Turkish Journal of Electrical Engineering and Computer Sciences




This paper presents a robust adaptive nonlinear proportional--integral (ANPI) scheme to control the speed of a direct-current (DC) motor. Unlike proportional--integral--derivative (PID) controllers, PI controllers have a simpler structure and they deliver effective control effort. However, due to inadequate controller gains, they are often unable to simultaneously improve the transient as well as the steady-state response of the system. A nonlinear PI (NPI) controller alleviates these issues and delivers a good response. In this research, the proportional and integral gains of the NPI controller are dynamically modulated via a nonlinear sigmoidal function (SiF) of the error dynamics of the motor's angular speed. The variation rates of these functions are manually tuned via trial-and-error method. These rates are also dynamically updated via an extended Kalman filter (EKF)-based adaptation mechanism. The performances of a linear PI controller, an NPI controller having fixed variation rates, and an NPI controller equipped with the EKF-based self-regulated SiFs are tested and compared in real time. The experimental results are analyzed to validate the effectiveness of the proposed ANPI controller in optimizing DC motor speed control.


DC motor, NPI control, sigmoidal function, self-tuning controllers, EKF

First Page


Last Page