Abstract : This paper introduces a new method of optimal control of stepper motor with shortest time using closed-loop stepper motor, proposes a mathematical model and optimal control strategy for optimal control of stepper motor, and gives the hardware and software technology for implementing optimal control using microcontroller. The application of the optimal control in industrial control system shows that the proposed optimal control has good control performance. Keywords : stepper motor; optimal control; microcontroller 1. Introduction Stepper motor is an electromechanical component that converts electrical pulse signals into corresponding angular displacement (or linear displacement) [1]. Control systems using stepper motors have the advantages of low price, simple control, and easy maintenance. In particular, with the development of microcomputer and microelectronics technology, stepper motors have been more widely used, and higher requirements have been put forward for the operating performance of stepper motors. Therefore, the rational selection of stepper motor control method plays a positive role in giving full play to the working performance of stepper motor. In order to obtain the optimal control of stepper motor and make the control system low cost, this paper uses optimal control theory to study and introduce the optimal switching time of stepper motor control voltage and the control strategy executed by microcontroller [2]. 2. Mathematical Model of the Optimal Control Problem for Stepper Motors When the stepper motor, its power supply, and the load are all determined, the length of the motor's starting, acceleration, deceleration, and stopping processes depends solely on the control pulse sequence. If an optimal control pulse sequence can be found that minimizes the starting, acceleration, deceleration, and stopping processes, optimal control of the stepper motor can be achieved. [Download the original text on the optimal control of stepper motors based on a microcontroller]