Experimental verification on vibration suppression of a flexible manipulator using MPID controller

This paper presents a MPID (modified proportional-integral-derivative) controller used to suppress vibration of flexible manipulator moving vertically. To attain the vibration suppression a vibration variable should play role in the control signal which drives the flexible manipulator. The proposed controller is based on the conventional PID control but the integral term is replaced with another one which mainly depends on the vibration of the end effector. Camera becomes an inherent part of space manipulator, using the MPID controller with the visual information recorded by the camera makes the strain measuring circuits and amplifiers unnecessary. This means reducing the hardware used in the control of flexible manipulator. The novelty of the results lies in the fact that the measurement of the rate of change in deflection, which is used as a vibration variable, has been done without the need of numerical differentiation. Experiments successfully demonstrate that using the visual data with an observer based on Kalman filer can achieve a noticeable damping of the end effector vibration of the flexible manipulator.