Academic literature on the topic 'Longitudinal coupling strategy'
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Journal articles on the topic "Longitudinal coupling strategy"
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Al-Budairi, Hassan, Patrick Harkness, and Margaret Lucas. "A Strategy for Delivering High Torsionality in Longitudinal-Torsional Ultrasonic Devices." Applied Mechanics and Materials 70 (August 2011): 339–44. http://dx.doi.org/10.4028/www.scientific.net/amm.70.339.
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A composite longitudinal-torsional vibration mode has applications in ultrasonic motors, ultrasonic welding and ultrasonic drilling. There are two ways to obtain this vibration behaviour using a single transducer, namely (i) coupling of a longitudinal and a torsional mode, which is known to be difficult; and (ii) degenerating a longitudinal mode to deliver longitudinal-torsional behaviour at the horn tip. A mode-degenerating horn is achieved by incorporating helical or diagonal slits in an otherwise traditional exponential horn driven by a Langevin transducer. However, it is often difficult with this configuration to avoid coupling of unwanted bending modes, low responsiveness, and loss of ultrasonic energy due to boundaries between tuned components. Therefore, in this study the mode-degenerating characteristics are achieved by incorporating the helical slits and exponential geometry features in the front mass of the transducer itself. Finite element analysis and vibration experimental analysis show that this strategy prevents coupling of bending modes, increases responsiveness, and reduces energy losses. Most importantly the transducer delivers a very high torsionality.
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Cheng, Shuo, Ming-ming Mei, Shi-yong Guo, Liang Li, Cong-zhi Liu, Xiang Chen, and Xiu-heng Wu. "A novel coupling strategy for automated vehicle’s longitudinal dynamic stability." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 235, no. 10-11 (April 5, 2021): 2753–63. http://dx.doi.org/10.1177/09544070211006530.
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The autonomous vehicle has been developed widely, and attracted much attention of global automotive industry. Wherein, longitudinal dynamics control is one of the most crucial issues of autonomous vehicles. The throttle-by-wire (TBW) control could implement the acceleration command through adjusting the throttle opening, thus control the driving torque of the fuel autonomous vehicle. However, an automated vehicle controlled by traditional TBW in low-friction road conditions could reach large slip ratio region, which could adversely cause the loss of vehicle longitudinal dynamic stability. To tackle the mentioned issues, this paper proposes an adaptive sliding-mode control (SMC) algorithm to optimize tire slip speed of the automated vehicle. When the intervention conditions of active acceleration are satisfied, the TBW can take over the throttle opening control instead of the driver. Firstly, the SMC can calculate an intervention of the effective torque input based on tire torque balance dynamics. Moreover, a traction control system (TCS) and TBW coupling strategy based on the logic threshold method is put forward to response the optimum slip speed curve. Thus, during the vehicle starting process, a three-layer control strategy consisting of TBW, torque control, and pressure control of TCS is involved. Finally, real-car snow and ice road tests are carried out, and experimental results demonstrate great performance of the proposed strategy in complicated low-friction road.
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Chen, Zhi, Daobo Wang, Ziyang Zhen, Biao Wang, and Jian Fu. "Take-off and landing control for a coaxial ducted fan unmanned helicopter." Aircraft Engineering and Aerospace Technology 89, no. 6 (October 2, 2017): 764–76. http://dx.doi.org/10.1108/aeat-01-2016-0017.
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Purpose This paper aims to present a control strategy that eliminates the longitudinal and lateral drifting movements of the coaxial ducted fan unmanned helicopter (UH) during autonomous take-off and landing and reduce the coupling characteristics between channels of the coaxial UH for its special model structure. Design/methodology/approach Unidirectional auxiliary surfaces (UAS) for terminal sliding mode controller (TSMC) are designed for the flight control system of the coaxial UH, and a hierarchical flight control strategy is proposed to improve the decoupling ability of the coaxial UH. Findings It is demonstrated that the proposed height control strategy can solve the longitudinal and lateral movements during autonomous take-off and landing phase. The proposed hierarchical controller can decouple vertical and heading coupling problem which exists in coaxial UH. Furthermore, the confronted UAS-TSMC method can guarantee finite-time convergence and meet the quick flight trim requirements during take-off and landing. Research limitations/implications The designed flight control strategy has not implemented in real flight test yet, as all the tests are conducted in the numerical simulation and simulation with a hardware-in-the-loop (HIL) platform. Social implications The designed flight control strategy can solve the common problem of coupling characteristics between channels for coaxial UH, and it has important theoretical basis and reference value for engineering application; the control strategy can meet the demands of engineering practice. Originality/value In consideration of the TSMC approach, which can increase the convergence speed of the system state effectively, and the high level of response speed requirements to UH flight trim, the UAS-TSMC method is first applied to the coaxial ducted fan UH flight control. The proposed control strategy is implemented on the UH flight control system, and the HIL simulation clearly demonstrates that a much better performance could be achieved.
