concept for an enhanced V2X pedestrian collision avoidance system was developed and introduced. The concept uses new information sources such as smart devices to improve the prediction of the pedestrian's presence in the near future and considers challenges that come along with the usage of these information sources.
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Reddy, Nitin. "DRIVER ASSISTANCE FOR ENHANCED ROAD SAFETY AND TRAFFIC MANAGEMENT." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1237493386.
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Mojtaba, Forghani (Forghani Oozroody). "Design and implementation of safety control for a class of stochastic order preserving systems with application to collision avoidance near intersections." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/93856.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 55-56).
In this thesis, we have designed and implemented a safety control system for collision avoidance near intersections. We have solved the corresponding control problems for a general class of systems that also includes the scenario of the two consecutive vehicles approaching an intersection, which leads to the design of the collision avoidance system. We have gathered the data of behavior of drivers as they approach intersections and have built a stochastic model for that through an optimization problem. The model generates a non-deterministic profile for acceleration of a vehicle which is not equipped with the collision avoidance system and it is used to estimate and predict future stopping profiles of the vehicle in order to take the right control action for avoidance or mitigation of accidents. First we have verified the consistency of the theoretical model with its expected behavior after implementation and then we have implemented the control system on the Prius vehicle in collaboration with TTC (Toyota Technical Center), Ann Arbor, Michigan.
by Mojtaba Forghani.
S.M.
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Na, Xiaoxiang. "Game theoretical modelling of a driver's interaction with active steering." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708392.
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Agardt, Erik, and Markus Löfgren. "Pilot Study of Systems to Drive Autonomous Vehicles on Test Tracks." Thesis, Linköping University, Department of Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-12217.
Full textAbstract:
This Master’s thesis is a pilot study that investigates different systems to drive autonomous and non-autonomous vehicles simultaneously on test tracks. The thesis includes studies of communication, positioning, collision avoidance, and techniques for surveillance of vehicles which are suitable for implementation. The investigation results in a suggested system outline.
Differential GPS combined with laser scanner vision is used for vehicle state estimation (position, heading, velocity, etc.). The state information is transmitted with IEEE 802.11 to all surrounding vehicles and surveillance center. With this information a Kalman prediction of the future position for all vehicles can be estimated and used for collision avoidance.
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Wikle, Jared Kevin. "Integration of a Complete Detect and Avoid System for Small Unmanned Aircraft Systems." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6361.
Full textAbstract:
For unmanned aircraft systems to gain full access to the National Airspace System (NAS), they must have the capability to detect and avoid other aircraft. This research focuses on the development of a detect-and-avoid (DAA) system for small unmanned aircraft systems. To safely avoid another aircraft, an unmanned aircraft must detect the intruder aircraft with ample time and distance. Two analytical methods for finding the minimum detection range needed are described. The first method, time-based geometric velocity vectors (TGVV), includes the bank-angle dynamics of the ownship while the second, geometric velocity vectors (GVV), assumes an instantaneous bank-angle maneuver. The solution using the first method must be found numerically, while the second has a closed-form analytical solution. These methods are compared to two existing methods. Results show the time-based geometric velocity vectors approach is precise, and the geometric velocity vectors approach is a good approximation under many conditions. The DAA problem requires the use of a robust target detection and tracking algorithm for tracking multiple maneuvering aircraft in the presence of noisy, cluttered, and missed measurements. Additionally these algorithms needs to be able to detect overtaking intruders, which has been resolved by using multiple radar sensors around the aircraft. To achieve these goals the formulation of a nonlinear extension to R-RANSAC has been performed, known as extended recursive-RANSAC (ER-RANSAC). The primary modifications needed for this ER-RANSAC implementation include the use of an EKF, nonlinear inlier functions, and the Gauss-Newton method for model hypothesis and generation. A fully functional DAA system includes target detection and tracking, collision detection, and collision avoidance. In this research we demonstrate the integration of each of the DAA-system subcomponents into fully functional simulation and hardware implementations using a ground-based radar setup. This integration resulted in various modifications of the radar DSP, collision detection, and collision avoidance algorithms, to improve the performance of the fully integrated DAA system. Using these subcomponents we present flight results of a complete ground-based radar DAA system, using actual radar hardware.
