Lyapunov Controller for Cooperative Space Manipulators
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Authors
Yale, G. E.
Agrawal, B.N.
Subjects
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Date of Issue
1998
Date
May-June, 1998
Publisher
Language
Abstract
The cooperative control of multiplemanipulatorsattached to the samebase asthey reposition a common payload
is discussed. The theory is easily appliedto inertially based problems, as well asspace-based free- oating platforms.
The system equations of motion are developed, as well as a Lyapunov-based controller that ensures stability. The
closed chain aspect of the problem reduces the system’s degrees of freedom resulting in more actuators than
degrees of freedom. This actuator redundancy is used to minimize a weighted norm of the actuator torques. A
polynomial reference trajectory describes the path the payload will follow. The disturbance torque transmitted
to the spacecraft centerbody by the motion of the manipulatorsis reduced by altering the order of the reference
trajectory polynomial and its coef cients. Results from a two-dimensional, dual-arm con guration are included.
Compared to the Lyapunov point controller alone, the addition of a fth-order polynomial reference trajectory
leads to superior performance in terms of actuator torque magnitudes,spacecraft centerbody attitude control, and
payload repositioning accuracy and time. An eighth-order polynomial reference trajectory results in only small
improvement over the fth-order case.
The cooperative control of multiplemanipulatorsattached to the samebase asthey reposition a common payload
is discussed. The theory is easily appliedto inertially based problems, as well asspace-based free- oating platforms.
The system equations of motion are developed, as well as a Lyapunov-based controller that ensures stability. The
closed chain aspect of the problem reduces the system’s degrees of freedom resulting in more actuators than
degrees of freedom. This actuator redundancy is used to minimize a weighted norm of the actuator torques. A
polynomial reference trajectory describes the path the payload will follow. The disturbance torque transmitted
to the spacecraft centerbody by the motion of the manipulatorsis reduced by altering the order of the reference
trajectory polynomial and its coef cients. Results from a two-dimensional, dual-arm con guration are included.
Compared to the Lyapunov point controller alone, the addition of a fth-order polynomial reference trajectory
leads to superior performance in terms of actuator torque magnitudes,spacecraft centerbody attitude control, and
payload repositioning accuracy and time. An eighth-order polynomial reference trajectory results in only small
improvement over the fth-order case.
The cooperative control of multiplemanipulatorsattached to the samebase asthey reposition a common payload
is discussed. The theory is easily appliedto inertially based problems, as well asspace-based free- oating platforms.
The system equations of motion are developed, as well as a Lyapunov-based controller that ensures stability. The
closed chain aspect of the problem reduces the system’s degrees of freedom resulting in more actuators than
degrees of freedom. This actuator redundancy is used to minimize a weighted norm of the actuator torques. A
polynomial reference trajectory describes the path the payload will follow. The disturbance torque transmitted
to the spacecraft centerbody by the motion of the manipulatorsis reduced by altering the order of the reference
trajectory polynomial and its coef cients. Results from a two-dimensional, dual-arm con guration are included.
Compared to the Lyapunov point controller alone, the addition of a fth-order polynomial reference trajectory
leads to superior performance in terms of actuator torque magnitudes,spacecraft centerbody attitude control, and
payload repositioning accuracy and time. An eighth-order polynomial reference trajectory results in only small
improvement over the fth-order case.
The cooperative control of multiplemanipulatorsattached to the samebase asthey reposition a common payload
is discussed. The theory is easily appliedto inertially based problems, as well asspace-based free- oating platforms.
The system equations of motion are developed, as well as a Lyapunov-based controller that ensures stability. The
closed chain aspect of the problem reduces the system’s degrees of freedom resulting in more actuators than
degrees of freedom. This actuator redundancy is used to minimize a weighted norm of the actuator torques. A
polynomial reference trajectory describes the path the payload will follow. The disturbance torque transmitted
to the spacecraft centerbody by the motion of the manipulatorsis reduced by altering the order of the reference
trajectory polynomial and its coef cients. Results from a two-dimensional, dual-arm con guration are included.
Compared to the Lyapunov point controller alone, the addition of a fth-order polynomial reference trajectory
leads to superior performance in terms of actuator torque magnitudes,spacecraft centerbody attitude control, and
payload repositioning accuracy and time. An eighth-order polynomial reference trajectory results in only small
improvement over the fth-order case.
Type
Article
Description
The article of record as published may be found at http://dx.doi.org/10.2514/2.4261
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Citation
AIAA Journal of Guidance, Control, and Dynamics, Vol. 21, No. 3, May-June, 1998, pp. 477-484.
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This publication is a work of the U.S. Government as defined
in Title 17, United States Code, Section 101. As such, it is in the
public domain, and under the provisions of Title 17, United States
Code, Section 105, is not copyrighted in the U.S.