Papers by Author: Xiao Kang Liu

Abstract: Time grating displacement sensor is briefly introduced for measuring space with time. The measured values of time grating will not update during the measuring period. To use the sensor as position feedback component for CNC rotary table positioning servo control, this paper firstly introduces prediction conception to measurement field, and predictive measurement method is firstly proposed. Predicted values are derived form past measured values and the prediction error is corrected in real time using the new measured values. The positioning accuracy of the CNC rotary table is improved greatly. Experiment results conform the validity of the proposed method.

Abstract: A theory of time-space coordinate transformation is presented for measuring space with time. A novel type of displacement sensor named time grating is developed, and methods of electronic rectifying, self-compensation and self-correction are proposed to intelligentize the sensor. Experiment results coming from applications conform to the validity of the proposed theory and methods. The experiment and test results show that high-precision measurement is achieved without high-precision manufacture and that angular displacement is measured very accurately without a dividing scale, which embeds the remarkable characteristics of low cost but high accuracy to the time grating sensor.

Abstract: Machining precision deficiency and installing error are very common problems for many sensors, which may result in unstable amplitude i the signal detected by the probe and further cause measurement errors of the sensors. The concept of using electronic technology to offset machinery precision deficiency is utilized. A new method of electronic rectifying is proposed. The automatic gain control (AGC) technology used in the field of wireless communication is applied for sensor signal processing. An AGC circuit consisting of a multiplier and divider AD534 is designed. A new smart time grating displacement sensor currently under development by us is used to provide experimental results for comparison with and without the AGC technology.

Abstract: For many reasons, the study of differential frequency measurement had disappeared for some years. This paper applies the differential frequency measurement previously used to measure transmission error to static differential frequency measurement. A new method called method of duality for gear and electric wave is proposed to explain the differential frequency measurement in a new way to discover its essence. A novel angular displacement sensor is designed. The composite error is ±17″ based on the static differential frequency measurement.