Dynamical simulation of a nonlinear stepper motor system

Abstract

Coupled electromechanical interactions observed in a closed-loop control system actuated by a stepper motor are studied. Analysed system consists of a PID controller used to maintain constant vertical inclination of a single DOF pendulum. This pendulum serves as a tensioner for a string being pulled by a rotary motion of the electric stepper motor. The second end of the string is being fed to the motor with a variable speed. The mathematical model governing dynamics of the mentioned system consists of a non-linear system of four ordinary differential equations. In addition to the mathematical model, various ways of control of the electric stepper motor have been applied. In particular, the rotor control using the micro-stepping approach has been used to model the real dynamics of the motor controller. Comparison of the proposed theoretical considerations and modelling of the studied system fits well with the experimental investigations.