齿梳式油茶果采摘机采摘执行机构的研制与试验

Development and test of picking actor in oil-tea camellia fruit picking machine of tooth comb type

为了实现油茶果采摘的机械化,该文论述了齿梳式油茶果采摘机执行机构的研制和试验,重点论述了可避让式采摘头、多自由度采摘臂的设计。建立了空间坐标系,应用D-H矩阵变换,建立了采摘执行机构中采摘齿的空间运动方程。现场采摘试验表明,当齿梳式采摘头上升速度约为0.8m/s左右,采摘头回转速度约为15r/min时,既可以获得较高的采摘效率,又能使采摘范围内的漏摘率控制在3.2%以内,同时保证花蕾的掉落率控制在3%以内,从而验证了齿梳式油茶果采摘机的可行性。

Oil-tea camellia is one of the most important economic forest products in southern China, and it has a characteristic of whose florescence overlaps with the fruiting period. During the fruiting period, the fruits should be picked, while buds falling should be avoided. At present, the oil-tea camellia fruit picking is finished by the classical manual method that results in high cost and lower efficiency. With the promotion of the good varieties and the cultivation method of oil-tea camellia, mechanization and intellectualization of fruit picking have become an important aspect in upgrading the oil-tea industry as well as one of the important development directions of forestry machinery. This paper discussed the development and test of the picking machine of the toothcomb type from several aspects as the following. Firstly, the design of the rotary picking head and the picking arm of the machine were discussed. The picking arm, which consists of two parallel quadrilateral mechanisms connected in series, locates on the end of the picking arm. This kind of structure makes it easy to keep the posture of the picking head during the picking process. The rotary picking head consists of three parallel quadrilateral mechanisms connected in parallel, revolving around the common axis. This type of picking head can increase the picking efficiency significantly. Secondly, the space coordinates of the picking executive mechanism were established in this paper, and the motion equation of mechanism was established by the D-H matrix transform, and the main parameters of the transformation matrix was calculated and analyzed. Thirdly, the field experiments showed that each part of the picking machine of the toothcomb type works in phase and legitimately, and that the power matching is in accordance with the requirements. After the test data were analyzed, a conclusion can be calculated that higher picking efficiency can be obtained. The rate of oil-tea fruits not been picked can be controlled within 3.3 percent, the rate of buds dropping can be controlled within 3.2 percent, and the branches have rarely been damaged when the speed of the picking head raised is about 0.8m/s and the velocity of the picking tooth circumgyrated is about 15r/min. Lastly, there are also some shortages in the picking machine of the toothcomb type. For one thing, there is some existing difficulty in controlling the speed of the rising of the picking head accurately, as the picking arm consists of rotary pairs connected and driven by hydraulic pressure. Therefore, the machine needs a further improvement on this aspect. For another, the picking machine of the toothcomb type can only pick the fruits distributed on the surface layer, so the inner oil-tea fruits can only be picked by manual power. In the end, it seemed unrealistic to thoroughly avoid damage to the branches of oil-tea during the course of picking.