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Guan, Wenyang. "Adaptive QoS control of DSRC vehicle networks for collaborative vehicle safety applications." Thesis, Swansea University, 2013. https://cronfa.swan.ac.uk/Record/cronfa42507.
Full textAbstract:
Road traffic safety has been a subject of worldwide concern. Dedicated short range communications (DSRC) is widely regarded as a promising enabling technology for collaborative safety applications (CSA), which can provide robust communication and affordable performance to build large scale CSA system. The main focus of this thesis is to develop solutions for DSRC QoS control in order to provide robust QoS support for CSA. The first design objective is to ensure robust and reliable message delivery services for safety applications from the DSRC networks. As the spectrum resources allocated to DSRC network are expected to be shared by both safety and non-safety applications, the second design objective is to make QoS control schemes bandwidth-efficient in order to leave as much as possible bandwidth for non-safety applications. The first part of the thesis investigates QoS control in infrastructure based DSRC networks, where roadside access points (AP) are available to control QoS control at road intersections. After analyse DSRC network capabilities on QoS provisioning without congestion control, we propose a two-phases adaptive QoS control method for DSRC vehicle networks. In the first phase an offline simulation based approach is used to and out the best possible system configurations (e.g. message rate and transmit power) with given numbers of vehicles and QoS requirements. It is noted that with different utility functions the values of optimal parameters proposed by the two phases centralized QoS control scheme will be different. The conclusions obtained with the proposed scheme are dependent on the chosen utility functions. But the proposed two phases centralized QoS control scheme is general and is applicable to different utility functions. In the second phase, these configurations are used online by roadside AP adaptively according to dynamic traffic loads. The second part of the thesis is focused on distributed QoS control for DSRC networks. A framework of collaborative QoS control is proposed, following which we utilize the local channel busy time as the indicator of network congestion and adaptively adjust safety message rate by a modified additive increase and multiplicative decrease (AIMD) method in a distributed way. Numerical results demonstrate the effectiveness of the proposed QoS control schemes.
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Svensson, Ulrika. "Blink behaviour based drowsiness detection : method development and validation /." [Linköping, Sweden] : Swedish National Road and Transport Research Institute, 2004. http://www.vti.se.
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Wozniak, Peter. "Range imaging based obstacle detection for virtual environment systems and interactive metaphor based signalization." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAD013/document.
Full textAbstract:
Avec cette génération d'appareils, la réalité virtuelle (RV) s'est réellement installée dans les salons des utilisateurs finaux. Ces appareils disposent de 6 degrés de liberté de suivi, ce qui leur permet de se déplacer naturellement dans les mondes virtuels. Cependant, pour une locomotion naturelle dans le virtuel, il faut un espace libre correspondant dans l'environnement réel. L'espace disponible est souvent limité. Les objets de la vie quotidienne peuvent rapidement devenir des obstacles pour les utilisateurs de RV s'ils ne sont pas éliminés. Les systèmes actuellement disponibles n'offrent qu'une aide rudimentaire pour résoudre ce problème. Il n'y a pas de détection d'objets potentiellement dangereux. Cette thèse montre comment les obstacles peuvent être détectés automatiquement avec des caméras d'imagerie à distance et comment les utilisateurs peuvent être avertis efficacement de leur présence dans l'environnement virtuel. 4 métaphores visuelles ont été évaluées à l'aide d'une étude des utilisateursWith this generation of devices, virtual reality (VR) has actually made it into the living rooms of end-users. These devices feature 6 degrees of freedom tracking, allowing them to move naturally in virtual worlds. However, for a natural locomotion in the virtual, one needs a corresponding free space in the real environment. The available space is often limited. Objects of daily life can quickly become obstacles for VR users if they are not cleared away. The currently available systems offer only rudimentary assistance for this problem. There is no detection of potentially dangerous objects. This thesis shows how obstacles can be detected automatically with range imaging cameras and how users can be effectively warned about them in the virtual environment. 4 visual metaphors were evaluated with the help of a user study
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Gariel, Maxime. "Toward a graceful degradation of air traffic management systems." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34799.
