Kinematics Analysis And Control System Research On A 4-DOF Industrial Robot

With the advancement of industry 4.0,more and more industrial robots are being used in automated production lines to replace manual on repetitive and hazardous tasks.The motion control algorithm of the robot and a low-cost,easy-used,high-precision embedded control system based on the ARM chip are studied in this paper,which is controlled by a 4-DOF punching and loading industrial robot.The main contents are as follows:First,the 4-DOF industrial robot linkage system is constructed by D-H method,and its forward and inverse kinematics equations are deduced.The trajectory planning of the robot is studied,the interpolating algorithm of fifth polynomial in joint space with variable interpolation period is proposed.Aiming at the problem that the S-shape acceleration and deceleration of7-segment have many constraints and is difficult to planning,a 5-segment S-shaped acceleration and deceleration control method is proposed.Aiming at the velocity control problem of the Cartesian space trajectory,the linear acceleration and deceleration control is applied to linear and circular interpolation.A speed optimization algorithm based on displacement equivalence is proposed,this algorithm can reduce velocity step at the acceleration and deceleration point due to discrete interpolation equation by adjusting acceleration and deceleration.Secondly,the Robotics toolbox was used to model the 4-DOF industrial robot and the kinematics simulation interface of 4-DOF industrial robot is designed by MATLAB GUI.The simulation interface includes the simulation of working space,simulation of forward and inverse solutions,simulation of teaching and simulation of trajectory planning.Using STM32F407 as the master chip to program,use MODBUS protocol to communication,and designed the overall scheme of software.The function module and the stamping process of 4-DOF industrial robot control system are studied.The motion control program of 4-DOF industrial robot is programmed in C language,including manual teaching,homing,auto-run and online control programs.The motion of the servomotor is controlled by PWM generated by the timer.The Kinematics algorithm is programmed into the controller,which realizes the point to point controland the linear and circular interpolation functions of the robot.Finally,The whole 4-DOF industrial robot control system was debugged,and a testing platform is built to test the effect of fifth polynomial interpolating algorithm with variable interpolation period and the speed optimization algorithm.The debugging and test results show that: the control system is stable;The repeat positioning accuracy of PTP control is ±0.01mm;The speed optimization algorithm can reduce the speed step at the acceleration and deceleration point,and ensures the smooth motion of the robot.