Inchworm motor

The inchworm motor is a device that uses piezoelectric actuators to move a shaft with nanometer precision. The term is a trademark of the patent holder for this scheme, EXFO.

The inchworm motor uses three piezo-actuators connected together. The outer two actuators can independently grip the shaft, the middle one is used to change the spacing between the end actuators. To move the shaft in a direction the first actuator grips the shaft, then the second actuator enlarges moving the first actuator and the shaft it is gripping away from the fixed location third actuator. When the middle actuator has reached its maximum increase the third actuator grips the shaft and the first actuator releases the shaft, the middle actuator returns to its normal size; the process can now be repeated. The process can also be reversed to move the shaft in the opposite direction.

If the expansion of the center actuator is precisely calibrated (and the two outer actuators do not slip) then the position of the shaft can be precisely controlled while having substantial travel distance.

External links

(BROKEN LINK) * [http://documents.exfo.com/Products/LifeSciences/LSS-8000-Inchworm.pdf An explanation of the motor operation principle on EXFO's website]
* [http://www.physikinstrumente.com/en/news/fullnews.php?newsid=123&Wiki_iw Miniature Piezo Stepping Motor Principle]