Resonance Tracking of Continua Using Self-Sensing Actuators

Abstract

This paper proposes and develops an innovative method to solve the resonance tracking problem for actuator and sensor applications to obtain maximum power transmission or signal selectivity using a modified phase-locked loop (PLL). The tracking of a higher eigenfrequency is very useful in some cases, but it is more challenging than the excitation of the only eigenfrequency of a 1-DoF system. The resonances are identified through employing their characteristic phase difference. The conventional PLL was modified to track a certain phase difference without deviation. The closed loop is a nonlinear control system due to the conversion between harmonic signals and phase signals. However, a model simplification to linear elements allows the goal oriented determination of the controller parameters. The advantages of self-sensing in combination with resonance tracking are attractive for practical applications such as ultrasonic motors and compact force sensors. The conducted experiments approved the effectiveness of the resonant excitation of higher oscillation modes of continua using self-sensing actuators.