Research On Joint Design And Control Strategy Of Flexible Robot Joint

As robotics technology is widely used in electronic device processing,aerospace and other industrial manufacturing and production,cooperative robot and human-machine integration have become the direction of development now and in the future.Traditional industrial robotic arms are difficult to satisfy this type of scene due to their large rigidity and inertia.To ensure the safety of human-robot interaction,it is necessary to improve the flexibility of the joint.How to design a flexible joint and analyze its dynamic model,how to design a reasonable and effective control algorithm to suppress the residual vibration of the joint,and how to compensate the gravity of the flexible joint have become the key problems.In order to solve these problems,this paper designs a new series elastic actuator(SEA),builds an experimental platform of flexible manipulator joint,identifies the system parameters,studies the dynamic model of flexible robot and the compliance control method of flexible robot,and finally verifies the effectiveness of the control algorithm through the experimental platform.Firstly,the design scheme of flexible joint is studied,mainly including the overall structure design of flexible joint,the design and simulation of flexible joint series elastic actuator,the hardware selection and control system design of flexible joint experimental platform.The experimental platform of flexible joint provides the basis for the design and experimental verification of control algorithm.Secondly,for the modeling of the flexible joint robot,four reasonable hypotheses are put forward,the dynamic model of the flexible joint is established.The dynamic parameters identification of the single joint is carried out on the experimental platform,which provides dynamic parameters for subsequent experiments.Next,a time-delay controller(PIR)is used,and the stability of the controller is analyzed by the direct integration method,and a PR controller based on the Sigmoid function(SPR)is proposed.These two controllers can greatly reduce the residual vibration of flexible joint.Subsequently,the inaccuracy of static gravity compensation is solved through online gravity compensation,and the stability of the algorithm is analyzed.Finally,a number of experiments are carried out,including step response experiment without gravity,step response experiment with gravity,trapezoidal signal tracking experiment,and sinusoidal signal tracking experiment.The results show that the proposed control algorithm can effectively suppress residual jitter and online gravity compensation can effectively compensate gravity.