| China has a long history of greenhouse cultivation,but because the greenhouse has been in the natural environment for a long time,it is easy to be attached to dust and breed bacteria in rainy and snowy weather,wind and sun,causing pollution,especially in the greenhouse roof,the light transmittance is greatly reduced,seriously affecting the normal use of the greenhouse.However,the cleaning of greenhouse is not easy.Most greenhouse cleaning equipment can only complete the single-line cleaning work,which requires the help of crane or lifting auxiliary mechanism to complete the line-changing work,and the degree of automation is low.There are very few automatic line-changing platforms for greenhouse roof auxiliary cleaning in the research of line-changing machinery and equipment at home and abroad,and there is no relevant mature machinery and equipment in China for the time being.In view of the above problems,this paper designs an automatic line-breaking platform at the top of the greenhouse,which is used to assist the cleaning equipment to complete the linebreaking task in the cleaning work and realize the whole process automation of cleaning and line-breaking of the cleaning equipment.The main research contents and conclusions of this paper are as follows:(1)The structure design of the automatic line change platform.According to the structural characteristics of the greenhouse roof,the overall design scheme of the automatic line-changing platform is determined.The structure design of the traveling device and the guide rail retracting and releasing device is mainly carried out.The traveling device is composed of the active part and the driven part,which are separated from the ground and run on the upper and lower tracks respectively.The guide rail retracting and releasing device is driven by the crank and connecting rod mechanism.The kinematics simulation analysis of the crank and connecting rod mechanism is carried out by using ADAMS.Through the analysis,it is concluded that it has certain quick-return motion characteristics,which makes the average speed smaller and the operation stable.At the same time,the support part of the automatic line change platform is designed as a height adjustable structure,so that it can be applied to greenhouses of different heights.(2)Stress analysis and finite element analysis of the whole machine.Based on the moment balance method,the stress analysis of the whole machine is carried out,and the static analysis and modal analysis of the whole machine are carried out by using the ANSYS Workbench software.Through the static analysis,it is concluded that the platform has sufficient strength and stiffness to meet the use requirements.The first six natural frequencies are obtained through modal analysis,which verifies that the platform will not produce vibration and meets the design requirements.(3)Design of the control system for the automatic line changing platform.The control system of the platform is designed based on multiple sensors,realizing the automatic operation of the platform.In order to ensure the efficient operation of the line changing platform,the traveling drive system adopts the method of driving two driving wheels with two motors respectively.The motor and reducer of the traveling drive part are selected and calculated.A safety protection system has been designed,with proximity switches and travel switches used together to monitor the entire working process in real time.(4)Prototype processing and test.The prototype was processed in Shandong Hualong Agricultural Equipment Co.,Ltd.,and the strain gauge resistance method was used to test the stress of the automatic line-changing platform.The test data obtained were processed using the t-test criterion,and the processed test data were compared with the finite element analysis results.The results showed that the error between the two was within 8%,which verified the correctness of the finite element analysis results. |
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