协同式多目标自适应巡航控制

Multi-objective adaptive cruise control (ACC) algorithm for cooperative ACC platooning

  • 摘要: 针对自动化高速公路(Automated highway system,AHS)车队稳定性问题,发展了一种多目标自适应巡航控制算法,根据李雅普诺夫(Lyapunov)稳定性理论对该问题进行了量化分析,并给出了同质与异质车队稳定性的设计要求,基于模型预测控制(Model predictive control,MPC)理论,综合协调驾驶员期望响应、跟驰安全性、车队稳定性、车队整体品质等控制目标,采用加权二次型性能泛函以及线性矩阵不等式约束的形式,将协同式多目标自适应巡航(Adaptive cruise control, ACC)设计问题最终转化成带约束的在线凸二次规划问题。仿真结果表明,相比单车ACC而言,协同ACC的约束空间更为严苛,车队互联系统稳定性易受车间时距、车队规模、多目标权重、瞬态工况、车辆异质性等因素的影响,建议在跟驰安全性、车队稳定性良好的前提下寻求一定的驾乘舒适性与燃油经济性,以确保车队整体品质。

     

    Abstract: With the rapid progress of the automated highway system, the issue of platoon stability, which might significantly affect highway traffic characteristics, such as traffic efficiency, traffic capacity, and traffic safety, has attracted considerable attention. A string of vehicles equipped with adaptive cruise control (ACC) and moving longitudinally in an automated manner is regarded as an autonomous vehicle platooning system. During car following, the quality of the ride could be poor and rear-end collisions could occur, particularly if the spacing and velocity errors are amplified to some extent as they propagate upstream. Research on platoon stability has been the focus of significant interest. However, a method to coordinate multiple sub-objectives dynamically during autonomous vehicle platooning against multiple traffic scenarios has not yet been developed. In this study, a multi-objective ACC algorithm for cooperative adaptive cruise control (CACC) platooning based on vehicle-to-vehicle (V2V) real-time communication technology, which enabled the interconnection of vehicles within a limited range to share vehicle position and motion state information, was thus proposed. The quantization of homogeneous and heterogeneous platoon stability was analyzed on the basis of the Lyapunov stability theory. Furthermore, on the basis of the model predictive control framework, the coordination among various conflicting sub-objectives, such as driver-desired car-following response, rear-end safety, platoon stability, and platoon overall quality, was comprehensively considered. Then, by utilizing a quadratic cost function with linear multi-constraints, the design of the multi-objective CACC was transformed into the convex quadratic programming problem with multiple constraints. The comparative simulations show that the I/O constraints and slack relaxation of platoon control are strict, indicating that platoon stability is easily affected by certain factors, such as time gap, platoon size, sub-objective weight coefficient, transient traffic scenarios, and heterogeneous features. Thus, rear-end safety and platoon stability should be prioritized to guarantee the overall quality of the platoon.

     

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