Ultrasonic motor having generators formed of cooperating and spaced apart first and second sub-generators

A method for actuating an ultrasonic motor having an element to be driven;

• an ultrasonic actuator made of polarized electromechanical material in the form of a plate having a length L, a height H and a thickness T, and with main surfaces, and side surfaces that are smaller in terms of area than said main surfaces and connect said main surfaces to each other;
• at least two friction elements arranged on at least one of said side surfaces and provided for frictional contact with said element to be driven;
• at least two generators (Gl, Gr) which are each formed of an excitation electrode, a general electrode, and electromechanical material disposed between said excitation electrode and said general electrode, such that said ultrasonic actuator can be excited by applying electrical excitation voltage to said electrodes of said at least two generators (Gl, Gr) to form an acoustic standing wave usable for driving said element to be driven;
• and
• each of said at least two generators (Gl, Gr) having first and second cooperating and spaced first and second sub-generators, the first sub-generator of a generator of said at least two generators being respectively located between the first and second sub-generators of an adjacent generator of said at least two generators;
• and the first and second sub-generators of one generator of said at least two generators being arranged in mirror image to the first and second sub-generators of an adjacent generator of said at least two generators;
• wherein a polarization direction of electromechanical material of the first sub-generator of one generator of said at least two generators (Gl, Gr) differs from a polarization direction of electromechanical material of the second sub-generator of the same generator (Gl, Gr), the method comprising:
• providing an electrical excitation device for applying an electrical voltage to said excitation electrodes and/or said general electrodes;
• applying an electrical voltage to the first and second sub-generators of said at least two generators (Gl, Gr) by way of said electrical excitation device so that a diagonal transverse acoustic standing wave is formed in said ultrasonic actuator by which said friction elements each perform a motion along a trajectory that is inclined relative to said side surface on which said friction elements are arranged such that a defined phase shift is given between the motions of said friction elements.