Proceedings of COBEM 2005 Copyright c  2005 by ABCM 18th International Congress of Mechanical Engineering November 6-11, 2005, Ouro Preto, MG DEVELOPMENT OF AN ELECTROTHERMOMECHANICAL XY MICROPOSITIONER Wagner Shin Nishitani Department of Mechatronics and Mechanical Systems Engineering - Universidade de São Paulo, São Paulo, Brazil wagner.nishitani@poli.usp.br Flávio Honda Department of Mechatronics and Mechanical Systems Engineering - Universidade de São Paulo, São Paulo, Brazil flavio.honda@poli.usp.br Paulo Henrique de Godoy Department of Mechatronics and Mechanical Systems Engineering - Universidade de São Paulo, São Paulo, Brazil pegodoy@uol.com.br Emílio Carlos Nelli Silva Department of Mechatronics and Mechanical Systems Engineering - Universidade de São Paulo, São Paulo, Brazil ecnsilva@usp.br Abstract. The research regarding small object manipulation, mechanical or biological, has its importance increasingly evidenced by the world trend towards systems miniaturization. The micromechanisms that allow from teleoperation to complete automation in its use are called MEMS (Micro-Electro-Mechanical Systems), whose mechanical elements and actuators are made by microfabrication technology. Almost all of them are based on compliant mechanisms technology, whose mobility is given by their own structure compliance instead of using joints and pins which are hard to be made in the micro-scale. A simple type of actuation is called electrothermomechanical, based on the thermal expansion of the structure caused by an electrical current. The objective of this work is to study the complete development cycle of an electrothermomechanical XY micropositioner, including its simulation by finite element method (using ANSYS), its fabrication and development of the positioning command system (programmed in Matlab), implemented by using a remote controlled DC source with GPIB interface and a probe station with a CCD camera to monitor it. The complete system prototype (actuator and command system) was successfully implemented and tested at the Brazilian Synchrotron Light Laboratory (LNLS) at Campinas (SP). To reduce mechanical stresses and to increase maximum displacement, an investigation was conducted about the use of more than one material in the same mechanism. Keywords: MEMS, microfabrication, compliant mechanisms, electrothermomechanical, electronic command 1. Introduction The research regarding small object manipulation, mechanical or biological, has its importance increasingly evidenced by the world trend towards systems miniaturization. Its main direct applications have a wide range, varying from assembly of mechanical systems with reduced size, to microsurgeries and biotechnology. Due to its large scale use, it is necessary to have a high accuracy under high positioning speed of the device. Micromechanisms that allow from teleoperation to complete automation in its use are called MEMS (Micro-Elecrto- Mechanical Systems), whose mechanical elements and actuators are made by microfabrication technology. Almost all of them are based on compliant mechanisms technology, whose mobility is given by their own structure compliance instead of using joints and pins which are hard to be made in the micro-scale. A simple type of actuation is called electrothermomechanical, based on the thermal expansion of the structure caused by an electrical current, converting an electric input into a mechanical output (Ananthasuresh, 2003; Yin and Ananthasuresh, 2002; Sigmund, 001a,b; Mankame and Ananthasuresh, 2001). Among the designed electrothermomechanical MEMS, two of them have been more discussed in the literature: MEMS in open “V" format (Que et al., 1999; Park et al., 2000; Chu and Gianchandani, 2003; Chu et al., 2003) and the pseudo-bilaminars (Chen et al., 2002; Moulton and Ananthasuresh, 2001; Comtois et al., 1998). The open “V" will be the base for the present design. The objective of this work is to study the complete development cycle of an electrothermomechanical XY microposi- tioner, including its simulation by finite element method (using ANSYS), its fabrication and development of the position- ing command system (programmed in Matlab), implemented by using a remote controlled DC source with GPIB interface and a probe station with a CCD camera to monitor it. At the end, the complete system prototype (actuator and command system) was successfully implemented and tested at the Brazilian Synchrotron Light Laboratory (LNLS) in Campinas (SP). To reduce mechanical stresses and to increase maximum displacement, an investigation was conducted about the use of more than one material in the same mechanism.