Cải tiến mô tơ quay siêu nhỏ và ứng dụng trong hệ thống bánh răng

JOliRNAL OF SCIENCE & TECHNOLOGV * No. 88 - 2012

DEVELOPMENT OF THE MICRO ROTATIONAL MOTOR AND APPLICATION

IN GEARING SYSTEMS

CAI TIEN MO TO QUAY Sl&U NH 6 VA LTNG DUNG TRONG H$ THQNG BANH RANG

P/iant Hong Phuc

Hanoi University of Science and Teclmology

Received February 21, 2012; accepted May 5, 2012

ABSTRACT

This paper pmsents the design and fabrication of a Micm Rotational Motor (MRM) and its

appticatk3ns in which four micm mtational comb-drive acluators (MRCA) are used to drive the rotor

thmugh ratchet teeth. For the geanng system, a ring with ratchet teeth inside and involute teeth

outside will be used Instead of the mtor The novel design of the anti-reverse and anti-gap structure

overcomes the gap pmblem after deep reactive ion etching of silicon The actuators and gearing

system have been fabricated by using a SOI wafer with the device layer of 30 pm and tested for

periormance They am driven by a periodic voltage (Vpp = 80 V) with diffemnt frequencies ranging

fmm 1 Hz to 30 Hz. In this range, the angular velocity of the ratchet ring was proportional with the

frequency and matched very well with theoretical calculation

TOM TAT

Bdi bdo ndy trinh bdy qud trinh thiit ki vd ehi tao md ta quay kich thu&c micmmet (MRM) vd

ung dung cua nd. tmng dd bdn bd kich ho^t rdng luge dugc su dung di din ddng rd to nh& cdc rdng

cdc. Tmng hd thdng bdnh rdng. vdnh rdng v&i phin rdng cdc bdn trong vd rdng thdn khai bdn ngodi s§

duge sir dung. Thidt ki m&i /g cda ciu true chdng ddo vd chdng khe h& giOp khic phuc cdc khe ha

smh ra sau khi chi t$o. Cdc bd kich boat vd h$ thdng bdnh rdng duge chi t^o bdng vat lidu Silicon v6i

bi ddy Idm viec 30 micmmet va da dugc kiim tra ho^t ddng lai didn dp xoay chieu 80 V, trong ddi tin

so tu 1 din 30 Hz. Tmng gi&i h^n ddi tin ndy. v$n tic gde cOa vdnh rang Id ly Id thudn v&i tin s6 dan

vd khd sdt v&i tinh todn ly' thuyit.

I. INTRODUCTION

Electrostatic comb-drive actuators and

their applications are important components in

MEMS. Since the first reports on micro￾machined comb actuator by Tang el al. [1],[2],

there has been a substantial number of

researches on comb-drive actuators and their

applications. The electrostatic effect of comb

actuators were well investigated analytically

[3], hi [4],[5], research on micro-machined

comb actuator focuses on the structure design lo

obtain large displacement and high stability.

Comb actuators have been used in many

applications, e.g., as optical switches [6], as

drivers for micro gear trains [7],[8] or to move a

shuttle forward in a linear inchworm motor [9].

The design and fabrication of micro

rotational motor have been a topic of many

recent publications. Sniegowski el al. used two

sets of linear comb actuators to drive the output

gear [7],[8]. The linear motion of comb actuator

has been converted to rotary motion via

linkages pinned into the output gear. Kim

developed a rotary motor by inchworm motion.

The rotor is wrapped by two opposite belts

which are connected to piezoelectric actuators

[10]. Sammoura demonstrated a rotary

inchworm motor using four gap-closing

actuators to rotate a free moving rotor [11].

Advantages of these types are high angular

velocity and low driving voltage. However they

required sophisticated control systems

In this paper, the electrostatic comb-drive

actuators (MRCA) will be used to drive the

rotor through ratchet mechanism The micro￾ratchet was first used in MEMS by Sandia

National Laboratories [12].[13] and b\ the

author [14],[15]. The advantages of this system

are balch fabrication, simple configuration and

control.