Research On Key Technology Of Driving System For 3 Ton Electric Forklift Truck

With the rapid development of China’s logistics and transportation industry,a large amount of cargoes need to be carried in factories,ports,airports,supermarkets,express warehouses and other places.Forklifts serve as a main mean of transportation of cargoes,therefore the market demand of them will be increased.The environmental pollution and energy consumption caused by traditional internal combustion engine forklifts have become increasingly prominent.With China’s strong support for new energy policies and people’s increasing emphasis on green environmental protection,electric forklifts will surely replace internal combustion engine forklifts based on their advantages in terms of emissions,noise,energy efficiency,etc.However,the current single-motor and single-reducer electric forklifts have disadvantages such as poor power,short effective working time,and the layout of the drive system which causes the vehicle relatively bulky,making it difficult to completely replace the internal combustion engine forklift.At present,the configuration of dual power sources and even multi-power source drive systems has become a hot spot,and has significant effects in improving the overall performance of electric forklifts.In view of this situation,this thesis aims to design and study the new configuration of electric forklift drive system and its control strategy.First of all,the thesis conducts a comprehensive comparison and analysis of the various drive system configurations in terms of economy,power,layout,cost,and the particularity of electric forklift working conditions,then it works out the combined independent drive of the motor and the reducer.The solution uses two low-power motors to replace the original high-power motors and adopts a distributed arrangement,which greatly reduces the weight of the entire electric forklift.At the same time,it matches the parameters of the dual-motor independent drive system electric forklift,and optimizes the parameters of the independent drive system by applying genetic algorithm based on energy efficiency.What’s more,it establishes a five-degree-of-freedom mathematical model based on the full-load climbing condition of the electric forklift.Based on the characteristics of the electric forklift’s operating conditions,it designs an adaptive starting pedal closed-loop control strategy.For the accelerator pedal,it designs three working modes of electric forklift including normal mode,economic mode and power mode.Moreover it calculates the permanent magnet synchronous motor torque MAP and designs the target speed method differential strategy under two-wheel drive for the steering of electric forklift.Finally,based on the MATLAB/Simulink simulation platform,it builds the simulation model of the main components of the electric forklift drive system and the vehicle dynamics model to carry out simulation and comparison with the traditional single-motor drive system electric forklift.The verification shows that the power and energy utilization of new drive system electric forklift is better.