Demonstration of non-collocated vibration control of a flexible manipulator using electrical dynamic absorbers

This paper describes an experimental study into the vibration control of a servo system comprising a servo motor and a flexible manipulator. Two modes of the system are controlled by using the servo motor and an accelerometer attached to the tip of the flexible manipulator. The control system is thus non-collocated. It consists of two electrical dynamic absorbers, each of which consists of a modal filter and, in case of an out-of-phase mode, a phase inverter. The experimental results show that each absorber acts as a mechanical dynamic vibration absorber attached to each mode and significantly reduces the settling time for the system response to a step input.

Lumped Element Modeling of a Flexible Manipulator System

This paper is concerned with a modeling method that can be used for an experimental identification of a dynamic system. More specifically, an equivalent lumped element system is presented to represent in a unique and exact manner a complete proportional-derivative (PD) controlled servo positioning system having a flexible manipulator. The impedance and mobility approach is used to transform the P and D control gains to an electrical spring and an electrical damper, respectively. The impedance model method is used to transform the flexible manipulator to a coupled system between a single contact mass at the driving position and a series of noncontact masses each of which is connected to the contact mass via a resilient member. This method is applicable whenever the driving point response of such a manipulator is available. Experimental work is presented to support the theory developed.