基于参数辨识的电液伺服非线性模型预测控制

Nonlinear Model Predictive Control of Electro-Hydraulic Servo Based on Parameter Identification

针对电液伺服系统存在的非线性、模型不确定性和约束问题,提出了一种基于参数辨识的非线性模型预测控制方法。利用递推最小二乘法辨识电液伺服系统模型参数,以克服模型不确定性;基于模型参数辨识结果,考虑负载流量非线性、控制量约束和状态约束需求,构建性能指标函数,设计了非线性模型预测控制方法,并进行闭环稳定性分析。仿真结果表明,辨识方法可以较快估计出模型参数,最大估计误差为1.802%,相比于PID控制,控制算法的最大轨迹跟踪误差减小了88.66%。所提方法能有效处理系统约束与非线性,具有较好的控制效果。

Aiming at the problems of nonlinearity,model uncertainty and constraints in electro-hydraulic servo system,a nonlinear model predictive control method based on parameter identification is proposed.The model parameters of electro-hydraulic servo system are identified by recursive least square method to overcome the uncertainty of the model.Based on the results of model parameter identification,the performance index function is constructed considering the load flow nonlinearity and requirements of control quantity constraint and state constraint.The nonlinear model predictive control method is designed,and the closed-loop stability analysis is carried out.The simulation results show that the identification method can quickly estimate the model parameters,the maximum estimation error is 1.802%,and the maximum trajectory tracking error of the control algorithm is reduced by 88.66%compared with PID control.The proposed method can effectively deal with system constraints and nonlinearity,and has good control effect.