Miniature Robot Finger Using a Micro Linear Ultrasonic Motor and a Closed-Loop Linkage

To prioritize miniaturization, the actuators of micro robot hands are placed far from the end effectors, but such mechanisms restrict controllability and dexterity. We propose a miniature robot finger driven by a new micro linear ultrasonic motor as a key component for micro robot hands. It enables dexterous and multiple motions for micro hands used in limited spaces. In this paper, we build a new micro linear ultrasonic motor involving a cuboid stator with a side length of approximately 2 mm, making it one of the smallest linear motors. The micro linear ultrasonic motor prototype shows an output torque of approximately 7.75 mN at low voltage operation, which is sufficient force to handle tiny objects. The miniature finger, a closed-loop six-bar-linkage mechanism, is built by micro fabrication and connected to the motor prototype. The first demonstration of the miniature finger is shown under a high-speed camera with a high power lens.