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Kim, Jinhee. "사업전략과 인사관리의 결합성이 기업성과에 미치는 효과에 대한 종단분석." Journal of the Korea Management Engineers Society 24, no. 1 (March 31, 2019): 55–72. http://dx.doi.org/10.35373/kmes.24.2.4.
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Bai, Yunlong, Gang Li, Hongyao Jin, and Ning Li. "Research on Lateral and Longitudinal Coordinated Control of Distributed Driven Driverless Formula Racing Car under High-Speed Tracking Conditions." Journal of Advanced Transportation 2022 (August 11, 2022): 1–15. http://dx.doi.org/10.1155/2022/7344044.
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Aiming at the problem that it is difficult to ensure the trajectory tracking accuracy and driving stability of the distributed driven driverless formula racing car under high-speed tracking conditions, a lateral and longitudinal coordinated control strategy is proposed. Based on the adaptive model predictive control theory, the lateral motion controller is designed, and the prediction time domain of the controller is changed in real time according to the change of vehicle speed. Based on the sliding mode variable structure control theory, a longitudinal motion controller is designed to accurately track the desired vehicle speed. Considering the coupling between the lateral and longitudinal controls, the lateral controller inputs the longitudinal speed and displacement of the vehicle, using the feedback mechanism to update the prediction model in real time, the longitudinal controller takes the front wheel angle as the input, the driving torque is redistributed through the differential drive control, and the lateral and longitudinal coordinated control is carried out to improve the trajectory tracking accuracy and driving stability. The typical working conditions are selected for co-simulation test verification. The results show that the lateral and longitudinal coordinated control strategy can effectively improve the vehicle trajectory tracking control accuracy and driving stability.
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Zhang, Sheng, and Xiangtao Zhuan. "Two-Dimensional Car-Following Control Strategy for Electric Vehicle Based on MPC and DQN." Symmetry 14, no. 8 (August 17, 2022): 1718. http://dx.doi.org/10.3390/sym14081718.
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For the coupling problem of longitudinal control and lateral control of vehicles, a two-dimensional (2-D) car-following control strategy for an electric vehicle is proposed in this paper. First, a 2-D car-following model for longitudinal following and lateral lane keeping is established. Then, a 2-D car-following control strategy is designed, and the longitudinal following control and lateral lane keeping control are integrated into one model predictive control (MPC) framework. The 2-D car-following strategy can realize the multi-objective coordinated optimization for longitudinal control and lateral control during the 2-D car-following process, and the multiple objectives are: safety, tracking, comfort, lane keeping, lateral stability and economy. In addition, the economy is important for electric vehicles. The weight matrix of the objective function in the MPC framework is symmetric, and the weight coefficients for the weight matrix have a great influence on the control. The contribution of this paper is: in order to adapt to different dynamic processes of lane keeping, the weight coefficients in the MPC framework are optimized in real-time based on the deep Q network (DQN) algorithm. Finally, to verify the 2-D car-following control strategy, a comparison strategy and two experimental scenarios are set, and simulation experiments are carried out. In scenario 1, compared with the comparison strategy, the lane keeping, lateral stability and economy of the proposed strategy are improved by 37.21%, 17.57% and 9.26%, respectively. In scenario 2, compared with the comparison strategy, the lane keeping, lateral stability and economy of the proposed strategy are improved by 36.45%, 16.66% and 18.52%, respectively. Therefore, compared with the comparison strategy, the 2-D car-following control strategy can have better lane keeping, lateral stability and economy on the premise of ensuring other performances during the 2-D car-following process.
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Wang, B., J. F. Guo, L. Yi, and W. H. Zhou. "Anti-impact tension control strategy for the space-tethered combination after target capture." Aeronautical Journal 122, no. 1257 (November 2018): 1775–87. http://dx.doi.org/10.1017/aer.2018.98.
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ABSTRACTAn electromechanical coupling model is established for the space-tethered combination (STC) under microgravity environment after target capture by the tethered robot system (TRS). A linearized dynamic model of the STC is put forward with its controllability and observability as a control system analyzed. A double closed-loop tension control strategy is proposed to mitigate the impact and suing longitudinal vibration caused by the velocity difference between the platform and target. Experiment setup is built on a ground-based flotation platform to investigate the impact of the STC. Results of simulation and experimental validation show that the proposed tension control strategy is responsive and rapid in tension tracking and effectively prevent impact.
