A Hydraulic Flexible Joint Robot Simulator

by Dezfulian, Shahram

Abstract (Summary)
The objective of this project was to design and implement an experimental hydraulic system that simulates joint flexibility of a single rigid link flexible joint robot manipulator, with the ability of changing the joint flexibilitys parameters. Such a system could facilitate future control studies of robot manipulators by reducing investigation time and implementation cost of research. It could also be used to test the performance of different strategies to control the movement of flexible joint manipulators.

A hydraulic rotary servo motor was used to simulate the action of a flexible joint robot manipulator. It was a challenging task, since the control of angular acceleration was required.

A single-rigid-link, elastic-joint robot manipulator was mathematically modeled and implemented using Matlab. Joint flexibility parameters such as stiffness and damping, could be easily changed. This simulation was considered as a function generator to drive the hydraulic flexible joint robot. In this study the desired angular acceleration of the manipulator was used as the input to the hydraulic rotary motor and the objective was to make the hydraulic system follow the desired acceleration in the frequency range specified. The hydraulic system consisted of a servovalve and rotary motor.

A hydraulic actuator robot was built and tested. The results indicated that if the input signal had a frequency in the range of 5 to 15 Hz and damping ratio of 0.1, the experimental setup was able to reproduce the input signal with acceptable accuracy. Because of the inherent noise associated with the measurement of acceleration and some severe non-linearities in the rotary motor, control of the experimental test system using classical methods was not as successful as had been anticipated. This was a first stage in a series of studies and the results provide insight for the future application of more sophisticated control schemes.

Bibliographical Information:

Advisor:Schoenau, Greg J.; Gokaraju, Ramakrishna; Fotouhi, Reza; Burton, Richard T.; Dolovich, Allan T.

School:University of Saskatchewan

School Location:Canada - Saskatchewan

Source Type:Master's Thesis

Keywords:pressure control servovalve frequency response


Date of Publication:06/28/2007

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