Tracking control of a flexible-link manipulator using neural networks: experimental results

Robotica ◽  
2002 ◽  
Vol 20 (4) ◽  
pp. 417-427 ◽  
Author(s):  
H.A. Talebi ◽  
K. Khorasani ◽  
R. V. Patel
Keyword(s):  
Neural Network ◽  
Tracking Control ◽  
Dynamic Range ◽  
Experimental Results ◽  
Flexible Manipulator ◽  
System Response ◽  
Position Tracking ◽  
Pd Controller ◽  
Flexible Link ◽  
Tracking Controller

In this paper, the problem of tip position tracking control of a flexible-link manipulator is considered. Two neural network schemes are presented. In the first scheme, the controller is composed of a stabilizing joint PD controller and a neural network tracking controller. The objective is to simultaneously achieve hub-position tracking and control of the elastic deflections at the tip. In the second scheme, tracking control of a point along the arm is considered to avoid difficulties associated with the output feedback control of a non-minimum phase flexible manipulator. A separate neural network is employed for determining an appropriate output to be used for feedback. The controller is also composed of a neural network tracking controller and a stabilizing joint PD controller. Experimental results on a single-link flexible manipulator show that the proposed networks result in significant improvements in the system response with an increase in controller dynamic range despite changes in the desired trajectory.

Cascaded Robust Nonlinear Position Tracking Control of an Electrohydraulic Actuator: Sliding Mode and Feed Forward

2006 ◽  
Author(s):  
Beshahwired Ayalew ◽  
Kathryn W. Jablokow
Keyword(s):  
Tracking Control ◽  
Measurement Errors ◽  
Sliding Mode ◽  
Test System ◽  
Position Tracking ◽  
Performance Bounds ◽  
Feed Forward ◽  
Tracking Controller ◽  
Force Tracking ◽  
Position Tracking Control

An approach to position tracking control based on a cascade of a nonlinear force tracking controller derived from a near input-output linearization framework and a simple feedback plus feed forward position controller is presented. The method exploits the cascade structure to employ a sliding mode pressure force tracking controller as inner-loop and the position tracking controller as an outer-loop. Furthermore, it is highlighted that Lyapunov backstepping analysis can be used to drive performance bounds and reveal trade-offs between the size of uncertainty and measurement errors and the tracking accuracy. The performance of the proposed cascaded robust controller is demonstrated with experiments and simulations on a test system that doesn't necessarily satisfy all of the assumptions made for controller derivation. In particular, a typical comparison of the robust and nominal cascade controllers shows the robust version can recover the performance of the nominal near IO linearizing controller. In addition, model simulation results are included to show the performance of the controller in the presence of some combinations of perturbations or difficult to estimate parameters such as valve coefficient, supply pressure, piston friction, and inclusion of servovalve spool dynamics.

A force observation method for tracking control of flexible-link manipulators

Robotica ◽  
2012 ◽  
Vol 31 (4) ◽  
pp. 669-677 ◽  
Author(s):  
S. Farokh Atashzar ◽  
M. Shahbazi ◽  
H. A. Talebi ◽  
F. Towhidkhah
Keyword(s):  
Tracking Control ◽  
Flexible Manipulator ◽  
Control Technique ◽  
Flexible Link ◽  
Robust Controller ◽  
Estimation Errors ◽  
Control Scheme ◽  
Lyapunov Redesign ◽  
Single Link ◽  
Observation Method

SUMMARYIn this paper, a composite controller is proposed for single-link flexible manipulators exposed to external tip force disturbances. In the proposed scheme, the extended Kalman filter is utilized to observe the environmental forces and the Lyapunov redesign robust controller is applied to control the destabilizing effect of the observation errors in noisy situations. The observed force can be utilized in different applications (such as tele-surgical robotics) in order to eliminate the necessity of additional force sensors. This fact is important for structural miniaturization and cost reduction. The main contributions of this paper are (1) proposing a disturbance observation technique for in-contact flexible link manipulators (note that the challenge of Jacobian singularity is studied as a possible diverging factor of the observation) and (2) proposing the composite robust controller to eliminate the destabilizing effect of estimation errors. The advantages of the proposed control scheme over the conventional techniques are analyzed. Simulation results are given for a single-link flexible manipulator to illustrate the effectiveness of the composite control technique and experimental results are given to validate the performance of the observation method.

scholarly journals Adaptive Learning Based Tracking Control of Marine Vessels with Prescribed Performance

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Zhao Xu ◽  
Shuzhi Sam Ge ◽  
Changhua Hu ◽  
Jinwen Hu
Keyword(s):  
Neural Network ◽  
Adaptive Learning ◽  
Tracking Control ◽  
Tracking Error ◽  
Adaptive Tracking ◽  
Performance Constraints ◽  
Tracking Controller ◽  
Unknown Disturbances ◽  
The Stability ◽  
Marine Vessels

A novel adaptive tracking controller of fully actuated marine vessels is proposed with completely unknown dynamics and external disturbances. The model of dominant dynamic behaviors and unknown disturbances of the vessel are learned by a neural network in real time. The controller is designed and it unifies backstepping and adaptive neural network techniques with predefined tracking performance constraints on the tracking convergence rate and the transient and steady-state tracking error. The stability of the proposed adaptive tracking controller of the vessel is proven with a uniformly bounded tracking error. The proposed adaptive tracking controller is shown to be effective in the tracking control of marine vessels by simulations.

scholarly journals Modelling and State Variable Feedback Control with Proportional Action of a One-Link Flexible Manipulator Incorporating Payload

2021 ◽  
Vol 26 (1) ◽  
pp. 9-17
Author(s):  
M. Khairudin ◽  
S. P. Herlambang ◽  
Y. Sigit ◽  
A. Andik ◽  
T. Herawan ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Steady State ◽  
Feedback Control ◽  
Angular Position ◽  
Flexible Manipulator ◽  
Flexible Link ◽  
State Variable ◽  
Tracking Controller ◽  
The One

This paper presents a state variable feedback (SVF) control with proportional gain to control a one-link flexible manipulator incorporating payload. The dynamic model of a one-link flexible manipulator is developed through a finite element method. The system is uncertain due to the variation of payloads and numbers of elements. There is a challenge in designing a controller for each number of elements. To obtain the effectiveness of the controllers, a combination of SVF control-based LQR controls with proportional gain is developed for a flexible link manipulator with payload variations. An assessment is conducted to examine the input tracking controller capability of the hub angular position, deflection, hub velocity and end-point residual of the one-link flexible manipulator. The responses of the system are shown in domains of time and frequency, while the SVF control with proportional gain schemes is also discussed. This study finds that the payload effects on the response incorporating payload with SVF control and proportional gain schemes can provide input tracking performance with zero steady state error.

Sign in / Sign up

Export Citation Format

Share Document