Motion Planning And Control Method For Multi-axis Direct Drive Motion Platform

Efficient production and processing is the goal always pursued in the industrial fields such as machine tool processing and intelligent manufacturing,and it is also a key issue in the rapid development of the current intelligent manufacturing industry.This requires motion planning and precise control of the equipment processing process to achieve high efficient and high-precision manufacturing process.This paper studies the motion planning and control algorithms of direct drive systems commonly used in high-end automation equipment,and proposes a complete solution that integrates path planning,path curve fitting,shortest time trajectory planning,and trajectory motion control.First of all,according to the industrial application scenarios of surface mount,dispensing,welding,etc.,which require processing equipment to go through more processing points,we abstract the typical traveling salesman problem in the combination optimization problem,that is,how to ensure that the workbench passes through the processing points in a certain order so that the processing equipment has the shortest path.In this paper,the ant colony algorithm is used to find a shorter path,and a path cross detection and elimination method and a neighboring point to be processed replacement method are designed to improve the ant colony search process and shorten the path length.Then,NURBS(Non-uniform rational B-splines)curve is used to fit the optimized path,and an adaptive curve fitting method based on path length error and curvature extreme value is proposed.It is ensured that the finally fitted curve passes through each point to be processed and can be as close as possible to the length of the original planned path,and the effectiveness of the method is verified by simulation.Subsequently,a bidirectional reverse forward detection trajectory planning is performed on the obtained fitting path.Under the premise of considering the speed and acceleration constraints of the motion system,bidirectional trajectory planning is carried out from the forward direction of the starting point and the reverse direction of the end point to obtain the maximum speed at each moment under the constraint conditions.So as to ensure that the movement time is shortest and the equipment workbench reaches the end point at a steady speed,and the trajectory planning of the fitted path is simulated and verified.Finally,a tracking control experiment of the planned path is designed on the multi-axis linear motor gantry platform to verify the effectiveness of the design scheme.Using Euler's method to design the linear motor discrete second-order dynamics model,according to the path information generated by the trajectory planning,such as position,speed and acceleration,design the discrete fast terminal sliding mode controller,and design appropriate sliding mode surface and control parameters to achieve the expected control effect.The experimental results verify the effectiveness of the entire motion planning and control scheme.From the results of simulation and experiment,the motion planning scheme designed in the article can not only get a shorter planned path,but also take the maximum value of the speed or acceleration of at least one axis at any time,and realize the shortest time trajectory planning,based on sliding mode control.The path tracking effect is good and can meet the accuracy requirements.