Full textAbstract:
Abstract:
This thesis addresses the problem of graceful degradation for air traffic management systems (ATMS). The graceful degradation is the process by which the safety of the airspace is ensured in the event of failures or operational degradation in the system. After listing the main areas where failures and degradation can affect the ATMS, an ontology of the ATMS is proposed. The ontology allows to introduce failures at different levels, track their propagation throughout the system, and measure their operational impact.
Then, two operational degradations are studied: The first degradation studied is a reduction in the landing capacity at San Francisco International Airport. The aircraft queueing process for terminal area is modeled and optimized to ensure a graceful degradation. The second degradation encompasses Communication, Navigation and Surveillance systems failures. The graceful degradation is ensured by increasing the spacing distance between aircraft, using novel algorithms of avoidance under uncertainties. Those algorithm also serve as probes to compare the degradation capabilities of different traffic configurations such as Miles-In-Trail and Free-Flight arrivals.
Finally, this thesis focuses on monitoring the airspace for potential degradation. The ability and the difficulty of en-route traffic configuration are evaluated using degradation maps. Those maps can be used controller to rapidly and efficiently steer traffic from nominal mode of operations to mode of operations under abnormal conditions. Finally, a monitoring tool for terminal area is presented: the conformance of current flight to pre-identified typical operations is determined in real time. As the number of non-conforming aircraft increases, the complexity seen by air traffic controllers increases, and can become a threat for the airspace safety.
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Martin, Wayne Leslie. "Pathological Behaviours in Pilots during Unexpected Critical Events: The Effects of Startle, Freeze and Denial on Situation Outcome." Thesis, Griffith University, 2014. http://hdl.handle.net/10072/366319.
Full textAbstract:
Over the last 40 years significant advances in aviation technology have contributed strongly to improvements in aviation safety. Recent figures suggest that fourth generation aircraft are now achieving fatal accident rates in the order of 10-7 and ongoing work continues to improve this rate. Significant improvements in engine and systems reliability, coupled with safety technologies such as Enhanced Ground Proximity Warning (EGPWS), Airborne Collision Avoidance Systems (ACAS), Global Positioning System (GPS), and Vertical Situation Displays (VSD) have contributed to reductions in accident rates. Additionally, initiatives such as RNAV and RNP (AR) approaches continue to improve non-precision approach accuracy and safety while air traffic control improvements continue to accommodate this increased safety as aircraft traffic continues to grow strongly.
Nevertheless, the reliability engendered by all these incremental improvements to safety has a downside. While pilots in the earlier years of airline transport had a healthy expectation for engine and systems failures, the modern airline pilot does not necessarily share this. Indeed, the modern airline aircraft is so reliable, and failures are so rare, that pilots are now unwittingly conditioned into an expectation of unwavering reliability. This unintentional complacency means that attention to emergency procedures and an expectation for dealing with real malfunctions is not as well honed as it perhaps once was.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical Sciences
Science, Environment, Engineering and Technology
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Xausa, Ilaria [Verfasser], Matthias [Akademischer Betreuer] Gerdts, and Olivier [Akademischer Betreuer] Bokanowski. "Verification of Collision Avoidance Systems using Optimal Control and Sensitivity Analysis / Ilaria Xausa. Universität der Bundeswehr München, Fakultät für Luft- und Raumfahrttechnik. Betreuer: Matthias Gerdts. Gutachter: Matthias Gerdts ; Olivier Bokanowski." Neubiberg : Universitätsbibliothek der Universität der Bundeswehr München, 2015. http://d-nb.info/1081029749/34.
