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Du X.,Zhejiang Sci-Tech University | Du X.,Zhejiang Provincial Key Laboratory of Advanced Manufacturing Technology | Ni K.,Zhejiang Sci-Tech University | Wu C.,Zhejiang Sci-Tech University | Wu C.,Zhejiang Provincial Key Laboratory of Transplanting Equipment and Technology
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2016

To further improve the efficiency of vibratory harvesting on tree fruit and reduce the mechanical damage on tree body, a hypothesis about ideal fruit tree excitation pattern was put forward based on the working principle of vibratory harvesting mechanism. The influence of different kinds of displacement patterns on vibratory fruit harvesting was simulated based on finite element software (ANSYS). According to the simulation results, a vibratory fruit harvesting mechanism was designed based on planetary gear train to generate epitrochoid trajectory. Then, its characteristics and working principle were analyzed and its kinematics model was established to derive the equations of vibratory displacement and acceleration amplitude. By meeting the requirement of displacement and acceleration amplitude, main parameters of the epitrochoid mechanism were optimized based on the parameter-guided optimization algorithm. A prototype of vibratory harvesting mechanism for fruit tree was manufactured and its trajectory was recorded by high-speed photography system. Trajectories of experiment, theoretical analysis and virtual simulation were consistent, which verified the design of this harvesting mechanism. A dynamic response test of one fruit tree sample was carried out in lab. Statistics results on the mean value and standard deviation of the maximum synthesized acceleration of the test points on the tree sample confirmed that the epitrochoid mechanism could stimulated the fruit tree effectively. © 2016, Chinese Society of Agricultural Machinery. All right reserved. Source


Chen J.,Zhejiang Sci-Tech University | Chen J.,Zhejiang Provincial Key Laboratory of Transplanting Equipment and Technology | Zhang P.,Zhejiang Sci-Tech University | Wang Y.,Ningbo University | And 2 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2015

In order to get the best parameters of rotary seedling planting mechanism quickly and easily, this paper proposes the requirements of rotary seedling planting mechanism for prefect planting, such as kinematics (trajectory, pose and speed) characteristics of planting nozzle, geometrical characteristics of holes, avoidance of interference and convexity preservation of non-circular gears. According to these requirements, this paper establishes eleven subgoal functions of planting mechanism with planetary eccentric-elliptical gears. By using fuzzy theory, the multi-objective optimization problem was turned into a single objective optimization problem. Then, the parameters satisfied the above perfect requirements were got. According to the parameters which were obtained with optimization, this paper carries out structural design, virtual simulation, test bed machining and the experimental simulation of field planting. The result shows that this mechanism has high seedling erectness rate and the optimization model is correct. The proposed optimization model conquered the defect of trial and error that the simulation software has in the process of parameter design for planting mechanism, improved the optimization efficiency and reduced the demands for people who implement the optimization of parameters. ©, 2015, Chinese Society of Agricultural Machinery. All right reserved. Source


Tong J.,Zhejiang Sci-Tech University | Tong J.,Zhejiang Provincial Key Laboratory of Transplanting Equipment and Technology | Jiang H.,Zhejiang University | Wu C.,Zhejiang Sci-Tech University | Wu C.,Zhejiang Provincial Key Laboratory of Transplanting Equipment and Technology
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2016

Seedlings need to be transplanted from high density into lower density trays for more space to grow in the greenhouse. Automatic transplanter could detect seedlings health state and do the tasks of lower density transplanting. It can work in high efficiency and good quality comparing with the traditional manual work. The lower density transplanting path includes end-effector leaving from original point, grasping health seedlings from high density to lower density trays one by one, and going back to the start at last. The distances of transplanting path were decided by seedlings grasping order. Traversing search algorithm consumed large calculation to plan this transplanting path which does not meet the real time requirement. In this paper, four schemes of fixed sequences were optimized by using the greedy algorithm separately, and eight schemes were formed totally. The path planning methods were used in the sparse and dense trays to verify the effectiveness of the greedy algorithm scheme. Comparing with the longest mean value of fixed sequence schemes for high density trays path planning, optimal scheme of GAS3 could get a better result with more than 10.6% amplitude optimization. The average calculation time of the optimization scheme was 0.84 s. Significance test showed the increase of vacancy holes reduced the effectiveness of length shorten. As a whole, the greedy algorithm scheme optimizes the lower density transplanting path, meets the real-time work requirement, and improves the transplanting work efficiency. © 2016, Chinese Society of Agricultural Machinery. All right reserved. Source


Sun L.,Zhejiang Sci-Tech University | Sun L.,Zhejiang Provincial Key Laboratory of Transplanting Equipment and Technology | Zhu J.,Zhejiang Sci-Tech University | Zhu J.,Zhejiang Provincial Key Laboratory of Transplanting Equipment and Technology | And 6 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2015

In order to obtain a spatial planetary gear train with higher transmission ratio, which can shorten the large horizontal offset of picking seeding trajectory, a kind of special shaped non-circular bevel gears based on spherical curve was put forward, and a wide-narrow distance transplanting mechanism composed of special shaped non-circular bevel gears and crossed cylindrical gears was obtained. The pitch curve of special shaped non-circular bevel gears was designed by two non-uniform B-splines which had continuous angles and discontinuous radius. The gear pair could continuously and smoothly work after adjusting the height of tooth profile curve in the transition section of two non-uniform B-splines. The theoretical model of wide-narrow distance transplanting mechanism was built up. An optimization program was finished, and the effect of the different shape of special shaped non-circular bevel gears to the wide-narrow distance planting trajectory was analyzed. A three-dimensional model was built up by computer, and an actual physical model was processed. The shapes and speeds of the planting trajectory which formed by the two models were compared, and the values of measuring parameters were almost the same. A test with seeding by transplanting mechanism was carried out based on rotary trial soil bin. Speed comparison between the transplanting mechanism composed of special shaped non-circular bevel gears and transplanting mechanism composed of non-circular bevel gears was made, and the result showed that the wide-narrow distance transplanting mechanism composed of special shaped non-circular bevel gears had the advantages in shortening the large horizontal offset of picking seeding trajectory, and the planting trajectory was better. ©, 2015, Chinese Society of Agricultural Machinery. All right reserved. Source

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