PRECISION PIEZOELECTRIC DRIVE AND METHOD TO CONTROL IT Russian patent published in 1997 - IPC

FIELD: electrical engineering. SUBSTANCE: drive includes piezoelectric converters made of piezoelements grouped into units placed between guides. Each unit incorporates braking and running sections oriented perpendicular and in parallel to movement correspondingly. Electrodes of all units are connected to outputs of sources of controlling signals. Each running section is made of two groups of piezoelements identical by piezomechanical properties which adjacent ends are rigidly interjoined and are connected to element of joining of load of drive and which opposite ends are made fast to symmetry centers of braking sections of piezoelements located on longitudinal symmetry axis of running sections. One pair of guides is common for all units and at least one of guides of this pair has one degree of freedom in direction perpendicular to movement and is connected via restoring members to immobile part of drive. Braking and/or running sections are fabricated from one plate or in the form of package of plates. Method to control precision piezoelectric drive includes excitation of running piezoelements with saw-tooth voltage and excitation of braking elements with pulses of voltage of rectangular or close to its shape. Excitation signals in one phase are fed to braking piezoelements one of which is located ahead of point of connection of running piezoelements to element of connection of load of drive and another one located in the other unit is placed behind relative to this point. Excitation signals are fed in counterphase to parts of running piezoelements one of which is ahead whither the other one, in the other unit in movement path relative to this point of connection. Saw-tooth voltage is fed without pauses between phases of working and return strokes. Duration of phase of working stroke exceeds duration of phase of return stroke. Unbraking pulses are supplied to braking piezoelements working in counterphase with time break exceeding sluggishness of braking piezoelements. In this case finish of leading edge of braking pulse across braking piezoelement leads occurrence of phase of return stroke of running piezoelement coupled to it and start of trailing edge of this pulse lags relative to start of next cycle of working stroke. EFFECT: enhanced precision. 5 cl, 3 dwg