In order to verify the reliability of this method, the author carried out experimental verification. The tested helical gears are two 1.5 module 45 ° left helical gears, two 1.25 module 19 ° left helical gears and one 1.5 module 45 ° right helical gear (rusted). The technical indicators of helix angle of different manufacturers are slightly different. The comparison between the measurement results of the proposed method and the design values is shown in the table.
Based on the platform, for 45 ° helical gears, the measurement result of the algorithm is 44.1006 °. The relative error of the method is reduced by 1.74%. According to the data, the average relative error of the method is reduced by 0.56%. The accuracy of universal angle ruler is 2 ‘or 5’, and the detection accuracy of this method is close to that of universal angle ruler.
| Helical gear specification | Design value | Measured value | Absolute error | Relative error |
| 45 ° 1.5 m 26z left hand gear 1 | 45． 00° | 45． 105 7° | 6． 34′ | 0． 23% |
| 45 ° 1.5 m 26z left hand gear 2 | 45． 00° | 45． 125 5° | 7． 53′ | 0． 28% |
| 19 ° 1.25 m 25Z left hand gear 3 | 19． 524° | 19． 451 0° | 4． 38′ | 0． 37% |
| 19 ° 1.25 m 25Z left hand gear 4 | 19． 524° | 19． 617 2° | 5． 59′ | 0． 48% |
| 45 ° 1.5 m 26z right hand gear 5 | 45． 00° | 44． 871 0° | 7． 74′ | 0． 29% |
Compared with the use of ordinary industrial cameras, when measuring 45 ° helical gears at close range, because it is difficult to accurately compensate for parallax, the relative error of the helix angle measured by the tooth lines with small parallax in the middle reaches 2.7%, and the error of the helix angle measured by the tooth lines with large parallax on both sides reaches 5.01%. Methods double telecentric lens was used to reduce the relative error by more than 2%.
The total running time of the algorithm is about 1 s, the detection time is reduced by about 7 s, and the detection time is reduced by about 17 s compared with the universal angle ruler method, which can meet the needs of the online measurement system as shown in the figure.
