Biologically-Inspired Micro-Robots: Volume 2: Investigation of a Micro- Joint Angle Sensor Using MEMS Cilia

摘要

This is one of three reports on the study of micro-robots. This document describes the design and fabrication of a joint angle sensor composed of an array of curled, directionally-sensitive MEMS cantilever beams with piezoresistive sense elements, analogous to an insect hair plate. The sensor is to be embedded in the limb such that the surface of the chip is flush with the surface of the limb. Actuation is then to be accomplished mechanically using a stylus that bends the hairs. An alternative actuation method is magnetic actuation. A layer of a hard magnetic material can be sputtered on the beams and magnetized. The beams would then be actuated with a permanent magnet. The magnetic actuation is preferable, as it is a non-contact solution. The polysilicon piezoresistors used to sense motion of the cilia have been tested, and using MemCAD to obtain stress values, coefficients of piezoresistivity have been obtained for both Advanced Monolithic Systems (AMS) and Hewlett-Packard (HP) fabrication processes. A low-voltage rail-to-rail common-mode input, rail- to-rail output operational amplifier has been designed to amplify the output of the polysilicon wheatstone. A second report (NATICK/TR-05/010) focuses on robots based on crickets, and a third report (NATICK/TR-05/012) examines micro- robots on abstracted biological principles.