University of Twente Student Theses


Power-port modelling of an in-plane 3 DOF parallel micro-manipulator with feed-forward position control

Lammertink, Tijs (2005) Power-port modelling of an in-plane 3 DOF parallel micro-manipulator with feed-forward position control.

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Abstract:As part of the Multi Axis MicroStage project (MAMS), a 20-sim model of a 3 DOF parallel micromanipulator was created. The model serves as a design tool and as verification in order to understand the behaviour of the actual system. The micro-manipulator was fabricated with MEMS technology. One of the possible applications for the manipulator is manipulation of samples in a Transmission Electron Microscope (TEM). A multibody model of the manipulator was created with 20-sim's 3D Mechanics Editor. The multibody model contains the rigid bodies (with their positions, masses and inertias), and the kinematic construction of joints and rigid bodies. An equation submodel of the multibody model is exported to 20-sim. The compliant behaviour of the manipulator is added in 20-sim. Stiffness, masses and inertias were estimated on the basis of the physical dimensions of the actual device. The damping has been estimated roughly from measurements and is very low, which is typical for MEMS devices. The manipulator is actuated by comb-drives. Since it is not trivial what voltage to apply to which combdrive for movement of the manipulator's end-effector in a specific direction, a feed-forward position control was designed, which controls the manipulator in the desired coordinates. Measurements on the real manipulator were performed: The platform deflection was measured for different comb-drive voltages as well as the resonance frequencies. The model was validated with measurements, which shows very similar relations between simulated and measured platform deflection as a function of the comb-drive voltages. The difference between simulations and measurements are: 2.3 % in x-direction, 3.9 % in y-direction and 12.8 % in ϕ-rotation. The simulated and measured resonance frequencies of the manipulator are also very similar: 7.1 % deviation in rotational resonance frequency, and 3.3 % and 3.1 % for the resonance frequencies in x and y-direction.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:53 electrotechnology
Programme:Electrical Engineering MSc (60353)
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