Pub Date : 2024-01-11DOI: 10.1177/09544070231220750
Jiawei Zhao, Wei Du, Honglin Xiang, Lei Gu
To improve the thermal uniformity of power battery packs for electric vehicles, three different cooling water cavities of battery packs are researched in this study: the series one-way flow corrugated flat tube cooling structure (Model 1), the series two-way flow corrugated flat tube cooling structure (Model 2), and the parallel sandwich cooling structure (Model 3). Based on the fluid-solid coupling method, this study analyzes the cooling performance of the three models, including thermal uniformity, heat dissipation, and pressure loss. At a high discharge rate, compared with the series cooling system, the parallel sandwich cooling system makes the average temperature and maximum temperature of the battery pack decrease by 26.2% and 26.9% respectively, and the battery pack temperature difference decreases by 62%, and the coolant pressure loss decreases by 95.8%. The results show that the Model 3 overcomes the temperature accumulation caused by the series flow of coolant and achieves a better level of thermal uniformity while improving the heat dissipation and pressure loss performance. The research provides scholars and industries with a reference for upgrading thermal management and improving the stability of the power battery pack for electric vehicles, which has both theoretical and practical significance.
{"title":"Heat transfer characteristics of liquid cooling system for lithium-ion battery pack","authors":"Jiawei Zhao, Wei Du, Honglin Xiang, Lei Gu","doi":"10.1177/09544070231220750","DOIUrl":"https://doi.org/10.1177/09544070231220750","url":null,"abstract":"To improve the thermal uniformity of power battery packs for electric vehicles, three different cooling water cavities of battery packs are researched in this study: the series one-way flow corrugated flat tube cooling structure (Model 1), the series two-way flow corrugated flat tube cooling structure (Model 2), and the parallel sandwich cooling structure (Model 3). Based on the fluid-solid coupling method, this study analyzes the cooling performance of the three models, including thermal uniformity, heat dissipation, and pressure loss. At a high discharge rate, compared with the series cooling system, the parallel sandwich cooling system makes the average temperature and maximum temperature of the battery pack decrease by 26.2% and 26.9% respectively, and the battery pack temperature difference decreases by 62%, and the coolant pressure loss decreases by 95.8%. The results show that the Model 3 overcomes the temperature accumulation caused by the series flow of coolant and achieves a better level of thermal uniformity while improving the heat dissipation and pressure loss performance. The research provides scholars and industries with a reference for upgrading thermal management and improving the stability of the power battery pack for electric vehicles, which has both theoretical and practical significance.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139438147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The powertrain is a core component of military heavy tracked vehicles, and the accurate evaluation of its reliability and health is gradually becoming a key technology to improve our military combat effectiveness. However, the powertrain is a complex system integrating mechanical, electrical, and hydraulic components, which is difficult to achieve its accurate assessment and comprehensive characterization. Therefore, using data-driven and expert opinion fusion method to evaluate the mechanical system health is gradually becoming a research trend. This paper points out the composition of evaluation system, and puts forward how to calculate the index. Then using subjective and objective fusion method to analyze these indexes of mechanical system health and calculate the weights of each index. Based on the weights, the fuzzy comprehensive evaluation method is used to score and summarize the change law of mechanical system health. In conclusion, this study enriches the method of effectively evaluating the mechanical system health, and verifies the accuracy of this evaluation method. It will provide an evaluation basis for improving the mechanical system reliability.
