Control of flexible-link manipulator

Flexible-Iink manipulator has many advantages over classic rigid body manipulator in industrial and space applications. However, it also poses high requirements on controller design, to ensure the accurate tip position tracking and suppression of tip deflection/vibration. This thesis sets up the model, both linear sections and nonlinear sections, for a typical apparatus. It discusses, by simulations and experiments, the solutions for these control problems. PD controller plus conditional I control is found elective on rigid body tracking control, and P controller with second-order lowpass filter proves effective on the suppression of deflection/vibration. Optimized PIDP controllers are experimentally implemented and the system performances are shown. Further this thesis discusses a LQR controller which uses a ninth-order full state feedback. Experimental results using the LQR controllers show an improvement over the PIDP controller, particularly in the suppression of flexible beam deflection

DYNAMIC MODELLING OF A FLEXIBLE LINK MANIPULATOR ROBOT USING AMM

This paper presents modeling of a flexible link manipulator using Lagrangian technique in conjunction with the assumed mode method (AMM). The links are modeled as Euler-Bernoulli beams satisfying proper mass boundary conditions. A payload is added to the tip of the outer link, while hub inertias are included at the actuator joints. The Lagrangian approach is used to derive the dynamic model of the structure. In this research, the dynamic model of a flexible link manipulator verified using Matlab/Simulink simulation. The model formulation proposed in this work is complete in the sense that it considers the effects of payload and damping structural of the link. The emphasis has been set on obtaining accurate equations of motion that display the most relevant aspects of the coupling between rigid and flexible dynamics

Intelligent PID Controller of Flexible Link Manipulator with Payload

This paper presents the experimental study of intelligent PID controller with the present of payload. The controllers were constructed to optimally track the desired hub angle and vibration suppression of DLFRM. The hub angle and end-point vibration models were identified based on NNARX structure. The results of all developed controllers were analyzed in terms of trajectory tracking and vibration suppression of DLFRM subjected to disturbance. The simulation studies showed that the intelligent PID controllers have provided good performance. Further investigation via experimental studies was carried out. The results revealed that the intelligent PID control structure able to show similar performance up to 20 g of payload hold by the system. Once the payload increased more than 20 g, the performance of the controller degrades. Thus, it can be concluded that, the controllers can be applied in real application, provided the tuning process were carried out with the existence of the maximum payload which will be subjected in the system. The 20 g payload value can act as uncertainty for the controller performance

Control of a flexible-link manipulator

This thesis focuses on the tip-position control of a single flexible link which rotates in the horizontal plane. It offers an original design for an experimental test-bed to implement and assess the performance of the controller

Extended Kalman Filter Based Modelled Predictor for Fusion of Accelerometer and Camera Signal to Estimate the Vibration of a Mobile Flexible Link Manipulator

This paper presents the fusion of accelerometer and camera for active vibration prediction for a mobile flexible link manipulator based on Extended Kalman filter-based modelled predictor. The tip position of the manipulator is unpredictable due to the singularity of the mobile flexible manipulator, as well as the phase lag in the control system due to the time delay between the sensor feedback and the control input. The purpose is thus to improve the prediction accuracy of the tip position. The time delayed in camera data estimates is used to correct the drifting accelerometer’s signal. The dynamic model of the mobile flexible link manipulator is derived and is used to feed to the prediction stage of the Extended Kalman filter, which is used for vibration prediction. In order to investigate the efficiency of the proposed method, simulation and experimental studies are performed considering a single link flexible manipulator on a wheeled base. Experimental verifications showed that the proposed method produced good vibration prediction of the mobile manipulator compared to other model based predictor

Neural network based modeling and control of a flexible-link manipulator

"This research work is aimed at developing a neural network based strategy to solve the problem of tip-position control for a single flexible-link manipulator.