基于LuGre摩擦模型的转台伺服系统自适应摩擦补偿研究

Study on Adaptive Friction Compensation of Turntable Servo Systems Based on LuGre Friction Model

为消除非线性摩擦对测试转台性能的影响,选用LuGre摩擦模型描述转台系统所受的非线性摩擦。根据转台直流电机系统数学描述,提出了非线性摩擦补偿方法。设计了双观测器结构估计LuGre模型中的不可测状态;考虑LuGre模型中3个参数的非一致性变化,设计了自适应摩擦补偿控制算法,在线估计摩擦模型中的参数,并对非线性摩擦进行补偿。用李雅普诺夫方法证明了采用自适应摩擦补偿方法的闭环系统的稳定性。仿真结果表明:正弦波输入时,摩擦补偿后的位置跟踪误差(峰-峰值)较无摩擦补偿减小了1个量级,位置跟踪性能有较大改善,辨识出的摩擦模型参数能稳定收敛于真实值附近;三角波输入时,自适应控制的位置跟踪精度更高。

To eliminate the effect of nonlinear friction on test turntable,LuGre friction model was selected to describe nonlinear friction of the test turntable.According to the mathe description of the DC motor system,the method to compensate the nonlinear friction was put forward.The dual-observer was designed to estimate the unmeasurable state in the LuGre friction.Taking into account the occurrence of 3 non-uniform parameters change in LuGre friction model,the control algorithm with adaptive friction compensation was designed,which estimated the parameters in the friction model on line and compensate the nonlinear friction.The system stability of the closedloop with adaptive friction compensation was proved by Lyapunov approach.The simulation results showed that the position tracking error(peak-peak)with compensation was 1 order smaller than the one without compensation and the performance of the position tracking was improved greatly as well as the estimated parameters of the friction model were converged to around the true value for sinusoidal input.The accuracy of the position tracking with adaptive control was much higher for triangular waveform input.