CarMaker at the OEM
Testing Controller Networks
A well known German OEM uses CarMaker/HIL to test prototype and production controllers and controller networks in all vehicle lines. This includes:
- ESP - Electronic Stability Program
- ABS - Anti-lock Braking System
- CDC/SADS - Semi-active Damping System
- TCM - Transmission Control Management
- ECM - Engine Control Management
- EHPS - Electrohydraulic Power Steering
- CIM - Column Integrated Module
They use the maximum amount of available hardware components in the simulation environment, such as the brake system, throttle, injection system, instruments, brake and gas pedal, camshaft speed sensor, transmission selector lever, hydraulic dampers, wheel speed sensors and exhaust-gas recirculation valve.
One of the primary testing areas involve the CAN networks. For example, the transfer rates are measured to make sure that they comply with specification during all conditions, such as high bus loads. CAN messages are also checked to see if they are correct and complete. In addition error codes are evaluated for accuracy and to be sure that all the necessary codes are available. Network testing includes an analysis of the diagnostic tests to ensure the actuators are working correctly and also whether the controller flashing procedures are working in the controller network.
Another important testing area is fault insertion testing. Here the FailSafeTester is used to programmatically simulate short circuits, cable breaks, and other electrical faults. Also, CAN messages are modified and the voltage levels are adjusted automatically to check the effects. This is necessary to verify that the functionality of the controller meets the specifications when an error occurs and that the error is, in fact, recognized properly. Also important are tests that examine the effects on all networked controllers when an error occurs on a single controller. For example, special tests determine how the powertrain controller is effected if the ESP controller has a problem.
In addition, the German OEM is using CarMaker for quality control, such as testing during extreme conditions like high and low temperature, endurance tests, over voltage and other quality and reliability tests. Also, controller errors that are recorded in the field can be reproduced within the simulation environment, helping the engineers and perhaps the suppliers understand and hopefully correct the problem.
"The main focus, above all, is the diagnostics and the information that the controllers are exchanging over the CAN bus," states the OEM's project manager. He adds, "Testing the controllers together, in other words, the ESP together with transmission control, engine control and other components, is becoming more and more important and we therefore try to simulate with as much of the real chassis and drivetrain components as possible."
