On amplification in inchworm™ precision positioners

Abstract Mechanical amplification in inchworm™ piezoelectric linear motors is investigated. The motivation behind mechanical amplification is to increase the precision positioner's potential for speed through augmented step size. The inchworm™ motor traversing speed can be roughly the product of step size and operating frequency. The simultaneous maximization of both step size and operating frequency would be ideal. It is shown through the development of a set of design equations and finite element modeling and analysis that the simultaneous maximization of both step size and operating frequency cannot be accomplished for a lever amplifying frame. A trade-off exists between step size and operating frequency. While amplification increases a motor's step size, it introduces much uncertainty and complexity, reduces the stiffness of the motor and limits the potential for high frequency operation.