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Ling, Hongwei, and Bin Huang. "Research on Torque Distribution of Four-Wheel Independent Drive Off-Road Vehicle Based on PRLS Road Slope Estimation." Mathematical Problems in Engineering 2021 (September 11, 2021): 1–11. http://dx.doi.org/10.1155/2021/5399588.
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In view of the high difficulty in coupling of various electric vehicle parameters, intractable parameter estimation, and unreasonable distribution of vehicle driving torque, the four-wheel hub motor is applied to drive electric vehicles, which can instantly obtain the torque and speed of the hub motor and achieve precise control of the torque of each wheel. According to the vehicle longitudinal dynamics model, a progressive RLS (PRLS) algorithm for real-time estimation of vehicle mass and road gradient is proposed. Meanwhile, by means of taking the longitudinal acceleration of the vehicle and the road gradient obtained from the estimation algorithm as the parameter of the torque distribution at the front and rear axles, a dynamic compensation and distribution control strategy of the front and rear axle torques is designed. Moreover, based on hardware-in-the-loop real-time simulation and real-vehicle tests, the effectiveness of the proposed estimation algorithm and the rationality of the real-time distribution control strategy of driving torque are verified.
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Wang, Jianfeng, Weihua Li, Jun Li, Yiqun Liu, Baoyu Song, and Haibo Gao. "Modeling a Driver’s Directional and Longitudinal Speed Control Based on Racing Track Features." Shock and Vibration 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/7487295.
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This study firstly analyses the driver’s manipulation behaviour and relates the different components of the driver model. Then, a model controlling the driver directions is built according to the prediction-follower theory with the aim of improving the point search algorithm. A model of the driving system of an electric vehicle is used to establish the longitudinal speed control model of the driver by using a feedforward-PID feedback control strategy. Our approach is to release the coupling between direction and speed control and build an integrated model that includes the direction and speed for an arbitrary path. Finally, the characteristics of an actual racing track are considered to establish the fastest driver control model. We simulated the typical operating conditions of our driver operation model. The simulation confirmed the effectiveness of the improved predictive point search algorithm and the integrated driver model to control the direction and speed for an arbitrary path.
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Olivieri, Carlo, Francesco de Paulis, Antonio Orlandi, Giorgio Giannuzzi, Roberto Salvati, Roberto Zaottini, Carlo Morandini, and Lorenzo Mocarelli. "Remote Monitoring of Joints Status on In-Service High-Voltage Overhead Lines." Energies 12, no. 6 (March 14, 2019): 1004. http://dx.doi.org/10.3390/en12061004.
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This work presents the feasibility study of an on-line monitoring technique aimed to discover unwanted variations of longitudinal impedance along the line (also named “impedance discontinuities”) and, possibly, incipient faults typically occurring on high voltage power transmission lines, like those generated by oxidated midspan joints or bolted joints usually present on such lines. In this paper, the focus is placed on the application and proper customization of a technique based on the time-domain reflectometry (TDR) technique when applied to an in-service high-voltage overhead line. An extensive set of numerical simulations are provided in order to highlight the critical points of this particular application scenario, especially those that concern the modeling of both the TDR signal injection strategy and the required high-voltage coupling devices, and to plan a measurement activity. The modeling and simulation approach followed for the study of either the overhead line or the on-line TDR system is fully detailed, discussing three main strategies. Furthermore, some measurement data that were used to characterize the specific coupling device selected for this application at high frequency—that is, a capacitive voltage transformer (CVT)—are presented and discussed too. This work sets the basic concepts underlying the implementation of an on-line remote monitoring system based on reflectometric principles for in-service lines, showing how much impact is introduced by the high-voltage coupling strategy on the amplitude of the detected reflected voltage waves (also named “voltage echoes”).
Conference papers on the topic "Longitudinal coupling strategy"
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Baheri, Ali, Joseph Deese, and Christopher Vermillion. "Combined Plant and Controller Design Using Bayesian Optimization: A Case Study in Airborne Wind Energy Systems." In ASME 2017 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/dscc2017-5242.
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This paper presents a novel data-driven nested optimization framework that aims to solve the problem of coupling between plant and controller optimization. This optimization strategy is tailored towards instances where a closed-form expression for the system dynamics is unobtainable and simulations or experiments are necessary. Specifically, Bayesian Optimization, which is a data-driven technique for finding the optimum of an unknown and expensive-to-evaluate objective function, is employed to solve the nested optimization problem. The underlying objective function is modeled by a Gaussian Process (GP); then, Bayesian Optimization utilizes the predictive uncertainty information from the GP to decide the best subsequent control or plant parameters. The proposed framework differs from the majority of co-design literature where there exists a closed-form model of the system dynamics. We validate the proposed framework for Altaeros’ Buoyant Airborne Turbine (BAT). We choose the horizontal stabilizer area and longitudinal center of mass relative to center of buoyancy (plant parameters) and the pitch angle set-point (controller parameter) as our decision variables. Our results demonstrate that plant and control parameters converge to optimal values within only a few iterations.