{"title":"Investigation on the health evaluation of mechanical system in powertrain based on subjective and objective fusion method","authors":"Jianpeng Wu, Jian Yang, Yuxin Wang, Liyong Wang, Ruihan Chen","doi":"10.1177/09544070231212531","DOIUrl":"https://doi.org/10.1177/09544070231212531","url":null,"abstract":"The powertrain is a core component of military heavy tracked vehicles, and the accurate evaluation of its reliability and health is gradually becoming a key technology to improve our military combat effectiveness. However, the powertrain is a complex system integrating mechanical, electrical, and hydraulic components, which is difficult to achieve its accurate assessment and comprehensive characterization. Therefore, using data-driven and expert opinion fusion method to evaluate the mechanical system health is gradually becoming a research trend. This paper points out the composition of evaluation system, and puts forward how to calculate the index. Then using subjective and objective fusion method to analyze these indexes of mechanical system health and calculate the weights of each index. Based on the weights, the fuzzy comprehensive evaluation method is used to score and summarize the change law of mechanical system health. In conclusion, this study enriches the method of effectively evaluating the mechanical system health, and verifies the accuracy of this evaluation method. It will provide an evaluation basis for improving the mechanical system reliability.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139438191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-11DOI: 10.1177/09544070231225506
Inhwan Han
The backward behavior of tractor-semitrailer vehicles is particularly challenging compared to passenger vehicles, causing many difficulties not only for drivers but also for autonomous driving. Offset backing, which is one of the most important backward scenarios for articulated vehicles, can be applied to various path planning in a confined space, such as parking, and can be used for Advanced Driver Assistance Systems (ADAS) and autonomous driving. First of all, by analyzing the slow movement of a tractor-semitrailer vehicle in a confined space, standard unit motions and compound motions for general posture adjustment were defined. By approximating the offset backing driving paths of expert tractor-semitrailer drivers with a geometric method, qualitative path planning was completed by combining compound and unit motions. In addition, complementary motions were added to respond to errors that occur due to the simplicity of the qualitative path planning based on the geometric method. The usefulness of the developed offset backing path planning for tractor-semitrailer vehicles was demonstrated through repeated experimental tests with a model autonomous vehicle.
{"title":"Offset backing path planning of tractor-semitrailer vehicles based on qualitative rules and geometric methods considering uncertainties","authors":"Inhwan Han","doi":"10.1177/09544070231225506","DOIUrl":"https://doi.org/10.1177/09544070231225506","url":null,"abstract":"The backward behavior of tractor-semitrailer vehicles is particularly challenging compared to passenger vehicles, causing many difficulties not only for drivers but also for autonomous driving. Offset backing, which is one of the most important backward scenarios for articulated vehicles, can be applied to various path planning in a confined space, such as parking, and can be used for Advanced Driver Assistance Systems (ADAS) and autonomous driving. First of all, by analyzing the slow movement of a tractor-semitrailer vehicle in a confined space, standard unit motions and compound motions for general posture adjustment were defined. By approximating the offset backing driving paths of expert tractor-semitrailer drivers with a geometric method, qualitative path planning was completed by combining compound and unit motions. In addition, complementary motions were added to respond to errors that occur due to the simplicity of the qualitative path planning based on the geometric method. The usefulness of the developed offset backing path planning for tractor-semitrailer vehicles was demonstrated through repeated experimental tests with a model autonomous vehicle.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139626912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.1177/09544070231209796
Bo Wang, Bing Lu, Wenyi Huang, Chao Sun, Pingping Lu
The instantaneous vehicle turn center is of great significance in the design and analysis of vehicle steering and handling. Due to the influences of vehicle flexible components, the vehicle turn center is not intersected at one point and the traditional determination method for vehicle turn center is not applicable for multi-axle vehicles. In this paper, a novel instantaneous tire turn center (TTC) method is proposed to estimate the instantaneous vehicle turn center to provide a guidance for the design of vehicle steering and analysis of handling. The motivation of the tire turn center concept is introduced and the calculation method is developed. The instantaneous vehicle turn center is estimated based on the calculation of instantaneous TTC. The estimation results of the vehicle turn center of a two-axle vehicle and a three-axle off-road vehicle under different vehicle velocities and lateral accelerations during steering are presented based on the vehicle dynamics models built by ADAMS software. Since there is no simplifications of the vehicle in the proposed estimation method, the determined instantaneous vehicle turn center is more accurate and can reflect the actual vehicle motion better as compared to the traditional vehicle turn center in transient motion process. The estimated instantaneous vehicle turn center provides a guidance for design and optimization of vehicle steering as well as steering angles control strategies to make all tire turn centers controlled at the instantaneous vehicle turn center, thus reducing tire wears and improving the whole vehicle steering coordination performance.
