Space is the driving force of the world’s sustainable development, and ensuring the sustainability of human activity in space is also necessary. Robotic arm active debris capture removal (RA-ADCR) is a noteworthy technology for containing the dramatic increase in space debris and maintaining orbital safety. This review divides the RA-ADCR technology progress history into three periods and presents the status of related research. Two major development trends are summarized and subdivided through the analysis and collation of research achievements over the past three years. Taking the treatment of parameter uncertainties as the entry point, researchers would like to improve the discrimination accuracy and scope to reduce uncertainties. On the other hand, researchers accept such uncertainties and would like to offset and avoid the impact of uncertainties by extending the error margins. Subsequently, the challenges of RA-ADCR are analyzed in line with the task execution flow, which mainly focuses on the conflict between on-satellite computing power and the performance of task execution. In addition, feasible solutions for the current phase are discussed. Finally, future outlooks are evaluated and discussed.

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This paper mainly studies the practical fault tolerant formation tracking for multi-agent systems under directed topology. The objective is to achieve the desired formation in the spatial positions and track the reference signal generated by one and multiple leaders. Considering that the real state information is unavailable, the distributed observer is proposed using the relative information of neighborhood agents, where the observer gain calculation is not constrained by the number of agents. With the adaptive updating mechanism, two effective distributed fault-tolerant formation tracking protocols are proposed and the feasible condition of time-varying formation is introduced. Furthermore, based on the proposed control protocol, the formation tracking errors and other signals converge to bounded region around the origin. Towards the end, three simulations are considered to illustrate the effectiveness of the proposed techniques.