双菱形仿袋鼠腿悬架的PID和Fuzzy-PID控制特性研究

Characteristics study based on PID and Fuzzy-PID control of a double-diamond bionic kangaroo leg suspension

为改善传统车辆悬架的性能,借鉴自然进化而来的袋鼠腿部结构,提出一种双菱形仿袋鼠腿悬架。为研究该悬架的行为特性,采用Lagrange方程法推导其动力学模型;基于动力学模型分别设计其PID和Fuzzy-PID控制器;在MATLAB/simulink环境下,建立其被、主动仿真模型并开展特性仿真与分析。研究发现:①被、主动模式下,车身垂向加速度、悬架动挠度及轮胎动位移均方根,随着车速和路面等级的增加均有所增加且在允许范围内。②不同路面等级下,随着车速的增加,被、主动模式的车身垂向加速度传递率数值基本相同,均呈单调递减趋势,(如,被动模式的车身垂向加速度传递率在1.64%~0.80%之间变化),但主动模式优于被动模式,Fuzzy-PID控制优于PID控制(约下降0.5%~0.6%);③不同路面等级下,随着车速的增加,被、主动模式的轮胎动位移传递率数值均增加,但其增加率呈下降趋势。从传递率数值上看,主动模式明显优于被动模式(约减少15%~25%,高车速时下降明显),但Fuzzy-PID控制与PID控制效果基本相同;④由车身加速度、悬架动挠度和轮胎动位移传递率频响特性可知双菱形仿袋鼠腿悬架有两个峰值,第一个峰值在0.8 Hz附近,第二个峰值在15 Hz附近;主动控制下悬架的舒适性和稳定性均优于被动悬架,Fuzzy-PID较PID控制效果更佳。研究结果表明:所提悬架的结构设计合理、方案可行。该悬架具有良好的路面适应性、高速舒适性和稳定性,这些特性与袋鼠腿的运动特性相吻合,验证了该研究思路的正确性和控制方法的有效性。

In order to improve the performance of traditional vehicle suspension,a double-diamond bionic kangaroo leg suspension was proposed based on the kangaroo leg structure evolved from nature.In order to study the behavior characteristics of the suspension,a dynamic model was established by the Lagrange’s Equations;PID and Fuzzy-PID controllers were designed respectively based on the dynamic model;passive and active simulation models were established and the simulation characteristic was analyzed through MATLAB/simulink.It is found that:①In the passive and active modes,with the increase of vehicle speed and road grade,root mean square values of the body vertical acceleration,the suspension deflection and the tire dynamic displacement increase and they are limited in the allowable ranges.②Under different road levels,with the increase of vehicle speed,the body vertical acceleration transmissibility values are basically the same,and it has a monotonous decreasing trend.(For example,the body vertical acceleration transmissibility in passive mode is 1.64%~0.80%),but the control effect of the active mode is better than that of the passive mode,and the control effect of Fuzzy-PID control is better than that of PID control(approximately 0.5%~0.6%);③At different road levels,with the increase of vehicle speed,the value of the dynamic displacement transmissibility increases in active and passive modes,but the numerical increase rate presents a downward trend.Seen from the value of the transmissibility,the active mode is significantly lower than the passive mode(about 15%to 25%reduction,decreasing significantly at high speed),but the effects of Fuzzy-PID control and PID control are basically the same.④From the frequency response characteristics of vehicle body acceleration,suspension deflection,and tire dynamic displacement transmissibility,it can be seen that the double-diamond bionic kangaroo leg suspension has two peaks.The first peak is near 0.8 Hz,and the second peak is around 15 Hz;the comfort and stability of the suspension is better in the active mode than in the passive mode.Fuzzy-PID control is better than PID control.The research results show that:the structure design of the proposed suspension is reasonable and the scheme is feasible;the suspension has good road adaptability,high-speed comfort and stability.These characteristics are consistent with the kangaroo leg motion characteristics,which verifies the correctness of the research ideas and the effectiveness of the control method.