{"title":"An estimation method for dynamic vehicle turn center","authors":"Bo Wang, Bing Lu, Wenyi Huang, Chao Sun, Pingping Lu","doi":"10.1177/09544070231209796","DOIUrl":"https://doi.org/10.1177/09544070231209796","url":null,"abstract":"The instantaneous vehicle turn center is of great significance in the design and analysis of vehicle steering and handling. Due to the influences of vehicle flexible components, the vehicle turn center is not intersected at one point and the traditional determination method for vehicle turn center is not applicable for multi-axle vehicles. In this paper, a novel instantaneous tire turn center (TTC) method is proposed to estimate the instantaneous vehicle turn center to provide a guidance for the design of vehicle steering and analysis of handling. The motivation of the tire turn center concept is introduced and the calculation method is developed. The instantaneous vehicle turn center is estimated based on the calculation of instantaneous TTC. The estimation results of the vehicle turn center of a two-axle vehicle and a three-axle off-road vehicle under different vehicle velocities and lateral accelerations during steering are presented based on the vehicle dynamics models built by ADAMS software. Since there is no simplifications of the vehicle in the proposed estimation method, the determined instantaneous vehicle turn center is more accurate and can reflect the actual vehicle motion better as compared to the traditional vehicle turn center in transient motion process. The estimated instantaneous vehicle turn center provides a guidance for design and optimization of vehicle steering as well as steering angles control strategies to make all tire turn centers controlled at the instantaneous vehicle turn center, thus reducing tire wears and improving the whole vehicle steering coordination performance.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139442984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.1177/09544070231215636
S. Yahagi, Itsuro Kajiwara
Lateral vehicle dynamics control is important for autonomous driving. This paper presents a data-driven design of model-referenced model-free control (DD-MR-MFC) based on an ultra-local model for vehicle yaw rate control. The characteristics of lateral vehicle dynamics systems depend on vehicle velocities and weights. For this system, fixed proportional–integral–derivative (PID) controllers cannot provide the desired control performance. Additionally, although model-based control can be applied to lateral vehicle dynamics, the modeling process is time-consuming. To efficiently design controllers that can realize the desired performance, we adopt a model-free approach. In this study, the control law of practical MR-MFC is derived by extending the traditional MFC based on an ultra-local model and using a data-driven design method. The MFC approach can be applied to nonlinear systems with few parameters, and the data-driven method provides optimized parameters from single-experiment time-series data without the need for repeated experiments and system model to be controlled. Additionally, the processing cost is considerably low because the controller parameter can be obtained using least-square methods. The effectiveness of the proposed method is verified using a multibody vehicle simulator. The yaw rate tracking performance is examined under different velocities and loads. Results showed that the root-mean-square error of the proposed method is approximately 1/100th of that when using a fixed PID controller optimized using a data-driven method.
