Stability Analysis And Optimization Of Super Long Arm Forklift

Super long arm forklift truck is a new type of Engineering vehicle,which combines the telescopic function of crane arm and the loading and unloading function of heavy forklift truck.The height and distance required for operation are realized by the amplitude and telescopic function of arm.It is widely used in stations,construction sites,workshops,ports and other places.It is also because of the long arm frame of forklift truck and the complex working environment,especially when passing through the ditch road surface and steering,the deflection angle of the center of gravity of the whole vehicle is very large,which leads to vehicle instability and rollover accidents happening repeatedly.This paper combines the stability development project of a new super-long-arm forklift in a heavy industrial enterprise,builds the electro-hydraulic simulation model of the vehicle in the simulation software,and then analyses whether the stability of the super-long-arm forklift truck can meet the relevant national standards,and analyses the relevant factors affecting the vehicle stability,finally puts forward the optimization scheme to improve the vehicle stability.It is verified by real vehicle test.The main research contents are as follows:(1)Referring to the real truck of the super long arm forklift,the equal proportion dynamic model of the real truck is built in ADAMS,and the hydraulic model of the rear axle drive and stability system(RAS)related to the stability of the ultra long arm forklift is built in AMESim software.The core component of the RAS system,the electric proportional flow valve,is modeled separately,so as to build the electromechanical hydraulic co simulation model of the whole truck.(2)In order to test the reliability of the simulation model,the experiments of slow uphill stop and first gear obstacle crossing were carried out,and the oil pressure and displacement data of RAS cylinder and frame leveling cylinder were collected during the experiment.The simulation value of oil pressure and displacement is compared with the experimental value,and the accuracy of the calibration result is more than 90%,which verifies the reliability of the electromechanical and hydraulic co-simulation model.(3)Based on the verified mechanical and Electromechanical and hydraulic co-simulation model,the stability test of the super long arm forklift truck is carried out according to the existing stability standard(GB/T 26949.14-2016)and the automobile industry standard(GB/T 6323-2014).The stability of vehicles is verified to meet the national standards,and the relevant factors influencing the stability of vehicles in the process of turning on the road and crossing obstacles in straight way are analyzed in combination with the actual working characteristics of vehicles.The simulation results show that the stability of the super long arm forklift truck meets the corresponding national standards,and the factors affecting the driving stability are: the vehicle speed,the angle of the boom,the load quality and the shape of the roadblock.Finally,through the simulation analysis of typical working conditions of forklift,the index suitable for evaluating the dynamic stability of the super long arm forklift is proposed.(4)Based on the analysis of the stability of the super long arm forklift and the existing RAS system of the real vehicle,two optimization schemes for the RAS system current are proposed.The first scheme: when the boom angle is greater than 40 ° The fixed current350 m A of RAS system is set to decrease linearly with the increase of boom angle,and its value is I = 380-4 ×(θ-40).The feasibility of the scheme is verified by simulation,and the real vehicle experiment is carried out.The final result shows that the vehicle roll angle is optimized by 9.7%.In the second scheme,the cascade PID control is composed of roll angle and roll angle speed.When the vehicle is running normally,the RAS system is in free mode.When the vehicle is rolling,the stiffness of the RAS cylinder can be adjusted by adjusting the current of the RAS system in real time.At this time,the vehicle is in the semi-active safety control mode.The simulation results show that the roll angle is optimized by 18.9% and the roll speed is optimized by 24.1%.In conclusion,this paper has practical significance for stability analysis and optimization of super-long-arm forklift truck,and also has certain guiding function for stability research of the same type of super-long-arm forklift truck.In conclusion,this paper has practical significance for stability analysis and optimization of super-long-arm forklift truck,and also has certain guiding function for stability research of the same type of super-long-arm forklift truck.