Model of the attachment/detachment cycle of electrostatic micro actuators

Keith M. Anderson*, Ed Colgate

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations


Several recent electrostatic micromotor designs, including harmonic motors, rely on an attachment/detachment cycle of operation. The cycle commences when the voltage of a particular stator electrode is increased, creating an attractive force between the stator and rotor (which is grounded). This force brings the rotor into contact with the stator (therefore, either the rotor or stator must be insulated). The cycle ends and another begins when the stator electrode is grounded, releasing the rotor, while the voltage of a neighboring stator electrode is increased. Such motor designs exploit the inverse sequence attraction between image charges to generate large pull-down forces; also, they may incorporate certain geometrical features that result in mechanical advantage. Thus, these motors hold the promise of serving as high-force actuators in the microdomain. Experience with a linear microactuator based on the attachment/detachment cycle has, however, pointed to a basic difficulty with this type of operation; the accumulation of charge on the interfacial insulation can lead, in the long-term, to 'sticking', erratic behavior, and even complete motor failure. A simple model of an attachment/detachment cycle has been used to study the charge accumulation process. Simulations performed with this model indicate that, given a simple commutation scheme for switching stator voltages, resistive-capacitive processes can lead to an accumulation of charge sufficient to cause sticking. Criteria incorporating long-term charging effects are suggested for the design of electrostatic micro motors.

Original languageEnglish (US)
Title of host publicationMicromechanical Sensors, Actuators, and Systems
PublisherPubl by ASME
Number of pages14
ISBN (Print)0791808637
StatePublished - Dec 1 1991
EventWinter Annual Meeting of the American Society of Mechanical Engineers - Atlanta, GA, USA
Duration: Dec 1 1991Dec 6 1991


OtherWinter Annual Meeting of the American Society of Mechanical Engineers
CityAtlanta, GA, USA

ASJC Scopus subject areas

  • Software
  • Mechanical Engineering


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