Frequency Modulation Based on Hyperbolic Tangent Function for Position Closed Loop Control of Stepper Motor

Generally, the position closed-loop control of stepper motors requires high-precision models, however are complex nonlinear systems, and models difficult to obtain. In order solve this problem, a variable frequency controller based on hyperbolic tangent function is proposed. Similar proportional integral (PI) method, method does not require an exact model plant. The experimental results show that when tracking sinusoidal signal 180°sin(0.628 t ), error Tanh algorithm reduced by nearly 60% compared with PI algorithm, which provides new idea for motor.