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Li, Hao, Yuping Li, Zhongliang Zhao, Xiaobing Wang, Haiyong Yang e Shang Ma. "High-Speed Virtual Flight Testing Platform for Performance Evaluation of Pitch Maneuvers". Aerospace 10, n.º 11 (15 de novembro de 2023): 962. http://dx.doi.org/10.3390/aerospace10110962.
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To research serious nonlinear coupling problems among aerodynamics, flight mechanics, and flight control during high maneuvers, a virtual flight testing platform has been developed for a large-scale, high-speed wind tunnel, based on the real physical environment, and it can significantly mitigate risks and reduce the costs of subsequent flight tests. The platform of virtual flight testing is composed of three-degrees-of-freedom model support, measuring devices for aerodynamic and motion parameters, a virtual flight control system, and a test model. It provides the ability to realistically simulate real maneuvers, investigate the coupling characteristics of unsteady aerodynamics and nonlinear flight dynamics, evaluate flight performance, and verify the flight control law. The typical test results of a pitch maneuver with open-loop and closed-loop control are presented, including a one-degree-of-freedom pitch motion and a two-degrees-of-freedom pitch and roll motion. The serious pitch and roll-coupled motion during a pitch maneuver at a high angle of attack is revealed, and the flight control law for decoupled control is successfully verified. The comparison of the test results and the flight data of a real pitch maneuver proves the reliability and capability of virtual flight testing.
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Cai, Haohao, e Xiaomei Xu. "Lateral Stability Control of a Tractor-Semitrailer at High Speed". Machines 10, n.º 8 (20 de agosto de 2022): 716. http://dx.doi.org/10.3390/machines10080716.
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To improve the high-speed lateral stability of the tractor-semitrailer, a lateral stability control strategy based on the additional yaw moment caused by differential braking is proposed and investigated based on the co-simulation environment. First of all, a five-degree-of-freedom (5-DOF) yaw-roll dynamic model of the tractor-semitrailer is established, and the model accuracy is verified. Secondly, the lateral stability control strategy of the tractor-semitrailer is proposed, two yaw moment controllers and the braking torque distributor are designed. Then, the effectiveness of the proposed control strategy and the influence of the yaw moment controller on the lateral stability of the tractor-semitrailer are investigated under the high-speed lane-change maneuvers. Finally, the controller robustness is discussed. Research results show that the proposed high-speed lateral stability control strategy can ensure the tractor-semitrailer to perform safely the single lane-change (SLC) maneuver at 110 km/h and the double lane-change (DLC) maneuver at 88 km/h; the yaw moment controller has significant influence on the lateral dynamic performance of the tractor-semitrailer; compared with the proportional-derivative (PD) control, the model predictive control (MPC) can make the tractor-semitrailer obtain better lateral stability under high-speed lane-change maneuvers; MPC and PD controllers exhibit good robustness to the considered vehicle parameter uncertainties.
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Rodriguez, Renato, Yan Wang, Joseph Ozanne, Dogan Sumer, Dimitar Filev e Damoon Soudbakhsh. "Adaptive Takeoff Maneuver Optimization of a Sailing Boat for America’s Cup". Journal of Sailing Technology 7, n.º 01 (17 de outubro de 2022): 88–103. http://dx.doi.org/10.5957/jst/2022.7.4.88.
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This paper presents the development of optimal takeoff maneuvers for an AC75 foiling sailboat competing in the oldest and most prestigious sailboat competition in the world, America’s Cup. The AC75 sailboat presents many challenges to developing these optimal maneuvers due to its nonlinear, high-dimensional, and highly unstable dynamics. During the takeoff maneuver, the boat starts in the water with low speed (displacement mode) and increases its speed until it reaches steady-state foiling (the hull stays out of the water). We optimized the time for the boat’s transitions from displacement mode to foiling mode while maximizing the projection of the velocity in the desired target direction (VMG). We used an adaptive control approach to obtain these optimal maneuvers, which involved using a high-fidelity sailboat simulator for data generation and Jacobian learning for optimization. The optimal solutions were subject to value and rate constraints based on the physical limitations of the actuators, as well as the constraints enforced by human (sailors) abilities to perform such maneuvers. The optimal takeoff maneuver had an average VMG of 7.42 [m s-1], the boat reached the desired takeoff velocity in 14.8 [s] and completed the entire maneuver in 36.4 [s]. The optimal solutions provide insightful information about the dynamic behavior of this complex system and serve as benchmarks for the sailors.
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Kitano, M., K. Watanabe, Y. Takaba e K. Togo. "Lane-change maneuver of high speed tracked vehicles". Journal of Terramechanics 25, n.º 2 (janeiro de 1988): 91–102. http://dx.doi.org/10.1016/0022-4898(88)90017-1.
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Hirano, Masahiro, Akihito Noda, Masatoshi Ishikawa e Yuji Yamakawa. "Networked high-speed vision for evasive maneuver assist". ICT Express 3, n.º 4 (dezembro de 2017): 178–82. http://dx.doi.org/10.1016/j.icte.2017.11.008.
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Quinn, Daniel, Daniel Kress, Eric Chang, Andrea Stein, Michal Wegrzynski e David Lentink. "How lovebirds maneuver through lateral gusts with minimal visual information". Proceedings of the National Academy of Sciences 116, n.º 30 (9 de julho de 2019): 15033–41. http://dx.doi.org/10.1073/pnas.1903422116.
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Flying birds maneuver effectively through lateral gusts, even when gust speeds are as high as flight speeds. What information birds use to sense gusts and how they compensate is largely unknown. We found that lovebirds can maneuver through 45° lateral gusts similarly well in forest-, lake-, and cave-like visual environments. Despite being diurnal and raised in captivity, the birds fly to their goal perch with only a dim point light source as a beacon, showing that they do not need optic flow or a visual horizon to maneuver. To accomplish this feat, lovebirds primarily yaw their bodies into the gust while fixating their head on the goal using neck angles of up to 30°. Our corroborated model for proportional yaw reorientation and speed control shows how lovebirds can compensate for lateral gusts informed by muscle proprioceptive cues from neck twist. The neck muscles not only stabilize the lovebirds’ visual and inertial head orientations by compensating low-frequency body maneuvers, but also attenuate faster 3D wingbeat-induced perturbations. This head stabilization enables the vestibular system to sense the direction of gravity. Apparently, the visual horizon can be replaced by a gravitational horizon to inform the observed horizontal gust compensation maneuvers in the dark. Our scaling analysis shows how this minimal sensorimotor solution scales favorably for bigger birds, offering local wind angle feedback within a wingbeat. The way lovebirds glean wind orientation may thus inform minimal control algorithms that enable aerial robots to maneuver in similar windy and dark environments.
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HARA, Kiyoshi. "Safety of Collision Avoidance Maneuver under High Speed-Navigation". Journal of Japan Institute of Navigation 82 (1990): 69–75. http://dx.doi.org/10.9749/jin.82.69.
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Chen, Wenyu, Weimin Li, Lei Shao e Tao Zhang. "Correction Strategy of Online Midcourse Guidance for High-Speed Gliding Target Interceptor". Applied Sciences 13, n.º 11 (30 de maio de 2023): 6661. http://dx.doi.org/10.3390/app13116661.
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During the interception of a high-speed gliding vehicle (HGV), the predicted intercept point (PIP) is updated many times, so the interceptor must continuously adjust its trajectory. In this paper, we propose an online guidance correction algorithm for the interceptor, which can effectively meet the position constraints and energy management of the guidance process. Firstly, we simplify the interceptor’s maneuvering problem to a two-body orbital transfer problem. The Lambert orbit transfer method is used to enable the interceptor to maneuver towards the target’s PIP. Secondly, by comparing the target’s high probability existence area (THPEA) with the interceptor-interceptable area (IIA), the engine start threshold is set in stages to avoid frequent redundancy maneuvers caused by frequent engine starting during missile correction. This approach achieves energy management. Simulation results show that our midcourse guidance strategy is effective.
