Micro-force Sensor, Micro-friction Tester

The appearance of the Micro Electro Mechanical System (MEMS) shows that the 1C technology has penetrated into some traditional domains such as mechanics and optics. It makes the batch and integrated microsystem possible. However many new problems arose. Since the first micromotor appeared, the problem of friction becomes serious. In fact, it can't be avoided for all motional mechanisms. Whether the traditional frictional theory is still suitable for microsystem should be studied.The research of macro friction phenomena is a synthetically analytical method based on test. However, in micro world, the friction force and vertical press are all minute, which brings difficulties to test. When high measure precision is required, the resolution and sensitivity will be higher and not easy to obtain. There are several possible ways to solve the problem. Considering the size, the cost and the stability of the measuring system, the method based on strain gauge was chosen.Micro force sensor is a key part of the measurement. The silicon force sensor using bulk silicon process has lots of advantages such as batch producible, low cost, high precision, small driving force, high reliability, low power consuming, small dimension, light weight and quick response, etc. Therefore, a scheme is proposed in this paper. Under the guidance of the researchers in the group of MEMS in CIOMP, the developments are as follows:The configuration of a micro friction test instrument was designed with references to large quantities of domestic and foreign literatures.A kind of micro force sensor for the micro friction test was designed and fabricated.In order to obtain high resolution of the instrument, the effect of input noise of amplifier must be decreased. Hereby, an amplifier circuit based on the chopping theory was developed for it.The performances of the micro force sensor were tested and a decent result was obtained.