Disturbance Observer-based Impedance Control for a Compliance Capture of an Object in Space

Flores-Abad, Ángel; Crain, Alexander; Nandayapa, Manuel; Garcia-Teran, Miguel A.; Ulrich, Steve

doi:10.2514/6.2018-1329

Cited by 17 publications

(11 citation statements)

References 18 publications

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“…Roveda et al [8], [9] designed an optimal impedance force-tracking controller to obtain the performance of partially unknown contact environment properties even with errors in the initial estimate of the environment stiffness. Flores-Abad et al [10] proposed a disturbance-based impedance controller for the compliance capture of an object using a free floating robot. Zeng et al [11] used impedance control as the control outer loop to complete a peg-in-hole assembly task.…”

Section: Eliminating the Deviation Of A Workpiece Position By Robotmentioning

confidence: 99%

A Robotic Peg-in-Hole Assembly Strategy Based on Variable Compliance Center

Wang

Chen

et al. 2019

IEEE Access

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Many kinds of peg-in-hole assembly strategies for an industrial robot have been reported in recent years. Most of these strategies are realized by utilizing visual and force sensors to assist robots. However, complex control algorithms that are based on visual and force sensors will reduce the assembly efficiency of a robot. This issue is thoughtless in traditional assembly strategies but is critical to further improve the efficiency of assembly automation. In this work, a new assembly strategy that is based on a displacement sensor and a variable compliant center is proposed to improve robot performance in assembly tasks. First, an elastic displacement device for this assembly strategy is designed, and its performance is analyzed. The displacement signal generated by the displacement sensor is used to detect the contact state of the peg and hole and to guide the robot to adjust the posture. Second, an assembly strategy, including the advantages of passive compliance and active compliance, and a simple assembly control system are designed to improve the assembly efficiency. Last, the effectiveness of the proposed assembly method is experimentally verified using a robot with 6 degrees of freedom and a chamferless peg and hole with a small clearance (0.1 mm). The experimental results show that the assembly strategy can successfully complete the precision peg-in-hole assembly and assist the robot in accurate assembly in industrial applications.

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Section: Eliminating the Deviation Of A Workpiece Position By Robotmentioning

confidence: 99%

A Robotic Peg-in-Hole Assembly Strategy Based on Variable Compliance Center

Wang

Chen

et al. 2019

IEEE Access

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show abstract

“…The related research [4][5][6][7][8][9] shows that the space robot is in a free-floating state during the process of capturing the target, and the collision from the target contact may lead to a large pulse momentum. The strong dynamic coupling between the spacecraft base and the manipulator may lead to instability of the attitude of the space robot base, which in turn may cause problems such as space robot rollover.…”

Section: Introductionmentioning

confidence: 99%

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

Dong

Hong

2019

Electronics

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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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“…Related studies [4][5][6] have shown that when using the traditional multi-rigid manipulator to carry out space debris removal tasks, collisions from non-cooperative target contacts such as space debris may lead to large pulse momentum, which may cause problems such as space manipulator tumbling. The space manipulator equipped with a flexible mechanism can better achieve the collision force buffering and unloading during the contact with the non-cooperative target.…”

mentioning

confidence: 99%

Research on Angle and Stiffness Cooperative Tracking Control of VSJ of Space Manipulator Based on LESO and NSFAR Control

Hong

Dong

2019

Electronics

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With the increase in on-orbit maintenance and support requirements, the application of space manipulator is becoming more promising. However, how to control the vibration generated by the space manipulator has been a difficult problem to be solved. The advent of variable stiffness joint (VSJ) has brought about a dawn in solving this problem. But how to achieve coordinated control of joint angle and stiffness is still a problem to be solved, especially when considering system model parameter uncertainty, unknown disturbance and control input saturation. In order to realize the controllable attenuation of the vibration of the space flexible manipulator based on the variable stiffness joint, the dynamic model of the variable stiffness joint was constructed. Then the linear transformation and feedback linearization method are used to transform its complex nonlinear dynamic model system into a pseudo-linear system containing aggregate disturbance and input saturation constraints. This paper constructs a linear extended state observer (LESO) for estimating the state of unknown systems in pseudo-linear systems. Based on the idea of state feedback control, a Neural State Feedback Adaptive Robust (NSFAR) control is constructed by using Radial Basis Function Neural Network. The adaptive input saturation compensation control law is also designed by using Radial Basis Function Neural Network to deal with the input saturation compensation problem. The ultimate uniform bounded stability of the constructed system is proved by the stability analysis based on Lyapunov function. Finally, the effectiveness and superiority of the constructed tracking algorithm are verified by compared simulation and semi-physical experiment.

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Disturbance Observer-based Impedance Control for a Compliance Capture of an Object in Space

Cited by 17 publications

References 18 publications

A Robotic Peg-in-Hole Assembly Strategy Based on Variable Compliance Center

A Robotic Peg-in-Hole Assembly Strategy Based on Variable Compliance Center

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

Research on Angle and Stiffness Cooperative Tracking Control of VSJ of Space Manipulator Based on LESO and NSFAR Control

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