Study of the dynamic behaviour of a piezo-walker

We have examined two configurations of a piezo-walker, the inertial one and the frictional one, both of which are capable of moving samples with submi crometer steps over a distance of some millimeters. We demonstrated that, c ontrary to expectations, operation of the frictional walker in which six pi ezos shear one by one, is still dependent on inertial slip-stick action. We studied the dependence of the step-size on the time delay between rising f ronts applied to consecutive piezos and we found that the characteristic ti me associated with the minimum value of the step-size is of the order of th e time of a sound wave propagating along the rod between the piezos. (C) 19 99 Elsevier Science B.V. All rights reserved.