A method is disclosed for determining the idle travel of a piezo-injector which has a piezo-actuator and a nozzle needle which is activated directly by the piezo-actuator. A test pulse is applied to the piezo-actuator, which pulse brings about a continuous increase in the piezo-travel. The time period is measured which passes between the starting of the test pulse and the time when the idle travel is overcome. The idle travel of the piezo-injector is then determined from the measured time period.

For tuning a vibrating conveyor having an electric vibrator that drives a vibration element connected to a conveying unit of the vibrating conveyor for oscillating the conveying unit to a mechanical resonance frequency f.sub.R of the vibrating conveyor, an electric drive unit varies the frequency f.sub.v of a AC drive voltage (u.sub.v) in a given frequency range, measures a current consumption of the electric vibrator unit for different applied frequencies f.sub.v of the AC drive voltage (u.sub.v) and using the frequency f.sub.v with the lowest current consumption of the electric vibrator unit as frequency f.sub.v of the AC drive voltage (u.sub.v) for operating the vibrating conveyor.

Disclosed are a linear motion platform driven by an external thread piezoelectric actuator and a method thereof. The linear motion platform comprises an actuator, a first fixed support, a second fixed support, a rolling bearing, a connecting plate, an objective table, and M guide assemblies. The actuator comprises a metal matrix, a driving nut, a first piezoelectric assembly, a second piezoelectric, a front beam, a rear beam, and first and second fixed bolts. The platform can drive the objective table to perform a linear motion directly through the actuator, is simple and compact in structure, high in precision, capable of being self-locked in case of power failure and good in universality, and has relatively high application values in the field of precision transmission.