Fault Insertion Adds Reality to Virtual Vehicle HIL Tests
Opal-RT Technologies and add2 Ltd. integrate dynamic simulation with electrical fault insertion for ECU testing

Testing of in-vehicle electronic control units (ECU) has made dramatic leaps in the last five years. As the demands placed on them grows, the need for testing ECUs with high-fidelity simulations of target power-train, chassis and body systems has driven the development of HIL simulators to the point where they can now be tested with the entire vehicle, long before the vehicle is built.

Instead of waiting for the test vehicle in order to run long, laborious road tests, ECU designers can now develop and prototype their controllers with a virtual test vehicle, "driving" it through extensive simulated test circuits, while calibrating and optimizing the ECU without leaving the lab. This allows them to deliver the finished product in a fraction of the time and cost it used to take just three or four years ago.

If a fault should occur in the vehicle's electrical system, it is sometimes challenging to see how the ECU behaves and how it ensures the safety of the driver and passengers. For example, if the yaw sensor shorts to ground as the vehicle makes a left turn at 100km/hr, it is questionable if the vehicle is still stable. Then the question can also be raised, what is the chain effect when a steering angle sensor fails but the signal is transmitted to three other ECUs?

These types of real-world scenarios can now be tested using the range of fault insertion products from add2 Ltd, integrated with RT-LAB Engineering Simulators from Opal-RT Technologies. Initially developed for automatic fault testing of ECUs, to test ECU response to the application of a variety of electrical faults to the input and output lines, the FIBB has now been integrated with the RT-LAB Simulator so that the ECU developer can gain a much better understanding of the effect of electrical faults on the dynamic behavior of the controller/component subsystem, or even the entire vehicle.

"This project was largely driven by one of our customers, who needed to perform electrical fault simulation on one of their vehicle stability control ECUs", said Wensi Jin, Automotive Product Manager for Opal-RT Technologies in Michigan. "However, we quickly realized that this system had potential as an off-the-shelf product for a broader market. Basically, anyone who needs to perform rigorous fault tests on any or all in-vehicle controllers will find this product invaluable."

Not only does RT-LAB provide the dynamic vehicle simulation, it also incorporates a programmable interface to the FIBB, allowing the engineer to insert five possible electrical faults:

• Open Circuit
• Short to Ground, Load Connected
• Short to Ground, Open Circuit
• Short to Battery, Load Connected, and
• Short to Battery, Open Circuit

It can apply this on any combination of up to 63 I/O lines on a single FIBB, and multiple FIBBs can be added - new versions of the FIBB now offer virtually unlimited I/O and enhanced functions including self-test.

"This has been a real success story for us." said Brett Dowen, Managing Director of add2 in the UK. "This customer probably saved around 50% of their costs and a huge amount of time by using our FIBB system in conjunction with Opal-RT I'm convinced that other ECU manufacturers will realize the benefits of this product and will incorporate it into their arsenal of control, testing and prototyping tools."