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Yasukawa, Hironori, Noritaka Hirata e Yoshiyuki Nakayama. "High-Speed Ship Maneuverability". Journal of Ship Research 60, n.º 04 (1 de dezembro de 2016): 239–58. http://dx.doi.org/10.5957/jsr.2016.60.4.239.
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In this paper, the effects of changes in hull attitude and the presence of stern append- ages such as rudders, shaft brackets, bossing, and propeller shafts on the maneuver- ability of a high-speed ship are investigated. The study is conducted for a ship operating within a Froude number range of 0.6–1.0. To determine the effect of attitude changes on the hydrodynamic derivatives during maneuvering, the hydrodynamic forces acting on the ship model with/without stern appendages are measured in three conditions: an even keel with the designed draft, and the same setup including hull rise or trim. For each condition, measurements are conducted for oblique motion, steady turning, and straight motion with heel, for various ship speeds. The hydro-dynamic derivatives excluding the attitude change are obtained from the measured results, along with the changes in these derivatives due to hull rise and trim. Using the hydrodynamic derivatives, the maneuverability indexes are calculated.
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Yang, Yun Gang, Feng Wang e Zhao Wei Sun. "A Rapid Maneuver Method with High Accuracy for Spacecraft Based on CMG and RW". Advanced Materials Research 591-593 (novembro de 2012): 2395–400. http://dx.doi.org/10.4028/www.scientific.net/amr.591-593.2395.
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The mission of ground tracking satellite requires not only the ability of large angle rapid maneuver, but also the ability of attitude stability with high accuracy during and after maneuver. A rapid maneuver method with high accuracy for spacecraft based on CMG and RW is proposed to solve this problem. By use of initial quaternions and target quaternions, a minimum path trajectory tracking algorithm is designed along the instantaneous Euler rotation axis. This algorithm requires that during the accelerating stage and the decelerating stage, the torque command is assigned to CMG system; however, during the constant-speed stage and after maneuver, the torque is assigned to RW system. Mathematical simulation indicates that, compared with the situation of just using CMG, the new method endows the spacecraft with the ability of rapid maneuver with high accuracy.
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Hou, Yu, e Xiaomei Xu. "High-speed lateral stability and trajectory tracking performance for a tractor-semitrailer with active trailer steering". PLOS ONE 17, n.º 11 (14 de novembro de 2022): e0277358. http://dx.doi.org/10.1371/journal.pone.0277358.
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An active trailer steering (ATS) controller is investigated to improve the lateral stability and trajectory tracking performance of the tractor-semitrailer. First of all, a linear yaw-roll dynamic model of the tractor-semitrailer with steerable trailer wheels is established, and the model accuracy is verified. Then a linear quadratic regulator (LQR) for actively steering the trailer’s wheels is designed. For the LQR controller, the lateral acceleration and the sideslip angle at the center of gravity (CG) of the trailer are taken as the optimization objectives, and the steering angle of the wheel on the middle axle of the trailer is set as the control input. Finally, the effectiveness of the designed controller is tested based on the co-simulation platform under the single lane-change (SLC) maneuver at the speed of 100 km/h and the double lane-change (DLC) maneuver at the speed of 80 km/h and 88km/h. Research results show that under the high-speed SLC maneuver, the designed LQR controller can significantly improves the lateral stability and trajectory tracking performance of the trailer, and cannot affect apparently the trajectory and dynamic responses of the tractor. Under the high-speed DLC maneuver, the designed controller can still make the tractor-semitrailer reach a new steady state in a short time, and improve the vehicle lateral stability and the trajectory tracking performance of the trailer at the same time.
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A., Elhemly, Zeyada Y. e Fayed A. "IMPROVEMENT OF TRACTOR SEMITRAILER STABILITY DURING SEVERE MANEUVER AT HIGH SPEED". International Conference on Applied Mechanics and Mechanical Engineering 12, n.º 12 (1 de maio de 2006): 659–79. http://dx.doi.org/10.21608/amme.2006.41682.
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Vorwerk, Ulrich, Matthias Hey, Gunnar Steinicke e Klaus Begall. "High-Speed Digital Videoimaging of Fast Eardrum Motions During Valsalva Maneuver". ORL 60, n.º 3 (1998): 138–42. http://dx.doi.org/10.1159/000027582.
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Hein, Andrew M., Michael A. Gil, Colin R. Twomey, Iain D. Couzin e Simon A. Levin. "Conserved behavioral circuits govern high-speed decision-making in wild fish shoals". Proceedings of the National Academy of Sciences 115, n.º 48 (12 de novembro de 2018): 12224–28. http://dx.doi.org/10.1073/pnas.1809140115.
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To evade their predators, animals must quickly detect potential threats, gauge risk, and mount a response. Putative neural circuits responsible for these tasks have been isolated in laboratory studies. However, it is unclear whether and how these circuits combine to generate the flexible, dynamic sequences of evasion behavior exhibited by wild, freely moving animals. Here, we report that evasion behavior of wild fish on a coral reef is generated through a sequence of well-defined decision rules that convert visual sensory input into behavioral actions. Using an automated system to present visual threat stimuli to fish in situ, we show that individuals initiate escape maneuvers in response to the perceived size and expansion rate of an oncoming threat using a decision rule that matches dynamics of known loom-sensitive neural circuits. After initiating an evasion maneuver, fish adjust their trajectories using a control rule based on visual feedback to steer away from the threat and toward shelter. These decision rules accurately describe evasion behavior of fish from phylogenetically distant families, illustrating the conserved nature of escape decision-making. Our results reveal how the flexible behavioral responses required for survival can emerge from relatively simple, conserved decision-making mechanisms.
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Chin, Yao-Wei, Jia Ming Kok, Yong-Qiang Zhu, Woei-Leong Chan, Javaan S. Chahl, Boo Cheong Khoo e Gih-Keong Lau. "Efficient flapping wing drone arrests high-speed flight using post-stall soaring". Science Robotics 5, n.º 44 (22 de julho de 2020): eaba2386. http://dx.doi.org/10.1126/scirobotics.aba2386.
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The aerobatic maneuvers of swifts could be very useful for micro aerial vehicle missions. Rapid arrests and turns would allow flight in cluttered and unstructured spaces. However, these decelerating aerobatic maneuvers have been difficult to demonstrate in flapping wing craft to date because of limited thrust and control authority. Here, we report a 26-gram X-wing ornithopter of 200-millimeter fuselage length capable of multimodal flight. Using tail elevation and high thrust, the ornithopter was piloted to hover, fly fast forward (dart), turn aerobatically, and dive with smooth transitions. The aerobatic turn was achieved within a 32-millimeter radius by stopping a dart with a maximum deceleration of 31.4 meters per second squared. In this soaring maneuver, braking was possible by rapid body pitch and dynamic stall of wings at relatively high air speed. This ornithopter can recover to glide stability without tumbling after a 90-degree body flip. We showed that the tail presented a strong stabilizing moment under high thrust, whereas the wing membrane flexibility alleviated the destabilizing effect of the forewings. To achieve these demands for high thrust, we developed a low-loss anti-whirl transmission that maximized thrust output by the flapping wings to 40 grams in excess of body weight. By reducing the reactive load and whirl, this indirect drive consumed 40% less maximum electrical power for the same thrust generation than direct drive of a propeller. The triple roles of flapping wings for propulsion, lift, and drag enable the performance of aggressive flight by simple tail control.
