To decrease the influence of friction on the angular speed tracking accuracy of a precision servo turning table, the methods of friction parameter identification and friction compensation based on the LuGre model was put forward. Firstly, the angular speed over zero phenomenon occurred in the angular speed free reduction was analyzed, and the genetic algorithm was used to fit the angular speed reduction curve to obtain LuGre model parameters and rotational inertia. Then, the parameter I-dentification method was tested and verified by a simulation experiment. Finally, the friction compensation was computed by identfication parameters and was added to the angular speed tracking system of the turning table . The actual experimental system achieves a angular speed loop and a current loop and its data update rate is 1 kHz. In the actual angular speed measuring experiment, the mean square deviation of error between actual angular speed curve and fitting curve is 2. 9× 10-3rad/s. In the angular speed tracking experiment, when the given signal is sine wave with an amplitude of 0. 032 4 rad/s and frequency of 0. 5 Hz, friction compensation can eliminate the waveform distortion, and the mean square deviation of angular speed tracking error has decreased by 27% as compared with that of double loops control system without friction compensation. It is concluded that the friction parameter identification method can obtain high accurate parameters, and can improve the angular speed tracking accuracy of servo turning tables prominently.%为降低摩擦对光学精密伺服转台速度跟踪精度的影响,提出了基于LuGre模型的转台摩擦参数辨识和补偿方法.首先,分析转台在自由减速过程中的速度过零现象,采用遗传算法拟合减速曲线从而获得转台摩擦参数和转动惯量；然后,通过仿真实验验证辨识方法；最后,利用辨识得到的参数计算摩擦补偿并叠加到转台速度伺服系统.实际实验系统的数据更新率达1 kHz,已实现了速度-电流双闭环控制.实际拟合实验中,拟合与实测速度曲线的误差均方差为2.9×10-3 rad/s;速度跟踪实验中,对于幅值为0.032 4 rad/s,频率为0.5 Hz的给定正弦信号,摩擦补偿消除了波形失真,系统速度跟踪误差的均方差减少27％.实验表明,用该方法测量转台摩擦参数精确度高,基于辨识参数的摩擦补偿可提高光学伺服转台低速低频段的速度跟踪精度.
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