Multiple linear motor control system based on FPGA

This paper introduces a system based on FPGA which controls multiple permanent magnet synchronous linear motors based on current, location and speed feedbacks. In the FPGA, several proportional-integral-derivative (PID) control units are settled. Each control unit drives a Hall Effect sensor to acquire the speed of the motor, a raster to acquire the position and 2 current sensors to acquire the value of the currents inputted to the motor. Each control unit independently controls a linear motor with 6 channels of Pulse-Width Modulation (PWM) waves based on the information of the current, location and speed from the sensors. Meanwhile, control units communicate with each other to drive the linear motors at different, specific speeds based on certain mathematical relationships. Compared with the conventional linear motion driving system, the system improves the acceleration and the feed rate, and increases the accuracy of movement between the coupling motions. The FPGA is used to simplify the control system and improve the control efficiency. Experimental result shows that the system has a higher efficiency and higher accuracy.