考虑参数不确定性的主动悬架H_2/H_∞保性能控制  

H_2/H_∞ guaranteed cost control for active suspensions considering parameter uncertainty

作　　者：庞辉[1] 王延 刘凡 PANG Hu;WANG Yan;LIU Fan(School of Mechanical and Precision Instrument Engineering,Xi'an University of Technology,Xi'an 710048)

机构地区：[1]西安理工大学机械与精密仪器工程学院,西安710048

出　　处：《控制与决策》2019年第3期470-478,共9页Control and Decision

基　　金：国家自然科学基金项目(51675423;51305342);陕西省重点研发计划项目(2017GY-029)

摘　　要：针对车辆主动悬架系统参数不确定性所引起的控制稳定性问题,提出一种基于线性分式变换的混合H_2/H_∞保性能状态反馈控制策略.首先,为了提高车辆平顺性、确保汽车行驶安全性能,在考虑系统参数不确定的条件下建立1/4车辆主动悬架模型,并将车身垂向加速度的H_2范数作为控制输出性能指标并使其最小化,悬架动挠度约束和轮胎动载荷约束作为控制器的H_∞性能约束输出指标.然后,基于Lyapunov稳定性理论设计一种最优H_2/H_∞保性能状态反馈控制律,将保性能控制律问题转化为线性矩阵不等式的凸优化问题,并利用不确定矩阵结构信息进一步引入自由变量以降低控制器设计的保守性.最后,通过某1/4车辆主动悬架的仿真实验结果表明,所提出控制策略在外部路面扰动下能够使该主动悬架系统具有更好的扰动抑制能力,并能够明显改善车辆悬架综合性能.Aiming at the control and stability problem of vehicle active suspension systems with parameter uncertainty,a mixed H2/H∞ guaranteed cost state feedback control strategy based on linear fractional transformation(LFT) is proposed. Firstly, to improve vehicle ride comfort and ensure the security of vehicle driving, the quarter dynamics model of vehicle active suspension is established when considering the uncertainties of the active suspension system. The H2 norm of vehicle body acceleration is selected as the output performance index of the controller to be minimized, and the constraints of suspension dynamic deflection and tire dynamic load are determined as the H∞ constraint performance output indicators of the designed controller. Then, based on the Lyapunov stability theory, an optimal mixed H2/H∞guaranteed cost state feedback control approach is presented to reduce the conservatism of controller design. Finally,a numerical example of quarter-vehicle active suspensions is provided, and the simulation results demonstrate that the proposed control strategy has better disturbance attenuation capability against the external road disturbance, and can obviously improve the overall performance of vehicle suspension.

关 键 词：主动悬架 参数不确定 线性分式变换 Lyapunov稳定 H2/H∞保性能控制 保守性 

分 类 号：U463.33[机械工程—车辆工程]