车辆舒适停车二次速度曲线算法

Algorithm of Quadratic Speed Curve for Comfortable Parking

停车制动过程中车速变为0时,车辆加速度的阶跃变化是影响制动舒适性的主要原因。通过对纵向制动工况进行控制,即对制动后期的加速度和速度重新规划,对速度的规划采用二次曲线形式。规划后车辆制动时的冲击度(加速度的时间变化率)明显减小。在MATLAB软件中验证了算法的正确性,并通过Simulink和Carsim联合仿真得到了整车层面上的优化结果。针对制动舒适性与制动安全性的问题,提出制动系统“减压-保压-增压”的解决方案,并进行了实车试验,试验结果表明各项评价指标良好,在保证安全性的情况下提高了舒适性。

Reconstructing the vehicle braking process again and judging the late braking period plays a decisive role in vehicle braking comfort.To control the longitudinal braking condition,it is necessary to re-plan the acceleration and speed in the later braking period,in which the speed planning adopts the form of quadratic curve.After speed planning,the impact degree(the time change rate of acceleration)when the vehicle brakes is obviously reduced.The correctness of the algorithm is verified in MATLAB software,and the optimization results at the vehicle level are obtained through the joint simulation of Simulink and Carsim.Aiming at the problems of braking comfort and braking safety,the solution of“decompression-pressure maintaining-pressure increasing”of the braking system is put forward,and the real vehicle test is carried out.The test results show that all evaluation indexes are good,and the braking comfortableness is improved while ensuring the safety.