制动与转向协调动作的车辆避撞控制研究
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摘要
为了弥补现有汽车避撞控制策略以及碰撞风险评价指标单一的不足,提出转向和制动协调的主动避撞控制系统。首先规划了五次多项式换道路径,在对其理论分析的基础上得到转向临界避撞距离和与目标车道车辆的安全距离约束。其次,考虑道路附着系数和系统延迟的影响,基于制动过程给出制动临界避撞距离,并以纵向行驶安全系数ξ和碰撞时间倒数T■划分安全行驶区域,利用驾驶人实车跟车数据标定稳态跟随/定速巡航区域的阈值。随后,通过转向/制动临界避撞距离的对比给出2种避撞方式的安全收益范围。最后搭建Simulink/CarSim联合仿真模型,并对其进行不同初始条件下的避撞仿真试验。研究结果表明:转向操作在制动距离不足时仍是有效的;当主车高速近距离接近静止前车时,主车可以顺利采取转向换道动作,而常规ACC系统在2.5 s处的车间相对距离为-0.76 m,事实上已经发生了碰撞;当相邻车道前车与主车纵向间距不满足换道安全距离约束时,避撞控制系统进入紧急制动模式,最大制动减速度达到-0.8g(g为重力加速度),实际最小车间距为5.1 m;通过转向和制动的协调动作,充分发挥了车辆的避撞潜力;ξ和T■指标的融合,可以更好地评估碰撞风险并实现不同控制模式的转换,在保证行车安全的同时可避免过分制动给乘客造成的紧张感。
The existing strategy of vehicle collision avoidance separates steering and braking operations from each other. To compensate for the deficiency, we proposed an active collision avoidance system that integrates both steering and braking operation in this paper. Firstly, this paper gives the lane change reference path using a fifth polynomial function. Based on this theoretical analysis, the steering critical distance and lane change safety constraints were obtained. Secondly, considering the influence of the road adhesion coefficient and the system delay, the critical braking distance was deduced, based on the braking process. The safe driving range is divided by the warning index ξ and T■, and the thresholds of the steady follow/constant speed cruise area were calibrated by actual driving data. Subsequently, the safety benefits of the two collision avoidance methods were provided by comparing the critical steering/braking distances. Finally, the Simulink/CarSim co-simulation model was constructed, and the collision avoidance simulation test under different initial conditions was conducted. The test results demonstrate that steering operation is still applicable when the braking distance is insufficient. When the ego vehicle approaches the stationary lead vehicle at a high speed, the ego vehicle can smoothly take a steering lane change action, while the typical ACC system has a relative distance of-0.76 m at 2.5 s. Therefore, the collision has already occurred. When the longitudinal distance between the ego and lead vehicles cannot meet the lane change safety constraints, the active collision avoidance system adopts an emergency braking control strategy with the maximum deceleration being nearly-0.8g, and the actual minimum vehicle clearance was 5.1 m. Through the coordinated actions of steering and braking, the collision avoidance potential of the vehicle is significantly exerted. In addition, the combination of the warning index ξ and T■ can better realize the conversion of different control modes, while ensuring the safety of driving and mitigating the driving tension caused by excessive braking.
The existing strategy of vehicle collision avoidance separates steering and braking operations from each other. To compensate for the deficiency, we proposed an active collision avoidance system that integrates both steering and braking operation in this paper. Firstly, this paper gives the lane change reference path using a fifth polynomial function. Based on this theoretical analysis, the steering critical distance and lane change safety constraints were obtained. Secondly, considering the influence of the road adhesion coefficient and the system delay, the critical braking distance was deduced, based on the braking process. The safe driving range is divided by the warning index ξ and T■, and the thresholds of the steady follow/constant speed cruise area were calibrated by actual driving data. Subsequently, the safety benefits of the two collision avoidance methods were provided by comparing the critical steering/braking distances. Finally, the Simulink/CarSim co-simulation model was constructed, and the collision avoidance simulation test under different initial conditions was conducted. The test results demonstrate that steering operation is still applicable when the braking distance is insufficient. When the ego vehicle approaches the stationary lead vehicle at a high speed, the ego vehicle can smoothly take a steering lane change action, while the typical ACC system has a relative distance of-0.76 m at 2.5 s. Therefore, the collision has already occurred. When the longitudinal distance between the ego and lead vehicles cannot meet the lane change safety constraints, the active collision avoidance system adopts an emergency braking control strategy with the maximum deceleration being nearly-0.8g, and the actual minimum vehicle clearance was 5.1 m. Through the coordinated actions of steering and braking, the collision avoidance potential of the vehicle is significantly exerted. In addition, the combination of the warning index ξ and T■ can better realize the conversion of different control modes, while ensuring the safety of driving and mitigating the driving tension caused by excessive braking.
