The Research Of Static Resistance Strain Digital Measurement Method

Strain measurement is one of the important means that analyzes accessory or structure stress,validates design correctness,confirms complete machine load status while working and studies some physical phenomena mechanism in mechanical engineering.The traditional strain test technology gradually can't keep up with the step of modern test technology's development.Therefore,developing high-performance strain measuring instruments is very necessary.The paper firstly introduces the strain measurement current conditions, developing trend at home and abroad,and traditional strain measurement instruments'features,illustrating this paper's researching background and major researching contents. And then,it introduces existing strain measuring technologies'theory, methods and their existing shortages:firstly,traditional strain measuring technologies mostly employ bridge for measurement, which inevitably brings non-linear errors to the system, secondly,the measuring errors brought by the long connecting wires are not yet eliminated properly, thirdly, we are required to balance the measuring system each time before measuring, that is time-consuming and energy-comsuming.Based on above shortages which exist in traditional strain measurement technologies, this paper offers a new method for static resistance strain measurement. Firstly,as to the acquisition of strain signal,we abandon the mothod of traditional bridge measurement, but employ constant current source to drive the system and bring self-adjustment circuit design method into the system design, accordingly, the non-linear errors caused by bridge measurement are eliminated; secondly,the system employs three-wire method and twice measuring method to eliminate the measuring errors caused by long connecting wires and uncertain zero resistance;lastly, the system employs the embedded system BL2000 as the control core,and the hardware and software are designed based on it,besides,we use digital filter technology to eliminate the influence caused by noise signals.