| Agricultural machinery automatic navigation technology is an important part of precision agriculture technology,and it is also a significant technical means for achieving accurate operations.The agricultural machinery automatic navigation system has the advantages of improving land utilization,prolonging working hours,reducing input costs,and improving driving comfort.With the continuous advancement of technology,Heilongjiang,Xinjiang and other large-scale reclaimed areas and large-scale agricultural machinery cooperatives in our country have begun to widely use agricultural automatic navigation system.However,due to differences in the use of sensor performance,control algorithms and so on in different automatic navigation products,the performance of various systems in the actual operation process is quite different.In order to analyze the influence of on-line coefficients,median reference values,posture compensation before and after attitude compensation on the accuracy of navigation system operation,the following experimental work was done in this study.In order to assess the operational effect of agricultural machine automatic navigation systems,we proposes three evaluation indicators: pass accuracy,pass-to-pass accuracy,overlap and skip,and evaluates the accuracy of agricultural machine navigation system operation by calculating the lateral deviation between the trajectory points and the predefined route of the automatic navigation system of agricultural machinery,the deviation between the actual job width and the default job width,the overlapping rate of work and the missing rate.Experiments were conducted with Lovol 704 on an agricultural automatic navigation test platform.The results of the test showed that the average value of the overall lateral deviation of the automatic navigation test was-0.08 cm,the average deviation between ridges was 0.03 cm,the standard deviation was 0.7cm,the work overlap rate was 0.053%,and the work omission rate was 0.037%,verifying the feasibility and effectiveness of the navigation system operation accuracy evaluating method.In this paper,we analyzes the influence of different on-line coefficients,different median reference values,and attitude compensation before and after on the accuracy of navigation by using the navigation accuracy evaluation method.In the case of ignoring the influence of speed and other factors,when the on-line coefficients are 1,3,and 4,the average lateral deviation of the navigation system operation is 0.8cm,-1.37 cm,and-4.54 cm respectively.We found that the smaller the preset value of the online coefficient is,the faster the agricultural machine reaches the predefined route,the higher the navigation accuracy is,but when the value is too small,the vehicle body will have a various sense of vibration,and the front wheel vibration will be faster,which will affect the operation effect;The median reference value has a great influence on the accuracy of the navigation,when the median reference value are 0,2,and 4,the average horizontal deviation of the navigation system operation are 5.6cm,1.83 cm,and-2.26 cm respectively.We found that the setting value of the median reference value improve obviously the accuracy of the navigation system.However,if the value is too large or too small,it is not conducive to navigation accuracy.The contrast of before and after attitude compensation is quite different,without posture compensation,the average value of the horizontal deviation of the navigation system operation reaches-8cm and the standard deviation is 15.44 cm.After the attitude compensation,the average horizontal deviation of the navigation system is-0.6cm,and the standard deviation is 3.26 cm.We can see that the attitude compensation is absolutely crucial to the automatic navigation system operation of agricultural machinery especially on the rugged farmland. |
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