Real-time dynamic singularity avoidance while visual servoing of a dual-arm space robot
TL;DR: This paper presents a real-time dynamic singularity avoidance approach for such autonomous free-floating space robots where visual servoing is used as feedback in the control loop and uses manipulability measure as distance criteria and does not require any prior knowledge of singular configurations.
Abstract: Singularity of robotic manipulators is an important issue in the stability and control of autonomous robotic systems. This paper presents a real-time dynamic singularity avoidance approach for such autonomous free-floating space robots where visual servoing is used as feedback in the control loop. The proposed method uses manipulability measure as distance criteria and does not require any prior knowledge of singular configurations. Velocities in task space are projected on a surface of constant manipulability measure to avoid singular configurations. Numerical experiments are carried out, to validate the proposed method, on a 6-Degrees-of-Freedom dual-arm space robot mounted on a service satellite.
Citations
More filters
[...]
TL;DR: The field of space robotics regarding the kinematics, dynamics and control of manipulators mounted onto spacecraft is explored, concluding that space robotics is well-developed and sufficiently mature to tackling tasks such as active debris removal.
Abstract: Space-based manipulators have traditionally been tasked with robotic on-orbit servicing or assembly functions, but active debris removal has become a more urgent application. We present a much-needed tutorial review of many of the robotics aspects of active debris removal informed by activities in on-orbit servicing. We begin with a cursory review of on-orbit servicing manipulators followed by a short review on the space debris problem. Following brief consideration of the time delay problems in teleoperation, the meat of the paper explores the field of space robotics regarding the kinematics, dynamics and control of manipulators mounted onto spacecraft. The core of the issue concerns the spacecraft mounting which reacts in response to the motion of the manipulator. We favour the implementation of spacecraft attitude stabilisation to ease some of the computational issues that will become critical as increasing level of autonomy are implemented. We review issues concerned with physical manipulation and the problem of multiple arm operations. We conclude that space robotics is well-developed and sufficiently mature to tackling tasks such as active debris removal.
15 citations
Cites background from "Real-time dynamic singularity avoid..."
[...]
[...]
TL;DR: A method named off-line optimizing visual servoing algorithm is innovatively proposed to minimize the base disturbance during the visual Servoing process where the degrees-of-freedom of the manipulator is not enough for a zero-reaction control.
Abstract: During visual servoing space activities, the attitude of free-floating space robot may be disturbed due to dynamics coupling between the satellite base and the manipulator. And the disturbance may cause communication interruption between space robot and control center on earth. However, it often happens that the redundancy of manipulator is not enough to fully eliminate this disturbance. In this paper, a method named off-line optimizing visual servoing algorithm is innovatively proposed to minimize the base disturbance during the visual servoing process where the degrees-of-freedom of the manipulator is not enough for a zero-reaction control. Based on the characteristic of visual servoing process and the robot system modeling, the optimal control method is applied to achieve the optimization, and a pose planning method is presented to achieve a second-order continuity of quaternion getting rid of the interruption caused by ambiguity. Then simulations are carried out to verify the method, and the results show that the robot is controlled with optimized results during visual servoing process and the joint trajectories are smooth.
4 citations
Additional excerpts
[...]
[...]
TL;DR: Neural networks are constructed under the proposed torque control design as to approximate the unknown dynamics and achieve small tracking errors in the operation-space to cope with the unknown and unstructured dynamic nonlinearities of the robot model.
Abstract: In this paper, adaptive operation-space control with joint limits avoidance is proposed for a redundant robot manipulator. Utilizing redundant properties of the robotic manipulator, joint limits avoidance is achieved without interfering the main-task objective in the operation-space. Two control objectives are unified under one common control framework. To cope with the unknown and unstructured dynamic nonlinearities of the robot model, neural networks (NNs) are constructed under the proposed torque control design as to approximate the unknown dynamics and achieve small tracking errors. Simulation studies are carried out to verify the effectiveness of the proposed framework.
2 citations
References
More filters
[...]
TL;DR: In this article, a measure of manipulability of robotic mechanisms in positioning and orienting end-effectors has been proposed and the best postures of various types of manipulators are given, and a four degree-of-freedom finger is considered from the viewpoint of the measure.
Abstract: This paper discusses the manipulating ability of robotic mechanisms in positioning and orienting end-effectors and proposes a measure of manipulability. Some properties of this measure are obtained, the best postures of various types of manipulators are given, and a four-degree-of-freedom finger is considered from the viewpoint of the measure. The pos tures somewhat resemble those of human arms and fingers.
2,097 citations
"Real-time dynamic singularity avoid..." refers background in this paper
[...]
[...]
[...]
30 Nov 2006
TL;DR: This paper is the first of a two-part series on the topic of visual servo control using computer vision data in the servo loop to control the motion of a robot using basic techniques that are by now well established in the field.
Abstract: This paper is the first of a two-part series on the topic of visual servo control using computer vision data in the servo loop to control the motion of a robot. In this paper, we describe the basic techniques that are by now well established in the field. We first give a general overview of the formulation of the visual servo control problem. We then describe the two archetypal visual servo control schemes: image-based and position-based visual servo control. Finally, we discuss performance and stability issues that pertain to these two schemes, motivating the second article in the series, in which we consider advanced techniques
1,775 citations
[...]
TL;DR: The authors develop a control method for space manipulators based on the resolved motion control concept that is widely applicable in solving not only free-flying manipulation problems but also attitude-control problems.
Abstract: The authors establish a control method for space manipulators taking dynamical interaction between the manipulator arm and the base satellite into account. The kinematics of free-flying multibody systems is investigated by introducing the momentum conservation law into the formulation and a novel Jacobian matrix in generalized form for space robotic arms is derived. The authors develop a control method for space manipulators based on the resolved motion control concept. The proposed method is widely applicable in solving not only free-flying manipulation problems but also attitude-control problems. The validity of the method is demonstrated by computer simulations with a realistic model of a robot satellite. >
523 citations
"Real-time dynamic singularity avoid..." refers methods in this paper
[...]
[...]
358 citations
"Real-time dynamic singularity avoid..." refers methods in this paper
[...]
[...]
TL;DR: The existence of the ZRM is very limited for a 6 DOF manipulator arm mounted on a free-flying base, but it is discussed how more operational freedom is obtained with a kinematically redundant arm.
Abstract: Presents the experimental results and post-flight analysis of reaction null-space based reactionless manipulation, or zero reaction maneuver (ZRM). The concept has been developed with an insight into the motion dynamics of free-flying multibody systems and its practical availability is clearly demonstrated with ETS-VII, a Japanese space robot. The ZRM is proven particularly useful for removing the velocity limit of manipulation due to the reaction constraint and the time loss due to waiting for the attitude recovery. The existence of the ZRM is very limited for a 6 DOF manipulator arm mounted on a free-flying base, but it is discussed how more operational freedom is obtained with a kinematically redundant arm.
139 citations
Related Papers (5)
[...]
[...]
[...]