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Li, Gen, e Lu Sun. "Characterizing Heterogeneity in Drivers’ Merging Maneuvers Using Two-Step Cluster Analysis". Journal of Advanced Transportation 2018 (2018): 1–15. http://dx.doi.org/10.1155/2018/5604375.
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In order to investigate the heterogeneity in merging behaviors on freeways, a novel data mining tool, called two-step cluster analysis, is applied to the merging maneuvers (namely, initial speed, merging speed, and merging position). Merging maneuvers of 370 drivers collected from the NGSIM dataset are automatically and optimally segmented into four clusters (Early Merging Drivers at High Speed, Early Merging Drivers at Low Speed, Late Merging Drivers at Low Speed, and Late Merging Drivers at High Speed) by the two-step cluster analysis. Hypothesis test confirms the significant differences in merging maneuvers between different clusters. The clustered data are used to find the best corresponding fitting distributions. Seven distributions (Normal, Log-normal, Student’s t, Logistic, Log-Logistic, Gamma, and Weibull) are considered for each cluster and the Kolmogorov-Smirnov test statics are used to select the best fitted distributions. It is found that merging drivers may merge either early or late, under congestion or uncongested traffic condition. Further analysis of merging durations shows that Late Merging Drivers use significantly shorter time than Early Merging Drivers to finish the merging maneuver, no matter if they are at high or at low speed. Hypothesis test of accepted lead gaps and lag gaps indicate that merging drivers are more sensitive to the lag gaps under congestion. The proposed method can automatically identify the heterogeneity in merging drivers and the results obtained in this paper can be used to enhance the accuracy of the merge behavior models in microscopic simulation software.
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Jeyed, Hamze Ahmadi, e Ali Ghaffari. "Development of a novel nonlinear estimator based on state-dependent Riccati equation technique for articulated vehicles". Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 233, n.º 3 (10 de dezembro de 2018): 516–30. http://dx.doi.org/10.1177/1464419318811254.
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In this article, for the first time, a novel nonlinear estimator based on state-dependent Riccati equation filter technique is developed for state estimation of the articulated heavy vehicles. The state-dependent Riccati equation filter approach has a structure similar to the Kalman filter, and compared to the Kalman filter, which is based on linearization, the state-dependent Riccati equation filter is based on parameterization. Also, the state-dependent Riccati equation approach due to the nonuniqueness of the state-dependent coefficient matrix prevented singularity (uncontrollability or unobservability), and this advantage can be used to improve the efficiency of the system. For this purpose, using the Newton's method, a ten-degrees-of-freedom nonlinear model of the articulated heavy vehicle including the longitudinal, lateral and yaw motion of the tractor, the articulation angle, and rotational motion of each wheel is developed. Then, the developed model of articulated heavy vehicle is verified using nonlinear TruckSim model in high-speed lane change maneuver. The vehicle model validation results indicated that the development model is near to the actual articulated vehicle nonlinear model and can be utilized in the nonlinear estimator design. Then, using the state-dependent Riccati equation filter approach, the state variable estimation algorithm based on parametrization is designed and the articulated vehicle states are estimated online. In order to assess the performance and the efficiency of the developed estimator, the simulations with two standard maneuvers including low-speed 90 ° turn maneuver and high-speed lane change maneuver in the slippery road are performed. The simulation results indicate the remarkable impacts of the developed estimator based on state-dependent Riccati equation filter technique on the state estimation of the articulated heavy vehicles.
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Zuhdi, Muhammad, Muh Makhrus e Wahyudi Wahyudi. "Aspek Fisika dalam Perancangan Pesawat Aeromodeling Jenis Delta Wing". Kappa Journal 5, n.º 1 (30 de junho de 2021): 49–56. http://dx.doi.org/10.29408/kpj.v5i1.3443.
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The Delta Wing aeromodeling aircraft uses a symmetrical airfoil where the top of the wing is the same as the bottom. The main aspects in the design of the Delta Wing aircraft are center of gravity, the engine thrust, the air resistance, the lift and the weight. Delta Wing aircraft are dominated by jet-engined aircraft with the advantages of high speed and small air resistance. From the design and field trials, it was concluded that the minimum thrust of the Delta Win aircraft must be equal to 2 times the total weight of the aircraft so that the aircraft is able to maneuver vertically, perform looping maneuvers, roll maneuvers and hovering.
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YANG, Xiaokang, Hao YANG, Gongmin YAN e Sihai LI. "A high-accuracy SINS attitude update algorithm based on Legendre polynomial". Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 40, n.º 5 (outubro de 2022): 1021–29. http://dx.doi.org/10.1051/jnwpu/20224051021.
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The large-acceleration motion of HFV (hypersonic flight vehicle), the high-speed rolling of spinning missile, and the large-maneuver flight of fighter aircraft has put forward higher performance demand for SINS (strapdown inertial navigation system). The high-accuracy positing will be realized under the high-dynamic maneuver environment after decreasing measurement error of IMU (inertial measurement unit), meanwhile the algorithm of SINS must be improved. The conventional algorithm calculates the flight attitude with determining the compensation term of coning error, after ignoring the high-order term of the Bortz equation. To improve the algorithm accuracy of SINS under high-dynamic maneuver environment, a high-accuracy algorithm, which uses Legendre polynomial to complete angular velocity function approximation and takes the numerical method of quaternion differential equation as core, is proposed herein. The high-order coning error is compensated in the numerical solving period in the proposed novel algorithm, because no approximation exists in deducing process. The attitude calculating simulations are finished in coning motion condition and high-dynamic maneuver condition respectively. Compared with the quadruple-cross-product compensation algorithm which has the highest accuracy at present, the attitude error of proposed algorithm is less than its 1/3 in coning motion condition. And algorithm accuracy is raised an order of magnitude under the high-dynamic maneuver environment. The high-accuracy algorithm based on Legendre polynomial has reference significance for accurate positing of future HFV, atomic gyroscope INS research and high-accuracy algorithm design of SINS.
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Sanchez-Mateo, S., E. Perez-Moreno, F. Jimenez, F. Serradilla, A. Cruz Ruiz e S. De la Fuente Tamayo. "Validation of an Assistance System for Merging Maneuvers in Highways in Real Driving Conditions". Science & Technique 18, n.º 6 (5 de dezembro de 2019): 525–31. http://dx.doi.org/10.21122/2227-1031-2019-18-6-525-531.
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In the latest study conducted by the National Highway Traffic Safety Administration in 2018, it was published that human error is still considered the major factor in traffic accidents, 94 %, compared with other causes such as vehicles, environment and unknown critical reasons. Some driving scenarios are especially complex, such as highways merging lanes, where the driver obtains information from the environment while making decisions on how to proceed to perform the maneuver smoothly and safely. Ignorance of the intentions of the drivers around him leads to risky situations between them caused by misunderstandings or erroneous assumptions or perceptions. For this reason, Advanced Driver Assistance Systems could provide information to obtain safer maneuvers in these critical environments. In previous works, the behavior of the driver by means of a visual tracking system while merging in a highway was studied, observing a cognitive load in those instants due to the high attentional load that the maneuver requires. For this reason, a driver assistance system for merging situations is proposed. This system uses V2V communications technology and suggests to the driver how to modify his speed in order to perform the merging manoeuver in a safe way considering the available gap and the relative speeds between vehicles. The paper presents the results of the validation of this system for assisting in the merging maneuver. For this purpose, the interface previously designed and validated in terms of usability, has been integrated into an application for a mobile device, located inside the vehicle and tests has been carried out in real driving conditions.
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Diachuk, Maksym, e Said M. Easa. "Simultaneous Trajectory and Speed Planning for Autonomous Vehicles Considering Maneuver Variants". Applied Sciences 14, n.º 4 (16 de fevereiro de 2024): 1579. http://dx.doi.org/10.3390/app14041579.
