Comparison of PID and SMC methods in DC motor speed control

Abstract

DC motor speed control was carried out in this study using Proportional Integral Derivative (PID) and Sliding Mode Control (SMC) methods. Disturbance is added to and removed from the motor shaft for short periods using a relay to compare the performances of the controllers. SMC and the PID Controller were designed using LabVIEW and tools. The motor is rotated at the desired speed by controlling the H-bridge through the DAQ card. The experimental setup uses LabVIEW software, an N-6024E DAQ card, an H-bridge, a DC motor, and encoder. A variable PWM signal is used at the PID control, and a constant amplitude voltage (± 5V) is applied to the DC motor by the SMC. The settling time is 450 milliseconds for the PID control and 110 milliseconds for the SMC when the motor is rotated at the reference speed of 1,500 rpm. The performances of the controllers were examined while the disturbance effect was applied to the motor shaft via a relay for two seconds. After that, the experimental results were compared to each other. The PID and SMC controllers reach their respective reference speeds at approximately 1 second and 15 milliseconds when the disturbance effect is applied to the motor. Although SMC reaches its reference speed much faster, it has a chattering problem with the motor. This disadvantage can be eliminated using some methods that remove the chattering.