Introduction to satellite posture control and determination practice kit (ADCS Kit)

General introduction

The satellite posture control and determination practice kit (ADCS Kit) is a scientific and technological product of the Technology Development Program at the Vietnam Academy of Science and Technology, label "Development of a satellite posture control and determination practice kit for space technology training", code UDPTCN 04/19-21, by MSc. Truong Xuan Hung as the director and the Vietnam Space Center as the chairing unit. The mission has researched and developed the ADCS Kit with simple structure and compact size to be suitable for practice purposes for undergraduate and graduate students. During the implementation of the Task, the research team proposed a technical solution to the conversion mechanism of the momentum wheel configurations and this technical solution was patented by the National Office of Intellectual Property with Patent No. 30577, granted under Decision 18923w/QD-SHTT dated November 23, 2021.

Figure 1. ADCS Kit

The finished product of ADCS Kit (Figure 1) consists of two main parts: a weightless, frictionless state simulator table and a defined block, controlling posture in three axes. In which, determining the posture only uses the IMU sensor to measure the set of angular speed/posture parameters; Posture control using momentum wheels obeys the law of conservation of momentum. These are very basic components of ADCS in satellite. The toolkit connects to the control software on the computer via a wireless communication channel. Students interact with the ADCS Kit through the user interface.

Main technological features of ADCS Kit

Momentum wheel configuration conversion mechanism

In the satellite position determination and control module, the momentum wheels are arranged in many configurations, of which the three most common types are three-axis configuration, pyramid configuration and tetrahedron configuration (illustrated as Figure 2). A technical solution has been proposed and implemented, allowing to change the installation position of the momentum wheel according to the above three configurations in the pre-limited space. At the same time, the configuration change process is done quickly. This is the basis for the research team to apply for patent No. 30577, "The mechanism for converting the configurations of the momentum wheel for a practical toolkit for satellite posture control and determination practice kit for space technology training”. With the application of such a mechanism, the ADCS Kit can operate flexibly in one of three configurations and allow the practitioner to have the opportunity to familiarize himself with different satellite position control options; adjust the angular momentum transformation matrix and controller parameters for each configuration.

Figure 2. Mounting mechanism for converting momentum wheel configurations

Simulate zero-gravity and frictionless state

This is an important technical specification of the ADCS Kit, which allows simulation of an operating environment similar to that in space. The simulator table is a special mechanical mechanism, capable of creating free rotation in three axes with very little friction, used to simulate a frictionless state. The weightless state is defined to correspond to the neutral equilibrium of the simulator table, including the ball joint and other components. When the coordinates of the center of gravity coincide with the center of rotation of the ball joint, the simulator table tends to stay in any position and the effect of the radial gravity component is eliminated.

Figure 3. Weightless and frictionless simulation solution

Conclusion

The ADCS Kit is a technology product that combines new technology ideas with previous research results. ADCS Kit is expected to make a positive contribution to the training of students majoring in space technology in general and the practice of determining and controlling satellite postures in particular. Due to the specific nature of the industry, the training process urgently needs such toolkits. In addition, in the product development process, the research team has made two new contributions in terms of technology and practical application orientation. First, a solution for mounting the momentum wheel was developed to create three different configurations: pyramid, tetrahedron and three-axis. The solution was patented in 2021. In addition, initially mastering the technology of designing and manufacturing air-cushioned ball joints, implemented entirely domestically, allows the entire mechanical part of ADCS kit to be manufactured with a 100% localization rate.

Translated by Tuyet Nhung
Link to Vietnamese version