Modeling And Development Of Horizontal Control System For Leveling Machine

In recent years,laser leveling machine has been widely used in the precise leveling of agricultural cultivated land and construction of modern engineering.The leveling precision of concrete is higher than that in farmland.At the present stage,the leveling precision of the laser leveling machine developed by our country can not meet the requirements.In order to improve leveling precision,we need to thoroughly study the control mechanism of leveling machine and establish the dynamic model of leveling system to facilitate the simulation and optimization of control algorithm.There are many actuators and sensors in the leveling machine system,hence a reliable communication system is required to supervise the control system.The RS-485 bus can only be a single master-slave structure and its performance for fault tolerance is poor.If a node fails,the system can't guarantee the accuracy of the data communication for other nodes.The collision avoidance mechanism and error detection function of the CAN bus can effectively solve the issues and improve the reliability of communication.Because of the rough road,leveler will incline.In order to simulate the actual operating conditions,an experimental platform of the horizontal control system for the laser leveling machine is set up and a suitable controller is designed according to the leveling system.The main research contents and achievements are as follows:(1)The overall design scheme of the pitch angle control system for the laser leveling machine is presented.An experimental platform of horizontal control system for laser leveling machines is developed.A nine axis inertial sensor is chosen as the angle transducer.The master and slave controllers are chosen as STM32F407 and TMS320F28335 processor,respectively.(2)Based on the principle of rigid body movement,the model of pitch angle control system of concrete laser leveling machine is established on the basis of the model of roll angle control system for an agriculture laser leveling machine.The simulation results of MATLAB/SIMULINK show that the model can reflect the relation between the expansion of hydraulic rod and the change of pitch angle.(3)The protocol and features of the CAN bus is investigated.Controllers are connected to the CAN bus through extended transceivers and the CAN bus is used to realize the communication between the STM32F407 and TMS320F28335 processors.The data is measured by a logic analyzer to verify the reliability of communication.(4)An experiment platform for the leveling machine is developed.Based on the extended Kalman filter and attitude calculation,the control of the leveling angle for the leveling machine is realized.The dynamic response under different PID parameters is compared,and the PID parameters with better control effect are selected.The experimental results show that the system has high measurement precision and can be stably controlled.The horizontal control of the leveler is achieved.