A straight-line dual-track absolute steel tape ruler and its reading method

Abstract

The invention discloses a linear double-code-track absolute steel tape ruler and a reading method thereof. The invention comprises a steel tape ruler, a first detection head group, a second detection head group, a third detection head group and a fourth detection head group, the steel tape ruler is composed of an absolute code track and an identification code track. The detection method is as follows: the first detection head group and the second detection head group detect the absolute code channel to obtain the first absolute code and the second absolute code, respectively, and the third detection head group and the fourth detection head group detect the identification code channel to obtain respectively. The first identification encoding and the second identification encoding, according to whether the first absolute encoding is zero, select the corresponding absolute encoding and identification encoding, and finally obtain the absolute distance value and the identification distance value according to the absolute encoding mapping table and the identification encoding mapping table, thus Absolute position is available. The steel tape ruler of the invention has the advantages of high resolution, large measuring range, simple manufacture, low cost and real-time detection of absolute position.

Description

technical field [0001] The invention relates to the field of position measurement technology research, in particular to a straight-line double-track absolute steel tape ruler and a reading method thereof. Background technique [0002] At present, grating ruler measurement technology is widely used in the field of position measurement. The grating ruler is a measurement feedback device that uses the optical principle of the grating. Grating rulers are often used to detect linear displacement or angular displacement. [0003] Grating rulers are divided into incremental grating rulers and absolute grating rulers. [0004] The working principle of the incremental grating scale is to use the relative movement of the light source and the grating scale to modulate the light, and obtain the displacement information by receiving the modulated optical signal. The disadvantages of incremental grating rulers are: 1. After power failure or restarting the system, it is necessary to res...

AI Technical Summary

Problems solved by technology

The disadvantages of incremental grating rulers are: 1. After power off or restarting the system, it is necessary to reset the reference point to zero; 2. Accumulation of errors

The disadvantages of the single-track absolute grating ruler are: 1. When the code length remains unchanged, if the range is increased, the resolution will decrease; if the resolution is increased, the range will be shortened

The disadvantages of the multi-code absolute grating ruler are: 1. It is difficult to manufacture the multi-code grating ruler; 2. The cost is high; 3. The volume of the grating ruler and the code reader increases, which is not conducive to installation in a narrow shaft

The defects of the double code track absolute grating ruler are: 1. Since the incremental code track is used, there are also defects of the incremental code track, that is, when the power is turned off or the system is restarted, only the absolute code can be obtained but the incremental value cannot be obtained. The position data is inaccurate, and the incremental value must be obtained after running a certain distance; 2. In order to ensure high resolution, the grating of the incremental code track is very dense, which not only makes it difficult to make the grating ruler but also increases the cost

Images