引文
[1] 《中国公路学报》编辑部.中国汽车工程学术研究综述·2017[J].中国公路学报,2017,30(6):1-197. Editorial Department of China Journal of Highway and Transport. Review on China's Automotive Engineering Research Progress: 2017 [J]. China Journal of Highway and Transport, 2017, 30 (6): 1-197.
[2] 裴晓飞,齐志权,王保锋,等.汽车前向主动报警/避撞策略[J].吉林大学学报:工学版,2014,44(3):599-604. PEI Xiao-fei, QI Zhi-quan, WANG Bao-feng, et al. Vehicle Frontal Collision Warning/Avoidance Strategy [J].Journal of Jilin University: Engineering and Technology Edition, 2014, 44 (3): 599-604.
[3] 章军辉,李庆,陈大鹏.基于 BP 神经网络的纵向避撞安全辅助算法[J].西安交通大学学报,2017,51 (7):140-147. ZHANG Jun-hui, LI Qing, CHEN Da-peng. Safety Assistance Algorithm for Longitudinal Collision Avoidance Based on BP Neural Network [J]. Journal of Xi'an Jiaotong University, 2017, 51 (7): 140-147.
[4] BRANNSTROM M, COELINGH E, SJOBERG J. Model-based Threat Assessment for Avoiding Arbitrary Vehicle Collisions [J]. IEEE Transactions on Intelligent Transportation Systems, 2010, 11 (3): 658-669.
[5] 朱西产,刘智超,李霖.基于车辆与行人危险工况的转向避撞控制策略[J].汽车安全与节能学报,2015,6(3):217-223. ZHU Xi-chan, LIU Zhi-chao, LI Lin. Evasive Maneuvre for Emergency Steering Based on Typical Vehicle-pedestrian Use Case [J]. Journal of Automotive Safety and Energy, 2015, 6 (3): 217-223.
[6] GUO J, HU P, WANG R. Nonlinear Coordinated Steering and Braking Control of Vision-based Autonomous Vehicles in Emergency Obstacle Avoidance [J]. IEEE Transactions on Intelligent Transportation Systems, 2016, 17 (11): 3230-3240.
[7] LIU J, JAYAKUMAR P, STEIN J, et al. Combined Speed and Steering Control in High Speed Autonomous Ground Vehicles for Obstacle Avoidance Using Model Predictive Control [J]. IEEE Transactions on Vehicular Technology, 2017, 66 (10): 8746-8763.
[8] 田彦涛,王晓玉,胡蕾蕾,等.电动汽车侧向换道行驶主动避撞控制算法[J].吉林大学学报:工学版,2016,46(5):1587-1594. TIAN Yan-tao, WANG Xiao-yu, HU Lei-lei, et al. Active Collision Avoidance Algorithm In Electric Vehicle Lateral Lane Change [J].Journal of Jilin University: Engineering and Technology Edition, 2016, 46 (5): 1587-1594.
[9] JANSSON J, JOHANSSON J, GUSTAFSSONF. Decision Making for Collision Avoidance Systems [J]. SAE Paper 2002-01-0403.
[10] 裴晓飞,刘昭度,马国成,等.汽车主动避撞系统的安全距离模型和目标检测算法[J].汽车安全与节能学报,2012,3(1):26-33. PEI Xiao-fei, LIU Zhao-du, MA Guo-cheng, et al. Safe Distance Model and Obstacle Detection Algorithm for a Collision Warning and Collision Avoidance System [J]. Journal of Automotive Safety and Energy, 2012, 3 (1): 26-33.
[11] VN UNEN E, ESPOSTO F, SABERI A K, et al. Evaluation of Safety Indicators for Truck Platooning [C]// IEEE.Intelligent Vehicles Symposium (IV). New York: IEEE, 2017: 1013-1018.
[12] JIANG X, WANG W,BENGLER K. Intercultural Analyses of Time-to-collision in Vehicle-pedestrian Conflict on an Urban Midblock Crosswalk [J]. IEEE Transactions on Intelligent Transportation Systems, 2015, 16 (2): 1048-1053.
