Precise manipulation of micro objects became great interest in engineering and science with the advancements in microengineering and microfabrication. In this thesis, a magnetically levitated microgripper is presented for microhandling tasks. The use of
magnetic levitation for positioning reveals the problems associated with modeling of complex surface forces and the use of jointed parts or wires. The power required for the levitation of the microgripper is generated by an external drive unit that makes further minimization of the gripper possible. The gripper is made of a biocompatible material and can be activated remotely. These key features make the microgripper a great candidate for manipulation of micro components and biomanipulation.
In order to achieve magnetic levitation of microrobots, the magnetic field generated by the magnetic levitation setup is simulated. The magnetic flux density in the air gap region is improved by the integration of permanent magnets and an additional electromagnet to the magnetic loop assembly. The levitation performance is evaluated
with millimeter size permanent magnets. An eddy current damping method is implemented and the levitation accuracy is doubled by
reducing the positioning error to 20.3 µm.
For a MEMS-compatible microrobot design, the electrodeposition of Co-Ni-Mn-P magnetic thin films is demonstrated. Magnetic films are deposited on silicon substrate to form the magnetic portion of the microrobot. The electrodeposited films are extensively
characterized. The relationship between the deposition parameters and structural properties is discussed leading to an understanding of the effect of deposition parameters on the magnetic properties.
It is shown that both in-plane and out-of-plane magnetized films can be obtained using electrodeposition with slightly differentiated deposition parameters. The levitation of the electrodeposited
magnetic samples shows a great promise toward the fabrication of levitating MEMS devices.
The end-effector tool of the levitating microrobot is selected as a microgripper that can achieve various manipulation operations such as pulling, pushing, tapping, grasping and repositioning. The
microgripper is designed based on a bent-beam actuation technique. The motion of the gripper fingers is achieved by thermal expansion through laser heat absorption. This technique provided non-contact
actuation for the levitating microgripper. The analytical model of the displacement of the bent-beam actuator is developed. Different designs of microgripper are fabricated and thoroughly characterized
experimentally and numerically. The two microgripper designs that lead to the maximum gripper deflection are adapted for the levitating microrobot.
The experimental results show that the levitating microrobot can be positioned in a volume of 3 x 3 x 2 cm^3. The positioning error is measured as 34.3 µm and 13.2 µm when
electrodeposited magnets and commercial permanent magnets are used, respectively. The gripper fingers are successfully operated
on-the-fly by aligning a visible wavelength laser beam on the gripper. Micromanipulation of 100 µm diameter electrical wire,
125 µm diameter optical fiber and 1 mm diameter cable strip is demonstrated. The microgripper is also positioned in a closed
chamber without sacrificing the positioning accuracy.
| Identifer | oai:union.ndltd.org:WATERLOO/oai:uwspace.uwaterloo.ca:10012/4067 |
| Date | January 2008 |
| Creators | Elbuken, Caglar |
| Source Sets | University of Waterloo Electronic Theses Repository |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
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