Inchworm motor

The inchworm motor is a device that uses piezoelectric actuators to move a shaft with nanometer precision.

Figure 1. Diagram of Piezo Inchworm Motor in action.
Figure 2. Six Step Actuation Processes of the Piezo Inchworm Motor.

In its simplest form, the inchworm motor uses three piezo-actuators (2 and 3, see Figure 1.) mounted inside a tube (1) and electrified in sequence to grip a shaft (4) which is then moved in a linear direction. Motion of the shaft is due to the extension of the lateral piezo (2) pushing on two clutching piezos (3).