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Hangzhou, China

He X.,Zhejiang University | Wang J.,Zhejiang University | Lu G.,Zhejiang University | Tang X.,China CO OP
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2014

In order to realize column clamping of fresh tea in tea leaf and stalk separation, a self-locking gripper consisted of slider-crank mechanism and RRR assur group was designed. Analysis showed that, retraction phenomenon might happen if parameters were not suitably selected, which make it difficult to grip small diameter objects. However, it could be avoided by the constraining of retraction height. Secondly, relations between parameters were deduced, based on which an appropriate method was proposed on the determination of design parameters. The design problem was attributed to a transcendental equation, which was solved by particle swarm optimization method. Experimental results showed that grippers designed with this method can realize clamping and self-locking successfully, and a clamping length of 5~15 mm was suitable.


He X.,Zhejiang University | Wang J.,Zhejiang University | Lu G.,Zhejiang University | Tang X.,China CO OP
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2014

To automatically recognize the geometric parameters of fresh tea leaves with different orientations, constrained Delaunay triangulation was introduced to triangulate the area of fresh tea leaf after operations, which made the contour points distribute evenly and sparsely. Then, with the character of end triangle, adjacent triangle and connect triangle, median axis of tea leaves and tea stalks were calculated, thus the orientation of a fresh tea leaf was determined and the tea leaf was labeled. At the same time, the length, width, and area of each tea leaf was calculated, as well as distance between petioles. Based on above results, a geometric feature index concerning the oldness of fresh bulk tea was proposed, and a possible method to finely divide the grade of fresh tea was also discussed. Totally 150 images with 174 pieces of fresh tea leaves were used to validate the algorithm, and a recognition rate of 94.2% was obtained, and the average time to treat a single fresh tea leaf was 74.7 ms.


He X.,Zhejiang University | Wang J.,Zhejiang University | Wang B.,Zhejiang University | Lu G.,Zhejiang University | Tang X.,China CO OP
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2013

The design of tea production line was considered in a 3-D level, and it was transformed into an assembly modeling problem. At first, a position irrelevant plane layout method was introduced which made the frequent adjustment of devices' positions unnecessary, thus the workload of designers were relieved dramatically. Then, with the orientation coding of devices and their connection relations, absolute and relative orientation of devices were determined. Finally, datum constraints were exerted to devices which realize the assemblying or positioning of devices automatically, rather than manual. According to this idea, by secondary development of SolidWorks, a program called TPLLayout was written by VB 6.0. The example showed that the system was user-friendly, and easy to operate, which improved the design efficiency dramatically, and the cost was reduced as well.


He X.,Zhejiang University | Wang J.,Zhejiang University | Lu G.,Zhejiang University | Tang X.,China CO OP
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2013

Fresh tea leaf and stem separation for coarse tea not only improves the quality of finished tea, but also reduces heat energy consumption. To realize the separation, the key issue is the recognition of tea stems and petioles. Tilted chute was used to constrain the direction of fresh tea. Then, the problem was transformed into determining whether the tea sprout was facing up or down. At first, according to the stem end length, fresh tea was classified into two categories: for those with long stem ends, an algorithm based on the feature size was proposed, and the side with longer feature size was recognized as tea sprout. For those with short stem ends, the "local extreme points of fresh tea contour" was utilized, and the side with more local extreme points was recognized as tea sprout. Then, 168 randomly obtained images and a background image was used to validate the algorithm, and a recognition rate of 93.3% was reached. The average time to recognize the direction of a single fresh tea was 17.8 ms which fulfilled the requirements of real-time processing.


He X.,Zhejiang University | Wang J.,Zhejiang University | Tang X.,China CO OP | Lu G.,Zhejiang University | And 2 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2014

In order to enrich the kind of teas being produced, and improve the utilization of fresh tea materials, a multi-functional preprocessing machine for fresh tea was developed which could realize spreading of green tea, withering of black tea, and green-making of oolong tea. The general structures as well as the working principle of some key parts like mechanical transmission system, leaf turning device, ventilation and heating system were introduced. With multi-branch pipe for air intake, the uniformity of wind field was ensured; pump with high pressure and low flow rate, together with small spray nozzle ensured the uniformity of moisture; temperature was accurately controlled according to different layers. Experimental results show that teas produced with this machine had higher physical and chemical indexes and scores compared to the control groups. The results show that the design was reasonable, and the machine was reliable.

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