Xiaokang Liu

Study on the time-grating displacement sensor of mix-motivating type

In this paper a new novel time-grating displacement sensor of mix-motivating type with the mechanism movement and the traveling wave magnetic field is proposed for the first time. In the research of time-grating displacement sensor, the mechanism-motivating modulation sensor are compared with the electricity-motivating modulation sensor rom various fields. It is found that, on the one hand, the two set of designing thoughts are the same from their essence, their mathematics model are also the same, and they are expressed by the same traveling wave formula; On the other hand, there exists the difference of obtaining the moving coordinate. The former is dependent on the rotary machine equipment, and the later is dependent on the rotary magnetic field. In terms of the two type of motivation, two types of time-grating sensor are developed, that is, the mechanism time-grating sensor and the field time-grating sensor. In the development of two types of time-grating sensor, the presented time-grating sensor of mix-motivating type is firstly developed which is based on the advantage and disadvantage of two types of time-grating sensor as mentioned above. Various experiments are carried out on the time-grating sensor of mix-motivating type, compared with the mechanism time-grating sensor and the field time-grating sensor. The experimental results show that the precision of time-grating sensor of mix-motivating type is improved markedly in comparison with the other two types of time-grating sensor.

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.

Analysis of fluctuation equation in time-grating and new method for generating travelling wave

In this paper, the principle to generate the moving coordinate in time grating displacement sensor is analyzed. In order to simplify the structure of the time grating sensor and make its manufacture more easily, its fluctuation equation is analyzed and the relation and distinction between electric traveling wave and magnetic traveling wave are discussed. Then a new method to generate traveling wave is proposed based on these discussions. The method is employed with its corresponding mechanical structure to form a new type time grating sensor. Experimental results show that the sensor can generate correct signal and the method is feasible. Thus the traditional electrical machinery method can be replaced by a new method to generate the moving magnetic field. This new method can simplify the manufacture process greatly.

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.

High-precision time-grating displacement sensor based on harmonic wave correcting method

Time-grating displacement sensor is a new type angular displacement sensor with initial invention. In the research of time-grating sensor, it is found that the cost of high precision only dependent on the high-precision machining and fitting technology is very high generally, and it is very difficult to achieve it. In terms of special structure of time-grating sensor including multi-probes and multi-poles, harmonic wave correcting method is firstly proposed for error correction and compensation of sensors. The data acquired system acquires data from time-grating sensor and the raster at scores of evenly spaced data points in the range of one pole synchronously. These data is input computer to achieve spectrum analysis of the error, and to obtain the best-fitting curve including the main harmonic wave component. The best-fitting curve can be utilized to correct the error curve associated with the special algorithm. Numeric experiments on time-grating sensor of different size are devised to verify the effectiveness of the method, and experimental results coming out from applications confirm the validity of the proposed method. The precision of time-grating angular displacement sensor has been improved greatly after applying this method.