Elastic Fin Research Articles

PZT thin film actuated elastic fin micromotor

A piezoelectric elastic fin micromotor based on a PbZr(0.53 )Ti(0.47)O(3) thin film driving a micromachined silicon membrane was fabricated and studied. The stator was characterized by interferometry, and a laser set-up was used to measure the angular velocity and acceleration of the motor. The torque, the output power, and the efficiency of the device were extracted from these measurements. Values up to 1020 rpm and 0.94 microNm were observed for the velocity and the torque, respectively, which would be sufficient for a wristwatch application. The present version exhibited an efficiency of 0.17%, which could theoretically be increased to 4.8%

Flexural-standing-wave elastic force motor using ZnO and PZT thin film on micromachined silicon membranes for wristwatch applications

Ultrasonic motors for low electrical power applications are considered for portable devices such as an electronic wristwatch. For the study of a standing wave type motor, a modular approach was proposed, where stators and rotors are added in an assembly step. The mode conversion principle called the `elastic fin motor' and its extension to an `elastic force motor' suitable for a flat profile motor are discussed. Fabrication methods and the mechanical response of silicon diaphragms covered by PZT and ZnO (zinc oxide) piezoelectric thin films are compared. A closed loop position control using an integrated piezoelectric stress detection is proposed and demonstrated. The target torque of at a mechanical power of a few has been achieved. A long-term test during 2 months of continuous operation proved an acceptable reliability for the specified applications.

永久磁石を用いた微小泳動機構の試作

This paper proposes two kinds of swimming micromechanisms with low Reynolds numbers. One is a fin-type mechanism, which is composed of a cylinder magnet and an elastic fin. The other is a spiral-type mechanism, which is composed of a cubic magnet and a spiral wire. Both mechanisms are remotely operated by magnetic torque in an alternating magnetic field. The fin-type mechanism generates a bending wave that passes along the fin, allowing the mechanism to swim in one direction. The spiral-type mechanism generates a spiral wave, and can swim both forward and backward.

A Miniature Mobile Robot Using Piezo Vibration for Mobility in a Thin Tube

This paper proposes a miniature mobile robot that uses piezo vibration to move within a thin tube. The robot consists of a piezo bimorph with elastic fins attached at an angle. Robot movement is driven by differences in the friction of the fin’s against the tube wall between the forward and backward fin movements induced by piezo vibration. After analyzing the dynamics of the piezo elements, we analyzed the robot’s mobile mechanism by extending Hamilton’s principle using the dynamic results of the piezo vibration analysis. Measurements of both mobile velocity and tractive force of an experimental robot agree closely with theoretical results. This indicates that the proposed dynamic mobile mechanism accurately expresses robot motion within a thin tube.

Ultrasonic Motor Utilizing Elastic Fin Rotor

An ultrasonic micromotor which has vibration conversion `elastic fins' in the rotor is proposed and constructed for trial. The motor, which is 5 mm in diameter, has proved to work quite well, and this suggests the possibility of further miniaturization of the motor. The principle and experimental evaluations of the characteristics of the motor are presented.

細径管移動ロボットの最適弾性板位置に関する検討

細径管移動ロボットの最適弾性板位置に関する検討