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The paper presents a technique of motion planning for autonomous vehicles (AV) based on simultaneous trajectory and speed optimization. The method includes representing the trajectory by a finite element (FE), determining trajectory parameters in Frenet coordinates, composing a model of vehicle kinematics, defining optimization criteria and a cost function, forming a set of constraints, and adapting the Gaussian N-point scheme for quadrature numerical integration. The study also defines a set of minimum optimization parameters sufficient for making motion predictions with smooth functions of the trajectory and speed. For this, piecewise functions with three degrees of freedom (DOF) in FE’s nodes are implemented. Therefore, the high differentiability of the trajectory and speed functions is ensured to obtain motion criteria such as linear and angular speeds, acceleration, and jerks used in the cost function and constraints. To form the AV roadway position, the Frenet coordinate system and two variable parameters are used: the reference path length and the lateral displacement perpendicular to reference line’s tangent. The trajectory shape, then, depends only on the final position of the AV’s mass center and the final reference’s curvature. The method uses geometric, kinematic, dynamic, and physical constraints, some of which are related to hard restrictions and some to soft restrictions. The planning technique involves parallel forecasting for several variants of the AV maneuver followed by selecting the one corresponding to a specified criterion. The sequential quadratic programming (SQP) technique is used to find the optimal solution. Graphs of trajectories, speeds, accelerations, jerks, and other parameters are presented based on the simulation results. Finally, the efficiency, rapidity, and prognosis quality are evaluated.
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Osman, Kawther, Jawhar Ghommam e Maarouf Saad. "Guidance Based Lane-Changing Control in High-Speed Vehicle for the Overtaking Maneuver". Journal of Intelligent & Robotic Systems 98, n.º 3-4 (11 de outubro de 2019): 643–65. http://dx.doi.org/10.1007/s10846-019-01070-6.
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Liu, Kai, Jianwei Gong, Arda Kurt, Huiyan Chen e Umit Ozguner. "Dynamic Modeling and Control of High-Speed Automated Vehicles for Lane Change Maneuver". IEEE Transactions on Intelligent Vehicles 3, n.º 3 (setembro de 2018): 329–39. http://dx.doi.org/10.1109/tiv.2018.2843177.
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Harmat, Adam, Michael Trentini e Inna Sharf. "Jumping behaviour for a wheeled quadruped robot: simulation and experiments". Journal of Unmanned Vehicle Systems 01, n.º 01 (1 de dezembro de 2013): 41–60. http://dx.doi.org/10.1139/juvs-2013-0010.
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In this paper, we describe a new jumping behaviour developed for the quadruped robot, PAW (Platform for Ambulating Wheels). The robot has very few degrees of freedom and no knee joints. It employs springy legs and wheels at the distal ends of the legs to achieve various modes of legged, wheeled, and hybrid locomotion, such as high-speed breaking, bounding, and presently jumping. The jumping maneuver developed in this manuscript is designed specifically to take advantage of the wheels on the robot and compliance in its legs and it involves the following principal stages: acceleration to jumping speed, body positioning via front hip thrusting, rear leg compression and thrusting, and flight. A high-fidelity MSC.ADAMS/Simulink co-simulation was developed and used to test and optimize the jumping process. Because of the strong coupling between the parameters defining the jump maneuver, manual parameter tuning is difficult and thus a genetic algorithm is employed for the optimization process. The data generated by the genetic algorithm is further used for the fitting of a quadratic response surface, which allows identifying those parameters that contribute most to a successful jump. Finally, the jumping maneuver is implemented on the physical PAW to demonstrate its feasibility on a hybrid quadruped, and to provide insights into the robot response during this highly dynamic maneuver.
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Fahami, Sheikh Muhammad Hafiz, Hairi Zamzuri, Saiful Amri Mazlan e Sarah Atifah Saruchi. "The Variable Steering Ratio for Vehicle Steer by Wire System Using Hyperbolic Tangent Method". Applied Mechanics and Materials 575 (junho de 2014): 781–84. http://dx.doi.org/10.4028/www.scientific.net/amm.575.781.
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In conventional steering system, during the parking maneuver, driver required large turned on the steering wheel to move the fornt tyre. Thus, it will increase the driver burden when turned the steering wheel. The feature of variable steering ratio (VSR), help to reduce driver burden. Moreover, it improves the vehicle maneuver at lower and high speed. This paper, proposed a control algorithm of variable steering ratio (VSR) in vehicle SBW system. The concept of hyperbolic tangent is used where it not only improved the maneuverability at lower speed, but also reduces the driver burden on the steering wheel. To investigate the effectiveness of the proposed VSR algorithm, the result is compared with conventional steering system
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Siramdasu, Yaswanth, e Saied Taheri. "A Tool for Tire Handling Performance Evaluation". Tire Science and Technology 44, n.º 2 (1 de abril de 2016): 74–102. http://dx.doi.org/10.2346/tire.16.440201.
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ABSTRACT In the past, handling performance of the tire–vehicle combination has been evaluated using tire models such as the Pacejka Magic Formula. These models usually lack realistic representation of tire–road interaction and are not suitable for combined steering and braking maneuvers that may activate the antilock braking system. The objective of this study is to develop a computationally simple and accurate tire model, which can be used in the development and evaluation of handling performance of the tire on uneven road surfaces. For an emergency obstacle avoidance maneuver at high speeds, transient tire behavior plays a crucial role in the generation of forces between tire and road. Road undulations and steering inputs both induce high-frequency tire belt vibrations, which have detrimental effects on the handling and tractive behavior of the tire. To meet these requirements, a dynamic six degrees of freedom tire model–based rigid ring approach is developed and integrated with a multiple tandem elliptical cam to include enveloping behavior of the tire. The tire model that is developed in this research is partially based on the work of Schmeitz found in the literature. The tire model was parameterized using experimental parameters found in the literature. The tire model is validated using fixed axle high-speed oblique cleat experimental data. The developed tire model is integrated with the vehicle model in CarSim®. From the simulation of successive step steering input, the increasing influence of tire belt vibrations at higher slip angles was observed due to sudden steering wheel inputs. From the simulation of the step steering input on the bad asphalt road surface with an added cleat and on the flat smooth road surface, it was observed that the lateral performance of the tire at higher slip angles is strongly influenced by the vertical load variations. A single lane change maneuver was simulated on the smooth and bad asphalt road surfaces, demonstrating the strong influence of tire lateral and vertical belt vibrations on the lateral performance of the vehicle. Simulation of high-speed emergency obstacle avoidance braking maneuvers on measured rough and smooth roads showed that the influence of high-frequency vibrations due to road undulations and step steering inputs causes large variations of longitudinal and lateral forces at the axle, thus creating large variations in slip and slip angle of the tire with a degraded braking distance on rough roads.
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Esmaeili, Naser, Reza Kazemi e S. Hamed Tabatabaei Oreh. "An adaptive sliding mode controller for the lateral control of articulated long vehicles". Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 233, n.º 3 (4 de novembro de 2018): 487–515. http://dx.doi.org/10.1177/1464419318806801.
