Transpose Jacobian Control of Flexible Joint Upper Limb Exoskeleton System (original) (raw)

Control of Flexible Robot by Harmonic Functions

Applied Sciences

This work deals with the control of flexible structures as underactuated systems. The invariant control method performs the control of a flexible robot as a representative of an underactuated system with zero dynamics. The control input is separated into two parts. The arbitrary part of the control input is designed to control the directly actuated part of the dynamic system. The invariant part of the control is selected to steer the system zero dynamics in the desired way. The harmonic functions create the base for the invariant part of the control function. The residual vibration cancellation is the target of the presented invariant control strategy. The harmonic function frequencies are overtaken from the so-called natural motion, amplitudes are the results of the optimization process. The main target of this paper is to show the invariant control approach and its application to the system with flexible elements.

Vibration Control of an Onelink Flexible Manipulator with Harmonic Excitation

Flexible manipulators are more desirable than rigid manipulator due to lightweight arm, higher motion speed and better energy efficiency. The flexibility causes residual vibrations at the end point after motion. Therefore, controlling residual vibration of flexible manipulators is important. In this study the residual vibration of a flexible beam is studied in ANSYS. The trapezoidal velocity profile is applied in the transient analysis. The residual vibrations are observed for the control-off case. A high frequency harmonic velocity excitation is applied after the end of the trapezoidal velocity profile to control the residual vibration. An exponential decaying is added to the harmonic excitation after a certain time. It is known that the vibration amplitudes of a system decrease when the system is excited at higher frequency than the natural frequencies. The effect of the amplitude, frequency, the duration of the application and the exponential decaying factor on the suppression of...