[13] COELINGH E, EIDEHALL A, BENGTSSON M. Collision Warning With Full Auto Brake and Pedestrian Detection-A Practical Example of Automatic Emergency Braking [C]// IEEE. 13th International IEEE Conference on Intelligent Transportation Systems (ITSC). New York: IEEE, 2010: 155-160.
[14] 贺锦鹏,马芳武,刘卫国,等.汽车前碰撞预警系统 ISO 15623 标准和 NHTSA 26555 评价规程对比试验[J].汽车技术,2014(7):28-33. HE Jin-peng, MA Fang-wu, LIU Wei-guo, et al. Comparative Test Between ISO 15623 on Forward Vehicle Collision Warning System and NHTSA 26555 Assessment Program [J].Automotive Technology, 2014 (7): 28-33.
[15] CHEN S L, CHENG C Y,HU J S, et al. Strategy and Evaluation of Vehicle Collision Avoidance Control via Hardware-in-the-Loop Platform [J]. Applied Sciences, 2016, 6 (11): 327-337.
[16] 李霖,朱西产,陈海林.驾驶员制动和转向避撞极限[J].同济大学学报:自然科学版,2016,44(11):1743-1748. LI Lin, ZHU Xi-chan, CHEN Hai-lin. Driver's Collision Avoidance Limit by Braking and Steering [J].Journal of Tongji University: Natural Science, 2016, 44 (11): 1743-1748.
[17] YI K, DO KWON Y. Vehicle-to-vehicle Distance and Speed Control Using an Electronic-vacuum Booster [J]. JSAE Review, 2001, 22 (4): 403-412.
[18] MAZRTENSSON J, NYBACKA M, JERRELIND J, et al. Evaluation of Safety Distance in Vehicle Platoons by Combined Braking and Steering [C]// JSAE. 11th International Symposium on Advanced Vehicle Control. Tokyo: Japan Society of Mechanical Engineers, 2012: 1-10.
[19] 刘志强,张春雷,张爱红,等.基于驾驶行为的追尾避撞控制策略研究[J]. 汽车工程,2017,39(9):1068-1073. LIU Zhi-qiang, ZHANG Chun-lei, ZHANG Ai-hong, et al. A Study on the Control Strategy for Rear-end Collision Avoidance Based on Drivers' Behavior [J].Automotive Engineering, 2017, 39 (9): 1068-1073.
[20] 张琨.智能汽车自主循迹控制策略研究[D].哈尔滨:哈尔滨工业大学,2013. ZHANG Kun. Research on Intelligent Vehicle's Path Tracking Control Strategy [D].Harbin: Harbin Institute of Technology, 2013.
[2] 裴晓飞,齐志权,王保锋,等.汽车前向主动报警/避撞策略[J].吉林大学学报:工学版,2014,44(3):599-604. PEI Xiao-fei, QI Zhi-quan, WANG Bao-feng, et al. Vehicle Frontal Collision Warning/Avoidance Strategy [J].Journal of Jilin University: Engineering and Technology Edition, 2014, 44 (3): 599-604.
[3] 章军辉,李庆,陈大鹏.基于 BP 神经网络的纵向避撞安全辅助算法[J].西安交通大学学报,2017,51 (7):140-147. ZHANG Jun-hui, LI Qing, CHEN Da-peng. Safety Assistance Algorithm for Longitudinal Collision Avoidance Based on BP Neural Network [J]. Journal of Xi'an Jiaotong University, 2017, 51 (7): 140-147.
[4] BRANNSTROM M, COELINGH E, SJOBERG J. Model-based Threat Assessment for Avoiding Arbitrary Vehicle Collisions [J]. IEEE Transactions on Intelligent Transportation Systems, 2010, 11 (3): 658-669.
[5] 朱西产,刘智超,李霖.基于车辆与行人危险工况的转向避撞控制策略[J].汽车安全与节能学报,2015,6(3):217-223. ZHU Xi-chan, LIU Zhi-chao, LI Lin. Evasive Maneuvre for Emergency Steering Based on Typical Vehicle-pedestrian Use Case [J]. Journal of Automotive Safety and Energy, 2015, 6 (3): 217-223.
[6] GUO J, HU P, WANG R. Nonlinear Coordinated Steering and Braking Control of Vision-based Autonomous Vehicles in Emergency Obstacle Avoidance [J]. IEEE Transactions on Intelligent Transportation Systems, 2016, 17 (11): 3230-3240.
