“…An ultrasonic motor uses two vibrations of the same frequency and different phases perpendicular to each other, so the surface particles of the stator of the ultrasonic motor form an elliptical trajectory, thus driving an object to move by friction [38] . Due to its simple structure, small size, light weight, fast response time, low noise level, large torque at low speed, good control characteristics, self-locking characteristic under power failure, freedom from magnetic field interference, and accurate motion [39] , [40] , ultrasonic motors are widely used in the automotive, aerospace, precision manufacturing, optical scanning, biotechnology and medicine [41] , [42] , [43] , [44] , [45] , [46] , [47] , and energy harvesting fields [48] , [49] , [50] , [51] .…”