Modeling and simulation of a DC motor control system with digital PID controller and encoder in FPGA using Xilinx system generator

Abstract

This paper presents a novel method for design and simulation of a DC motor closed loop control system in Field Programmable Gate Array device (FPGA). The digital designed PID controller is more advanced, beneficial and therefore produces a better response, as compared to the analog PID with velocity measurement. It can be implemented on system-on-chip devices easily. MATLAB Xilinx system generator toolbox based on Fixed-Point Arithmetic is used to design the digital PID controller using DSP architecture, plot the responses of the control system and generate the VHDL source code. The control system consists of a digital PID, the model of a real DC motor, a real and new incremental optical shaft encoder model, encoder to rpm and position blocks. Results show that the proposed system leads to lower the steady state and transient error.