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针对阀控非对称缸液压系统存在不确定性和干扰问题,提出综合滑模变结构控制与反馈线性化控制的鲁棒反馈线性化控制策略.利用反馈线性化控制提高非线性系统控制精度,利用变结构控制补偿外界干扰与系统不确定性,并采用边界层法减少滑模变结构控制可能导致系统高频抖动.针对位移信号直接微分得到的加速度信号存在高频噪声问题,提出利用改进二阶滑模算法抑制干扰的影响.通过建立统一的阀控非对称缸液压伺服系统非线性数学模型,以时变负载力扰动为例对系统的动态特性进行了研究,结果表明:鲁棒反馈线性化策略能有效抑制外界的干扰和负载力扰动对液压位置追踪精度的影响,提高了液压控制系统的精度和鲁棒性.
Aiming at the problem of uncertainty and interference of valve-controlled asymmetric cylinder hydraulic system, a robust feedback linearization control strategy based on sliding mode variable structure control and feedback linearization control is proposed. The feedback linearization control is used to improve the control accuracy of nonlinear system. Variable structure control compensates external disturbance and system uncertainty, and the boundary layer method to reduce sliding mode variable structure control may lead to high-frequency jitter of the system.Aiming at the problem of high-frequency noise of the acceleration signal obtained by the direct differential displacement signal, The sliding mode algorithm is used to suppress the disturbance.The nonlinear dynamics model of a valve-controlled asymmetric cylinder hydraulic servo system is established to study the dynamic characteristics of the system with the time-varying load disturbance as an example. The results show that the robust feedback linearization The strategy can effectively restrain the influence of disturbance and load disturbance on the tracking accuracy of hydraulic position and improve the accuracy and robustness of the hydraulic control system.