A hybrid-type micro-gripper with an integrated force sensor

Abstract

A new hybrid-type micro-gripper that uses an integrated force sensor to control the gripping force was developed for handling micro-objects. The micro-gripper is composed of a piezoelectric multilayer bender for actuating the gripper fingers, silicon fingertips fabricated by use of silicon-based micromachining, and supplementary supports. The micro-gripper is referred to as a hybrid-type micro-gripper because it is composed of two main components: micro-fingertips fabricated using micromachining technology to integrate a very sensitive force sensor for measuring the gripping force, and piezoelectric gripper finger actuators that are capable of large gripping forces and moving strokes. A systematic design approach was applied to the design of each of components of the developed gripper, which made it possible to establish the functional requirements and design parameters of the micro-gripper. The micro-gripper was installed on a manual manipulator to assess its performance in tasks such as moving micro-objects from one position to a desired position. The gripping force signal was found to have a sensitivity of 667 lN/V and several micro-objects were successfully moved (grasped and released) with the developed gripper. It was found during the testing experiments that the frictional forces between the working plane and the micro-object could be utilized to facilitate the release of micro-objects from the micro-gripper.

Design and implementation of a real-time vision-assisted system for micro-scaled object identification and tracking

“…Due to maturity of micro-technologies in late 1990s, rich literature primary on micro-scaled actuator developments has been reported since early 2000s (Zhou and Nelson 1999;Thompson and Fearing 2001;Park and Moon 2003;Ogawa et al 2005). To allow visual servoing along with mass-produced, low-cost micro-actuators, capital investment is usually needed in both industrial and academic sectors.…”

A Micro-Opto-Electro-Mechanical System (MOEMS) for Microstructure Manipulation

“…Other actuation techniques employed also in microgrippers have been electrostatic [6], piezoelectric [1,9], and shape memory alloy [2]. The microgrippers presented in this work require external actuation, which was accomplished by two different methods: initially with a micrometer screw, and later with a piezoelectric actuator commercially available, in both cases connected to the microgrippers through a shaft.…”

“…It should be mentioned that, even though the aforementioned microgrippers have demonstrated significant advances in the field of micromanipulation, none of them is equipped with any kind of integrated feedback. More sophisticated, or instrumented microgrippers, have been implemented in silicon, such as the microgripper presented by Beyeler [6] which is equipped with a monolithically fabricated force feedback sensor and is actuated electrostatically by means of a comb actuator, or the hybrid type microgripper presented by Park [9] which is implemented in silicon, actuated piezoelectrically and is equipped with a force sensor. Microgrippers have also been implemented in metal such as the one presented by Carrozza [3] which is implemented in nickel and is instrumented with a semiconductor strain-gauge force sensor.…”

“…Furthermore, different feedback mechanisms can provide different types of information about the microobject being manipulated. The types of feedback implemented in microgrippers are force sensing, implemented in silicon [6,9] and nickel [3], and a binary optical feedback implemented in SiO 2 through a CMOS process [10]. So, because of the limited feedback implemented so far, there is still physical, mechanical, optical and chemical information about the microstructure under study which requires the use of macroscopic instrumentation, such as confocal fluorescence microscopy, Raman spectroscopy, nanoindentation, among others [11].…”

Waveguide microgripper for identification, sensing and manipulation

“…Not many microgripper have been developed with an integrated feedback. The types of feedback implemented in microgrippers are force sensing [9,15,16] and binary optical feedback [17]. Due to limited feedback implementation so far, it is important to integrate a feedback mechanism which would allow the analysis of physical, mechanical, optical and chemical information of the micro object under study.…”