| Because of the narrow space,high temperature and humidity,poor working conditions in the domestic greenhouse environment,the work of frequently transporting,pesticide application etc.are high-intensitive and inefficiency.Transporting and mobile operating machinery are urgently need in the production in the greenhouse,so that various types of mobile greenhouse robot appeared in succession.This study is from the key science and technology support project in Jiangsu province.In this paper,a curb-following mobile platform based on arc array of photoelectric switches was developed according to the requirements of Multi-work modes and the automatic work between enterclose in the greenhouse.The main research contents and achievements are as follows:(1)Curb-following mobile platform of differential speed drive structure with six wheels was developed based on the idea of simple structure,high flexibility and strong commonality.The floating support structure of universal wheel was designed to make all the wheels be on the ground at the same time and the connector between work module and mobile platform was designed to switch and identify the work modules.The statics analysis of the frame was made using the Nx Nastran software and finally,the key electrical components and circuit of mobile platform control system were designed.(2)A curb line following navigation method based on arc array of photoelectric switches was proposed for the precision and instantaneity problem of existing greenhouse mobile robot navigation technology.Detection and control methods of position and orientation were proposed based on the target area of arc array of photoelectric switches,and two indexes which represent the number and the center of triggered photoelectric switches were introduced to establish the position and orientation detection model.The position and orientation were classified by different thresholds of the two indexes which can trigger the corresponding control program of trajectory.And then accurate position and orientation which were calculated by the values of two indexes were used to set the parameters of control program to realize the curb line following navigation in real time.(3)The experiments indicated that the deviation of mobile platform's position and orientation was kept-35mm~+15mm and-5°~+5°,which can satisfy the requirement of applying pesticide,transporting job etc.And the control cycle of trajectory was about 2m along the curb line,which indicated that the vehicle can run smoothly along the curb line under a low control frequency in the greenhouse based on the method above.The vehicle could walk along convex curb with little impact by sundries within the length of 300 mm.This paper proposed new technical ideas for robots running along edges with low cost in the greenhouse. |
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