Distributed disturbance-observer-based vibration control for a flexible-link manipulator with output constraints

This article investigates an adaptive neural network (NN) control algorithm for marine surface vessels with time-varying output constraints and unknown external disturbances. The nonlinear state-dependent transformation (NSDT) is introduced to eliminate the feasibility conditions of virtual controller. Moreover, the barrier Lyapunov function (BLF) is used to achieve time-varying output constraints. As an important approximation tool, the NN is employed to approximate uncertain and continuous functions. Subsequently, the disturbance observer is structured to observe time-varying constraints and unknown external disturbances. The novel strategy can guarantee that all signals in the closed-loop system are semiglobally uniformly ultimately bounded (SGUUB). Finally, the simulation results verify the benefit of the proposed method.

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Active vibration control of a flexible link robot with the use of piezoelectric actuators

MATEC Web of Conferences ◽

10.1051/matecconf/201814811005 ◽

2018 ◽

Vol 148 ◽

pp. 11005 ◽

Cited By ~ 1

Author(s):

Darren Williams ◽

Hamed Haddad Khodoparast ◽

Chenyuang Yang

Keyword(s):

Vibration Control ◽

Research Effort ◽

Active Vibration Control ◽

Beam Theory ◽

Flexible Link ◽

Flexible Links ◽

Robot Systems ◽

Active Vibration ◽

Euler Bernoulli Beam ◽

General Method

Within robot systems the use of flexible links could solve many issues raised by their rigid counterparts. However, when these flexible links are integrated within systems which include moving parts their main issue lies in the vibrations experienced along their length due to disturbances. Much research effort has been made to solve this issue, with particular attention being paid to the application of piezoelectric patches as actuators within active vibration control (AVC). The study will consist of accurate models of a flexible link and two surface bonded piezoelectric patches, where the link and the piezoelectric patches will be modelled through the use of Euler-Bernoulli beam theory (EBT). The link will be subject to an initial displacement at its free end, and the resulting displacement of this end of the beam is to be controlled using a classic proportional-differential (PD) controller. The voltages to be applied across each of the actuators is to be controlled in accordance with the displacement of the free end of the beam, the actuators will then induce a strain upon the link opposing the movement of the tip. This research outlines this general method, obtains the best location of the piezoelectric patches and the control gains to be used, and proves that the method can be used to attenuate the vibrations experienced by a flexible link.

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Motion and Vibration Control for Robot Arm with Elastic Joint. Application of Disturbance Observer Including Elastic Vibration.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C ◽

10.1299/kikaic.60.3045 ◽

1994 ◽

Vol 60 (577) ◽

pp. 3045-3050 ◽

Cited By ~ 4

Author(s):

Koichi Honke ◽

Yoshio Inoue ◽

Yoshiharu Nishida ◽

Toshihiko Nishimura

Keyword(s):

Vibration Control ◽

Disturbance Observer ◽

Elastic Vibration ◽

Robot Arm ◽

Elastic Joint ◽

Joint Application

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Delayed Reference Control Applied to Flexible Link Mechanisms: A Scheme for Effective and Stable Control

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.4005039 ◽

2011 ◽

Vol 134 (1) ◽

Cited By ~ 11

Author(s):

Giovanni Boschetti ◽

Dario Richiedei ◽

Alberto Trevisani

Keyword(s):

Vibration Control ◽

Vibration Damping ◽

Flexible Link ◽

Damping Force ◽

Flexible Links ◽

Equivalent Damping ◽

The Stability ◽

Delayed Time ◽

Reference Input ◽

Stable Control

This paper extends the use of delayed reference controllers to the simultaneous motion and vibration control of flexible link mechanisms. Vibration damping is achieved by introducing an “equivalent damping force” into the system through the computation of a suitable delayed time. The delayed time, which is based on the measured vibrations, is then employed in the trajectory planner to set the reference input. The stability of the controller is discussed and its effectiveness is proved by applying it to a four-bar planar linkage with flexible links.

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