A low-speed linear stage based on vibration trajectory control of a bending hybrid piezoelectric ultrasonic motor

Abstract The speed control tends to receive the restriction of dead-zone phenomenon when an ultrasonic motor (USM) works at the low speed range. A linear motion stage is designed and fabricated, in which a bending hybrid type USM using two separated bending modes is chosen for the low speed characteristic study. The shape and size of the vibration trajectory of the driving foot can be changed flexibly to realize the control of the output speed by controlling the vibration amplitudes of the driving foot in vertical and horizontal directions independently. The low speed characteristic experiment of the motion stage is accomplished based on a conventional PID controller, the speeds of 5 mm/s, 10 mm/s, 20 mm/s, 50 mm/s are achieved in the step control, respectively. In the sinusoidal speed control experiment, the reference speed varies sinusoidally with an amplitude of 20 mm/s, the maximum phase lag and amplitude error are lower than 3° and 3%, respectively. It is demonstrated that the low speed movement of the proposed linear motion stage can be realized by changing the vibration trajectory of the driving foot.