Design and multipoint control of an bar-shaped multi-DOF ultrasonic actuator

A bar-shaped multi-degree-of freedom (DOF) ultrasonic actuator has been developed for use in precision positioning stage device, such as X-Y table, etc. Six piezoelectric ceramic groups are located to excite a longitudinal vibration and two bending vibrations of the actuator respectively. The working principle of proposed actuator is analyzed. The actuator can work as three kinds of ultrasonic actuator, wobble actuator, linear actuator and multi-DOF actuator. Different from most bar-shaped multi-DOF ultrasonic actuator, the two ends of the proposed ultrasonic actuator can generate different 3-DOF motion trajectories simultaneously, using three driving control method with the combination of the three vibration modes. The actuator was designed by finite element analysis (FEA), and transient analysis is employed to testify the three kinds of multipoint control method for the bar-shaped ultrasonic actuator. The velocity and moving direction of actuator can by adjusted by using the appropriate control method and voltage amplitudes of the input electric signals. Multipoint multi-DOF motion control of the actuator was achieved successfully.