The investigation of the detection mechanism for micromachined accelerometers with gaseous proof mass

A new mechanism of acceleration detection that utilizes gas sealed in a hermetic chamber as proof mass is discussed in this paper, on the basis of which a new type of micromachined accelerometer can be developed. The natural convection of gas in an accelerating hermetic chamber is investigated. The analysis shows that the convection is affected by the local body force and the force caused by the gas static pressure gradient. The direction of the resultant buoyancy lift (which is the driving force of the convection) is the same as that of the specific force and the magnitude is proportional to that of the specific force. Thus the convection can be utilized to detect the acceleration of the chamber. The authors put forward a simple device to visually demonstrate the detection mechanism. The new concept of "Gas pendulum" is introduced to further explain this mechanism. Three types of macroscopic accelerometer prototypes based on this mechanism are demonstrated. The experimental results show that such kind of accelerometer can measure acceleration up to +/-5g, and has a resolution better than 2 x 10(-4)g. The characters of this method and the prospect of its application in micromachined accelerometers are also discussed.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000177299000005&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Engineering, Electrical & ElectronicSCI(E)EI0ARTICLE3311-3141