Research On Vibration Suppression Control Algorithm Of Drilling Robot For Aircraft Assembly

Drilling robot system for aircraft assembly used for drilling operation by joint robot has the unique advantages, such as low cost, high flexibility, which conform to the concept of flexible assembly for aircraft and joint robot decides the location of hole. But it is a very complex multi-input and multi-output(MIMO) system, and has time-varying, strong coupling and nonlinear dynamic characteristics. What’s more, due to the existing of elastic components, such as harmonic reducer, makes the joints of robot for drilling has flexibility, which increases the difficulty to control it. In order to improve the efficiency、quality of drilling hole, and reduce the cost, this paper focuses on how to effectively solve the problem of vibration suppression for robot system of drilling hole for aircraft assembly. Using the Newton-Euler method and parameter identification method establish the dynamics model of joint robot accurately. Based on the theoretical analysis and research on the joint robot, a fuzzy decoupling compensation algorithm is proposed. And the input shaping technology is introduced to further suppress the vibration of manipulator on the basis of decoupling. The main research contents of this paper include the following aspects:(1)First, set up the dynamic model of the drilling robot by the method of Newton-euler equation. Then, establish the transfer function block diagram of the robot joint angle servo system. At last, the controllers of current loop, speed loop and position loop are designed and their parameters are corrected. Frequency response characteristics of all feedback loops are analyzed.(2)The nonlinear dynamic model of the multi-joint drilling for aircraft is linearized. The recursive least square method is used as an algorithm of parameter identification for robot. And then identify dynamic parameter of each rod by using the combination method. Finally, the parameter identification of two link planar robot is verified in the Matlab/Simulink simulation environment. And set up a single degree of freedom rotating test platform to verify the effectiveness of the recursive least square parameter identification.(3)Joint robot vibration suppression algorithm is put forward. Through analyzing and researching the coupling between joints of the multi-joint robot, the fuzzy decoupling compensation control algorithm is put forward. The coupling value between joints is decreased or eliminated through compensation. And the combination algorithm of input shaping technology and semi-closed loop is put forward to suppress the vibration of single joint of multiple joints robot in order to effectively solve the problem of multi-joint robot vibration suppression.(4)Under the simulation environment of Matlab/Simulink, respectively set up the mathematical model of single and double joints robot to verify the vibration suppression algorithm proposed in this paper.