基于增量非线性动态逆的液压执行器力控制策略研究

针对液压执行器力控跟踪要求高度的非线性及不确定性的动力学模型问题,导致液压驱动系统高精度运动控制存在困难,提出采用一种基于传感器的增量式非线性动态逆控制方法来解决液压执行器的力跟踪问题。建立液压执行器动力学模型,理论分析了INDI控制策略在力控制模型上具有稳定性好、抗干扰能力强、系统标定范围大的优势。利用该控制器压力差导数作为反馈,不依赖于精确的液压执行器数学模型和参数标定,对模型不确定性具有固有的鲁棒性。仿真试验和理论分析表明: 采用高频率采样的INDI控制器力跟踪误差始终稳定在6%左右; 最大跟踪误差也不超过8%;对参数不确定性具有极强的鲁棒性。

Force Control of Hydraulic Actuator Based on Incremental Nonlinear Dynamic Inverse

Hydraulic actuators have characteristics such as highly nonlinear dynamics and model uncertainty, which make high-precision motion control of hydraulically driven systems extremely challenging. In this paper, a sensor-based incremental nonlinear dynamic inverse control method is used to solve the force tracking problem of hydraulic actuators. Firstly, the dynamic model of the hydraulic actuator is established, and the INDI control strategy has the advantages of good stability, strong anti-interference ability and large calibration range in the force control model. Secondly, the pressure differential derivative of the controller is used as feedback, independent of the accurate mathematical model and parameter calibration of the hydraulic actuator, and the model is built with inherent robustness to model uncertainty. Finally, the simulation test and theoretical analysis show that the force tracking error of INDI controller with high frequency sampling is always stable at about 6%. The maximum tracking error is not more than 8%; It has strong robustness to parameter uncertainty.