Trajectory Tracking for Two-Link Flexible Arm via Two-Time Scale and Boundary Control Methods

2008 ◽  
Author(s):  
A. Ashayeri ◽  
M. Eghtesad ◽  
M. Farid
Keyword(s):  
Trajectory Tracking ◽  
Time Scale ◽  
Perturbation Approach ◽  
Inverse Dynamic ◽  
Flexible Arm ◽  
Control Scheme ◽  
Fast Control ◽  
And Control ◽  
Scale Control ◽  
Composite Control Scheme

Main purpose of the study presented in this paper is to demonstrate the boundary controllers design by singular perturbation approach for trajectory tracking of two-link flexible arm. Applying the two-time scale control theory on the nonlinear PDE model, a control scheme is elaborated which makes hubs’ angles track a desired trajectory while damping out the links vibration. In the proposed controller, fast (flexible) subsystem controller will damp out the vibration of the flexible links by a Lyapunov-type design and the other slow (rigid) subsystem Inverse Dynamic controller dominates the trajectory tracking. These two controllers constitute the composite control scheme. The method does not require any information about the vibration of the links along the links for the proposed fast control law as well as discretizing the PDE of arm vibration to set of ODEs. Therefore, the method excludes the effect of both observation and control spillover instability. The simulation results confirm that the proposed boundary controllers are quite effective in performance.

Output Feedback Two-Time Scale Control of Multilink Flexible Arms

1992 ◽  
Vol 114 (1) ◽  
pp. 70-77 ◽  
Author(s):  
B. Siciliano ◽  
J. V. R. Prasad ◽  
A. J. Calise
Keyword(s):  
Output Feedback ◽  
Time Scale ◽  
Complex Dynamics ◽  
Industrial Robots ◽  
Flexible Arm ◽  
Loop Transfer Recovery ◽  
Recovery Technique ◽  
Flexible Arms ◽  
Fast Control ◽  
Scale Control

Lightweight flexible arms will most likely constitute the next generation robots. The design key is the adoption of flexible links, rather than rigid links like in today’s industrial robots. Despite all the potential advantages achievable with a flexible arm, the control problem is complex, due to the introduction of increasingly more complex dynamics. This paper represents an effort toward the goal of designing efficient control systems for multilink flexible arms. A two-time scale approach is pursued which allows the adoption of a composite control strategy. First a slow control can be designed for the slow (rigid) sybsystem, then a fast stabilizing control for the fast (flexible) subsystem. The main contribution of the paper is to address the problem of lack of full state measurements concerned with the fast control design. An output feedback dynamic compensator of fixed order is designed. Its optimal gains are computed according to a loop transfer recovery technique in order to obtain a robust design. The control is tested by means of simulation results for a nonlinear model of a two-link flexible arm.

Inverse Dynamics Based Trajectory Tracking for a One-Link Flexible Arm

1991 ◽  
Author(s):  
Santiago López-Linares ◽  
Roberto F. Jacobus ◽  
Eliodoro Carrera ◽  
Miguel A. Serna
Keyword(s):  
Trajectory Tracking ◽  
Dynamic Problem ◽  
Inverse Dynamics ◽  
Open Loop ◽  
Flexible Manipulator ◽  
Linear Quadratic ◽  
Unknown Parameters ◽  
Inverse Dynamic ◽  
Flexible Arm ◽  
Inverse Dynamic Problem

Abstract This paper presents a new method for controlling a one-link flexible manipulator, based on the solution to the Inverse Dynamic Problem and on a Linear Quadratic Gaussian regulator (LQG). The inverse dynamic solution provides the torque that must be applied by the actuator at the hub to obtain a given trajectory at the tip. This torque can then be used in an open-loop control but, in practice, errors in tip position will appear along the way due to friction, unknown parameters in the model, disturbances, etc. To cope with these problems a trajectory following control is suggested. The technique consists in designing an LQG capable of driving the arm to intermediate states computed in the Inverse Dynamic Problem. Computer simulations with a Finite Element Model of the flexible arm are presented showing a very accurate trajectory tracking.

A two-time scale control scheme for on-orbit manipulation of large flexible module

2019 ◽  
Vol 154 ◽  
pp. 92-102 ◽  
Author(s):  
Meibao Yao ◽  
Xueming Xiao ◽  
Yang Tian ◽  
Hutao Cui
Keyword(s):  
Time Scale ◽  
Control Scheme ◽  
Scale Control

scholarly journals Robust Course Keeping Control of a Fully Submerged Hydrofoil Vessel with Actuator Dynamics: A Singular Perturbation Approach

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Sheng Liu ◽  
Changkui Xu ◽  
Lanyong Zhang
Keyword(s):  
Feedback Control ◽  
Time Scale ◽  
Lyapunov Stability Theory ◽  
State Feedback Control ◽  
Scale Model ◽  
Perturbation Approach ◽  
Actuator Dynamics ◽  
Marine Surface ◽  
Scale Control ◽  
The Mathematical Model

This paper presents a two-time scale control structure for the course keeping of an advanced marine surface vehicle, namely, the fully submerged hydrofoil vessel. The mathematical model of course keeping control for the fully submerged hydrofoil vessel is firstly analyzed. The dynamics of the hydrofoil servo system is considered during control design. A two-time scale model is established so that the controllers of the fast and slow subsystems can be designed separately. A robust integral of the sign of the error (RISE) feedback control is proposed for the slow varying system and a disturbance observer based state feedback control is established for the fast varying system, which guarantees the disturbance rejection performance for the two-time scale systems. Asymptotic stability is achieved for the overall closed-loop system based on Lyapunov stability theory. Simulation results show the effectiveness and robustness of the proposed methodology.

Identification of Flexible Link Dynamics Using Neural Networks

1992 ◽  
Author(s):  
Lawrence D’Arcangelis ◽  
Satish S. Nair
Keyword(s):  
Neural Networks ◽  
Dynamic Systems ◽  
Time Scale ◽  
Flexible Link ◽  
Preliminary Results ◽  
Flexible Arm ◽  
Single Link ◽  
On Line ◽  
And Control

Abstract Multilayered neural networks have found widespread use in the identification and control of dynamic systems. This study considers modeling issues for two time scale systems using neural networks for reliably estimating gradients for on-line control purposes. A structure for identification of a single link flexible arm is proposed and preliminary results are presented.

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