{"title":"Data-driven design of model-free control for reference model tracking based on an ultra-local model: Application to vehicle yaw rate control","authors":"S. Yahagi, Itsuro Kajiwara","doi":"10.1177/09544070231215636","DOIUrl":"https://doi.org/10.1177/09544070231215636","url":null,"abstract":"Lateral vehicle dynamics control is important for autonomous driving. This paper presents a data-driven design of model-referenced model-free control (DD-MR-MFC) based on an ultra-local model for vehicle yaw rate control. The characteristics of lateral vehicle dynamics systems depend on vehicle velocities and weights. For this system, fixed proportional–integral–derivative (PID) controllers cannot provide the desired control performance. Additionally, although model-based control can be applied to lateral vehicle dynamics, the modeling process is time-consuming. To efficiently design controllers that can realize the desired performance, we adopt a model-free approach. In this study, the control law of practical MR-MFC is derived by extending the traditional MFC based on an ultra-local model and using a data-driven design method. The MFC approach can be applied to nonlinear systems with few parameters, and the data-driven method provides optimized parameters from single-experiment time-series data without the need for repeated experiments and system model to be controlled. Additionally, the processing cost is considerably low because the controller parameter can be obtained using least-square methods. The effectiveness of the proposed method is verified using a multibody vehicle simulator. The yaw rate tracking performance is examined under different velocities and loads. Results showed that the root-mean-square error of the proposed method is approximately 1/100th of that when using a fixed PID controller optimized using a data-driven method.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139443011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.1177/09544070231214333
Wei Yang, Yingfeng Cai, Xiaoqiang Sun, Youguo He, C. Yuan, Hai Wang, Long Chen
The autonomous vehicles make decisions and plans based on the environmental perception and generate the target command of the control layer. The vehicle dynamics model is an important factor that affects the vehicle control. The dynamic mechanism model has strong interpretability and good stability. However, in extreme conditions, the model accuracy is reduced due to the tire entering the nonlinear region. The data-driven dynamic model achieves high modeling accuracy. However, due to the lack of physical constraints and rationality in the data-driven models, the interpretability and stability of the control is reduced, which in turn increases the unpredictable risk in the driving process. This paper innovatively proposes a deep Lagrangian neural network dynamics model (DeLaN) for autonomous vehicles based on the Lagrangian mechanics and uses a neural network to encode the differential equations. This not only retains the interpretability of the physical model but also makes full use of the learning ability and fitting ability of the neural network to effectively capture the complex dynamic characteristics of the vehicle. To improve the robustness of the control system, this work uses DeLaN as feed-forward control and preview error feedback control to form a closed loop of trajectory tracking control for autonomous vehicles. The experimental results show that the trajectory tracking error of the proposed DeLaN is significantly reduced, the yaw stability and comfort are significantly improved, good longitudinal and lateral cooperative control performance is achieved, and the physical rationality of the neural network is also improved. Therefore, the proposed DeLaN has important engineering application value.
{"title":"Trajectory tracking control of autonomous vehicles based on Lagrangian neural network dynamics model","authors":"Wei Yang, Yingfeng Cai, Xiaoqiang Sun, Youguo He, C. Yuan, Hai Wang, Long Chen","doi":"10.1177/09544070231214333","DOIUrl":"https://doi.org/10.1177/09544070231214333","url":null,"abstract":"The autonomous vehicles make decisions and plans based on the environmental perception and generate the target command of the control layer. The vehicle dynamics model is an important factor that affects the vehicle control. The dynamic mechanism model has strong interpretability and good stability. However, in extreme conditions, the model accuracy is reduced due to the tire entering the nonlinear region. The data-driven dynamic model achieves high modeling accuracy. However, due to the lack of physical constraints and rationality in the data-driven models, the interpretability and stability of the control is reduced, which in turn increases the unpredictable risk in the driving process. This paper innovatively proposes a deep Lagrangian neural network dynamics model (DeLaN) for autonomous vehicles based on the Lagrangian mechanics and uses a neural network to encode the differential equations. This not only retains the interpretability of the physical model but also makes full use of the learning ability and fitting ability of the neural network to effectively capture the complex dynamic characteristics of the vehicle. To improve the robustness of the control system, this work uses DeLaN as feed-forward control and preview error feedback control to form a closed loop of trajectory tracking control for autonomous vehicles. The experimental results show that the trajectory tracking error of the proposed DeLaN is significantly reduced, the yaw stability and comfort are significantly improved, good longitudinal and lateral cooperative control performance is achieved, and the physical rationality of the neural network is also improved. Therefore, the proposed DeLaN has important engineering application value.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139443304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.1177/09544070231214829
Limei Liu, Wenjie Li
This paper studies the modeling and stability analysis of an extended car-following model based on delay of response and signal interruption probability. First, by linear analysis, we give the stability condition of the model. The result shows that the stability region of the traffic flow will expand with the decrease in the probability p of signal transmission interruption. When the delay of response effect of the driver weakens, the traffic flow will become more and more stable. Second, the mKdV equation is derived based on the nonlinear reduction perturbation method. This result shows that with the decrease of parameter p, the amplitude of the traffic flow density wave decreases, the traffic flow becomes more and more stable, and the traffic congestion is gradually improved. Finally, numerical simulation verifies the correctness of the solution results.
