Bent-beam electrothermal actuators-Part II: Linear and rotary microengines

• Published in: Journal of microelectromechanical systems Vol. 10; no. 2; pp. 255 - 262
• Main Authors: Jae-Sung Park, Chu, L.L., Oliver, A.D., Gianchandani, Y.B.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.2001; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Actuators; Applied sciences; Design engineering; Displacement; Displacement measurement; Drives; Electric potential; Electroplating; Electrothermal effects; Engines; Exact sciences and technology; Gears; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Laboratories; Mechanical engineering. Machine design; Micromachining; Network address translation; Nickel; Parks; Physics; Pneumatic actuators; Polysilicon; Power dissipation; Precision engineering, watch making; Rotary engines; Structural materials; Transducers; Voltage; Micromotor; Worm gear; Rotating machine; Positioner; Force; Linear machine; Precision engineering; Polycrystal; Silicon; Miniaturization; Actuator; Production process
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/84.925774

For Part I see L. Que, J.S. Park and Y.B. Gianchandani, ibid., vol.10, pp.247-54 (2001). This paper reports on the use of bent-beam electrothermal actuators for the purpose of generating rotary and long-throw rectilinear displacements. The rotary displacements are achieved by orthogonally arranged pairs of cascaded actuators that are used to rotate a gear. Devices were fabricated using electroplated Ni, p/sup ++/ Si, and polysilicon as structural materials. Displacements of 20-30 /spl mu/m with loading forces >150 /spl mu/N at actuation voltages <12 V and power dissipation <300 mW could be achieved in the orthogonally arranged actuator pairs. A design that occupies <1 mm/sup 2/ area is presented. Long-throw rectilinear displacements were achieved by inchworm mechanisms in which pairs of opposing actuators grip and shift a central shank that is cantilevered on a flexible suspension. A passive lock holds the displaced shank between pushes and when the power is off. This arrangement permits large output forces to be developed at large displacements, and requires zero standby power. Several designs were fabricated using electroplated Ni as the structural material. Forces >200 /spl mu/N at displacements >100 /spl mu/m were measured.