Abstract: The advantage and disadvantage of traditional displacement sensors are analyzed. The time space transform- ation idea, the time space transformation method and the principle of time grating sensor are discussed. By researching the high precision time grating displacement sensor, the prin- ciple, structure, resolution and accuracy of the single tooth type, frequency difference type, field type and composite type time grating are introduced. The time grating displacement sensor that has passed through the appraisal gets a 0.1″resolution and ±0.8″accuracy. Meanwhile a harmonic wave correcting idea is introduced. Besides the error decomposing and analysis of sensor, FFT is used to design parameter and correct error before and during the sensor is made. The technical advantages of time grating as a smart sensor and practical effect of harmonic wave correcting are obvious. The purpose is to realize high-precision measurement without the requirement of high precision machining and high precision scale ruler.

Key words: Correcting, Displacement sensor, Precision, Time grating