考虑负载质量影响的电液力加载系统自适应反步滑模控制

Adaptive backstepping sliding mode control of electro-hydraulic loading system considering the influence of load mass

针对被动式电液力加载系统的负载中含有较大质量力的应用场合,设计了一种自适应反步滑模控制策略,以提高系统的响应速度和加载精度。综合考虑系统非线性摩擦和液压缸的容腔效应、电液伺服阀的工作死区和电信号偏差等不确定因素以及位置干扰的影响,建立了系统的非线性数学模型;然后推导出系统自适应控制律,并利用Lyapunov稳定性理论得出自适应反步滑模控制器;最后通过MATLAB/Simulink进行系统特性分析。仿真结果表明,引入该控制器后,在质量力与负载力的比值约为1∶5的场合下,力加载系统响应速度得到有效提升,频宽可达到12 Hz,同时加载精度也有所提高,系统输出幅值误差约为1.8%,相位误差均值为-7.164°。

In order to improve the response speed and loading accuracy of passive electro-hydraulic loading system,an adaptive backstepping sliding mode control strategy was designed for applications where the system load contained much mass force.The system’s nonlinear mathematical model integrating several uncertainties was established by considering the nonlinear friction of the system,the cavity effect of the hydraulic cylinder,the working dead zone of the electro-hydraulic servo valve,the electrical signal deviation and the position interference.Then the adaptive control law of the system was derived and an adaptive backstepping sliding mode controller was obtained by using Lyapunov stability theory.Finally,MATLAB/Simulink was used to analyze the system characteristics.The results show that,when the ratio of mass force to load force is about 1∶5,the response of the system with the designed controller is accelerated effectively,the bandwidth reaches 12 Hz,and the loading accuracy is also improved,in which the output amplitude error of the system is about 1.8%,and the average phase error is-7.164°.