考虑关节铰隙机械臂末端位姿精度的模糊控制

Research on pose accuracy control of robot with joint clearances

以空间3R含铰间隙机械臂为研究对象,考虑关节铰隙机械臂末端位姿精度的模糊控制方法。首先,利用D-H坐标变换法建立不含间隙和含间隙的机械臂运动学模型,分析铰间隙对机械臂末端位姿精度的扰动影响;其次,通过所建立的含间隙三维模型并进行运动学仿真,研究其位姿误差大小;再次,基于减小误差提高精度设计模糊控制器,通过角位移来补偿末端位姿误差,从而得出相应的角位移补偿量;最后,采用补偿后的角位移对含间隙模型进行运动学仿真分析,得出其补偿后的位姿误差。研究表明,采用模糊控制方法,机械臂在x、y方向上末端位姿误差明显减小,其控制效果较好,而在z方向上的误差也有所降低,可见,在模糊控制策略下,补偿后的角位移对关节铰隙机械臂末端位姿的精度误差有明显的减小作用。

The paper taking 3R robot as the research object,and considering the method of research on pose accuracy control with joint clearances.First,using the D-H method to establish kinematic model of the manipulator arm with clearance and without clearance,getting the influence of joint clearance for the error of end position.Second,establishing 3D model and motion simulation in robot with joint clearance and without joint clearance,which will get the error of end position.Then,the fuzzy controller is designed based on the error reduction accuracy,and the angular position error is compensated by the angular displacement to obtain the corresponding angular displacement compensation amount.Finally,the kinematics simulation analysis of the model with gap is carried out by using the compensated angular displacement,and the postural error after compensation is obtained.The research shows that with the fuzzy control method,the end pose error of the manipulator in the x and y directions is significantly reduced,and the control effect is better,but the error in the z direction is also reduced.It can be seen that under the fuzzy control strategy,Compensated angular displacement has a significant effect on the accuracy error of the end position of the joint hinge arm.