Property Of The Micro-friction/Micro-adhesion Tester Based On Fiber Optic Sensor

The Micro friction & Micro adhesion tester is a test device developed for friction and adhesion phenomenon under the microscopic condition, which can effective measure friction force and adhesive force in the range of Micro cattle and Backhoe cattle, also can reflect the properties of friction and adhesion among the materials. And it provides testing methods to micro friction attrition properties for MEMS (micro electro mechanical system).Based on the advance development of micro friction & micro adhesion tester, the paper analyzes and researches the problem of signal processing, stepping motor control and piezoelectric ceramic control, which is against to the problem of great influence of vibration and intermittent movement of stepping motor. It used methods of composite filtering,closed loop control and composite loading to improve the tester, which is able to enhance the testing accuracy and stability. The main research work is showed as follows:(1) Use beryllium bronze for material produced elastic sensitive components; Process finite-element analysis and demarcation; Optimize the stiffness coefficient and in-out linear of component; Improve sensitivity of tester.(2) Analyze the frequency domain, time domain and wavelet for test signals of micro friction under of different working condition; According to signal characteristic, use the methods such as average filtering, sliding filter and wavelet de-noising for digital filtering, to filter external vibration interference and noise.(3) Analyze the loading errors of static and dynamic with step-motor loading method; Construct the PID closed-loop control system to reduce loading errors and improve load precision.(4) Research on the retardation and non-linear characteristics of piezoelectric ceramic; Control piezoelectric ceramic by adopting the way of feed forward open loop and displacement closed loop; Acquire higher precision of displacement output.(5) Adopt the composite loading with the stepping motor and piezoelectric ceramic to satisfy the different loading acquirement; Take the experiment of micro friction force test and micro adhesion force test to prove the stability and reliability of tester.