Research On Dynamic Control And Simulation Of Electric-drive Dozer

Crawler dozer is a main type of engineering machinery, whose workingconditions are complex, changeable and harsh. And the load from the external worldwill change dramatically when Crawler dozer is working. Facing the complex andchangeable working conditions, traditional dozer is poor in self-adaptation andworking efficiency. With the development of electric drive technology, powertrain andcontrol methods of traditional dozer can’t fully meet the needs of new designs anymore.Electric-drive dozer is the trend of the development of dozer. It also puts higherrequirements to the dynamic control of the electric-drive dozer because of thecompletely different transmission of energy and structure. It will become the keyissues in the development of electric-drive dozer to figure out how to coordinate theoperation of actuator, the executive body of drive and the transmission system. Thus,it is very necessary to work over the simulated study on the dynamic control ofelectric-drive dozer.From the view of the practical applying of dynamic control of electric-drivedozer, this article is carrying an in-depth research on the overall structure, controlscheme, control strategies, modeling and simulation of electric-drive dozer. The mainwork and conclusions are as follows:1. Selection of structure and analysis of dynamicsThrough the study on the overall structure of the electric drive system forelectric-drive dozer, the overall structure of the electric-drive dozer is decided in theform of series of "straight going motor and hydraulic steering motor"; In addition,according to the driving characteristics of the electric-drive dozer, the force by thedozer under three different states: straight going state, no-load steering state, loadsteering state were analyzed. What’s more, I also made a unified description of forcestates and finally created a dynamic model of the dozer.2. Study on the dynamics control scheme and control strategiesThe dynamic control scheme was proposed which is based on speed regulationand torque and speed regulation, and the speed regulation is adjusted by the PIDcontrol algorithm. Then the drivers’ output signals, the amount of feedbacks and theamount of controlled targets of the two control schemes were defined. the study ofdynamics control strategies of the two control schemes were finished. At the sametime, I made logical models for different control strategies by using the finite statemachine toolbox of Simulink/Stateflow.3. Building the drive system model of the electric-drive dozer Use the Look-Up Table module of Simulink to build the model of the outsidecurve, then build the motor controller’s simulated model of speed regulation andtorque regulation respectively. Part of the turning of the differential steering system isdriven by variable pump-quantitative motor closed system, according to whosemathematical description, the simulated model of speed regulation was built.According to the parameters of the differential steering system and use theSimDriveline toolbox of Simulink, the simulated model was built. And finallycombining with the dynamic model of the dozer, the integrated model of electric drivebulldozer systems for speed regulation as well as torque and speed regulation werecompleted.4. Simulation and analysis of the dynamics controlGiving the simulated parameters and defining global variables in Simulink.According to the working characteristics of the dozer, several typical workingconditions were set. Through the simulated analysis of speed regulation drive systemmodel, I can get the dynamic control strategies, which can interpret driver’s intentionfor operation in the greatest degree. And the overall control effect is good, which inturn verifies the accuracy of dynamic control strategy and simulated model. As theload on the dozer appears to be nonlinear change in very wide range, it has to tunePID for every single working condition. According to simulated analysis of drivingsystem model of the torque and speed regulating, conclusion can be obtained thatmotor torque control and pump and motor speed control can cooperate with each other,through which the intention of the driver’s operation can also be achieved. At last, bycomparison of the two control schemes and analysis of the feasibility of them, theconclusion is that the speed regulation control scheme is more suitable for thepractical application of electric drive of dozers.