Armature Reaction Analysis and Suppression of Voice Coil Actuator Based on an Improved Magnetic Equivalent Circuit Model

The high thrust density voice coil actuator (VCA) is a key component for the deployers to determine the CubeSats’ separation velocity in orbit directly. To improve the VCA's thrust density and power consumption, it is essential to analyze the armature reaction under heavy current work conditions. This article proposes a dynamic splitting method of the magnetic equivalent circuit (MEC) model for analyzing the armature reaction of the VCA. This MEC model can effectively reveal the interaction mechanism between the dynamic winding field and the permanent magnet (PM) field, which provides an approach to readily and quickly analyze the armature reaction. Based on the understanding of the mechanism, we found an effective way to suppress the armature reaction and propose a new VCA with double PM flux circuits. The electromagnetic performances of the new configuration are evaluated by comparing it with the conventional one. Both the theoretical and experimental results show that the new structure achieves lower magnetic saturation, lower armature reaction, and higher thrust density. A research prototype was constructed and experimentally tested to verify the theoretical results of the armature reaction, magnetic field, thrust, separation velocity, and other performances. The new VCA realizes a wide and accurate modulation of separation velocity for the CubeSats.

Introduction

Multiple CubeSats are generally released in clusters to accomplish advanced complex space missions cooperatively [1]. They are usually small in volume and light in weight and can be stored in a box deployer [2], [3]. In a complex cluster mission, CubeSats are supposed to naturally form a stable relative motion with each other when released by the deployer because of the limit of available fuel and weak orbit control capability. The separation velocity of CubeSats is a crucial factor determining their initial position after the release [4]. The deployer, thus, must be able to precisely adjust the thrust according to the mass of different CubeSats to achieve a specified separation velocity. However, the spring mechanism, which is commonly used to push CubeSats out of the deployer [5], [6], [7], cannot adjust the thrust repeatedly and accurately.