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Xausa, Ilaria Verfasser], Matthias [Akademischer Betreuer] [Gerdts, and Olivier [Akademischer Betreuer] Bokanowski. "Verification of Collision Avoidance Systems using Optimal Control and Sensitivity Analysis / Ilaria Xausa. Universität der Bundeswehr München, Fakultät für Luft- und Raumfahrttechnik. Betreuer: Matthias Gerdts. Gutachter: Matthias Gerdts ; Olivier Bokanowski." Neubiberg : Universitätsbibliothek der Universität der Bundeswehr München, 2015. http://nbn-resolving.de/urn:nbn:de:bvb:706-4394.
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Okoloko, Innocent. "Multi-path planning and multi-body constrained attitude control." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71905.
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Thesis (PhD)--Stellenbosch University, 2012.ENGLISH ABSTRACT: This research focuses on the development of new efficient algorithms for multi-path planning and multi-rigid body constrained attitude control. The work is motivated by current and future applications of these algorithms in: intelligent control of multiple autonomous aircraft and spacecraft systems; control of multiple mobile and industrial robot systems; control of intelligent highway vehicles and traffic; and air and sea traffic control. We shall collectively refer to the class of mobile autonomous systems as “agents”. One of the challenges in developing and applying such algorithms is that of complexity resulting from the nontrivial agent dynamics as agents interact with other agents, and their environment. In this work, some of the current approaches are studied with the intent of exposing the complexity issues associated them, and new algorithms with reduced computational complexity are developed, which can cope with interaction constraints and yet maintain stability and efficiency. To this end, this thesis contributes the following new developments to the field of multipath planning and multi-body constrained attitude control: • The introduction of a new LMI-based approach to collision avoidance in 2D and 3D spaces. • The introduction of a consensus theory of quaternions by applying quaternions directly with the consensus protocol for the first time. • A consensus and optimization based path planning algorithm for multiple autonomous vehicle systems navigating in 2D and 3D spaces. • A proof of the consensus protocol as a dynamic system with a stochastic plant matrix. • A consensus and optimization based algorithm for constrained attitude synchronization of multiple rigid bodies. • A consensus and optimization based algorithm for collective motion on a sphere.
AFRIKAANSE OPSOMMING: Hierdie navorsing fokus op die ontwikkeling van nuwe koste-effektiewe algoritmes, vir multipad-beplanning en veelvuldige starre-liggaam beperkte standbeheer. Die werk is gemotiveer deur huidige en toekomstige toepassing van hierdie algoritmes in: intelligente beheer van veelvuldige outonome vliegtuig- en ruimtevaartuigstelsels; beheer van veelvuldige mobiele en industrile robotstelsels; beheer van intelligente hoofwegvoertuie en verkeer; en in lug- en see-verkeersbeheer. Ons sal hier “agente” gebruik om gesamentlik te verwys na die klas van mobiele outonome stelsels. Een van die uitdagings in die ontwikkeling en toepassing van sulke algoritmes is die kompleksiteit wat spruit uit die nie-triviale agentdinamika as gevolg van die interaksie tussen agente onderling, en tussen agente en hul omgewing. In hierdie werk word sommige huidige benaderings bestudeer met die doel om die kompleksiteitskwessies wat met hulle geassosieer word, bloot te l^e. Verder word nuwe algoritmes met verminderde berekeningskompleksiteit ontwikkel. Hierdie algoritmes kan interaksie-beperkings hanteer, en tog stabiliteit en doeltreffendheid behou. Vir hierdie doel dra die proefskrif die volgende nuwe ontwikkelings by tot die gebied van multipad-beplanning van multi-liggaam beperkte standbeheer: • Die voorstel van ’n nuwe LMI-gebasseerde benadering tot botsingsvermyding in 2D en 3D ruimtes. • Die voorstel van ’n konsensus-teorie van “quaternions” deur “quaternions” vir die eerste keer met die konsensusprotokol toe te pas. • ’n Konsensus- en optimeringsgebaseerde padbeplanningsalgoritme vir veelvoudige outonome voertuigstelsels wat in 2D en 3D ruimtes navigeer. • Die bewys van ’n konsensusprotokol as ’n dinamiese stelsel met ’n stochastiese aanlegmatriks. • ’n Konsensus- en optimeringsgebaseerde algoritme vir beperkte stand sinchronisasie van veelvoudige starre liggame. • ’n Konsensus- en optimeringsgebaseerde algoritme vir kollektiewe beweging op ’n sfeer.
