Design Of Strength Test System For Cabin Of Agriculture And Forestry Tractor

In recent years,with the continuous improvement of the level of agricultural mechanization in China,agricultural automation machinery based on agricultural and forestry tractors（hereinafter referred to as agricultural machinery）plays an increasingly important role in agricultural production.However,due to the complicated operation of the agricultural machinery,the harsh working environment and the heavy workload,there is a rollover accident during the operation,resulting in serious casualties and property losses.In order to effectively reduce the losses caused by the dumping accidents of agricultural machinery,at present,Roll-over Protective Structures（ROPS）is installed in the driving control area of agricultural machinery to form a safety cab that meets the standard strength requirements.It has been proved that this technical protection can effectively reduce the loss of personnel and property caused by the dumping accident of agricultural machinery.However,currently,a highly automated cab ROPS strength test system for strength testing of agricultural machinery cab ROPS is still not complete.This subject has fully researched the latest nationally issued agricultural machinery cab ROPS strength test standard "GB/T 19498-2017 agricultural and forestry wheel tractor protection device strength test method and acceptance conditions",according to its specific test requirements and implementation steps,a set of ROPS strength test system for agricultural machinery cab with relatively complete functions and high degree of automation was developed.The structure of the cab ROPS strength test system is as follows.（1）Construction of the cab ROPS strength test bench.The cab ROPS test loading device is used for initial loading position adjustment of the horizontal loading cylinder and the compression cylinder,what’s more it can complete the load application process of the cab safety frame.At the same time,the initial loading position adjustment of the horizontal loading cylinder and the compression cylinder is executed by the X-Y axis geared motor and the electric hoist motor.In addition,the main structure of the cab ROPS test bench can be not only used as a main body hardware which is to carry the hydraulic loading system,but also utilized as an initial position adjusting motor of the loading device and other electrical line control cabinet.Overall,the ROPS strength test bench of the agricultural machinery cab provides an efficient basic support platform for the ROPS strength test and control system of the agricultural machinery cab.（2）The design of the cab ROPS strength test and control system.By simulating the damage of the safety frame under the load during the dumping accident of the agricultural machinery,the force and deformation of the safety member supporting the tractor’s own weight are obtained in real time,and the data acquisition and processing system is used to implement signal conversion,data display and storage,test state analysis and hydraulic loading control.In terms of the loading dynamics of the test,this topic uses a highly efficient hydraulic loading system.The hydraulic loading control system combined of the digital output combination principle of PLC and the OPC process communication service to control a series of intermediate relays connected to the digital output of the PLC,so that the relay coil is energized while the corresponding electromagnetic reversing valve in the hydraulic loading system is turned on.And the electromagnetic spill valve can complete the working condition switching of the hydraulic loading system,which realizes the real-time control of the test loading state.（3）Functional verification of the cab ROPS strength test and control system.Based on the hardware of the cab ROPS strength test bench,this subject completed the function verification of the cab ROPS strength test and control system through the on-site test of the cab ROPS strength test system,and successfully realized signal acquisition and processing,hydraulic loading control.Finally,the test data and relationship curves related to the ROPS strength test of the agricultural machinery cab were obtained.The test results show that the ROPS strength test and control system of the agricultural machinery cab can meet the relevant requirements of the test standard.