| In recent years,the planting area and greenhouse number of facility agriculture in China are increasing year by year.At the same time,the requirements for the development of precision agriculture and the intelligent degree of operation equipment in facility environment are also higher and higher.However,there is still a big gap between China and western developed countries in terms of mechanization technology and intelligence.Therefore,it is of great significance to carry out relevant research on the improvement of working machines and tools for improving the mechanization level and intelligent degree of facility agriculture in China.Based on the research status of AGV and agricultural navigation technology at home and abroad,this paper develops a working platform in the facility environment,which can realize the magnetic stripe navigation in the greenhouse,and realize the coordination and integration of different functions such as agricultural materials transportation,fertilizer application and fruit picking through the effective cooperation with other parts.The main contents of this paper are as follows:(1)Establishment of whole machine model of greenhouse working platform.Through field investigation,according to the planting conditions of most greenhouse facilities vegetables and the environmental factors of greenhouse itself,the overall design requirements of the working platform are determined,including the whole machine scheme,overall size,guiding mode,driving speed and load,etc.;on the basis of meeting the overall requirements of the working platform,the walking system,transmission system and power system are composed Then,the 3D model of the working platform is established based on Creo and other software.(2)Selection of key parts of greenhouse working platform.According to the operation requirements of the working platform,the key components of the body mechanical part,such as the drive motor,motor driver and reducer,and the main hardware of the control system,such as the main controller module and magnetic navigation module,are analyzed and selected,and the best hardware model for the working platform is finally determined.(3)Research on motion control process of greenhouse working platform and selection of motion control strategy.This paper studies the speed regulation principle of DC motor and the acquisition process of deviation information in the process of magnetic navigation,establishes the motion model based on the analysis of the motion state of the working platform,further proposes the motion control strategy of the working platform based on Fuzzy PID algorithm,and establishes the Fuzzy PID controller with the lateral deviation and deviation change rate of the platform as the input,and through the design and construction of the Simulink block diagram form to simulate and analyze the performance of the above-mentioned controller.The simulation results show that the Fuzzy PID controller has faster response speed and better stability in the process of error correction.(4)Software system design of greenhouse working platform.Based on STM32F4 MCU development platform and Keil μVison5 compiler environment,the serial communication module,PWM wave output module,motor speed detection module and drive control module are programmed and debugged.Finally,the effective operation of magnetic navigation control program software is realized through the orderly integration of different modules.(5)Prototype development and experimental verification of greenhouse working platform.The prototype of greenhouse working platform was developed,and its basic performance was tested,including straight running test,curve running test and load running test.The test results show that: under no-load condition,the variation range of straight running deviation of working platform is controlled within ±2.5 cm,and the variation range of curve running deviation is controlled within ±4.5 cm;under load condition,the variation range of straight running deviation of working platform is controlled within ±2 cm.To sum up,the working platform developed in this paper can successfully complete the autonomous navigation for the preset magnetic stripe track,and the car body has good load running ability and good driving stability in the running process. |
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