Position closed loop control of stepper motors based on arctangent function

The high-precision position closed-loop control of stepper motors usually use field-oriented control. This method requires high-precision models of motors, however stepper motors are complex nonlinear systems, and high-precision models are difficult to obtain. In order to solve this problem, a pulse frequency modulation controller based on arc tangent function is proposed in this paper. This algorithm does not need accurate mathematical model, and its turning parameters have clear physical significance, which can be calculated according to the control requirements. The experimental results show that when tracking the sinusoidal signal θref=450sin(0.628t), the tracking errors (peak-peak value) of the arctangent control algorithm is reduced by nearly 42% compared with the PI control algorithm, which provides a new idea for the position closed-loop control of stepper motors.