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Li, D. S., L. Cheng, and C. M. Gosselin. "Active Control of Sound Radiation Into Enclosures Using Structural Error Sensors." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33614.
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Active control of vibration and sound inside a structure-surrounded enclosure leads to many applications such as noise control inside vehicle cabins. Despite the extensive research carried out in the last two decades, ANVC technology is still in its infancy and has not yet been introduced massively in practical engineering applications. One of the problems to be resolved is that most of presently used techniques require the use of microphones inside the cavity, which is not practical in many situations. In addition, due to the coupling between the vibrating structure and the confined enclosure, demand for more robust control strategy is apparent. This paper tackles the aforementioned problem using a benchmark system in which only PVDF (Polymer polyvinylidene fluoride) sensors are used on the structural surface. A new method based on genetic algorithms is developed for sensor design. This design process ensures a proper consideration of the acoustic energy in the enclosure without the direct use of acoustic sensors inside the cavity. Roughly speaking, the sensor is designed to capture the most radiating motion of the structure via an automatic optimization process. In the proposed method, Genetic Algorithms and the least quadratic square optimal theory are organically combined together. For each configuration of error sensors, the amplitude of control forces, which can either be point forces or excitation generated by piezoceramic actuators, is first determined by minimizing the sum of the squared outputs of error sensors using the least quadratic square optimal theory. Then with the optimal amplitude of control forces, the acoustic potential energy of the sound cavity is computed and used as the evaluation criteria in the evolution process. Using Genetic Algorithms, the optimal configuration of the error sensors can be determined. A cylindrical shell with an internal floor partition is used as an example to illustrate the effectiveness of the proposed approach. To increase the computational efficiency, the structural surface is assumed to be covered with strip-typed PVDF sensors along both the circumferential and longitudinal directions. Both numerical and experimental results show the great effectiveness of the proposed GA-based design method. The sound reduction is achieved not only at the design frequency but also at most frequencies in the low frequency range. The proposed method demonstrates great merits in sensor design for complex structures.
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Duhr, Pol, Maximilian Schaller, Christopher H. Onder, Luca Arzilli, and Alberto Cerofolini. "Analysis of optimal energy management strategies for the hybrid electric Formula 1 car." In FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2021-adm-129.
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Contemporary Formula 1 racing cars feature a high-performance hybrid-electric powertrain. It consists of a turbocharged internal combustion engine and two electric motor-generators coupled to the engine crankshaft and the turbocharger shaft. Besides the fuel tank, the battery is a second on-board energy storage. The energy management strategy in terms of battery energy deployment must be carefully optimized in order to cover a lap on a given race circuit as fast as possible. In particular, the finite size of the battery must be taken into account, since the electric boosting and recuperation capabilities of the powertrain are restricted when the battery is depleted or fully charged, respectively. So far, this problem has scarcely been investigated in a time-optimal racing context. In this paper, we include path constraints on the battery energy trajectory in a previously developed off-line convex optimization framework that is based on a model of the powertrain and the car’s longitudinal dynamics. The resulting minimum lap time problem is formulated as a second-order cone program and is solved numerically with global optimality guarantees. With this tool, we conduct a case study for a sweep of initial conditions on the battery state-of-charge and different charge or discharge targets over the lap. Thereby, we study the optimal solution to the energy management problem when either the lower or the upper bound on the battery state-of-charge is attained. First, we show that the optimal operating strategy differs substantially for these two cases: Whilst it is optimal to hit the upper bound only in one particular time instant and then discharge the battery again, the battery state-of-charge can be kept at the lower bound for prolonged sections of the lap. We highlight that these differences are related to the particular topology of the Formula 1 power unit, and in particular to the interaction between the two motor-generator units. Second, based on Pontryagin’s minimum principle, we analyze the trajectory of the costate variable associated with the battery state-of-charge. Indeed, the costate variables are crucial for the parameterization of optimal control policies that can be implemented on the car for on-line control. Our findings show that the impact of battery deployment on the achievable lap time, and therefore the structure of the optimal control policy, varies over the course of the lap. In fact, the changes in the battery costate variable are linked to the limits on electric boosting and recuperation imposed by the Formula 1 regulations. The results underline the importance of considering all the relevant cross-couplings in this complex hybridized powertrain.