Mayur Vijay Pawar, MIT Art, Design and Technology University; Khushi Jain, MIT Art, Design and Technology University; Abhinav Krishnan, Independent Researcher; Sunil V Dingare, MIT Art, Design and Technology University
Keywords: Pointing Accuracy, Lyapunov Stability Theory, Single Gimbal Variable Speed Control Moment Gyroscope, Sliding Mode Control, Space-based Observations
Abstract:
With the growing significance of space domain awareness, the tracking of space objects has become a critical concern for the space industry. Given the sheer number of space objects and their minuscule size, it is quite challenging to track them using ground-based sensors alone. Consequently, space-based observation has become necessary to ensure accurate tracking of these small space objects. However, achieving precision in tracking requires a highly accurate pointing system to obtain reliable information about the space object. Nevertheless, the current pointing system presents certain challenges in meeting this requirement, as observations can be degraded despite the steady state error of about 0.1 degrees. The current level of error in the observations has resulted in a significant ambiguity that needs to be addressed to improve space situational awareness. To obtain a comprehensive understanding of the space environment, it is imperative to improve the pointing accuracy of tracking systems. This will facilitate the accurate monitoring of the movements and trajectories of space objects, including satellites and debris, thus reducing the likelihood of collisions. Enhancing pointing accuracy will also enable the identification and tracking of potential threats, such as space debris, that could endanger operational spacecraft. The objective of this research is to enhance the pointing performance of satellites through the implementation of a cutting-edge control scheme. By utilizing a single gimbal variable speed control moment gyroscope (SGVSCMG) coupled with a sliding mode controller, this control scheme surpasses existing methods in terms of stability and synchronization, particularly when faced with external disturbances. The study focuses on improving satellite attitude control systems for SDA space-based observations, with a specific emphasis on addressing issues related to external disturbances. To achieve this, the research begins by transforming the satellite attitude system model into a Lagrange nonlinear system, which serves as the foundation for the subsequent control design. The study then devises a terminal sliding mode surface to specifically tackle attitude-tracking errors. We present an innovative control scheme that harnesses the power of neural networks to achieve agile and adaptive control. Our scheme is designed to effectively counteract external disturbances. We’ve expanded the control strategy to cover actuator misalignment scenarios for comprehensive control coverage in real-world applications. We’ve analyzed the stability and synchronization of the closed-loop control using Lyapunov stability theory to provide theoretical support for the proposed approach. The findings of this study underscore the capabilities of SGVSCMG-based control systems to meet the exacting requirements of fine tracking of space-based observatories, particularly in contexts that necessitate exceptional precision, such as space-based observations. This research represents a significant stride forward for SDA satellites by introducing a powerful and versatile control solution that leverages cutting-edge control techniques and hardware configurations. Through various simulations under different operational conditions, our control strategy has been validated, even in scenarios with external disturbances. The preliminary results indicate that we have improved the pointing accuracy by approximately 0.01 degrees, though we are enhancing it to set new benchmarks in the domain. Our proposed control scheme has demonstrated efficiency in achieving satisfactory performance while upholding stability and synchronization while tracking. Going forward, the incorporation of further adaptive mechanisms holds the potential to bolster the strength and adaptability of the control scheme even further. Improved pointing accuracy contributes directly to the enhancement of SSA, ensuring a proactive approach to space safety and streamlined satellite operations.
Date of Conference: September 17-20, 2024
Track: Space-Based Assets