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Agarwal, Megha, Alisha Bandekar, Ashley Kang, Tyler Martis, Hossein Namazyfard, Alan Yeh, Megha Agarwal, et al. "Automotive LiDAR Collision-Avoidance System." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/624893.
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The project at hand is an Automotive LiDAR Collision Avoidance System sponsored by
Texas Instruments. The purpose of this project is to design and create a LiDAR system
that utilizes Texas Instruments' technology to avoid forward collisions when mounted on
a remote control car. The team is made up of six seniors from the University of Arizona
of four different engineering disciplines including electrical, mechanical, computer, and
optical engineering. The LiDAR Collision avoidance system is designed and built under a
budget constraint of $4,000 and a non-negotiable completion deadline of May 1, 2017,
otherwise known as Design Day.
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Nguyen, Minh Tri. "Commande prédictive sous contraintes de sécurité pour des systèmes dynamiques Multi-Agents." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC071/document.
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Cette thèse porte sur des techniques de commande à base d’optimisation dans le cadre des systèmes dynamiques Multi-Agents sous contraintes, plus particulièrement liées à l’évitement des collisions. Dans un contexte ensembliste, l’évitement des collisions au sein de la formation se traduit par des conditions de non intersection des régions de sécurité caractéristiques à chaque agent/obstacle. Grace à sa capacité à gérer les contraintes, la commande prédictive a été choisie parmi les méthodes de synthèse fondées sur des techniques d’optimisation. Tout d’abord, une structure de type leader-suiveur est considérée comme une architecture décentralisée élémentaire. La zone de fonctionnement de chaque suiveur est décidée par le leader et puis une loi de commande locale est calculée afin de garantir que les suiveurs restent à l’intérieur de la zone autorisée, permettant d’éviter les collisions. Ensuite, un déploiement des agents fondé sur l’approche de commande prédictive décentralisée, utilisant des partitions dynamiques de Voronoi, est proposé, permettant de ramener chaque agent vers l’intérieur de sa cellule Voronoi. Une des contributions a été de considérer le centre de Chebyshev comme cible à l’intérieur de chaque cellule. D’autres solutions proposent l’utilisation du centre de masse ou du centre obtenu par l’interpolation des sommets. Finalement, des méthodes ensemblistes sont utilisées pour construire un niveau supplémentaire de détection de défauts dans le cadre du système Multi-Agents. Cela permet l’exclusion des agents défectueux ainsi que l’intégration des agents extérieurs certifiés sans défauts dans la formation en utilisant des techniques de commande prédictive centraliséeThis thesis presents optimizationbased control techniques for dynamical Multi-Agent systems (MAS) subject to collision avoidance constraints. From the set-theoretic point of view, collision avoidance objective can be translated into non-overlapping conditions for the safety regions characterizing each agent/obstacle while maintaining the convergence towards a specified formation. Among the successful optimizationbased control methods, Model Predictive Control (MPC) is used for constraints handling. First, a leader-follower structure is considered as a basic decentralized architecture. The followers functioning zone assignment is decided by the leader and then the local linear feedback control is computed such that the follower operates strictly inside its authorized zone, offering anti-collision guarantees. Second, a dynamic Voronoi partition based deployment of the agents using an inner target driver is developed. The main novelty is to consider the Chebyshev center as the inner target for each agent, leading to an optimization-based decentralized predictive control design. In the same topic, other inner targets are considered such as the center of mass or vertex interpolated center. Third, set-theoretic tools are used to design a centralized FDI layer for dynamical MAS, leading to the exclusion of a faulty agent from the MAS formation and the integration of an external healthy/recovered agent in the current formation. The set-based FDI allows detecting and isolating these faulty agents to protect the current formation using centralized predictive control techniques
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Park, Jaeyong. "Safe Controller Design for Intelligent Transportation System Applications using Reachability Analysis." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366201401.
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