Traveling-Wave Ultrasonic Motor

A piezoelectric ultrasonic motor has no coils or magnets: two groups of piezo ceramics bonded to a metal ring, driven 90° apart in time and space, launch a flexural traveling wave around the stator. Because tangential displacement lags vertical displacement by 90° in a bending wave, each point on the surface traces a tiny ellipse rather than a straight line — and it is exactly this elliptical micro-motion, rectified by friction contact at the wave crests, that spins the rotor pressed against the stator teeth. This simulator renders the real two-phase superposition formula for the traveling wave, traces one surface point's actual elliptical path, and computes contact tip velocity and resulting rotor rpm live as you adjust drive frequency, amplitude, the inter-phase angle φ (which sets both direction and how "traveling" vs. "standing" the wave is), and the friction/preload coupling.