Four-Point-Latching Microactuator

Figure 1 depicts an experimental inchworm- type linear microactuator. This microactuator is a successor to the one described in “MEMS-Based Piezoelectric/ Electrostatic Inchworm Actuator” (NPO- 30672), NASA Tech Briefs, Vol. 27, No. 6 (June 2003), page 68. Both actuators are based on the principle of using a piezoelectric transducer (PZT) operated in alternation with electrostatically actuated clutches to cause a slider to move in small increments. However, the design of the present actuator incorporates several improvements over that of the previous one. The most readily apparent improvement is in geometry and, consequently, in fabrication: In the previous actuator, the inchworm motion was perpendicular to the broad faces of a flat silicon wafer on which the actuator was fabricated, and fabrication involved complex processes to form complex three-dimensional shapes in and on the wafer. In the present actuator, the inchworm motion is parallel to the broad faces of a wafer on which it is fabricated. The components needed to produce the in-plane motion are more nearly planar in character and, consequently, easier to fabricate. Other advantages of the present design are described below.