Using piezoelectric technology to improve servo gripper performance in mini- and microassembly

Purpose - Aims to research the possibilities of using piezoelectric technology to improve accuracy and other characteristics of parallel servo grippers. Design/methodology/approach - The paper presents in detail two different kinds of developed two-fingered servo grippers based on piezoelectric technology with parallel moving mechanics. The first gripper is based on standing wave ultrasonic motors. The other gripper is a traditional gripper, the characteristics of which have been improved with integrated piezoelectric stack actuators. Both servo grippers have been tested and the test results and experiences are introduced in the paper. Findings - It is possible to improve the accuracy and characteristics of a parallel servo gripper with piezoelectric technology. Research limitations/implications - In the future it is necessary to concentrate on the mechanical design of gripper bodies and the fingers. Grasping force feedback signal should be even more linear and noiseless. Practical implications - Piezoelectric stack actuator's limited displacement is a problem in many practical applications when elastic or rough surface parts are handled. When integrated piezoelectric stacks are used with servo grippers, it is very important to focus on gripper's mechanical design and especially on the mechanical rigidity for getting the best possible results. Originality/value - Further developed versions of these servo grippers can be used in high accuracy industry applications instead of traditional servo gripper technologies.