精密定位系统的摩擦力建模与补偿

为了提高由直线电机驱动的精密定位系统的定位精度，建立了优化Stribeck摩擦模型，对摩擦力这一影响定位精度的主要因素进行补偿。首先，对于传统的Stribeck摩擦模型进行优化，采用改进的最小二乘算法对模型参数进行辨识。然后，对所建立的摩擦模型补偿算法进行仿真并与扰动观测器的补偿算法进行比较，发现前者速度比后者速度在补偿后提高了4.33%，对摩擦力具有更好的补偿效果。最后，在大行程二维精密定位平台上进行验证，根据平台能够达到的最大速度定义0.005 m/s为低速运动，0.05 m/s为高速运动，在这两种速度下进行实验，并与基于库仑摩擦前馈补偿模型比较。实验结果表明：精密定位平台在速度为0.005 m/s的低速运动时，优化模型的跟随误差减小了67.67%；在速度为0.05 m/s的高速运动时，优化模型的跟随误差减小了51.63%，验证了优化Stribeck摩擦模型补偿算法的有效性。本文提出的优化Stribeck摩擦模型可用于提高由直线电机驱动的精密定位系统的定位精度。

Friction modeling and compensation of precision position system

To improve the positioning accuracy of a precise positioning system driven by a linear motor, the optimized Stribeck friction model was established that compensates for the main factors affecting the positioning accuracy of friction. First, the traditional Stribeck friction model was optimized. Second, the improved least square algorithm was used to identify the model parameters. Third, the friction model compensation algorithm was simulated and compared with the disturbance observer compensation algorithm. It is found that the speed of the former is 4.33% higher than that of the latter, and the friction compensation has a better compensation effect. Finally, the experiment was carried out on a two-dimensional precision positioning platform with large stroke according to the maximum speed of the platform; low and high speeds were defined as 0.005 and 0.05 m/s, respectively. Experiments were performed at these two speeds and compared with the Coulomb friction feed forward compensation model. The experimental results indicate that for the precision positioning platform at a low speed of 0.005 m/s, the proposed model tracking error is reduced by 67.67%; for a high-speed movement of 0.05 m/s, the proposed model tracking error is reduced by 51.63%, which verifies the validity of the improved Stribeck friction model compensation algorithm. The improved Stribeck friction model proposed in this paper can be used to improve the positioning accuracy of a precision positioning system driven by a linear motor.