Simulation Study On Trajectory-Following Control For The Manipulator Of A Wheel Loader

Low energy exhaust and high efficiency is one of the main trend to wheel loader,which is a widely-used engineering machine. The main working style of wheel loader is that it moves around of the working object. Due to the working object is very complicated,the working resistance is changed as time. However,almost all the domestic wheel loaders are operated by man through manipulating the control-handle of the arm and bucket. So the efficiency of the wheel loader is highly due to the manipulators'experience,skill and will.In order to improve the work efficiency of the wheel loader,and avoid the energy wasting resulting from the manipulators'limited skill level,the article do the researches that focused on the shoveling auto-control of the manipulators on the wheel loader. The detailed elaborations as following:⑴On the basis of the structure character of the manipulators of the wheel loader,it can be simplified to a two-degree-of-freedom robot arm. Then taking advantage of the D-H method,we can build its coordinate system and obtain D-H parameters. Then making use of the transformable matrix of the robot,we can deduce the kinematic equation,obtain the relationship between the position,velocity and acceleration of the bucket and the angle,angle-velocity,angle-acceleration of the joint angle.⑵Using the Lagrange method,we can calculate the dynamic equation of the manipulators of the wheel loader,and obtain the relationship between the joints'drive torque and the angle,angle-velocity,angle-acceleration of the joint angle. Taking advantage of the compute-torque method and the compensate -for-resistance method,we can build a trajectory/force control system with PD adjuster,which is based on the dynamic model.⑶Build the three-dimension model of the manipulators of the wheel loader in the Solidworks software. First,based on its two- dimension model ,we can build every part's three-dimension model. Second, taking all part's three-dimension model into the assemble block and restricting them,then we obtain the assemble model. Then building the plant model of the manipulators of the wheel loader in the ADAMS software. First,taking the assemble model into the ADAMS software. Second,setting the parameters and building the variable of the input and output. In the end,we can obtain the plant model.⑷Taking the plant model into Simulink block of the Matlab software and building the control system in it. Then in order to prove the control system is correct,this article does the ADAMS-Matlab simulation study according to the planning trajectory. Through adjusting the PD parameter of the control system,we can obtain the relatively best control. Then outputting the simulation results,which show that the trajectory/force control system designed in this article can track the trajectory as the resistance varying as time,and it achieve the high accuracy in the aspect of trajectory-following control.The studies in this theme make a solid foundation for the wheel loader's manipulator shoveling auto-control.