Design And Test Of Adaptive Adjustment System For Combine Harvester Header Height

The situation of cultivated land in China is complex and diverse.At present,when domestic combine harvesters are operating in the field,the height of the header is still controlled by manually controlling the hydraulic valve.The level of automation is low,and it is easy to cause the header to touch the ground and the height of the stubble to be inconsistent.The adjustment is timely and accurate.Problems such as poor performance seriously affect the quality of work and harvesting efficiency.In view of the above problems,this paper carries out the design and test of the height adaptive adjustment system of agricultural harvesting machinery header,and designs a surface height profiling detection device and header height control system,which can improve the consistency of cutting height and reduce the harvest loss rate.and so on are positive.The main research contents are as follows.(1)Aiming at the problems of the current header height detection device such as the lag in the acquisition signal and the inability of the control system to adjust the header in advance according to the terrain,a front-wheeled surface height profiling detection device was designed.The dynamic and static test tests have verified the detection accuracy of the surface height profiling detection device when the harvester is static and dynamic.The results show that: within the adjustment range of the harvesting header,the average error of static detection of the surface height profiling detection device is 5.97 mm,and the average error of dynamic detection is 9.67 mm,and the detection accuracy meets the requirements for use.(2)In view of the problems of low control precision and slow speed of the original header lifting hydraulic system,the system was modified,and the key hydraulic components were designed and selected.By carrying out the hydraulic system response speed test,the feasibility of the optimized hydraulic system is verified.The results show that the descending response speed of the header increases to 0.244 m/s after the modification;the response speed of the header rises to 0.157 m/s after the modification,and the response speed of the system is significantly improved after the modification.(3)In order to improve the response speed of the control system and reduce the number of adjustments,so as to reduce the energy consumption in the adjustment process of the hydraulic system,an adaptive adjustment control system for the height of the header is designed,and the hardware and software parts of the system are selected and designed respectively.A control strategy was developed to achieve a header adjustment threshold of ±10 mm from the target height.(4)Carry out the response accuracy test and response speed test of the header height adaptive adjustment control system to verify the feasibility of the header height adaptive adjustment control strategy during operation.The average deviation of the height of the cement road walking test header from the ground is 3.54 mm,the average deviation of the height of the field road walking test header from the ground is 6.09 mm,and the response speed is 182.59 mm/s,which can meet the requirements of use.