Design and Implementation of Adaptive PID Controller for Speed Control of DC Motor

This paper describes the design and implementation of adaptive PID control strategy for controlling the angular velocity of the DC motor. Adaptive PID controller is designed to calculate the control parameters which are tuned adaptively to give desired control performance even if parameters of DC Motor are changed. The controller's parameters are online tuned when the motor is running using a Recursive Least Squares (RLS) method. The controller is able to change the value of the controller's constants to maintain motor performance as it is desired when parameters of DC motor are changed. Initially a Pseudo Random Binary Sequence (PRBS) signal is given to the system for 0.07 seconds to get the estimated transfer function of the plant system (DC motor) using the RLS algorithm. From coefficients of the estimated system's transfer function, the poles of a desired characteristic equation can be obtained for the system that has the appropriate output. Thus, the proportional, integral and derivative constants of controller can be obtained by using online pole placement method. Here, an online identification system is used to determine the new control parameters. The effectiveness of this adaptive PID controller is verified by experimental results using a microcontroller STM32F446.