Research On Intelligent Shoveling And Control Strategy For Wheel Loader

In recent years,China’s infrastructure development has been on the rise.As one of the most important earth-moving machines,loaders are popular with consumers in production and construction.However,conventional loaders are cumbersome to operate.What’s more,due to the harsh working environment,it is difficult for even experienced drivers to achieve perfect control of the working device,thus resulting in wasted power.With regard to the development of control schemes for loader work units,domestic and international research are mainly focused on the derivation of bucket trajectories through calculations or simulations.The short in consideration of actual shovel loading experimental data has led to the development of solutions that are out of line with production reality.This article is involved in the university-enterprise cooperation project "Loader Development"（project number: FW/RD 201640）.In the pre-study phase,after extensive literature review,the research results on working devices for loaders,excavators and other equipment were summarized.What’s more,valuable experience was gained by reviewing research results on automatic control strategies for construction machinery.Based on operator experience,separate tyre slip and non-slip experiments were carried out.The relative experimental data,such as bucket angle of the boom,the cylinder pressure and the transmission system,were obtained.The kinematic mechanism of the work unit in the shoveling stage was described by establishing a model of the forces and kinematics of the work unit and the complete wheel loader during shoveling and loading.Principal component analysis（PCA）of the driveline data was conducted by SPSS software,and it was found that the engine torque was the most representative feature of the driveline.Combining with the driver’s demand torque,the shovel control strategy based on torque difference was proposed.The autonomous positioning control strategy was compiled based on the corresponding relationship between the movable arm and the bucket angle.The feasibility of the control strategy was verified experimentally.During the experiment,a difference between the actual memory angle and the set value was found.A number of control experiments were set up.Based on the experiments results,the lag between engine speed and the response of the internal links of the system were found to be the cause of the error.The difference between the actual memory angle and the set angle at different speedswas fitted.The fitted values were fed into the controller for error control and experimental verification.