The Strain-type Displacement Measuring System Based On Virtual Instrument Technology

With the development of science and technology, sensor technology can find wide application in every walk of the life. Testing and control system set a still higher demand on precision, sensitivity and stability of the sensor. The strain-type displacement sensor was widely used in industry, architecture and other sectors due to its sensitivity, high accuracy, easy miniaturization, batch production and etc. However, a sensor usually had cross sensitivity, and its output value depended on more than one parameter of its operating system, which also affected stability and measurement precision of the system. Some proper measures must be adopted for high performance against interference.Because the output voltage of the strain-type displacement sensor varied with temperature, the sensor must be subjected to temperature compensation. This paper discussed the causation of zero drift and temperature drift, and then introduced several kinds of compensation methods. Through a simple comparison, data fusion technology has been applied to temperature compensation of the system. Based on the virtual instrument technology and LabVIEW software development platform, strain type displacement sensor, temperature sensor LM35DZ, DAQ USB-6201and amplifying circuit put up the hardware platform of the displacement measuring system. Modularization method has been used in the software program, which divided the system into three parts. They were data collection and storage, data playback and determination of temperature compensation polynomial, and the displacement measuring system, respectively.Compared with results before compensation, the results of experiment are proven the efficiency of data fusion technology dealing with the zero drift, sensitivity coefficients, temperature stability and measurement precision. At the same time, virtual instrument technology has been applied to develop the testing system, which brought lots of advantages, such as low cost, simple design, full-function, excellent compensation and flexible expansion. The combination of data fusion technology and virtual instrument technology has a good extensive application prospect and research value during the automatic process.