基于机械臂位姿变换的柔性负载伺服驱动系统控制策略

Control Strategy of Flexible Load Servo Drive System Based on Manipulator Position and Position Transformation

伺服驱动系统的柔性负载端转动惯量等参数随柔性机械臂位姿变化而变化,进而影响伺服驱动系统电动机输出端转速。为降低电动机输出端速度波动,采用极点配置的方法设计伺服驱动系统转速环PI控制器参数,该参数的选择随柔性机械臂位姿变化而变化,从而使伺服驱动系统在不同位姿下获得良好的动态响应特性,避免机械谐振发生。首先根据连续体振动理论和拉格朗日原理建立了柔性负载伺服驱动系统动力学模型,并通过状态方程求得电动机转速到柔性负载驱动转矩的传递函数。将变参数PI控制策略应用于伺服驱动系统转速环控制中,分析了柔性负载对转速环的控制特性的影响,采用极点配置的方法设计控制器参数。接下来分别采用相同幅值、相同阻尼系数、相同实部3种极点配置策略设计控制器参数。讨论了这3种极点配置策略不同参数对系统谐振峰值、谐振频率和带宽的影响。最后通过数值仿真分析表明:伺服驱动系统等效柔性负载参数与机械臂的位姿有关;柔性负载回转半径、转动惯量较大的情况,不适宜使用相同实部的极点配置方法,但其余两种方法可通过适当选择参数使电动机输出转速波动程度减小。

The parameters such as the moment of inertia of the flexible load end of the servo drive system change with the position of the flexible manipulator, which affects the speed of the motor output of the servo drive system. In order to reduce the speed fluctuation of the motor output, the parameters of the servo drive system speed loop PI controller are designed by the pole configuration method. The selection of this parameter changes with the position of the flexible robot arm, so that the servo drive system can be obtained in different poses. Good dynamic response characteristics to avoid mechanical resonance. The dynamic model of the flexible load servo drive system is established based on the continuum vibration theory and the Lagrangian principle. The transfer function of the motor speed to the flexible load drive torque is obtained by the state equation. The variable parameter PI control strategy is applied to the servo drive system speed loop control. The influence of the flexible load on the control characteristics of the speed loop is analyzed. The pole parameters are used to design the controller parameters. Next, the controller parameters are designed by using the same amplitude, the same damping coefficient, and the same three real pole configuration strategies. The effects of different parameters of these three pole placement strategies on the system resonance peak, resonant frequency and bandwidth are discussed. Finally, the numerical simulation analysis shows that the equivalent flexible load parameters of the servo drive system are related to the pose of the mechanical arm;when the flexible load radius of gyration and the moment of inertia are large, it is not suitable to use the pole configuration method of the same real part, but the other two The method can reduce the fluctuation of the motor output speed by appropriately selecting parameters.