Comparison of two control schemes for operating an ultrasonic scanning device

An electromechanical device has been developed as a hand-held ultrasonic scanning probe. The device is composed of an oscillating probe where the ultrasound transducer is mounted, part of which is flexible so the probe can oscillate when energized. Electric current is supplied to two electromagnetic coils acting on two permanent magnets mounted on both sides of the probe. Two control schemes, a PID controller and a state-feedback controller, have been developed to control the angular position of the probe during operation. This paper presents the designs of both control schemes and the performance of the controllers in computer simulation. Although both control schemes showed promising performance over the entire operation frequencies, one control scheme performed better in terms of accuracy while the other one provided better energy efficiency.