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Dynamic Modeling, Experimental Identification, and Active Vibration Control Design of a "Smart Parallel Manipulator"

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Abstract:
This talk addresses dynamic modeling of a high-speed flexible-link planar parallel manipulator, experimental identification and active vibration control of vibration in flexible linkages on the parallel manipulator using distributed smart material components. Planar parallel manipulators undergo significant linkage vibration caused by large inertia forces associated with high accelerations and high-speed motion. Settling time of unwanted vibration slows down the operational speed of parallel manipulators and residual vibration adversely affects the trajectory control accuracy. A "smart parallel manipulator" is proposed to actively control vibration in intermediate linkages using distributed arrays of surface-bonded Lead Zirconate Titanate (PZT) patch sensors and actuators so that operation speed of the manipulator is greatly increased without sacrificing trajectory control accuracy. Modeling and control of the smart parallel manipulator is characterized by (i) closed-loop architecture of the parallel manipulator with multiple kinematic chains, (ii) coupling of nonlinear rigid body motion and flexible deformation, and (iii) configuration-dependent vibration characteristic of the parallel manipulator. A finite element (FE) model of flexible linkages is developed, where the coupling of translational motion, rotation, and flexible deformation and coupling of PZT sensors and actuators with the host structures are incorporated. A substructuring modeling procedure is presented to develop dynamic models for closed-loop flexible mechanisms that are capable of modeling essential dynamic behavior of the parallel manipulator with moderate model order. Motion control and active vibration control simulation numerically demonstrate the concept of smart structure control in the parallel manipulator. An experimental identification procedure using various combinations of transducers has been developed to identify linkage vibration characteristics when the planar parallel robot is in both a stationary state and during rigid body motion. Configuration dependency of linkage vibration characteristics is investigated through intensive identification experiments. An active vibration control algorithm in the modal space is developed and implemented to control configuration-dependent linkage vibration. Vibration caused by linkage flexibility is substantially reduced.

Type of Seminar:
Public Seminar
Speaker:
Dr. Xiaoyun (Frank ) Wang
University of Toronto, Canada
Date/Time:
Nov 03, 2005   17:15
Location:

ETH Zentrum, Gloriastrasse 35, Building ETZ, Room E6
Contact Person:

D. Niederberger
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Biographical Sketch:
Xiaoyun Wang received his B.Eng. in Engineering Mechanics from Xi'an Jiaotong University, China in 1997. From the same University, he finished his M.A.Sc. with Professor G. Yan in the State Key Laboratory of Mechanical and Structural Strength and Vibration in 2000. From 2001 to 2005, he finished his Ph.D. in Mechanical Engineering under the supervision of Professor J.K.Mills at the University of Toronto, Canada, where he currently is a Post-Doctoral Researcher. His research interests include Active Vibration Control, Smart Structures, Robotics, Modeling and Control of Multibody Systems, and Bio-Medical Applications of Smart Materials.