An object transport system using flexural ultrasonic progressivewaves generated by two-mode excitation

摘要

An object transport system using low amplitude and high frequencynprogressive waves generated by two-mode excitation is presented. Antheoretical model for the system was developed using normal modenexpansion and the modal participation factor. To identify the factorsnthat affect the transport speed, the changes with the mass of objects onnthe beam, the input power, the phase difference, and the excitationnfrequency were experimentally investigated. With a power input of 40 W,na transport speed of 10 cm/s was obtained for an object weighing 30 g.nThe tests indicate that, not only the phase difference but also thenexcitation frequency, were the dominant factors in determining thentransport speed and direction. Specifically, when the excitationnfrequency was chosen to be at the exact midpoint of the two modes, thenobject stopped moving. A slight change of frequency in either directionnresulted in change of object transport direction. For actual factorynapplication, a simple stop-go and tracking control using the GeneralnPurpose Interface Bus (GPIB) were implemented