The Design And Implementation Of An Electric Pallet Forklift’s Synchronous Control System

In the industrial production and logistics sector,forklifts are widely used in loading,unloading,transporting,entering,and leaving the warehouse of bulky goods.Compared with traditional diesel forklifts,electric pallet forklifts have low noise and pollution-less benefits,gradually becoming the mainstream of the forklift industry evolution.However,large forklifts handling heavy loads suffer from high prices and low utilization.Two small forklifts using a synchronous control system is an economical alternative.In the actual synchronous handling process,the operating conditions of the electric pallet forklifts are relatively complex,with effects such as varying friction on the ground,shaking of the steering gear,and so on.So far,there is no mathematical model for electric pallet forklifts that takes into account actual operating conditions.There is no mathematical model of an electric pallet forklift that takes into account the actual movement conditions so far.In this paper,the dynamics model of an electric pallet forklift is established to address the above problems.The cross-coupled global continuous robust control method is proposed to realize the high-precision motion synchronization control of the dual forklift.The main research contents of this paper are as follows:(1)A dynamics model of an electric pallet forklift was established.Firstly,based on the tire mechanics,the force analysis of the forklift tires is carried out,and the mathematical relationship between the forklift transverse rotation speed and the forklift tire lateral deflection combined force is established;secondly,the mathematical relationship between the forklift center of gravity lateral deflection angle,the forklift transverse rotation angular speed and the tire lateral deflection combined force is established;subsequently,the center of gravity lateral deflection angle,the transverse rotation angular speed,the transverse rotation angle and the forklift center of mass motion speed are selected as the state variables of the system,and the front wheel Then,the forklift body dynamics model is established by selecting the lateral deflection angle of the center of gravity,the angular velocity of the transverse pendulum,the transverse pendulum angle and the velocity of the center of mass of the forklift as the state variables of the system,the front wheel angle and acceleration of the forklift as the inputs of the system,and the X-axis direction velocity and Y-axis direction velocity of the ground coordinate system as the outputs of the forklift system.(2)A dual forklift cross-coupled global continuous robust synchronous control method is proposed.Firstly,a new body global continuous robust control(SC-GCRC)method is designed to realize the motion trajectory control of the forklift body;secondly,the cross-coupled global robust control(CC-GCRC)method is used to realize the motion synchronization control of two vehicles;finally,the simulation experiments of forklift straight and steering synchronization are conducted,which show that the CCGCRC method has the advantages of fast response,high synchronization accuracy The experiments show that the CC-GCRC method has the advantages of fast response,high synchronization accuracy,and high robustness.Compared with the existing crosscoupled input-output sliding mode(CC-IOSMC)synchronization control strategy and the traditional PID control method,this method significantly reduces the synchronization errors of attitude and position.It significantly improves the control accuracy of the dual forklift synchronization control system.