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Today, use of articulated long vehicles is surging. The advantages of using large articulated vehicles are that fewer drivers are used and fuel consumption decreases significantly. The major problem of these vehicles is inappropriate lateral performance at high speed. The articulated long vehicle discussed in this article consists of tractor and two semi-trailer units that widely used to carry goods. The main purpose of this article is to design an adaptive sliding mode controller that is resistant to changing the load of trailers and measuring the noise of the sensors. Control variables are considered as yaw rate and lateral velocity of tractor and also first and second articulation angles. These four variables are regulated by steering the axles of the articulated vehicle. In this article after developing and verifying the dynamic model, a new adaptive sliding mode controller is designed on the basis of a nonlinear model. This new adaptive sliding mode controller steers the axles of the tractor and trailers through estimation of mass and moment of inertia of the trailers to maintain the stability of the vehicle. An articulated vehicle has been exposed to a lane change maneuver based on the trailer load in three different modes (low, medium and high load) and on a dry and wet road. Simulation results demonstrate the efficiency of this controller to maintain the stability of this articulated vehicle in a low-speed steep steer and high-speed lane change maneuvers. Finally, the robustness of this controller has been shown in the presence of measurement noise of the sensors. In fact, the main innovation of this article is in the designing of an adaptive sliding mode controller, which by changing the load of the trailers, in high-speed and low-speed maneuvers and in dry and wet roads, has the best performance compared to conventional sliding mode and linear controllers.
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Capuano, Antonio, Matteo Spano, Alessia Musa, Gianluca Toscano e Daniela Anna Misul. "Development of an Adaptive Model Predictive Control for Platooning Safety in Battery Electric Vehicles". Energies 14, n.º 17 (26 de agosto de 2021): 5291. http://dx.doi.org/10.3390/en14175291.
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The recent and continuous improvement in the transportation field provides several different opportunities for enhancing safety and comfort in passenger vehicles. In this context, Adaptive Cruise Control (ACC) might provide additional benefits, including smoothness of the traffic flow and collision avoidance. In addition, Vehicle-to-Vehicle (V2V) communication may be exploited in the car-following model to obtain further improvements in safety and comfort by guaranteeing fast response to critical events. In this paper, firstly an Adaptive Model Predictive Control was developed for managing the Cooperative ACC scenario of two vehicles; as a second step, the safety analysis during a cut-in maneuver was performed, extending the platooning vehicles’ number to four. The effectiveness of the proposed methodology was assessed for in different driving scenarios such as diverse cruising speeds, steep accelerations, and aggressive decelerations. Moreover, the controller was validated by considering various speed profiles of the leader vehicle, including a real drive cycle obtained using a random drive cycle generator software. Results demonstrated that the proposed control strategy was capable of ensuring safety in virtually all test cases and quickly responding to unexpected cut-in maneuvers. Indeed, different scenarios have been tested, including acceleration and deceleration phases at high speeds where the control strategy successfully avoided any collision and stabilized the vehicle platoon approximately 20–30 s after the sudden cut-in. Concerning the comfort, it was demonstrated that improvements were possible in the aggressive drive cycle whereas different scenarios were found in the random cycle, depending on where the cut-in maneuver occurred.
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Peng, Xiangyu, Qiang Song, Yue Zhang e Wei Wang. "An Hybrid Integration Method-Based Track-before-Detect for High-Speed and High-Maneuvering Targets in Ubiquitous Radar". Remote Sensing 15, n.º 14 (12 de julho de 2023): 3507. http://dx.doi.org/10.3390/rs15143507.
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Due to the limited transmission gain of ubiquitous radar systems, it has become necessary to use a long-time coherent integration method for range-Doppler (RD) analysis. However, when the target exhibits high-speed and high-maneuver capabilities, it introduces challenges, such as range migration (RM), Doppler frequency migration (DFM), and velocity ambiguity (VA) in the RD domain, thus posing significant difficulties in target detection and tracking. Moreover, the presence of VA further complicates the problem. To address these complexities while maintaining integration efficiency, this study proposes a hybrid integration approach. First, methods called Keystone-transform (KT) and matched filtering processing (MFP) are proposed for compensating for range migration (RM) and velocity ambiguity (VA) in Radar Detection (RD) images. The KT approach is employed to compensate for RM, followed by the generation of matched filters with varying ambiguity numbers. Subsequently, MFP enables the production of multiple RD images covering different but contiguous Doppler frequency ranges. These RD images can be compiled into an extended RD (ERD) image that exhibits an expanded Doppler frequency range. Second, an improved particle-filter (IPF) algorithm is raised to perform incoherent integration among ERD images and to achieve track-before-detect (TBD) for a target. In the IPF, the target state vector is augmented with ambiguous numbers, which are estimated via maximum posterior probability estimation. Then, to compensate for the DFM, a line spread model (LSM) is proposed instead of the point spread model (PSM) used in traditional PF. To evaluate the efficacy of the proposed method, a radar simulator is devised, encompassing comprehensive radar signal processing. The findings demonstrate that the proposed approach achieves a harmonious equilibrium between integration efficiency and computational complexity when it comes to detecting and tracking high-speed and high-maneuvering targets with intricate maneuvers. Furthermore, the algorithm’s effectiveness is authenticated by exploiting ubiquitous radar data.
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Tian, Jie, Qingkang Zeng, Peng Wang e Xiaoqing Wang. "Active steering control based on preview theory for articulated heavy vehicles". PLOS ONE 16, n.º 5 (25 de maio de 2021): e0252098. http://dx.doi.org/10.1371/journal.pone.0252098.
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This paper investigates the active steering control of the tractor and the trailer for the articulated heavy vehicle (AHV) to improve its high-speed lateral stability and low-speed path following. The four-degree-of-freedom (4-DOF) single track dynamic model of the AHV with a front-wheel steered trailer is established. Considering that the road information at the driver’s focus is the most clear and those away from the focus blurred, a new kind controller based on the fractional calculus, i.e., a focus preview controller is designed to provide the steering input for the tractor to make it travel along the desired path. In addition, the active steering controllers based on the linear quadratic regulator (LQR) and single-point preview controller respectively are also proposed for the trailer. However, the latter is designed on the basis of the articulation angle between the tractor and trailer, inspired by the idea of the driver’s single-point preview controller. Finally, the single lane change maneuver and 90o turn maneuver are carried out. And the simulation results show that compared with the single-point preview controller, the new kind preview controller for the tractor can have good high speed maneuvering stability and low speed path tracking ability by adjusting the fractional order of the controller. On this basis, three different AHVs with the same tractor are simulated and the simulation results show that the AHV whose trailer adopts the single-point preview controller has better high-speed lateral stability and low-speed path tracking than the AHV whose trailer adopts the LQR controller.
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Lu, Liang, Adrian Carrio, Carlos Sampedro e Pascual Campoy. "A Robust and Fast Collision-Avoidance Approach for Micro Aerial Vehicles Using a Depth Sensor". Remote Sensing 13, n.º 9 (5 de maio de 2021): 1796. http://dx.doi.org/10.3390/rs13091796.
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Collision-avoidance is a crucial research topic in robotics. Designing a collision-avoidance algorithm is still a challenging and open task, because of the requirements for navigating in unstructured and dynamic environments using limited payload and computing resources on board micro aerial vehicles. This article presents a novel depth-based collision-avoidance method for aerial robots, enabling high-speed flights in dynamic environments. First of all, a depth-based Euclidean distance field mapping algorithm is generated. Then, the proposed Euclidean distance field mapping strategy is integrated with a rapid-exploration random tree to construct a collision-avoidance system. The experimental results show that the proposed collision-avoidance algorithm has a robust performance at high flight speeds in challenging dynamic environments. The experimental results show that the proposed collision-avoidance algorithm can perform faster collision-avoidance maneuvers when compared to the state-of-art algorithms (the average computing time of the collision maneuver is 25.4 ms, while the minimum computing time is 10.4 ms). The average computing time is six times faster than one baseline algorithm. Additionally, fully autonomous flight experiments are also conducted for validating the presented collision-avoidance approach.
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Polus, Abishai, Moshe Livneh e Benyamin Frischer. "Evaluation of the Passing Process on Two-Lane Rural Highways". Transportation Research Record: Journal of the Transportation Research Board 1701, n.º 1 (janeiro de 2000): 53–60. http://dx.doi.org/10.3141/1701-07.
