Performance Testing Of The Orchard Tractor

Mechanization of orchard is an important part of agricultural mechanization. Due to the low mechanization of orchard, fruit picking and transport require a lot of labor. In the process of fruit transportation, random vibration of orchard transport machinery will damage the fruit and reduce economic benefits to orchardists. In the process of fruit picking and transportation,the crawler tractor is an important orchard power machine and operation platform. In order to improve the efficiency of fruit picking and reduce the damage in the fruit transportation, the orchardists have increasingly high requirements on the stability and vibration of crawler tractor during the process of operation in the orchard.The orchard tractor mainly comprises a lifting picking platform and remote control of self-propelled hydraulic crawler tractor and it is more and more important to study the performance of the orchard tractor,which can provide theoretical basis for the development of high efficiency, high performance and low cost orchard tractor.In this paper, the research work and conclusions are as follows:(1)The static stability of orchard is modeled and analyzed, and ground reaction method was used to determine the height of the centroid position with load and unload when lifting picking platform was in different height. Through the stability test analysis, conclusion are follows: under load and unload, with the increase of the lifting picking platform, the centroid of the orchard engine gradually increased and maximum uphill angle of slope、maximum downhill angle of slope and the maximum horizontal traveling angle of slope decrease gradually;these angles are 27.5°、23.0°、19.8° with unload compared with 29.7°、24.1°、20.1°with load; under unload,the abscissa is gradually away from the front of caterpillar band while vertical axis does not change with the increase of lifting picking platform;under load, the abscissa is also gradually away from the front of caterpillar band and the vertical coordinates gradually deviate from the vertical- center plane of the orchard tractor with the increase of lifting picking platform. Compared with unload condition, maximum uphill angle of slope increases while maximum downhill angle of slope and the maximum horizontal traveling angle of slope do not change obviously.(2)Linear walking characteristics of orchard tractor is modeled and analyzed;under different road conditions the deviation of orchard tractor are on the right; in the same driving distance, the amount of field deviation is greater than the amount on the cement road; the fundamental reason of the deviation is that the driving torque of the driving wheels is not the same, so the speeds of driving wheels are different;(3)The lifting platform of orchard tractor is modeled and analyzed. A vibration model of two degrees of freedom of man- picking platform is established, and by using the FFT to analyze the vibration signals, the results show that the vibration of lifting picking platform is low frequency vibration. Its natural frequency range is 2Hz~4Hz, 8Hz~11Hz.And it avoids the sensitive area of the human body and is easy to cause damage to the fruit, so the structure design of the picking platform needs to improve. Load and road conditions have different effects on the vibration of lifting picking platform, and the impact of the road condition on the vibration of lifting picking platform is obvious;...