EXPERIMENTAL SYSTEM OF VEHICLE CAN BUS BASED ON J1939 PROTOCOL

摘要

Based on the training articles required by the J1939 protocol, the training experimental system based on J1939 vehicle bus protocol has been established. The part of hardware of the system is consist of the computer terminal, Kvaser CAN bus analyzer and a vehicle CAN bus module powered by J1939 protocol, including the dashboard modules, vehicle-body electrical modules and the engine ECU modules. The Interface of the system is designed by X-Analyser powered by Warwick, and the results of the test can be displayed on the monitor directly. In allusion to the requirement of the training of J1939, the system, especially during actual operation process, can do the real-time supervision on the vehicle J1939 data and keep the entire record, display the waveforms and print them out. As to the change of display on the dashboard, the result is as followed: (1) the measurement and display of moving velocity and distance: system makes a real-time measurement of velocity and display the current velocity on the Velocity Dashboard, with unit of Km per hour. The impulse input of the moving-velocity sensor will reach to 200Hz while the moving-velocity elevates to the maximum value of 180Km per hour. When the velocity is not 0, system will make a real-time measurement of the number of distance of vehicles, and data will be displayed on the multi-functional LCD zone on the dashboard, with the unit of Km and accuracy of 0.1Km. Simultaneously, system keeps data recording for the total mileage the vehicle had run with interval of 1Km and the data will be displayed on the multi-functional LCD zone on the dashboard. (2) The measurement and display of the quantity of fuel: displaying data in the dimensionless way, the quantity of fuel is scaled by oil-mass sensor, marked by F which stands for Full and E which stands for Empty. When the resistance varies from 0 to 200Ω, the corresponding scale varies from F to E. (3) The measurement and display of the front and rear axle air pressure: the system will make a measurement for front axle and rear axle air pressure before the real-time measurement, with data displayed on the dashboard. Front axle and rear axle are scaled by air-pressure sensor #1 and #2. When the resistance air-pressure sensor varies from 0 to 200, the corresponding scale varies from 0 to 12. (4) Steering control and display: the steering is controlled by two switches. When the switch is off, the output is 5V; when switch is on, the output is the impulse output with the minimum voltage of 5V and maximum voltage of 24V. Corresponding indicating light on the dashboard flashes. (5) Collected data is as followed: sensor of velocity with ID 18FF0D24 and PGN 0FF0D; sensor of quantity of fuel with ID 18FF0C24 and PGN 0FF0C; sensor of air-pressure 1 with ID 18FF0C23 and PGN 0FF0C; sensor of air-pressure 2 with ID 18FF0003 and PGN 0FF00; left-steering switch with ID and PGN; right-steering switch with ID 18FF0432 and PGN 0FF04.