抄録
This paper deals with a non-contact transportation system using ultrasonic levitation. It is the purpose of this paper to realize the two-dimensional non-contact transportation using a transversely infinite plate. To perform the precise positioning of a target object, both the levitation and transportation forces are essential. With an aim to generate these forces, if a finite plate is excited at ultrasonic frequency, a lot of vibration modes are then likely to be activated, and hence a traveling wave indispensable to the transportation force may not be generated. If an infinite plate is excited, the vibration modes do not give rise to, however the deflection amplitude of the panel is too small to generate the levitation force. To overcome this problem, a rectangular plate which has a pair of simply supported edges and a pair of anechoic boundaries is employed, thereby the transportation of the target object becomes viable due to a large amplitude of levitation force gained because of the boundary condition setup. To this end, a vibration analysis of an infinite plate is conducted, revealing the power flow emerging in the vibration field. Furthermore, control forces are introduced for the purpose of transporting the target object along the designated direction. With a non-contact transportation system designed which consists of a transversely infinite plate and four Langevin transducers, an experiment on the position control of the target object is carried out, demonstrating the validity of the proposed method.
