Dynamics and Control of Spacecraft Manipulators with Thrusters and Momentum Exchange Devices

Antonello, Alessandro; Valverde, Alfredo; Tsiotras, Panagiotis

doi:10.2514/1.g003601

Cited by 21 publications

(10 citation statements)

References 23 publications

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“…A coordinated control scheme which considers the contribution of reaction wheels to the system angular momentum, has been studied in Jayakody et al (2016) modifying the Adaptive Variable Structure Control (AVSC) scheme to a SMS. In Antonello et al (2019) , coordinated control of both the servicing vehicle and the manipulator end-effector, in face of disturbances (e.g., point contact with a serviced satellite), was proposed. A method for coordinated control of both the manipulator end-effector and the servicing vehicle attitude, and the translation of the global system CoM, was proposed ( Giordano et al, 2019 ).…”

Section: Feedback Controlmentioning

confidence: 99%

Robotic Manipulation and Capture in Space: A Survey

Papadopoulos

Aghili

et al. 2021

Front. Robot. AI

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Space exploration and exploitation depend on the development of on-orbit robotic capabilities for tasks such as servicing of satellites, removing of orbital debris, or construction and maintenance of orbital assets. Manipulation and capture of objects on-orbit are key enablers for these capabilities. This survey addresses fundamental aspects of manipulation and capture, such as the dynamics of space manipulator systems (SMS), i.e., satellites equipped with manipulators, the contact dynamics between manipulator grippers/payloads and targets, and the methods for identifying properties of SMSs and their targets. Also, it presents recent work of sensing pose and system states, of motion planning for capturing a target, and of feedback control methods for SMS during motion or interaction tasks. Finally, the paper reviews major ground testing testbeds for capture operations, and several notable missions and technologies developed for capture of targets on-orbit.

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Section: Feedback Controlmentioning

confidence: 99%

Robotic Manipulation and Capture in Space: A Survey

Papadopoulos

Aghili

et al. 2021

Front. Robot. AI

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“…Similar to [6,7,9], the authors of [54,65] made use of the target's inertial parameters to plan a detumbling trajectory that would bring the target's tumbling motion to rest in minimum time while being subjected to a torque limit at the endeffector. In [6,7,9,65], coordinated control of the servicer's base and its manipulator (i.e., [12,17]) is implemented to simultaneously track the desired end-effector detumbling trajectory and to reject the gained target's momentum as it is brought to rest.…”

Section: Ideal Scenariomentioning

confidence: 99%

Detumbling a Non-Cooperative Space Target With Unknown Inertial Parameters Using a Space Manipulator Subjected to End-Effector Force/Torque Limits