本文研究了基于响应延迟和信号中断概率的扩展汽车跟随模型的建模和稳定性分析。首先，通过线性分析，我们给出了模型的稳定性条件。结果表明，随着信号传输中断概率 p 的减小，交通流的稳定区域将扩大。当驾驶员反应延迟效应减弱时，交通流将变得越来越稳定。其次，基于非线性还原扰动法推导出 mKdV 方程。结果表明，随着参数 p 的减小，交通流密度波的振幅减小，交通流变得越来越稳定，交通拥堵状况逐渐得到改善。最后，数值模拟验证了求解结果的正确性。
{"title":"Modeling and stability analysis of an extended car-following model behavior of the currents vehicle based on delay of response and signal interruption probability","authors":"Limei Liu, Wenjie Li","doi":"10.1177/09544070231214829","DOIUrl":"https://doi.org/10.1177/09544070231214829","url":null,"abstract":"This paper studies the modeling and stability analysis of an extended car-following model based on delay of response and signal interruption probability. First, by linear analysis, we give the stability condition of the model. The result shows that the stability region of the traffic flow will expand with the decrease in the probability p of signal transmission interruption. When the delay of response effect of the driver weakens, the traffic flow will become more and more stable. Second, the mKdV equation is derived based on the nonlinear reduction perturbation method. This result shows that with the decrease of parameter p, the amplitude of the traffic flow density wave decreases, the traffic flow becomes more and more stable, and the traffic congestion is gradually improved. Finally, numerical simulation verifies the correctness of the solution results.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139443204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.1177/09544070231209395
Qitong Chen, Zhao Dong, Cong-zhi Liu, Liang Li
In this paper, a safety-guaranteed game-theoretical velocity planning framework in a hierarchical manner is proposed to generate safe, ride comfort, and travel efficiency-balanced velocity for autonomous vehicles (AVs). In the upper layer, a bang-bang decision-making method is utilized to determine which planning mode to be implemented based on acceleration and jerk constraints, including a comfort mode, an efficiency mode, and a game mode. In the lower layer, asymmetric jerk limits based on comfort characteristics sensibility analysis and safe velocity simultaneously considering longitudinal and lateral stability are firstly developed to maintain ride comfort and driving safety, respectively on curve roads, especially sharp curves where vehicle stability may be not fully considered in most researches. Based on these, a non-cooperative game-theoretical velocity planning method is presented to solve the conflict between comfort mode and efficiency mode by optimizing his own objective based on the other’s action. Finally, for the sake of solving efficiency and accuracy, a chaos optimization-based algorithm (COA) is designed to solve for the Stackelberg equilibrium solution of the bilevel game optimization problem. Three experimental tests are carried out to comprehensively demonstrate the effectiveness, robustness, and real time of the proposed framework. The results show that the proposed method can provide the great performance of ride comfort, travel efficiency, and longitudinal-lateral stability in real time in the velocity planning process.
