Experimental two-axis vibration suppression and control of a flexible robot arm

The dynamic analysis and control of flexible robot manipulators have been the main concerns of many recent studies in aeronautics and robotics. Moreover, the complexity of this problem increases when a flexible manipulator carries a payload. In this paper, we proposed a space two-link flexible manipulator with tip payload featuring surface-bonded piezoelectric torsional actuator and shear actuator. The equations of motion for the system are obtained using Hamilton’s principle. A Lyapunov-based controller is proposed to suppress the vibration of the system. Stability of the system is also investigated. The simulation results demonstrate the proposed control strategy is well suited for active control of vibration suppression on flexible manipulators.

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Experimental Investigation of Vibration Suppression Control for Flexible Robot Arm

Volume 6: International Symposium on Motion and Vibration Control ◽

10.1115/detc99/movic-8403 ◽

1999 ◽

Author(s):

Kengo Inoue ◽

Nobuyuki Kobayashi

Keyword(s):

Output Feedback ◽

Vibration Suppression ◽

Sliding Mode ◽

Output Feedback Control ◽

Sliding Mode Controller ◽

Robot Arm ◽

Flexible Robot ◽

Modeling Methodology ◽

Flexible Arm ◽

Good Agreement

Abstract Experimental evaluation of the vibration suppression control performance about the output feedback sliding mode controller for the two-link flexible robot arm is presented. The reduce-order controller is designed based on a kind of the component mode synthesis modeling methodology, and is also designed by the combination of the suboptimal output feedback control and the sliding mode control algorithm. From the experiments of the two-link flexible robot arm model, the good agreement between the numerical simulation results and the experimental ones are obtained not only the motion of the joints but also the arm vibration. And it is verified that the presented output feedback sliding mode controller suppresses the vibration of the flexible arm quit well for various attitude.

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Mechatronic robot arm with active vibration absorbers

Journal of Vibration and Control ◽

10.1177/1077546320918488 ◽

2020 ◽

Vol 26 (13-14) ◽

pp. 1145-1156 ◽

Cited By ~ 1

Author(s):

Karel Kraus ◽

Zbyněk Šika ◽

Petr Beneš ◽

Jan Krivošej ◽

Tomáš Vyhlídal

Keyword(s):

Vibration Suppression ◽

High Accuracy ◽

Robot Arm ◽

Frequency Range ◽

Flexible Robot ◽

Linear Quadratic ◽

Mass System ◽

End Effector ◽

End Point ◽

Serial Robots

Serial robots are typically able to cover large workspace, but their mass/stiffness ratio does not allow combining high accuracy and high dynamic of the end effector operations. Widely spread usage of serial robots, even for tasks such as drilling, leads to high accuracy demands through its workspace. Absolute measurement of the end point for position feedback can be challenging due to objects or even a workpiece in the workspace. Moreover, inbuilt motors of the serial robot cannot response in the frequency range high enough as vibration of the end point. Instead, an additional spring–mass system is attached to the robot to suppress vibrations. The narrow frequency range of a passive dynamic absorber can be extended with active elements between the robot and absorber. An active approach is also necessary because of robots eigenfrequencies and eigenmodes variability. The study deals with a planar flexible robot equipped with a three-degree-of-freedom planar active absorber. The absorber is tuned passively to one value of multiple eigenfrequency. The linear-quadratic regulator control with a state observer has been designed as an active absorber control algorithm. Feedback inputs are absorber body acceleration, end effector acceleration, and relative motions in three absorber actuators realized by voice coils. The end effector vibration suppression along the robot trajectory is achieved using gain scheduling of local controller’s outputs.

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