I- Introduction

II- The Mathematical Model

III- The Numerical Modeling of The Hybrid Stepper Motor

IV- Experimental Results

V- Conclusions

References

Abstract

The design of a hybrid stepper motor for achieving a specific performance requires its adequate geometrical sizing that may be performed through numerical modeling. With this aim, the current study documents several aspects of the three– dimensional numerical modeling that was used to predetermine the holding torque for a stepper motor and presents different approaching methods used to reduce redundancies. The results for holding torque calculation are compared with experimental measurements in order to validate the numerical model. Moreover, optimal economic and technical solutions were obtained through successive improvements made in the design phase and concurring to the requirements of the product specification are included.

INTRODUCTION

The increased demand towards motion control of stepper motors (SMs) play a key role in a wide range of applications demanding for accuracy and repeatability [1]. SMs are increasingly used as digital actuators because they do not require digital‒to‒analog (D/A) conversion. For instance, SMs are utilized as actuators in a spacecraft instrumentation system [2], or to control drum actuators [3]. Consistently, theoretical and experimental work was devoted to study and compare the SMs with conventional closed–loop positioning systems [4] and to deploy the SMs to a variety of applications. The SM main parameters are: parasitic torque, holding torque and running torque. Parasitic torque sums up the hysteresis torque, the irreversibility torque and the detent torque. The SM is largely presented in [5], where a study regarding the detent torque (the torque with the windings not energized) is presented. In SMs, position holding must occur without energy consumption [6–۱۰]. This paper is focused on another important parameter of the SM, namely the holding torque (the torque with the windings energized). Numerical modeling and experimental results are presented and discussed.