Development of Servo-Controller to Compensate Friction Disturbances Automatically by Using Adaptive Control Technique

为了使伺服系统具有较高的速度和精度，对系统中的未知摩擦力进行补偿是非常重要的。在这个项目中，提出了几种估计和补偿未知摩擦力的方案。由于旋转或重复运动伺服系统的摩擦扰动是周期性的，因此有必要估计周期性扰动以补偿摩擦力。提出了一种自适应观测器来估计这种扰动。观测器包含一个简单的方案来计算扰动的估计。给出了两种摩擦力补偿的自适应控制方案。第一种方案采用预估参数进行力补偿，并采用扰动解耦方法减小由预估误差引起的控制误差。在第二种方法中，采用基于双参数补偿方案的模型参考自适应控制系统补偿未知的摩擦扰动。这些方案是为计算机模拟而编制的。给出了控制系统稳定的充分条件。应用这一条件，证明了补偿摩擦扰动的系统是稳定的。研制了两种实验性伺服控制系统。这些系统有连接计算机的接口，它们可以被连接的计算机控制。第一个系统是与计算机连接的伺服电机。第二种是6自由度机械手，其轴由计算机控制。利用这些系统，进行了未知摩擦扰动的估计实验。

To control servo systems in high performance of speed and accuracy, it is important to compensate unknown friction forces in the systems. In this project, several schemes to estimate and compensate the unknown friction forces are proposed.1. Since friction disturbances are periodic in rotating or repeatedly moving servo systems, it is necessary to estimate periodic disturbances for compensating the friction forces. An adaptive observer to estimate such disturbances is proposed. The observer includes a simple scheme to calculate the estimate of the disturbances.2. Two adaptive control schemes to compensate the friction forces are given. The first scheme compensates the forces by using estimated parameters and reduces control errors caused by estimation errors by disturbance decoupling method. In the second method, the unknown friction disturbances are compensated by a scheme of model reference adaptive control systems based on the two-parameter compensation schemes. These schemes are programmed for computer simulations.3. A sufficient condition for control systems to be stable is given. Applying this condition, it is shown that the systems compensating the friction disturbances are stable.4. Two experimental servo control systems are developed. These systems have interfaces to connect computers and they can be controlled by the connected computers. The first system is a servo motor connected with a computer. The second is a manipulator with 6 degrees of freedom, whose axes are controlled by computers. Using these systems, experiments to estimate the unknown friction disturbances are conducted.