Research On Trajectory Planning And Vibration Suppression For Industrial Robot Carrying Flexible Loads

When an industrial robot is used to carry a flexible load,the flexible load often generates a relatively large vibration.Normally,work should not continue until the vibration has naturally decayed.However,some specific conditions do not allow the existence of the waiting process.For example,when industrial robots transport molten metal liquid for pouring,too long waiting time will cause the metal liquid to solidify,which will seriously reduce the operation efficiency.Therefore,how to suppress the vibration of the flexible load without affecting the working efficiency is particularly important.This paper studies how to suppress the vibration of the flexible load when the industrial robot handles the flexible load,and how to maintain the accuracy of vibration suppression when the parameters related to the vibration of the flexible load change.The research contents mainly include:Aiming at the problem that the vibration suppression ability of the conventional handling trajectory of industrial robots is weak,this paper makes a quadratic planning for the conventional handling trajectory.The acceleration trajectory is adjusted under the T-shaped trajectory planning framework,and a method of two-step acceleration vibration suppression trajectory is proposed to suppress the vibration of the flexible load from the perspective of trajectory planning.The smoothness of the trajectory is optimized to avoid the generation of sudden force,thereby further improving the vibration suppression effect of the flexible load.Aiming at the problem that the vibration mode of the flexible load is excited and generates vibration,this paper studies the input shaping vibration suppression algorithm.The vibration characteristics of the flexible load as well as the industrial robot body are analyzed and designed to suppress the vibration by the corresponding input shaper.In order to solve the combined application problem of multiple input shapers in the overall system of industrial robot and flexible load,this paper proposes a mutual convolution strategy of shaped pulses,which can suppress the vibration of the industrial robot body and the flexible load at the same time;In this paper,the problem of introducing delay time into the controller is studied,and a method of scaling the motion trajectory is proposed to ensure that the total duration and total distance of the reshaped motion trajectory are equal to the original trajectory.Aiming at the problem that the vibration modal parameters of the flexible load change during the handling process,which reduces the vibration suppression accuracy of the input shaper.Based on iterative learning,this paper proposes two vibration suppression parameters for the vibration characteristics of the flexible load and the industrial robot body.The optimization algorithm realizes the accurate acquisition of shaping vibration suppression parameters,thus ensuring the accuracy of vibration suppression when industrial robots carry flexible loads.In this paper,an experimental platform based on a six-degree-of-freedom industrial robot mounted on a flexible load is built.The proposed vibration suppression algorithm and vibration suppression parameter optimization algorithm are experimentally verified under the condition of an industrial robot handling a flexible load.The experimental results demonstrate the effectiveness of the algorithm proposed in this paper.