基于极点配置方法的机器人柔性关节转速抑制策略研究

Research on rotation speed suppression strategy of flexible joints based on pole placement method

针对含有柔性关节的机械臂易出现转速波动的问题,在PI控制策略的基础上利用极点配置的方法优化控制器参数,进而通过提高输出转速精度的方式减弱机械臂的振动程度。首先,根据双惯量模型建立机械臂中柔性关节的动力学模型,进而通过动力学模型的数学表达式获得柔性关节的状态空间方程;其次,根据状态空间方程求得电机转速到电机电磁转矩的传递函数;第三,采用基于相同幅值的基于极点配置的PI控制策略优化控制器参数,并分析不同的极点参数对于系统动态特性的影响;最后,为了验证所提出控制策略的有效性,利用MATLAB对机械臂柔性关节伺服系统进行数值仿真实验,并搭建柔性关节的物理样机控制实验平台开展输出转角控制实验。数值仿真实验和物理样机控制实验表明:该文所提出的控制策略可通过适当选择极点参数使系统获得良好的动态特性,相比于传统的PI控制策略能够提高输出转速控制精度、抑制机械臂振动。

Aiming at the problem that the speed fluctuation of the manipulator with flexible joints is prone to occur,based on the PI control strategy,the pole configuration method is used to optimize the controller parameters,and then the vibration degree of the manipulator is reduced by improving the output speed accuracy.Firstly,the dynamic model of the flexible joint in the manipulator is established according to the double inertia model,and then the state space equation of the flexible joint is obtained through the mathematical expression of the dynamic model.Then,the transfer function from the motor speed to the motor electromagnetic torque is obtained according to the state space equation.Next,the PI control strategy based on pole configuration based on the same amplitude is used to optimize the controller parameters,and the influence of different pole parameters on the dynamic characteristics of the system is analyzed.Finally,in order to verify the effectiveness of the proposed control strategy,a numerical simulation experiment is carried out on the servo system of the flexible joint of the manipulator by using MATLAB,and a physical prototype control experimental platform of the flexible joint is built to carry out the output angle control experiment.Numerical simulation experiments and physical prototype control experiments show that the control strategy proposed in this paper can obtain good dynamic characteristics of the system by properly selecting the pole parameters.Compared with the traditional PI control strategy,it can improve the output speed control accuracy and suppress the vibration of the manipulator.