Hybrid-Compliant System for Soft Capture of Uncooperative Space Debris

Abstract

Active debris removal (ADR) is positioned by space agencies as an in-orbit task of great importance for stabilizing the exponential growth of space debris. Most of the already developed capturing systems are designed for large specific cooperative satellites, which leads to expensive one-to-one solutions. This paper proposed a versatile hybrid-compliant mechanism to target a vast range of small uncooperative space debris in low Earth orbit (LEO), enabling a profitable one-to-many solution. The system is custom-built to fit into a CubeSat. It incorporates active (with linear actuators and impedance controller) and passive (with revolute joints) compliance to dissipate the impact energy, ensure sufficient contact time, and successfully help capture a broader range of space debris. A simulation study was conducted to evaluate and validate the necessity of integrating hybrid compliance into the ADR system. This study found the relationships among the debris mass, the system’s stiffness, and the contact time and provided the required data for tuning the impedance controller (IC) gains. This study also demonstrated the importance of hybrid compliance to guarantee the safe and reliable capture of a broader range of space debris.

Adaptive Control Scheme for Space Debris Capture in the Presence of Mass and Inertia Uncertainty

“…The Capturing Phase includes three sub-phases: Pre-Capture, Soft-Capture, and Hard-Capture [28]; these are in charge of the approach preparation, the impact absorption and stabilization, and the securing of the debris attachment. This paper focuses on the Soft Capture sub-phase.…”

“…In this class, among the different strategies, the rigid [20], [21] and flexible [22]- [26] robotic capturing mechanisms stand out as the most promising ones for their reliability [27]. In our previous work [28], we propose the integration of these two strategies into a unique concept. The proposed hybrid-compliant system is custom-built to fit a CubeSat.…”

“…An ADR mission consists of a succession of several crucial phases, being the capturing phase the most crucial one. In our previous work [28], we proposed a concept for the Capturing Phase. It includes three sub-phases: Pre-Capture (Approach Guidance & Control), Soft-Capture, and Hard-Capture; these are in charge of the approach preparation, the impact absorption and stabilization, and the securing of the debris attachment.…”

“…To address this challenge, our previous work [28] proposed an impedance-controlled hybrid-compliant FlexeS. Impedance Control (IC) stands out as a widely employed control strategy, regulating the relationship between the mechanism's tip position and the impact force [29], [30].…”

“…The novelty of the paper is based on the development of an adaptive control scheme for capturing uncooperative space debris in the presence of debris inertial parameter uncertainty. The proposed scheme integrates the IC control strategy employed by the ADR robotic mechanism presented in [28] with an identification law that estimates the required debris inertial parameters. From this point of view, the proposed controller is tailor for FlexeS oriented ADR robotic mechanism.…”