Xihou Chen

The principle of differential grating displacement sensor

Grating type sensor is one of the most important displacement sensors. But the number and the machining precision of their gratings limit the resolution of traditional grating displacement sensor. A new sensor called differential displacement sensor is proposed for the first time. Based on the principle resembling that of vernier calipers, using the scale differential of two staves with relative motion, it can gain more impulses, and achieve the goal of improving resolution. As a new displacement sensor, differential grating displacement sensor has its own characteristic. There are some special factors should be considered and some rules should be followed in designing differential grating sensor. And the parameter choice has a great effect on the performance of the sensor. The design idea, working principle and parameter design rules of differential grating sensor are introduced in details in this paper by making gear grating sensor as an example.

Development of a new angular displacement sensor based on principle of vernier caliper

In this paper, a new kind of angular high precision displacement based on principle of vernier caliper is proposed. This displacement is sourced from the idea of vernier caliper. The longer arm of vernier caliper with a linear scale and the L-shaped sliding attachment with a vernier are replaced by an inner round part and outer round part with reticle around them. The numbers of reticle around inner part is different from that of outer part. Using the reticle number difference between two parts having relative motion, in the condition of the similar reticle, there exist changes of some physical parameter among the reticles. It can gain more pulse signal. In some cases, the numbers of pulse signal is approximately equal to the product of the two numbers of reticles around inner and outer round parts, which has identical consequence of pulse interpolation or frequency doubling. Through which the goal of improving resolution is achieved. The design idea, the working principle, the signal analysis, the precision analysis and the experiment result of this angular displacement sensor are introduced. The research result shows that thickness, spacing and number of reticles can directly affect the number, amplitude, wave shape, accuracy and other characteristics of the pulse signal. It will play an important rule in improving the traditional grating type angular displacement sensor technology.