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The main purpose of this research was to develop models to quantify the major components of the passing process. A second goal was to compare the results with existing highway-design models and to arrive at conclusions about the applicability of the existing models. Additional objectives were to evaluate several time elements of the passing process, such as the response time of drivers from the arrival of a proper gap until the start of the passing maneuver. The evaluation is based on an analysis of data that were collected by videotaping six tangent two-lane highway sections from high vantage points and from a helicopter hovering above one site. Normal driver behavior was not disturbed during the data collection process. About 1,500 passings were recorded; of these, 54 percent were characterized as “single passing,” in which one driver passed a single, slower vehicle. About half of all passing maneuvers were found to involve two cars; in the other half, at least one truck was overtaken. A model showing the relationship between the speed of the impeding vehicle and the passing distance was calibrated, and the implications for highway-design procedures were discussed. Several of the findings had unique safety implications, such as the very short headway before the start of the passing maneuver and very short driver-reaction times. The primary results of the analyses enabled determination of the required passing distances and, therefore, the sight distances needed for different design speeds and various traffic combinations. Additional safety-related aspects are evaluated and discussed.
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Grossman, Lisa. "Life: Fruit flies maneuver on autopilot: High-speed video reveals clues to insect aerodynamic skills". Science News 177, n.º 10 (8 de maio de 2010): 8. http://dx.doi.org/10.1002/scin.5591771005.
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Menzer, Alec, Yan Ren, Jiacheng Guo, Bret W. Tobalske e Haibo Dong. "Wing Kinematics and Unsteady Aerodynamics of a Hummingbird Pure Yawing Maneuver". Biomimetics 7, n.º 3 (19 de agosto de 2022): 115. http://dx.doi.org/10.3390/biomimetics7030115.
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As one of few animals with the capability to execute agile yawing maneuvers, it is quite desirable to take inspiration from hummingbird flight aerodynamics. To understand the wing and body kinematics and associated aerodynamics of a hummingbird performing a free yawing maneuver, a crucial step in mimicking the biological motion in robotic systems, we paired accurate digital reconstruction techniques with high-fidelity computational fluid dynamics (CFD) simulations. Results of the body and wing kinematics reveal that to achieve the pure yaw maneuver, the hummingbird utilizes very little body pitching, rolling, vertical, or horizontal motion. Wing angle of incidence, stroke, and twist angles are found to be higher for the inner wing (IW) than the outer wing (OW). Unsteady aerodynamic calculations reveal that drag-based asymmetric force generation during the downstroke (DS) and upstroke (US) serves to control the speed of the turn, a characteristic that allows for great maneuvering precision. A dual-loop vortex formation during each half-stroke is found to contribute to asymmetric drag production. Wake analysis revealed that asymmetric wing kinematics led to leading-edge vortex strength differences of around 59% between the IW and OW. Finally, analysis of the role of wing flexibility revealed that flexibility is essential for generating the large torque necessary for completing the turn as well as producing sufficient lift for weight support.
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Martin, J. Ezequiel, Thad Michael e Pablo M. Carrica. "Submarine Maneuvers Using Direct Overset Simulation of Appendages and Propeller and Coupled CFD/Potential Flow Propeller Solver". Journal of Ship Research 59, n.º 01 (1 de março de 2015): 31–48. http://dx.doi.org/10.5957/jsr.2015.59.1.31.
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This article presents two approaches to simulate maneuvers of a model radio-controlled submarine. In the direct simulation approach, rudders, stern planes, and propellers are gridded and treated as moving objects using dynamic overset technology. The second approach couples the overset computational fluid dynamics (CFD) solver and a potential flow propeller code, with both codes exchanging velocities at the propeller plane and wake, body forces, and propeller forces and moments, whereas rudders and stern planes are still explicitly resolved. It is shown that during the maneuvers, the range of advance coefficients does not deviate much from the design point, making a coupled approach a valid choice for standard maneuvering simulations. By allowing time steps about an order of magnitude larger than for the direct simulation approach, the coupled approach can run about five times faster. The drawback is a loss of resolution in the wake as the direct propeller simulation can resolve blade vortical structures. Open water propeller curves were simulated with both the direct propeller approach and the coupled approach, showing that the coupled approach can match the direct approach performance curves for a wide range of advance coefficients. Simulations of a horizontal overshoot maneuver at two approach speeds were performed, as well as vertical overshoot and controlled turn maneuvers at high speed. Results show that both CFD approaches can reproduce the experimental results for all parameters, with errors typically within 10%.
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Zhang, Si Qi, Shu Wen Zhou e Guang Yao Zhao. "Study on Vehicle Stability Control Based on Yaw Following and 4WS". Advanced Materials Research 204-210 (fevereiro de 2011): 1724–27. http://dx.doi.org/10.4028/www.scientific.net/amr.204-210.1724.
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Because of the high speed and insufficient stopping distance, a sudden obstacle will force the vehicle to perform a lane change maneuver to avoid a crash or rear-end collision. A vehicle yaw following control system was designed in this paper to prevent vehicles from spinning and drifting out on high speed obstacle avoidance under emergency. However, yaw following control system, in some situation, may not react properly to, or even deteriorate on-road rollover events. Four-wheel steering control system can reduce the excessive yaw movement due to yaw following control system. An integration control system, including yaw following control system and four-wheel steering control system was presented and discussed. With this improved control system, the vehicle lateral stability can be improved on high speed obstacle avoidance.
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Bedo, Bruno L. S., Guilherme M. Cesar, Wodyson T. E. Soares, Danilo S. Catelli, João B. Marques, Matheus M. Gomes e Paulo R. P. Santiago. "The influence of athletic background, lower limb dominance and cutting angle on the center of mass kinematics during a sidestep cutting task". Brazilian Journal of Motor Behavior 17, n.º 1 (10 de abril de 2023): 39–47. http://dx.doi.org/10.20338/bjmb.v17i1.294.
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BACKGROUND: Successful performance in futsal depends on athletes' ability to change direction efficiently. AIM: To investigate the effect of athletic background on COM kinematics during sidestep cutting maneuver performed at different cutting angles towards both sides. METHOD: Eighteen futsal athletes participated, comprised of nine high-level training (Group high-level) and nine recreational (Group Control, GC). Twenty reflective markers were placed on the participant's trunk and upper and lower limbs. Participants performed acceleration at maximum speed and in a straight line for 10 meters, followed by a change of direction (30º, 60º, and 90º). The whole body's COM trajectory was identified using a body model for each trial. Differences in angular error and COM speed were evaluated with a three-way analysis of variance [Group (GH vs. GC) X Cutting angle (30º vs. 60º vs. 90º) X Side (dominant and non-dominant), with repeated measures for the last two factors]. RESULTS: The main results indicated that the angular error increased as the cutting angle increased. The high-level futsal athletes performed a cutting task for the dominant side with greater speed and higher angular errors than the control group. These findings provided important information for understanding the trajectory of the center of mass at different angles and velocities and the possible repercussions on body dynamics. CONCLUSION: Athletic background affected the kinematic patterns of the center of mass during sidestep cutting maneuvers; when sidestep is performed with the dominant side, high-level futsal athletes changed direction faster with more significant angular error than recreational athletes.
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Gao, Youtao, Jinghe Guo, Zhicheng You, Zezheng Dong e Yi Cheng. "Satellite Fast Maneuver Control Technology Based on Parallel System". International Journal of Aerospace Engineering 2023 (13 de outubro de 2023): 1–12. http://dx.doi.org/10.1155/2023/1711773.