{"title":"A safety-guaranteed game-theoretical velocity planning for autonomous vehicles on sharp curve roads","authors":"Qitong Chen, Zhao Dong, Cong-zhi Liu, Liang Li","doi":"10.1177/09544070231209395","DOIUrl":"https://doi.org/10.1177/09544070231209395","url":null,"abstract":"In this paper, a safety-guaranteed game-theoretical velocity planning framework in a hierarchical manner is proposed to generate safe, ride comfort, and travel efficiency-balanced velocity for autonomous vehicles (AVs). In the upper layer, a bang-bang decision-making method is utilized to determine which planning mode to be implemented based on acceleration and jerk constraints, including a comfort mode, an efficiency mode, and a game mode. In the lower layer, asymmetric jerk limits based on comfort characteristics sensibility analysis and safe velocity simultaneously considering longitudinal and lateral stability are firstly developed to maintain ride comfort and driving safety, respectively on curve roads, especially sharp curves where vehicle stability may be not fully considered in most researches. Based on these, a non-cooperative game-theoretical velocity planning method is presented to solve the conflict between comfort mode and efficiency mode by optimizing his own objective based on the other’s action. Finally, for the sake of solving efficiency and accuracy, a chaos optimization-based algorithm (COA) is designed to solve for the Stackelberg equilibrium solution of the bilevel game optimization problem. Three experimental tests are carried out to comprehensively demonstrate the effectiveness, robustness, and real time of the proposed framework. The results show that the proposed method can provide the great performance of ride comfort, travel efficiency, and longitudinal-lateral stability in real time in the velocity planning process.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139444529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To solve the problem of large fluctuation of vehicle following distance in cooperative adaptive cruise control (CACC), a distributed model predictive control (DMPC) strategy is proposed. The idea of hierarchical control is performed to control the CACC system. The controller is divided into an upper controller and a lower controller. The upper controller calculates the expected acceleration of the vehicle according to the platooning state, and the lower controller controls the throttle and braking system pressure of the vehicle according to the expected acceleration. Firstly, the longitudinal dynamic model of vehicle platooning is established. Secondly, the objective function is designed according to the control objectives, so that the platooning can obtain the optimal control quantity at the current time. Meanwhile, the robust design is used to improve the controller performance, and the optimization of reference trajectory and the extension of feasible domain are used to improve the stability of the controller. Car-following Stability therefore can be improved. Then the lower controller is designed based on a reverse engine model and a reverse braking model. Finally, the effectiveness of the designed control strategy is verified by the co-simulation of Carsim and MATLAB/Simulink. The results show that DMPC can reduce the peak value, the standard deviation, and the root mean square of vehicle following distance error and improve the following stability.
{"title":"Car-following stability improvement of cooperative adaptive cruise control based on distributed model predictive control","authors":"Yiping Wang, Shixuan Wang, Chuqi Su, Xueyun Li, Qianwen Zhang, Zhentao Zhang, Mohan Tian","doi":"10.1177/09544070231211377","DOIUrl":"https://doi.org/10.1177/09544070231211377","url":null,"abstract":"To solve the problem of large fluctuation of vehicle following distance in cooperative adaptive cruise control (CACC), a distributed model predictive control (DMPC) strategy is proposed. The idea of hierarchical control is performed to control the CACC system. The controller is divided into an upper controller and a lower controller. The upper controller calculates the expected acceleration of the vehicle according to the platooning state, and the lower controller controls the throttle and braking system pressure of the vehicle according to the expected acceleration. Firstly, the longitudinal dynamic model of vehicle platooning is established. Secondly, the objective function is designed according to the control objectives, so that the platooning can obtain the optimal control quantity at the current time. Meanwhile, the robust design is used to improve the controller performance, and the optimization of reference trajectory and the extension of feasible domain are used to improve the stability of the controller. Car-following Stability therefore can be improved. Then the lower controller is designed based on a reverse engine model and a reverse braking model. Finally, the effectiveness of the designed control strategy is verified by the co-simulation of Carsim and MATLAB/Simulink. The results show that DMPC can reduce the peak value, the standard deviation, and the root mean square of vehicle following distance error and improve the following stability.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139444571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wheel cylinder pressure (WCP) is a crucial state for vehicles, directly influencing safety, comfort, and fuel economy. Serving as the foundation for sensor-less control and sensor redundancy, WCP estimation is a promising work for brake-by-wire systems (BBW). Nevertheless, WCP estimation is a challenging problem due to the nonlinear characteristics and intricate coupling within the hydraulic control unit (HCU). To enhance the performance of BBW, this paper proposes a comprehensive WCP estimation scheme based on the systematic HCU model. Component models including direct current (DC) motor pump and normally open valve (NOV) are established first. Considering the pulsation of the plunger pump, a modified nonlinear observer (MNO) is used to observe the angular speed of the DC motor. Inspired by the critical state, the linear pressure-drop relationship of NOV is analyzed and the NOV is simplified as a relief valve model expressed by algebraic equations. Dividing the HCU into the pump front part, pump rear part, and cylinder part, the systematic HCU model is then established, based on which, the comprehensive cause-based WCP estimation scheme is proposed. Next, simulations utilizing Amesim validate the angular speed estimator, while bench experiments prove the NOV model. Finally, vehicle tests under active and passive pressure regulating conditions are conducted. The results indicate the proposed scheme exhibits satisfactory performance while preserving computational efficiency.
