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Design and validation of the control circuits for a micro-cantilever tool for a micro-robot
SIC, Departament d’Electrònica, Universitat de Barcelona, Barcelona, Spain.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
SIC, Departament d’Electrònica, Universitat de Barcelona, Barcelona, Spain.
SIC, Departament d’Electrònica, Universitat de Barcelona, Barcelona, Spain.
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2009 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 153, no 1, 76-83 p.Article in journal (Refereed) Published
Abstract [en]

The objective of this paper is to present the design and validation of a cantilever-based contact sensing system for a micro-robot. Key elements of the fabrication process of the sensor and the electrical model extraction used to design the control electronics are described. The architecture used for the sensor corresponds to a micro-cantilever fabricated of piezoelectric-polyvinylidene fluoride-trifluoroethylene stacked in a multilayer structure with the possibility of both actuating and sensing. A lumped electro mechanical equivalent model of the micro-cantilever was used to design the control electronics for the cantilever. A driving signal from, the control system is used to vibrate the cantilever at its first mechanical resonance frequency. The control system contains an analog front-end to measure the sensor output signal and a digital control unit designed to track and keep the resonance frequency of the cantilever. By integrating the cantilever control system is integrated in the application specified integrated circuit used to control of the circuit is simplyfied and very compact. Experimental results show a similar behavior between the electrical model and the fabricated system, and the deviations between the model and the measured structure are analyzed. The results also show that the designed control system is capable to detect the resonance frequency of the system and to actuate despite small deviations in process parameters of different batches of cantilevers. The whole system was designed to be integrated into an autonomous micro-robot, although it can be used in other applications.

Place, publisher, year, edition, pages
P.O. Box 211, Amsterdam, 1000 AE, Netherlands: Elsevier , 2009. Vol. 153, no 1, 76-83 p.
Keyword [en]
Vibrating cantilever, Multilayer PVDF-TrFE sensor, Control electronics, Interface circuits
National Category
Engineering and Technology
URN: urn:nbn:se:uu:diva-108493DOI: 10.1016/j.sna.2009.04.030ISI: 000267646600012ISBN: 09244247OAI: oai:DiVA.org:uu-108493DiVA: diva2:236048

Compilation and indexing terms, Copyright 2009 Elsevier Inc. 20092412122278 Analog front-end Contact sensing Control circuits Control electronics Digital control units Driving signal Electrical models Electro-mechanical Equivalent model Fabricated system Fabrication process In-process parameters Interface circuits Key elements Mechanical resonance frequency Micro robots Micro-cantilever Multilayer structures Other applications Polyvinylidene fluorides Resonance frequencies Sensor output Trifluoroethylene Vibrating cantilever Whole systems

Available from: 2009-09-20 Created: 2009-09-20 Last updated: 2016-04-14Bibliographically approved
In thesis
1. Applications of active materials
Open this publication in new window or tab >>Applications of active materials
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Energy efficiency is a vital key component when designing and miniaturizing self sustained microsystems. The smaller the system, the smaller is the possibility to store enough stored energy for a long and continuous operational time. To move such a system in an energy efficient way, a piezoelectrical locomotion module consisting of four resonating cantilevers has been designed, manufactured and evaluated in this work. The combination of a suitable substrate, a multilayered piezoelectric material to reduce the voltage, and a resonating drive mechanism resulted in a low power demand.

A manufacturing process for multilayer cantilever actuators made of P(VDF-TrFE) with aluminum electrodes on a substrate of flexible printed circuit board (FPC), has been developed. An important step in this process was the development of an etch recipe for dry etching the multilayer actuators in an inductive plasma equipment.

Formulas for the quasi static tip deflection and resonance frequency of a multilayered cantilever, have been derived. Through theses, it was found that the multilayered structures should be deposited on the polymer side of the FPC in order to maximize the tip deflection.

Both a large and a miniaturized locomotion module were manufactured and connected by wires to verify that the three legged motion principal worked to move the structures forward and backward, and turn it right and left. By touching and adding load, to a fourth miniaturized cantilever, its ability to act as a contact sensor and carry object was verified.

The presented locomotion module is part of a multifunctional microsystem, intended to be energy efficient and powered by a solar panel with a total volume of less than 25 mm3 and weight 65 mg. The whole system, consisting of a solar cell, an infra red communication module, an integrated circuit for control, three capacitors for power regulating, the locomotion module and an FPC connecting the different modules, was surface mounted using a state of the art industrial facility. Two fully assembled systems could be programmed both through a test connector and through optical sensors in the multifunctional solar cell. One of these was folded together to the final configuration of a robot. However, the entire system could not be tested under full autonomous operating conditions. On the other hand, using wires, the locomotion module could be operated and used to move the entire system from a peak-to-peak voltage of 3.0 V.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2009. 77 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 672
Energy efficient, microsystem, resonating cantilevers, microactuators, P(VDF-TrFE), surface mounting assembly, multi layers, flexible printed circuit board, conveyer, three legged
National Category
Materials Engineering
Research subject
Materials Science
urn:nbn:se:uu:diva-108696 (URN)978-91-554-7609-0 (ISBN)
Public defence
2009-10-30, 2001, Ångström Laboratory, Uppsala, 10:15 (Swedish)
Available from: 2009-10-09 Created: 2009-09-28 Last updated: 2009-10-09Bibliographically approved

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