Clamping Test And Simulation Analysis Of Banana Harvesting Manipulator

Banana picking is the key link of banana harvesting process. The technology of banana harvesting in our country is still mainly stay in manual picking. Throughout the banana industry chain, it includes harvesting, delivery, carpopodium cutting, cleaning, packaging, sterilization, ripening, sales. The mechanization degree of the entire banana industry chain in our country is lower, one of the most important reason is the low harvest mechanization degree of banana. This is because the special agronomic traits and gain characteristics of banana, the picking process become the most difficult part which contain labor-intensive and mechanical damage. This also directly restricts the banana mechanized production. In comparison with the low mechanization degree of banana harvesting, the production and sales of banana in our country is at the forefront of the world for a long time. Therefore, the development of banana harvesting mechanization will be significant.This article was based on the previous research results and physical prototype, with the analysis of whole banana harvesting manipulator clamping device simulation and optimization, to get the mechanical structure and size parameters which have a friendly performance with harvest target. Based on mechanical properties parameters and clamping characteristics of banana stem, through the orthogonal experiment test of banana stem with different clamping way and clamping material and the relationship between the clamping load, to acquire the suitable clamping scheme for banana harvesting. From the foundation of the mechanics performance parameters of banana stem, bionic banana stem model is set up, the simulation analysis was carried out on the clamping process in the process of clamping, and picking manipulator structure was optimized. Main research work are as follows:1) This paper analyzed the fruit and vegetable harvest robot and the research progress of banana harvesting equipment in the world. Now, there are a lot of fruit and vegetable harvest manipulator of research, but research on banana harvest is still in its infancy, the study of end effector of manipulator is very lack, picking operation of banana is still mainly depends on handwork, it contain low mechanization degree, human cost and difficult to operate. This article analysis plenty of fruit and vegetable harvest robot and based on the early stage of the laboratory of banana agronomic characteristics and design foundation, put forward a suitable end effector for large weights fruit like banana.2) The clamping object of for banana picking is banana stem, there is an anisotropic mechanical properties in stem. In order to make the simulation model fit the actual material as far as possible, divided the stem into epidermis, middle, stem core three parts, determining the density, the axial and radial elastic modulus, shear modulus respectively, and built the simulation model of the picking model based on the theory of homogenizing and the finite element method. Set test factors and test plan that affecting the effects of picking clamping, according to the relevant conditions between it, completed the design and manufacture of clamping testing board. Measuring clamping performance by the maximum axial drawing force of banana stem under the clamping before the stem begin to slip, carry on single factor and multiple factors experiment of the factor which have influence to clamping performance, such as clamping palm type, contact materials, clamping force, number of steel nails, diameter of steel nails, depth of screw-clamping. Finally, obtained the relationship between these factors and clamping performance and the best combination of factors. That is the combination of 6 nails, 10 mm of screw-clamping depth, 5 mm in diameter of nails.3) Combined with the results of clamping test and the goals of manipulator design, complete simulation model of rotating device, lifting device, and end effector through Pro/E, used the finite element analysis software ANSYS to analyze the security and stability of manipulator, check the rationality of end effector's key parts, accomplish the simulation of clamping process, optimization structure size of the key parts. Note only acquired strain data and motion parameters of manipulator under the limit condition of operation, but also obtained the core parameters and simulation of the clamping process.4)Results of simulation and experiment show that both friction clamping and screw-clamping can realize stable clamping under the clamping force of 500 N, but screw-clamping relatively more stable and reliable, it can undertake weight slightly larger, and the sliding trend is weaken. Besides, screw-clamping only need end effector to provide an instantaneous force for steel nail pierced the stem, this means that end effector has more stronger applicability of the power source of manipulator, and has important significance of decreasing the weight of device.5) Put the combination of 6 nails, 10 mm of screw-clamping depth, 5 mm in diameter of nails and the structure size optimization of key parts and the results of stability analysis of the overall manipulator into the harvest test of whole physical prototype, verify the effectiveness of the clamping, reliability of the institutions and the stability of prototype during the harvesting process under the actual working conditions. Result of the test shows that the prototype of banana harvest manipulator can meet the agronomic characters of banana harvest, simulate artificial picking process and realize mechanization harvest...