Abstract
The elevation detection accuracy of the laser receiver in the laser levelling control system directly affects land-levelling operations. To effectively improve the effect of levelling operations and meet the requirements for the accuracy of elevation detection in different industries, this study optimization designed a multilevel adjustable laser receiver. First, we examined the laser signal detection technology and processing circuit, designed the photoelectric conversion array for the detection of the rotating laser, and converted it into a photocurrent signal. We also designed the filter, amplifier, and shaping and stretching circuits for analogue-to-digital conversion of the photocurrent signal. The digital signal was calculated based on the deviation of the elevation by using a microprocessor and was output by a controller area network (CAN) bus. The laser beam spot diameter transmission and diffusion were then studied, and with the detectable spot diameters were compared and analyzed. Accordingly, an algorithm was proposed to calculate the deviation of laser receiver elevation. The resolution of the elevation deviation was set to ±3 mm; however, this value could be adjusted to ±6 mm, ±9 mm, ±12 mm, and ±15 mm, according to the requirements. Finally, the laser receiver was tested and analyzed, and the test results of the elevation detection accuracy showed that when the laser receiver was within a radius of 90 m, the elevation detection accuracy was within the ±3 mm range. The outcomes of the farmland-levelling test showed that the standard deviation S d of the field surface decreased from 9.54 cm before levelling to 2.42 cm after levelling, and the percentage of sampling points associated with absolute errors of ≤3 cm was 84.06%. These outcomes meet the requirements of high-standard farmland construction. The test results of concrete levelling showed that within a radius of 30 m, the standard deviation S d of the elevation adjustment of the left laser receiver was 1.389 mm, and the standard deviation S d of the elevation adjustment of the right laser receiver was 1.316 mm. Furthermore, the percentage of the sampling points associated with absolute elevation adjustment errors of ≤3 mm in the cases of the two laser receivers was 100% after levelling, whereas the standard deviation S d of the sand bed surface was 0.881 mm. Additionally, the percentage of the sampling points associated with absolute errors of ≤3 mm was 100%. This met the construction standards of the concrete industry.
Highlights
In the 1980s, laser-levelling technology was extensively used in the United States, the formerSoviet Union, Germany, and Japan [1]
Laser land-levelling technology can effectively improve the levelling of farmlands, ensure that the distribution of irrigation water is more homogeneous, increase the irrigation efficiency by 10%–15%, and save irrigation water by more than 10%
The of laser designed in thethe tests andreceiver analyses, rule ofdistance the elevation detection accuracy the receiver laser receiver on the this article can be shared agriculturalThe laser graders and concrete to meet farmland transmission distance waswith evaluated
Summary
In the 1980s, laser-levelling technology was extensively used in the United States, the former. The American Trimble company developed the LS908 laser receiver, and it selected a silicon photocell as the photodetector (photosensitive surface size of 5 mm × 20 mm) They designed an efficient operational amplifier circuit and signal processing circuit, with an elevation detection accuracy of. One example is the LR40 laser receiver that was developed by Trimble in the United States; it selected a small silicon photocell as the photodetector (photosensitive surface size of 3 mm × 5 mm) and the operational amplifier circuit and the signal processing circuit were optimized, of which the elevation detection accuracy could be set to ±3 mm, ±6 mm, ±9 mm [23]. The of laser designed in thethe tests andreceiver analyses, rule ofdistance the elevation detection accuracy the receiver laser receiver on the this article can be shared agriculturalThe laser graders and concrete to meet farmland transmission distance waswith evaluated. Laser receiver designed inlevelers this article can bethe shared with construction requirements andconcrete the construction requirements of the concrete industry, which are of agricultural laser graders and levelers to meet the farmland construction requirements and athe high standard. requirements of the concrete industry, which are of a high standard
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