Adaptive Control Algorithm Improving the Stability of Micro Force Measurement System
Based on the electrostatics principle, the measurement and realization of micro forces in the order of 10-6 N to 10-4 N (the resolution is 10-8 N) can be realized and it can be traced back to the SI such as length, voltage, capacitance, etc. Because the stiffness and damping ratio of the system are very small, both the external interference and the parameter variation would make the system unstable so that it is hardly to make the system get optimal by using the traditional PID control algorithm. This dissertation introduces an adaptive control algorithm based on minimum variance. Adjust the parameter values of the controller continuously to make the transient response and the output of the control object get optimal when the measurement system working. The system performance is tested by measuring standard weights of 5, 10 and 20 mg. The result shows that it can not only speed up the convergence but also reduce residual vibration, decreasing variance to 0.01 μm.
KeywordsElectrostatic force Traceability Adaptive Control Measurement Minimum variance
This work was supported by National Natural Science Foundation (No. 51175377) and Tianjin Natural Science Foundation (No. 12JCQNJC02700).
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