为降低伺服系统稳态误差的波动,并为摩擦模型的精确辨识创造条件,提出基于稳态误差分析的转矩纹波的辨识和补偿方法。确立伺服系统的稳态误差与其输入信号、干扰信号的关系。以此为基础研究匀速运动时稳态误差的组成,获得由转矩纹波和摩擦力矩等系统扰动引起的稳态误差,并利用频谱分析、最小二乘等方法确定转矩纹波的函数形式。通过可编程多轴控制器(Programmable multi-axis controller,PMAC)实现转矩纹波的补偿。经补偿,伺服系统稳态误差的波动不同程度减小,低速时效果明显,峰峰值由补偿前的10μm减小到3.3μm,高速时补偿后的峰峰值也降低为3.2μm,而且可以获得明显的Stribeck曲线。该方法能很好地实现转矩纹波的补偿,为精确补偿摩擦扰动、提高伺服系统动态性能奠定基础。
The identification and compensation methods of torque ripple based on steady state error analysis are presented in order to reduce the fluctuation of steady-state error of servo system and create environment for the accurate identification of the friction model.The relationship between steady state errors and input and interference of signals in servo system is determined.On this basis,the composition of steady state error for the uniform motion is researched.The steady state error induced by system disturbance including torque ripple,friction moment and others is obtained.The function form of torque ripple is obtained by using methods such as spectrum analysis and least squares criterion.The compensation of ripple can be achieved by programmable multi-axis controller(PMAC).The experimental results show that the fluctuation of steady state error decreases to different degrees.It has obvious effect at low speed;the peak-to-peak value reduces from 10 μm to 3.3 μm after compensation.At high speed,the peak-to-peak value also decreases to 3.2 μm after compensation.Besides,the Stribeck curve can be apparently acquired.Therefore,the method proposed can effective compensate the torque ripple and lay the foundation for precise compensation of friction disturbance and improvement of dynamic performance of servo system.