基于解耦的柔性关节机械臂振动抑制方法研究

Vibration suppression control for manipulator with flexible joints based on decoupling

针对多自由度柔性关节机器人手臂残余振动抑制问题,对双杆机械臂关节耦合及振动抑制方法进行了研究,提出了基于解耦的柔性关节振动抑制控制算法。首先,根据拉格朗日方法建立了系统的动力学模型。然后,分析了关节间存在的相互作用力及关节间的相互耦合对机械臂振动抑制的影响。利用模糊补偿控制方法对二自由度柔性关节机械臂进行了模糊解耦,并在解耦的基础上引入零振荡整形器(ZV整形器)对解耦后的各个单关节进行进一步控制,以抑制各臂杆由于关节刚度不足导致的残余振动。最后,通过数值算例进行了仿真,验证了该算法的有效性。研究结果表明,加入解耦环节之后,两杆的相互干扰明显减弱,耦合度明显降低,使该非线性系统近似成为线性系统,再通过零振荡整形器对各关节运动加以优化,使得机械臂的残余振动得到了有效的抑制。

Aiming at the problem of residual vibration suppression of multi-degree of freedom robot arm with flexible joints,the coupling between joints and vibration suppression of two-link mechanical arm were studied. The vibration suppression control algorithm for flexible joints based on decoupling was proposed. First of all,the dynamic model of the whole system was established by taking advantage of the Lagrange method. Then,the interaction between joints and the vibration suppression of mechanical arm affected by the mutual coupling between the joints were analyzed. Secend,the coupling between the flexible joints of the multiple degrees of freedom manipulator was eliminated by making the use of fuzzy control method. To suppress the residual vibration of the arm due to the lack of rigidity of joints,the zero vibration shaper（ ZV shaper） was introduced on the basis of decoupling to make further control of single joint after decoupling. At last,the effectiveness of the algorithm was verified through a numerical example. The results indicate that after adding the decoupling links,mutual interferences of the two rods are decreased obviously and the coupling degree is reduced,which make each rod become approximate linear system,and each joint is optimized through the zero vibration shaper to make the vibration of mechanical arm have been effectively suppressed.