Design And Experiment Of Self-propelled Variable Distance Arched Shed Machine

In modern agricultural production,small arched sheds have a broad prospect of application due to its low construction costs,high land utilization,and convenience to nest with other types of arched sheds.At present,however,the domestic construction of small arched sheds is almost done by manpower,with heavy labor load,high labor costs,and poor firmness.Taking small arched sheds as the research object,this paper designs and produces the self-propelled variable distance arched shed machine,to complete automatic taking rod,variable distance inserting rod and film covering precisely and efficiently.It aims to improve the mechanization and automation level of small arched sheds,and to provide reference for agricultural equipments.This article mainly completes five aspects of work:(1)General design scheme of the machine.To investigate the types and construction sizes of small sheds in China at present,and collect relevant data of arched sheds' cottage and film covering.Based on the practical application of small arched sheds and the specific requirements of crops and agronomy in China,the general design scheme of the self-propelled variable distance arched shed machine can be established through 3D mechanical modeling and parameter theoretical calculation.(2)Design of the key components of the self-propelled variable distance arched shed machine.Automatic taking rod device employs a sawtooth-disc structure,and adopts spacing ring to avoid interference of rods,which may interrupts automatic taking rod device.And also,electric machine is used to drive the dial link to complete the taking rod work.The automatic cottage device is the combination of hydraulic and mechanical transmission,the press-down device is offset slider-crank mechanism,and the bending rod device is symmetrically distributed on the automatic cottage device,which employs hydraulic device to drive bending rod device and press-down device to complete rods-bending work and cottage work.The film covering device is designed to be suitable for small arched sheds,and the film spreading mechanism is used to expand the film,and the film pressing wheel and the soil covering disk are used to complete film covering and burying work.(3)Simulation of the automatic cuttage device.In order to get the effective force,to determine each component's structure and size of the automatic cottage device,to press shed rods into soil steadily,the MATLAB simulation software is employed to do numerical simulation and optimization of the transmission device of offset slider-crank mechanism.When the ration coefficient of journey to speed is 1.25,the inertia impacting is small,the auxiliary angle is 0.69 rad,the minimum transmission angle is 1.5rad.therefore,the length of crank rod is determined to be 230 mm,the connecting rod is 220 mm,and the eccentricity is 220 mm.Through statics simulation of shed rod,the position and length of the bending plate in the bending arm are determined,which can ensure the best bending effect.In order to get the relationship between the arched shed's width and the rod's length,as well as the best wind resist effect,SOLIDWORKS modeling and ANASYS simulation are employed.Finally,the best scheme for shed rods selection can be achieved when arched shed's width/ rod's length is 0.60 ~ 0.66.(4)Design of PLC control system.Based on Siemens s7-1200 plc,the hardware,circuit structure and software design of the control system are completed,including the multi-sensor information collection,the start and end control of DC motor,the on and off of hydraulic solenoid valve,and the control surface design of touch screen.To select the working mode and set the parameters through the touch screen,the feedback of PLC control system can control the machine to complete automatic taking rod and variable distance inserting rod work.(5)Production and test of prototype.The prototype is produced in Shandong Huaxing Machinery Co.,Ltd.,and the performance test of machine cottage and film-covering and small arched sheds operation is carried out in the Agricultural Experiment Station of Shandong Agricultural University.The results show that when the working speed of the equipment is 1.2Km / h,the shed rod insertion rate is greater than 95%,the shed rod damage rate is less than 2%,the film damage rate is less tha1 n 2%,the average film light transmittance is greater than 81%,and the shed rod space error is less than 15 cm,which can meet the agronomic requirements of small arched sheds.