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Journal of Tea Science ›› 2022, Vol. 42 ›› Issue (2): 263-276.doi: 10.13305/j.cnki.jts.2022.02.003

• Research Paper • Previous Articles     Next Articles

Development and Test for Distributed Control Prototype of the Riding Profiling Tea Harvester

ZHAO Runmao1,2, BIAN Xianbing1, CHEN Jianneng1,2,*, DONG Chunwang3, WU Chuanyu1,2, JIA Jiangming1,2, MAO Ming1, XIONG Yongsen4   

  1. 1. Faculty of Mechanical Engineering & Automation, Zhejiang Sci-Tech University, Hangzhou 310018, China;
    2. Key Laboratory of Zhejiang Transplanting Equipment Technology, Hangzhou 310018, China;
    3. Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China;
    4. Key Laboratory of Crop Harvesting Equipment Technology of Zhejiang Province, Jinhua 321000, China
  • Received:2021-09-01 Revised:2021-10-14 Online:2022-04-15 Published:2022-04-15

Abstract: To better realize the mechanized picking of ordinary fresh tea leaves, reduce the system development cost, and improve the automation level and picking integrity rate, a profiling method of machine-made tea canopy surface cutter and a development method of low-cost and rapid control prototype machine with distributed control were both put forward in this study. Additionally, the profiling tea harvester prototype was developed and the indoor and field tests were launched. The profiling tea harvester uses ultrasonic sensor to sense the distance information from the reciprocating cutter to the tea canopy and realizes profiling transmission through screw rods. Then, Hampel filter and Low-pass filter algorithms are used to preprocess the distance information on-line to eliminate the influence of inter leaf vacancy and cutter vibration on the real height estimation of tea canopy surface. Meanwhile, a proportional nonlinear tracking differentiator (PNTD) control system based on nonlinear tracking differentiator was established in order to avoid the amplification of signal noise by digital difference in conventional PD control and improve the accuracy of profiling of each tea picking unit. Based on CAN bus network and code generation technology, the distributed fast control prototype with multiple execution units was realized and tested. The indoor step test results show that the maximum peak time of this control system was 0.14 s and the maximum overshoot was 3.6%. Finally, to verify the effectiveness of the distributed control profiling tea picking prototype, profiling picking experiments were conducted in the tea garden. The average picking rate of young shoots on the canopy covered by cutter was 92.01%,the integrity rate of buds and leaves was 82.6%, the impurity rate was 6.4%, and the young shoots with at least one bud and three leaves accounted for 87.91%. All the results demonstrate that the proposed methods had good performance and could be used for picking ordinary tea.

Key words: tea harvester, profiling, distributed, rapid control prototyping, nonlinear tracking differentiator

CLC Number: