Research On Trajectory Tracking And Vibration Suppression Method Of Flexible Joint Manipulator

Flexible joint manipulator has numerous advantages,such as high load ratio,light weight,low power consumption,compact component design and so on.Therefore,it is widely used in various fields,for instance,national defense and military,space and ocean exploration,medical services and so on.However,due to the existence of joint flexibility,the vibration of the manipulator,which could occur during the starting process and when the velocity changes suddenly,would increase the difficulty of the manipulator control.In this thesis,the first and second connecting rods of the Selective Compliant Assembly Robot Arm(SCARA)are selected as the control objects.Aiming at the two control requirements of the flexible SCARA manipulator for fast and accurate trajectory tracking control and vibration suppression at the end of the connecting rod,the trajectory tracking and vibration suppression methods were studied.Firstly,the flexible joint of the manipulator was analyzed and the mathematical model was established.On this basis,a complete dynamic model of the flexible joint two-link manipulator was established by using Lagrange equation,which lays a foundation for the following control method research.Secondly,for the purpose of SCARA fast and accurate trajectory tracking,the controller of the manipulator was designed,which was used by the feedforward two-degree-of-freedom IP(FF-I-P)controller in order to a better reference trajectory tracking.Based on the above method,fuzzy FF-I-P control method with self-tuning parameters was adopted to improve the robustness of the manipulator control system,for the influence of uncertainties such as external disturbance and system parameter variation on the tracking control performance of the manipulator.Finally,due to the existence of flexible joints,there is vibration problem at the end of the connecting rod during the motion of the manipulator.The physical parameter state observer was used to observed the parameters at the end of the connecting rod by using the motor control input and related parameters,and the torsional angular velocity was fed back to the motor control input to increase the damping of the system and restrain the motion of the flexible joint manipulator.Vibration phenomenon caused by external force or self-flexibility in the process.Taking the second connecting rod as an example,the observer model was built in Matlab,and the vibration suppression effect of the end of the manipulator was verified by simulation.