Reactionless camera inspection with a free-flying space robot under reaction null-space motion control

To overcome the problem of dynamics coupling between a space robot and a target satellite, this study introduces a new coordinated motion control approach with an adaptive filtering algorithm for a dual-arm free-floating space robot. Based on the reaction null space control scheme, one arm is used to complete the capture task and the other to counteract disturbance to the space base. However, when space robot captures a noncooperative target, the system may experience abrupt changes in dynamic parameters and output measurement noise, which can cause traditional control methods to achieve poor results in practical applications. Thus, an adaptive filtering algorithm with a variable forgetting factor is proposed to improve the tracking capabilities and robustness of the system. The convergence analysis is performed based on a Lyapunov function. The simulation results demonstrate the effectiveness of the proposed algorithm.

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Coordinated motion control of a dual-arm space robot with joint-limit avoidance and uncertain inertial parameters

International Journal of Advanced Robotic Systems ◽

10.1177/1729881417728020 ◽

2017 ◽

Vol 14 (5) ◽

pp. 172988141772802 ◽

Cited By ~ 3

Author(s):

Chunting Jiao ◽

Bin Liang ◽

Xueqian Wang ◽

Jingyan Song ◽

Bo Zhang

Keyword(s):

Motion Control ◽

Null Space ◽

Momentum Conservation ◽

Space Robot ◽

Coordinated Motion ◽

Control Approach ◽

Target Capture ◽

Inertial Parameters ◽

Dual Arm ◽

Joint Limit

In this article, a new adaptive coordinated motion control approach is introduced for a dual-arm free-floating space robot. This adaptive algorithm is used for the post-capture of a large noncooperative target with joint-limit avoidance and uncertain dynamic parameters. To overcome the problem of dynamics coupling between the space base, its manipulators, and the target, we develop a dual-arm space robotic system. One arm is used to complete the capture task and the other is used to counteract the disturbance to the space base. In this case, a new coordinated motion control law is derived based on reaction null space control. An improved joint-limit avoidance algorithm is implemented for large noncooperative target capture; otherwise, a significant base disturbance may result if the joint-limit constraints are not explicitly considered. Based on momentum conservation, the linear regression form of the estimation problem is obtained, and we further identify the unknown inertial parameters of the target. Finally, the simulation results demonstrate the effectiveness of the proposed algorithm.

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Assessment of Reaction-Null Space Based Motion Control During Practical Camera Inspection Task

The Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) ◽

10.1299/jsmermd.2016.2a2-17b3 ◽

2016 ◽

Vol 2016 (0) ◽

pp. 2A2-17b3

Author(s):

Hiroki SONE ◽

Kengo TAMOTO ◽

Daisuke SATO ◽

Yoshikazu KANAMIYA

Keyword(s):

Motion Control ◽

Null Space ◽

Reaction Null Space ◽

Inspection Task

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Research on Adaptive Reaction Null Space Planning and Control Strategy Based on VFF–RLS and SSADE–ELM algorithm for Free-Floating Space Robot

Electronics ◽

10.3390/electronics8101111 ◽

2019 ◽

Vol 8 (10) ◽

pp. 1111

Author(s):

Ye ◽

Dong ◽

Hong

Keyword(s):

Path Planning ◽

Control Strategy ◽

Null Space ◽

Robust Adaptive Control ◽

Space Robot ◽

Planning And Control ◽

Unknown Disturbance ◽

And Control ◽

Reaction Null Space ◽

Adaptive Reaction

With the increase of on-orbit maintenance and support requirements, the application of a space manipulator is becoming more promising. In actual operation, the strong coupling of the free-floating space robot itself and the unknown disturbance of the contact target caused a major challenge to the robot base posture control. Traditional Reaction Null Space (RNS) motion planning and control methods require the construction of precise dynamic models, which is impossible in reality. In order to solve this problem, this paper proposes a new Adaptive Reaction Null Space (ARNS) path planning and control strategy for the contact of free-floating space robots with unknown targets. The ARNS path planning strategy is constructed by the Variable Forgetting Factor Recursive Least Squares (VFF–RLS) algorithm. At the same time, a robust adaptive control strategy based on the Strategy Self-Adaption Differential Evolution–Extreme Learning Machine (SSADE–ELM) algorithm is proposed to track the dynamic changes of the planned path. The algorithm enables us to intelligently learn and compensate for the unknown disturbance. Then, this paper constructs a robust controller to compensate model uncertainty. A striking feature of the proposed strategy is that it does not require an accurate system model or any information about unknown attributes. This design can dynamically implement RNS path tracking performance. Finally, through simulation and experiment, the proposed algorithm is compared with the existing methods to prove its effectiveness and superiority.

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