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An on-orbit thrust estimation method of satellite based on parallel system, which can achieve high-efficiency and high-precision thrust estimation, is proposed. A complete satellite maneuvering parallel system framework is constructed. Initially, a real-time artificial model, which is consistent with the actual system, is established. The injection time of maneuvering control is estimated optimally based on the modification of the artificial model with the specific injection time treated as the optimization parameter. The jet time, with the minimum maneuvering error, is obtained. Then, a maneuver strategy is designed and fed back to the actual system. The method based on a parallel system with jet time as the optimal parameter has higher control accuracy than the previous maneuvering control, which only considers the speed increment. Simulation results show that the terminal error of the first maneuver using the parallel system method is less than 100 meters for a maneuvering mission of tens of kilometers.
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Mousa, Saleh R., Peter R. Bakhit, Osama A. Osman e Sherif Ishak. "A Comparative Analysis of Tree-Based Ensemble Methods for Detecting Imminent Lane Change Maneuvers in Connected Vehicle Environments". Transportation Research Record: Journal of the Transportation Research Board 2672, n.º 42 (11 de junho de 2018): 268–79. http://dx.doi.org/10.1177/0361198118780204.
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Lane changing is one of the main contributors to car crashes in the U.S. The complexity of the decision-making process associated with lane changing makes such maneuvers prone to driving errors, and hence, increases the possibility of car crashes. Thus, researchers have been investigating ways to model and predict lane changing maneuvers for optimally designed crash avoidance systems. Such systems rely on the accuracy of detecting the onset of lane-change maneuvers, which requires comprehensive vehicle trajectory data. Connected Vehicles (CV) data provide opportunities for accurate modeling of lane changing maneuvers, especially with the variety of advanced tools available nowadays. The review of the literature indicates that most of the implemented modeling tools do not achieve reliable accuracy for such critical safety application of lane-change prediction. Recently, eXtreme Gradient Boosting (XGB) became a well-recognized algorithm among the computer science community in solving classification problems due to its accuracy, scalability, and speed. This study implements the XGB in predicting the onset of lane changing maneuvers using CV trajectory data. The performance of XGB is compared to three other tree-based algorithms namely, decision trees, gradient boosting, and random forests. The Next Generation SIMulation trajectory data are used to represent the high-resolution CV data. The results indicate that XGB is superior to the other algorithms with a high accuracy value of 99.7%. This outstanding accuracy is achieved when considering vehicle trajectory data two seconds prior to a potential lane change maneuver. The findings of this study are promising for detection of lane change maneuvers in CV environments.
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Liu, Feng, Yang Gao e Weiwei Zhang. "Large angle maneuver and high accuracy attitude pointing steering law for variable speed control momentum gyroscopes". Journal of the Franklin Institute 358, n.º 7 (maio de 2021): 3441–69. http://dx.doi.org/10.1016/j.jfranklin.2021.02.019.
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Sánchez–Mateo, Sofia, Elisa Pérez–Moreno e Felipe Jiménez. "Driver Monitoring for a Driver-Centered Design and Assessment of a Merging Assistance System Based on V2V Communications". Sensors 20, n.º 19 (29 de setembro de 2020): 5582. http://dx.doi.org/10.3390/s20195582.
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Merging is one of the most critical scenarios that can be found in road transport. In this maneuver, the driver is subjected to a high mental load due to the large amount of information he handles, while making decisions becomes a crucial issue for their safety and those in adjacent vehicles. In previous works, it was studied how the merging maneuver affected the cognitive load required for driving by means of an eye tracking system, justifying the proposal of a driver assistance system for the merging maneuver on highways. This paper presents a merging assistance system based on communications between vehicles, which allows vehicles to share internal variables of position and speed and is implemented on a mobile device located inside the vehicle. The system algorithm decides where and when the vehicle can start the merging maneuver in safe conditions and provides the appropriate information to the driver. Parameters and driving simulator tests are used for the interface definition to develop the less intrusive and demanding one. Afterward, the system prototype was installed in a real passenger car and tests in real scenarios were conducted with several drivers to assess usability and mental load. Comparisons among alternative solutions are shown and effectiveness is assessed.
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Shimoda, Shingo, Yoji Kuroda e Karl Iagnemma. "High-speed navigation of unmanned ground vehicles on uneven terrain using potential fields". Robotica 25, n.º 4 (18 de janeiro de 2007): 409–24. http://dx.doi.org/10.1017/s0263574706003171.
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SUMMARYMany applications require unmanned ground vehicles (UGVs) to travel at high speeds on sloped, natural terrain. In this paper, a potential field-based method is proposed for UGV navigation in such scenarios. In the proposed approach, a potential field is generated in the two-dimensional “trajectory space” of the UGV path curvature and longitudinal velocity. In contrast to traditional potential field methods, dynamic constraints and the effect of changing terrain conditions can be easily expressed in the proposed framework. A maneuver is chosen within a set of performance bounds, based on the local potential field gradient. It is shown that the proposed method is subject to local maxima problems, rather than local minima. A simple randomization technique is proposed to address this problem. Simulation and experimental results show that the proposed method can successfully navigate a small UGV between predefined waypoints at speeds up to 7.0 m/s, while avoiding static hazards. Further, vehicle curvature and velocity are controlled during vehicle motion to avoid rollover and excessive side slip. The method is computationally efficient, and thus suitable for onboard real-time implementation.
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Clarke, James, e Antonio Filippone. "Unsteady Computational Analysis of Vehicle Passing". Journal of Fluids Engineering 129, n.º 3 (19 de agosto de 2006): 359–67. http://dx.doi.org/10.1115/1.2427085.
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This paper presents results of the simulation of two vehicles overtaking each other at highways conditions (30m∕s). The simulation was fully unsteady and tracks the maneuver for several body lengths from downstream to upstream. Different mesh strategies have been investigated and assessed. Structured methods with sliding planes have been found the most feasible. The results shown include the effects of relative speed and lateral separation. The passing maneuver is described in detail, and a number of physical phenomena are identified. In particular, the rapid fluid compression and acceleration at the nose passing situation yields a pulse in the drag of the overtaken vehicle. The high pressure bow wave followed swiftly by the low-pressure wake affects the side force and lateral stability at positions slightly different than the nose passing.
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Wu, Da Fang, Lin Zhu, Yue Wu Wang, Shou Gen Zhao e Ying Pu. "Study on Vibration Characteristics of the Vehicles Wing Structure in High Temperature Environment". Applied Mechanics and Materials 482 (dezembro de 2013): 200–206. http://dx.doi.org/10.4028/www.scientific.net/amm.482.200.
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During the flight of the long-range cruise missiles, aerodynamic heating can cause the temperature of the wing structure, fairing, missile body and other components to rise rapidly, along with serious structural vibrations. The thermal environment generated by aerodynamic heating significantly changes the mechanical properties of the materials and structure, including the elastic modulus, stiffness, and so on. The complex flight maneuver process will also produce high-temperature gradients, which affect the thermal stress field. Both of these impacts significantly affect the characteristics of the missile structures natural vibration. In this paper, thermal vibration joint testing was performed on two different wing structures of a high-speed missile under a thermal environment, and the vibration characteristics of the wing structure (e.g., the natural frequency) at various temperatures were obtained. The experimental results can provide a reliable basis for the safety design of the wing structure of missiles under high-speed thermal vibration conditions.
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Bakhit, Peter R., Osama A. Osman e Sherif Ishak. "Detecting Imminent Lane Change Maneuvers in Connected Vehicle Environments". Transportation Research Record: Journal of the Transportation Research Board 2645, n.º 1 (janeiro de 2017): 168–75. http://dx.doi.org/10.3141/2645-18.