[7] LIU J, JAYAKUMAR P, STEIN J, et al. Combined Speed and Steering Control in High Speed Autonomous Ground Vehicles for Obstacle Avoidance Using Model Predictive Control [J]. IEEE Transactions on Vehicular Technology, 2017, 66 (10): 8746-8763.
[8] 田彦涛,王晓玉,胡蕾蕾,等.电动汽车侧向换道行驶主动避撞控制算法[J].吉林大学学报:工学版,2016,46(5):1587-1594. TIAN Yan-tao, WANG Xiao-yu, HU Lei-lei, et al. Active Collision Avoidance Algorithm In Electric Vehicle Lateral Lane Change [J].Journal of Jilin University: Engineering and Technology Edition, 2016, 46 (5): 1587-1594.
[9] JANSSON J, JOHANSSON J, GUSTAFSSONF. Decision Making for Collision Avoidance Systems [J]. SAE Paper 2002-01-0403.
[10] 裴晓飞,刘昭度,马国成,等.汽车主动避撞系统的安全距离模型和目标检测算法[J].汽车安全与节能学报,2012,3(1):26-33. PEI Xiao-fei, LIU Zhao-du, MA Guo-cheng, et al. Safe Distance Model and Obstacle Detection Algorithm for a Collision Warning and Collision Avoidance System [J]. Journal of Automotive Safety and Energy, 2012, 3 (1): 26-33.
[11] VN UNEN E, ESPOSTO F, SABERI A K, et al. Evaluation of Safety Indicators for Truck Platooning [C]// IEEE.Intelligent Vehicles Symposium (IV). New York: IEEE, 2017: 1013-1018.
[12] JIANG X, WANG W,BENGLER K. Intercultural Analyses of Time-to-collision in Vehicle-pedestrian Conflict on an Urban Midblock Crosswalk [J]. IEEE Transactions on Intelligent Transportation Systems, 2015, 16 (2): 1048-1053.
[13] COELINGH E, EIDEHALL A, BENGTSSON M. Collision Warning With Full Auto Brake and Pedestrian Detection-A Practical Example of Automatic Emergency Braking [C]// IEEE. 13th International IEEE Conference on Intelligent Transportation Systems (ITSC). New York: IEEE, 2010: 155-160.
[14] 贺锦鹏,马芳武,刘卫国,等.汽车前碰撞预警系统 ISO 15623 标准和 NHTSA 26555 评价规程对比试验[J].汽车技术,2014(7):28-33. HE Jin-peng, MA Fang-wu, LIU Wei-guo, et al. Comparative Test Between ISO 15623 on Forward Vehicle Collision Warning System and NHTSA 26555 Assessment Program [J].Automotive Technology, 2014 (7): 28-33.
[15] CHEN S L, CHENG C Y,HU J S, et al. Strategy and Evaluation of Vehicle Collision Avoidance Control via Hardware-in-the-Loop Platform [J]. Applied Sciences, 2016, 6 (11): 327-337.
[16] 李霖,朱西产,陈海林.驾驶员制动和转向避撞极限[J].同济大学学报:自然科学版,2016,44(11):1743-1748. LI Lin, ZHU Xi-chan, CHEN Hai-lin. Driver's Collision Avoidance Limit by Braking and Steering [J].Journal of Tongji University: Natural Science, 2016, 44 (11): 1743-1748.
[17] YI K, DO KWON Y. Vehicle-to-vehicle Distance and Speed Control Using an Electronic-vacuum Booster [J]. JSAE Review, 2001, 22 (4): 403-412.
[18] MAZRTENSSON J, NYBACKA M, JERRELIND J, et al. Evaluation of Safety Distance in Vehicle Platoons by Combined Braking and Steering [C]// JSAE. 11th International Symposium on Advanced Vehicle Control. Tokyo: Japan Society of Mechanical Engineers, 2012: 1-10.
[19] 刘志强,张春雷,张爱红,等.基于驾驶行为的追尾避撞控制策略研究[J]. 汽车工程,2017,39(9):1068-1073. LIU Zhi-qiang, ZHANG Chun-lei, ZHANG Ai-hong, et al. A Study on the Control Strategy for Rear-end Collision Avoidance Based on Drivers' Behavior [J].Automotive Engineering, 2017, 39 (9): 1068-1073.
[20] 张琨.智能汽车自主循迹控制策略研究[D].哈尔滨:哈尔滨工业大学,2013. ZHANG Kun. Research on Intelligent Vehicle's Path Tracking Control Strategy [D].Harbin: Harbin Institute of Technology, 2013.