The performance of the Hatch Cover Drive Assembly operated in space is quite important for aircrafts. However, it is hard to experimental studies in space. As an alternative, theoretical analysis and simulation are employed to predict their performances on the ground. Herein, a mathematical model of the drive assembly was first established and simulated in Matlab. The armature current and mechanical efficiency were analyzed with respect to the operating temperature and load torque. Furthermore, a test setup according to the model was built to verify the validity of the proposed mathematical model. As a result, the prediction results are consistent with the experimental results very well with a maximum error of 11.0% in the armature current and 11.6% in the mechanical efficiency. The mechanical efficiency achieves to be the maximum value in vacuum as the load torque of 3.5N·m. It has the best performance as working around the room temperature. The proposed model would be used to predict the performance of drive assembly working in space. Our findings would be helpful for the designing, manufacturing and selection of motors and reducers for spacecrafts usage in future.

Introduction

Motors and reducers are the key components of the drive assembly of spacecrafts, which drive the payloads and functional components for finishing the specified actions and motions in space [1], [2]. Up to now, many kinds of motors and reducers are developed to fulfill the various missions, among them, the brushless DC motor driven by DC converter is widely used in aerospace due to its simple structure, reliable operation and long service life [3], [4]. In addition, the DC motor can drive a large load combined with the harmonic reducer. This drive assembly shows many advantages of the large transmission ratio, small mass and volume, high transmission accuracy, and is quite suitable for application in spatial motion [5], [7]. However, the special environment in space would degenerate the performance of the drive assembly of DC motor and harmonic reducer, resulting in a lot of disasters. For instance, the coil resistance and magnetic destiny in the motor, and the grease viscosity in harmonic reducer, are changed heavily upon the alternating of high and low temperature. As a result, the coupling effect of these factors highly degenerates the output performance of the drive assembly. Many studies have focused on these problems, but limited to DC motor or reducer or environment simulation technology [8], [9] rather than the drive assembly. Some scholars have carried out in-depth research on parameters, rotational speed, calculation of back EMF coefficient, thermal analysis and circuit control of brushless DC motor [10], [22].