Factor Analysis And Safety Device Design Of Scissors Orchard Operation Platform

The crawler orchard operation platform is mainly applied to the working environment of the slope land in the modern orchard garden,which is used to assist the manual overhead work in the daily management of the fruit tree.In this paper,according to study the tilting stability of the crawler operation platform in the slope working environment,design a leveling mechanism of the safety device,and simulates and tests the prototype,in order to improve the tilting stability of the platform.On the basis of scissors orchard operation platform with crawler walking mechanism,the unfolding research and design work includes:(1)The working environment of the slope land,the characteristics of the orchard operation platform and the research results of typical working conditions,the evaluation indexes of the orchard operation platform’s tilting stability are determined.Based on the moment equilibrium method and the standardized energy stability margin method,the static and dynamic tilting stability of the orchard operation platform are analyzed,and the influence factors are obtained.The simulation test for the factors affecting the tilting stability is designed on the typical working conditions.The software Adams is used to simulate and analyze the influence of platform structure,load distribution and personnel activities on platform tipping stability.Through simulation and analysis,obtaining these data:the maximum tilting stability angle of the operation platform at 4 lifting heights and at 5 typical load distribution conditions of the different slope angles,and the maximum lateral force which is partially allowed to bear under the different tilt angles when the operationg platform is unbalanced loading or balanced loading.(2)According to the analysed factors affecting the tilting stability,the overall design scheme of the anti tilting safety device is determined.According to the requirements of the scheme,the leveling mechanism of the safety device is designed.Based on the software Inventor,a digital prototype of the scissors orchard operation platform is built,and using the software Adams,the dynamic simulation test of leveling mechanism is carried out.The numerical changes of the evaluation index of the tilting stability before and after leveling,the numerical changes of the motion parameters that affect the comfort of the carrying personnel when the multiple groups of hydraulic cylinders are combined,as well as the speed curve of the leveling hydraulic cylinders to meet the leveling speed are obtained.According to the analysis results,the lifting effect of the leveling mechanism to the tilting stability,the rationality of the leveling angluar velocity and the action speed of the hydraulic cylinder are checked.At the same time,the necessary parameters are provided for the calculation of the performance parameters of the hydraulic cylinder,the hydraulic pump,and the response speed of the automatic control system in the design of the electro-hydraulic control system.(3)Based on the structure of leveling mechanism and the demand of orchard operation platform,the schematic diagram and execution strategy of hydraulic leveling system are designed.According to the hydraulic control scheme,performance parameters calculation,check and selection of main components such as leveling cylinder,hydraulic pump and so on are carried out.Based on the structure design of leveling mechanism and the illustrative diagram of the hydraulic leveling control system,the automatic leveling control scheme is designed.According to the requirements of the leveling speed and precision,the PID controller is selected.The hardware and software design of leveling control system is completed.The mathematical transfer function of the system is established by its physical parameters,and the simulation model is built by software Matlab/simulink.The control coefficient of the PID controller is K_p=3.5,K_i=0 and K_d=0.2,when the best response of the system is determined by the trial and error method.(4)Through the dynamic simulation test of the safety device’s leveling mechanism,the leveling mechanism of the anti-tilting safety device can effectively reduce the evaluation index value of the tilting stability.By the manufacturing of the leveling mechanism parts and the modification of the prototype,the leveling mechanism can realize horizontal adjustment for 8 degrees and vertical adjustment for 10 degrees.Simulation model of the leveling control system based on Matlab/simulink is used.When the angle deviation is 10 degrees,the response time of the system is 2.5s.with no overshoot and vibration.The designed automatic leveling control system has the fast response ability to meet the requirements.The simulation results of the designed safety device leveling mechanism and the automatic control system show that the designed safety device can effectively improve the tilting stability of the scissors orchard operation platform in the slope working environment.