重型汽车主动悬架次优控制策略设计与分析

Design and analysis of sub-optimal control strategy for heavy vehicle active suspension

为合理设计汽车主动悬架次优控制策略、探讨不同次优控制策略对重型汽车行驶性能的影响,建立了四自由度汽车-路面系统动力学模型,采用改进模糊层次分析法进行性能指标赋权,设计了主动悬架的次优控制器,以车身质心加速度和道路破坏系数的线性加权和为指标,对不同次优控制策略进行评价优选,在时频域范围内对比分析了被动、最优和次优控制悬架的行驶性能差异。结果表明,不同次优控制策略对汽车行驶平顺性和道路友好性的影响差异明显,综合考虑状态变量可测性及测试成本,对车身和车轴加速度测量、并进行一次积分处理的次优控制策略性能最优;合理设计的次优控制悬架性能与最优控制相当或接近,且优于被动悬架,具有更好的实用性。

In order to design a more reasonable sub-optimal control strategy of vehicle active suspension and study effects of different sub-optimal control strategies on heavy vehicle driving performance,a 4-DOF vehicle-pavement system dynamic model was established.A sub-optimal controller of vehicle active suspension was designed,and its performance indicators were weighted with the improved fuzzy hierarchy analysis method.Taking the linear weighted sum of vehicle body mass centroid acceleration and road damage coefficient as the index,different sub-optimal control strategies were evaluated and optimized.The driving performance differences of passive,optimal and sub-optimal control suspensions in time-frequency domain were contrastively analyzed.Results showed that influence difference of different sub-optimal control strategies on vehicle ride comfort and road friendliness is obvious;comprehensively considering the measurability of state variables and test cost,the sub-optimal control strategy to measure accelerations of vehicle body and axle and then perform an integral processing is optimal;the reasonably designed sub-optimal control suspension has the same performance as that of the optimal control one or is close to the latter,and it is superior to the passive suspension,so it has a better practicability.