Design And Experimental Research Of An Automatic Height Control System For Topping Of Cotton Top-cutting Machine

Cotton topping refers to the removal of cotton buds by artificial means, in order to eliminate the cotton apical dominance, easy field management and increase the yield of cotton. In this paper, according to the requirements of technology of cotton topping, domestic and foreign research results, design a kind of cotton topping height automatic control system. Manufacture d a cotton topping test device based on the system, and it was tested in the field.(1) Cotton height measuring system. By using shooting sensor as the cotton height measuring element laser, and the sensor is placed equidistant parallel along the vertical direction. According to the laser receiver signal distinguish cotton plant height, and the signals of height are converted to the corresponding number of encoder pulses.(2) Cutter height control system. Cutting height control system adopts the vertical lifting by gear rack transmission system. Guyed encoder is fixed on the machine frame and its rope end is connected with the cutter, and sends out pulse signal corresponding to the different height of cutter. The microcontroller controls motor according to the height differe nce of cotton and cutter. And Cutter is adjusted to the proper position and completing the topping process.(3) The overall design of control system. The system based on MC9S12XS128 as control core, aided by the minimum system, the serial communication module, the automatic distance measuring module etc. And finally make schematic diagram and PCB by Altium Designer.(4) Field experiment. Based on the analysis of test data, proved that the average operating speed of top-cutting machine is about 3km/h, the average productivity is 1.5km2/h, effectively topping rate more than 80%.And proved that this top-cutting machine can replace the manual to complete the work of cotton topping.