车轮气缸压力（WCP）是车辆的关键状态，直接影响车辆的安全性、舒适性和燃油经济性。作为无传感器控制和传感器冗余的基础，WCP 估计是线控制动系统（BBW）的一项前景广阔的工作。然而，由于液压控制单元（HCU）内的非线性特性和复杂耦合，WCP 估计是一个具有挑战性的问题。为了提高 BBW 的性能，本文提出了一种基于系统化 HCU 模型的综合 WCP 估算方案。首先建立了包括直流（DC）电机泵和常开阀（NOV）在内的组件模型。考虑到柱塞泵的脉动，采用改进的非线性观测器（MNO）来观测直流电机的角速度。受临界状态的启发，分析了 NOV 的线性压降关系，并将 NOV 简化为一个用代数方程表示的溢流阀模型。然后将 HCU 分成泵前部、泵后部和气缸部，建立了系统的 HCU 模型，并在此基础上提出了基于原因的 WCP 综合估算方案。接下来，利用 Amesim 进行仿真验证了角速度估算器，而台架实验则证明了 NOV 模型。最后，进行了主动和被动压力调节条件下的车辆测试。结果表明，所提出的方案在保持计算效率的同时，表现出令人满意的性能。
{"title":"Comprehensive wheel cylinder pressure estimation based on systematic hydraulic control unit model","authors":"Yicai Liu, Lingtao Wei, Dong Shao, Zhentao Chen, Xiang-yu Wang, Liang Li","doi":"10.1177/09544070231215684","DOIUrl":"https://doi.org/10.1177/09544070231215684","url":null,"abstract":"Wheel cylinder pressure (WCP) is a crucial state for vehicles, directly influencing safety, comfort, and fuel economy. Serving as the foundation for sensor-less control and sensor redundancy, WCP estimation is a promising work for brake-by-wire systems (BBW). Nevertheless, WCP estimation is a challenging problem due to the nonlinear characteristics and intricate coupling within the hydraulic control unit (HCU). To enhance the performance of BBW, this paper proposes a comprehensive WCP estimation scheme based on the systematic HCU model. Component models including direct current (DC) motor pump and normally open valve (NOV) are established first. Considering the pulsation of the plunger pump, a modified nonlinear observer (MNO) is used to observe the angular speed of the DC motor. Inspired by the critical state, the linear pressure-drop relationship of NOV is analyzed and the NOV is simplified as a relief valve model expressed by algebraic equations. Dividing the HCU into the pump front part, pump rear part, and cylinder part, the systematic HCU model is then established, based on which, the comprehensive cause-based WCP estimation scheme is proposed. Next, simulations utilizing Amesim validate the angular speed estimator, while bench experiments prove the NOV model. Finally, vehicle tests under active and passive pressure regulating conditions are conducted. The results indicate the proposed scheme exhibits satisfactory performance while preserving computational efficiency.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139444111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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