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Lane changing is a complex decision-making process that is affected by factors such as vehicle features, driver characteristics, network attributes, and traffic conditions. Understanding the changes in driver behavior and vehicle trajectory before the lane change initiation process is essential to the design of a safe and reliable crash avoidance system. The recently introduced connected vehicle (CV) technology provides opportunities for real-time, high-resolution data exchange capability between vehicles. This study explored the high-resolution vehicle trajectory data attainable in CV environments for detecting the onset of lane change maneuvers. The observed change in behavior before the initiation of such a maneuver was examined to identify the associated driving pattern. This pattern was used to develop two lane change detection models: an artificial neural network (ANN) model and a multiple logistic regression (MLR) model. The two models were trained and tested with Next Generation Simulation data collected from a weaving freeway segment in Arlington, Virginia. The results show 80% detection accuracy for the ANN model, compared with 72% for the MLR model. The developed models identified the vehicle speed, acceleration, and speed relative to the lead vehicle as the most significant attributes for lane change detection. Drivers’ intentions could be detected early and potential crashes could be prevented by training these models to capture similar driving behavior patterns.
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Phuc, Bui Duc Hong, Sang-Do Lee, Sam-Sang You e Natwar Singh Rathore. "Nonlinear robust control of high-speed supercavitating vehicle in the vertical plane". Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 234, n.º 2 (26 de setembro de 2019): 510–19. http://dx.doi.org/10.1177/1475090219875861.
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The supercavitating vehicle can quickly become unstable under the influence of the planing force and external disturbances due to waves and currents. The planing force demonstrates nonlinear characteristics which can be described by the vehicle state variables. Strict standards for maneuvering strategy are required for high-speed vehicles to operate, particularly guidance, navigation, and control of underwater maneuver. In reality, the high-speed supercavitating vehicle dynamics present various control issues and challenges. This article proposes the nonlinear robust control synthesis to manipulate the vertical plane of the high-speed supercavitating vehicle against the planing force or parameter variations as well as external disturbances. The control synthesis is implemented by solving an algebraic Riccati equation at each iteration of the control algorithm with the updated system states, which is a so-called state-dependent Riccati equation. The control loops in the dive-plane satisfy an [Formula: see text] performance criterion that can reject external disturbances with perturbations. Simulation results show that the controlled vehicle system guarantees fast transient responses with steady-state performance. Besides, the proposed controller can eliminate up to 62% of disturbances and provides the robust performance against large planing force and parametric uncertainties. This new vehicle technology with active controller offers the potential strategy of higher speed and higher maneuverability solutions for various purposes of underwater maneuvering.
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Alhanouti, Muhammed, e Frank Gauterin. "A Generic Model for Accurate Energy Estimation of Electric Vehicles". Energies 17, n.º 2 (16 de janeiro de 2024): 434. http://dx.doi.org/10.3390/en17020434.
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A systematic simulation model is proposed in this research paper to estimate the energy consumption of electric vehicles. The main advantage of this model is that it is made in a generic and simplified way in order to be adaptable to different electric vehicles. The overall electrical power corresponding to the performed maneuver is estimated considering: a tabular form of electric motor efficiency, mechanical power losses, a generalized efficiency map of the power electronics, the auxiliary power losses, and an electro-thermal Lithium-Ion battery pack model. The battery model was developed in a previous work, which simulates the open circuit voltage curves at different temperatures and the alteration in the internal resistance of the battery cells. The proposed model is validated with experimental data from the maneuver tests. The battery model proved high accuracy in estimating the voltage values relevant to the WLTP2 driving cycle on the chassis roller test bench. Furthermore, the mechanical and electrical power were estimated with excellent matching compared to actual test field driving test measurements, giving only the measured vehicle speed and auxiliary power losses. Finally, the state of charge change is predicted accurately along the performed test field dynamic maneuver.
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DAIDZIC, Nihad E. "An algebraic model of high-altitude aircraft decompression and emergency descent". Aviation 21, n.º 3 (3 de agosto de 2018): 92–101. http://dx.doi.org/10.3846/16487788.2017.1380081.
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An emergency descent maneuver initiated by pilots shortly after the onset of the decompression recognition was developed for subsonic, supersonic and hypersonic cruisers. Among other findings, the times when a passenger cabin is exposed to altitudes above 25,000 and 40,000 ft and the maximum cabin altitude reached are estimated. An airplane descent aerodynamic model was incorporated for high-speed and low-speed high-drag emergency descents. Airplane cabin atmosphere is assumed to be isothermal. The environmental atmosphere is simulated using the NLPAM nonlinear atmospheric model valid up to 47 geopotential kilometers. Rapid and slow decompressions at several discrete cruising altitudes ranging from 12 to 40 km and varying pilot reaction times in initiating the emergency descent were simulated. The main motivation for this work was to estimate times and altitudes a cabin reaches during depressurization for various flight conditions. This model can be utilized in optimizing the emergency-descent piloting techniques, calculating oxygen supplies, evaluating aeromedical factors, estimating harmful exposures to low pressures, and for other important high-altitude aircraft operations.
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Yuan, Y., D. Thomson e R. Chen. "Variable rotor speed strategy for coaxial compound helicopters with lift–offset rotors". Aeronautical Journal 124, n.º 1271 (27 de setembro de 2019): 96–120. http://dx.doi.org/10.1017/aer.2019.113.
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ABSTRACTThe coaxial compound helicopter with lift-offset rotors has been proposed as a concept for future high-performance rotorcraft. This helicopter usually utilizes a variable-speed rotor system to improve the high-speed performance and the cruise efficiency. A flight dynamics model of this helicopter associated with rotor speed governor/engine model is used in this article to investigate the effect of the rotor speed change and to study the variable rotor speed strategy. Firstly, the power-required results at various rotor rotational speeds are calculated. This comparison indicates that choice of rotor speed can reduce the power consumption, and the rotor speed has to be reduced in high-speed flight due to the compressibility effects at the blade tip region. Furthermore, the rotor speed strategy in trim is obtained by optimizing the power required. It is demonstrated that the variable rotor speed successfully improves the performance across the flight range, but especially in the mid-speed range, where the rotor speed strategy can reduce the overall power consumption by around 15%. To investigate the impact of the rotor speed strategy on the flight dynamics properties, the trim characteristics, the bandwidth and phase delay, and eigenvalues are investigated. It is shown that the reduction of the rotor speed alters the flight dynamics characteristics as it affects the stability, damping, and control power provided by the coaxial rotor. However, the handling qualities requirements are still satisfied with different rotor speed strategies. Finally, a rotor speed strategy associated with the collective pitch is designed for maneuvering flight considering the normal load factor. Inverse simulation is used to investigate this strategy on maneuverability in the Push-up & Pull-over Mission-Task-Element (MTE). It is shown that the helicopter can achieve Level 1 ratings with this rotor speed strategy. In addition, the rotor speed strategy could further reduce the power consumption and pilot workload during the maneuver.
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Raksincharoensak, Pongsathorn, e Yuta Akamatsu. "Development of Collision Avoidance System in Right Turn Maneuver Using Vehicle-in-the-Loop Simulation". Journal of Robotics and Mechatronics 27, n.º 6 (18 de dezembro de 2015): 627–35. http://dx.doi.org/10.20965/jrm.2015.p0627.
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<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00270006/04.jpg"" width=""300"" /> Right turn collision avoidance</div>Collisions in Japan between vehicles during right turns account for a high number of other intersection accidents. We present collision avoidance that introduces speed control assistance combined with autonomous emergency braking when vehicles approach and a collision becomes imminent. Our proposal uses on-board sensors such as radar and cameras to handle situations without depending on X2X communication and infrastructure. We also propose a speed control algorithm. A “vehicle-in-the-loop test” involving a virtual test drive for rapid system development verifies the effectiveness of our proposals.