Development And Testing Of An Automatic Height-Adjusting Cotton Topper

The development and evaluation of a fine-tuned height-adjustable cotton topper prototype is described in this article. Cotton is topped at the late period of flowering because spindling reduces cotton production and complicates harvest. The main defect of traditional cotton toppers is that they cannot adjust the topping height according to the height of individual cotton plants, resulting in a high percentage of missed topping and over-cutting that hurts the fruit branches.To solve the problem, procious researches on height-adjustable cotton topper are summerized. This article pointed out that an unreliable blade and a lack of height adjusting automatic control system are foundmental reasons for poor working performance of previous toppers.Based on these analysises, this article discribed a series models of cotton top geometrical parameters including: height distribution model, crown geometrical model and the model of height difference between two nearby plants. We also accumulated data of other cotton plant characters. Based on this model the working performence including passrate can be calculated and evaluated.Based on this data, we developed a mechanical-electronic topping prototype that can adjust topping height according to the height of cotton. It consisted of a machine system with a height-adjustable shear and an automatic height control system including an infrared emission height detector, a controller and a servo system. This mechanical design solved the problem of inefficiency cutting caused by the sliding because of unsuitable blade. In this design, sole rotating blade is replaced by two counter rotating discs that can scissor the leaves. This automatic control system is consisted of height detecting system,controller and a servo system. This cotrol system overcomed the default of unprecise testing and worked accurately and stably.This cotton topper was three-pointed, mounted on a tractor and tested in the field. In the trial, the prototype was tested respectively at the ground speed of 1.1 km/h, 1.5 km/h and 2.2 km/h; the excision length(from the peak down to the cutting point) was changed from 9 to 11 cm. In the trial,the pass rate(the percentage of buds cut accurately without hurting the fruit branch) of this prototype was significantly higher than the ideal pass rate of traditional toppers at all above ground speeds. The pass rate did not differ significantly at the three different excision lengths(9 cm and 11 cm). A replicate trial was conducted to confirm these results and evaluate the actual topping results. Topping at 1.1 km/h stopped spindling of 90% of the cotton; topping at 1.5 km/h stopped spindling of 83% of the cotton.