Gangapersaud¹

2021

Preprint

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This study addresses the problem of detumbling a non-cooperative space target, such as a malfunctioning satellite, using a space robot for the purpose of performing on-orbit servicing. The space robot is denoted as the servicer and consists of a satellite base equipped with a robotic manipulator. The formulation of a detumbling control strategy must respect limits on the grasping force and torque at the servicer’s end-effector without knowledge of the target’s inertial parameters (mass, inertia tensor, location of center of mass). In the literature, prior studies have formulated detumbling strategies under the assumption of accurate knowledge of the target’s inertial parameters. However, obtaining accurate estimates of the target’s inertial parameters is difficult, and parameter uncertainty may lead to instability and violation of the end-effector force/torque limits. This study will address the problem of detumbling a noncooperative target with unknown but bounded inertial parameters subjected to force/torque limits at the servicer’s end-effector. In this study, two detumbling control strategies are presented. The first detumbling strategy is presented under the assumption that force/torque measurements at the end-effector are available. Detumbling of the target is achieved by applying a reference force/torque to the target that is designed to bring the target’s tumbling motion to rest subjected to force/torque limits. To ensure stable detumbling of the target, a robust compensator is designed based on bounds of the target’s unknown inertial parameters. Furthermore, once the detumbling process starts, in order to reduce the robust control gains, bounds on the target’s unknown inertial parameters are estimated in real-time. The resultant detumbling controller enables the servicer to detumble the target while complying with the target’s unknown residual tumbling motion. The second detumbling control strategy is developed without the need of end-effector’s force/torque measurements and takes into account magnitude constraints on servicer’s control inputs in the detumbling controller’s design. Detumbling is achieved by tracking a desired detumbling trajectory that is delineated subjected to end-effector force/torque limits and requires bounds on the target’s inertial parameters. The hyperbolic tangent function is utilized to model the magnitude constraints on the servicer’s control inputs, resulting in a system that is non-affine in its control inputs. As a result, an augmented model of the servicer is presented to allow the formulation of the detumbling controller. Using bounds on the target’s inertial parameters, robust adaptive control approach is utilized to design the detumbling controller with the backstepping technique in order to track the desired detumbling trajectory and to reject the gained target’s momentum. Numerical simulation studies were conducted for both detumbling control strategies utilizing a servicer equipped with a 7-degree-of-freedom (DOF) manipulator. The results demonstrate that both control strategies are capable of detumbling a non-cooperative target with unknown inertial parameters subjected to force/torque limits. Experiments conducted with a 3-DOF manipulator demonstrate that the design procedure utilized to delineate the desired detumbling trajectory in the second detumbling strategy respects force/torque limits at the end effector. The study is concluded with a discussion comparing the two proposed detumbling strategies by highlighting their advantages and disadvantages.

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“…Although the coordination of thrusters and momentum exchange devices is not new in the field of single-body space systems, to the best of the authors' knowledge there is a substantial lack of methods to coordinately steer the thrusters, the momentum exchange devices, and the arm in case of a multibody system. A control strategy was derived in [31], which uses the thrusters for controlling the translation of the spacecraft and the momentum exchange devices for controlling the rotation, while the arm is commanded to follow a desired trajectory. However, the requirement of controlling the translation of the spacecraft leads to increased fuel consumption during the pre-contact phase of the robotic operation.…”

Section: Introductionmentioning

confidence: 99%

“…A different and more fuel-efficient requirement of controlling the translation of the center-of-mass (CoM) of the whole space robot may be enforced for stabilizing the translational motion, as observed in [30,32]. Compared to a base-control strategy such as [31], a CoM-control approach employs ideally 1 no thrusters during the pre-contact phase, because the CoM naturally conserves. Compared to a free-floating strategy, a CoM-control approach can stop the inertial drift during the post-contact phase.…”

Section: Introductionmentioning

confidence: 99%

Coordination of thrusters, reaction wheels, and arm in orbital robots

Giordano

Dietrich

Ott

et al. 2020

Robotics and Autonomous Systems

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A fuel-efficient control strategy for a manipulator-equipped spacecraft is presented. The strategy uses the thrusters, the reaction wheels, and the arm drives in a coordinated way to limit the use of the thrusters and achieve ideally zero fuel consumption in contact-free maneuvering. The thrusters are activated automatically only after contact, to stabilize the inertial motion of the system. The controller regulates the translation of the center-of-mass (CoM) of the whole space robot, the rotation of the spacecraft, and the pose of the end-effector (EE) in a decoupled way, utilizing the thrusters to control the CoM translation only and the remaining actuators to control the rotation and endeffector coordinately. The method is validated experimentally using a hardware-in-the-loop simulator composed of a seven degrees-of-freedom (DOF) arm mounted on a 6DOF simulated spacecraft. Numerical simulations with discrete thrusters assess the fuel efficiency of the proposed strategy.

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Dynamics and Control of Spacecraft Manipulators with Thrusters and Momentum Exchange Devices

Cited by 21 publications

References 23 publications

Robotic Manipulation and Capture in Space: A Survey

Robotic Manipulation and Capture in Space: A Survey

Detumbling a Non-Cooperative Space Target With Unknown Inertial Parameters Using a Space Manipulator Subjected to End-Effector Force/Torque Limits

Coordination of thrusters, reaction wheels, and arm in orbital robots

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