Tweezers for Micromanipulation With Grasp Detection of Small Object

This paper deals with tweezers using bimorph piezoelectric actuators for micromanipulation. It measures 51 mm × 24 mm × 10 mm and weighs 62 g including electric cables of 27 g. Each finger consists of a bimorph piezoelectric actuator with a stainless steel tip. The tweezers open and close by driving both the actuators synchronously. One of the tweezers (vibrator) is oscillated by rectangular wave at its resonance frequency, and another (receiver) detects the vibration. When the tweezers grasp an object, the receiver is vibrated through the object. By using a lock-in amplifier with a reference signal, noise components can be eliminated. The resonance frequency was analyzed by finite element method and experiments. They almost agreed each other. Glass beads with a diameter of 60–70 μm could were grasped. The tweezers were used for micromanipulation.