Research On Portable Digital Force Measuring System Based On Quartz Resonance Force Sensor

The quartz resonant force sensor is one kind of digital sensors which has begun to be put into practical use in recent years. The purpose of the research conducted in this essay is to design a kind of portable force measuring system with quartz resonance force sensor. Force-frequency effect of AT-cut symmetrical incomplete circular crystal resonator is studied in this dissertation. Based on the research result and the new techniques of sensor produced,crystal resonator force sensor with high accuracy is designed and produced. On the basis of the above work, the corresponding loading structure is designed. The micro-controller is used as the central control unit and the hardware and the software are designed. The techniques such as the way of multi-cycle synchronism to measure the frequency and digital filter are employed in this system which make the force response highly accuracy and highly stable with fast speed, besides these it also has the feature of convenience and reliance. The method using the quartz resonant force sensor's out-put frequency sampling differential values to eliminate the sensing error caused by the temperature drift, without any other temperature compensation components and circuits, is presented. Principle of the differential method depressing the drift noise is analyzed, the algorithm in the quartz resonant force sensor is offered. As to the part of the design of load structure and hardware, ways such as minimizing the size of structure ,circuit as small as possible, and low power dissipation are adopted. Then a practical portable system is shaped.