Application of NI PXI and LabVIEW software-based simulation solutions to verification testing

National Instruments (NI) announced that major automakers, such as Japan's Subaru, have adopted NI Hardware-in-the-Loop (HIL) technology for simulating real-world road environments required for electric vehicle testing, thereby eliminating environmental factors and reducing test time and costs.

Generally, vehicle performance and safety response tests are conducted using finished vehicles on test tracks or public roads. However, it is difficult to perform reproducible tests in a timely manner due to constraints such as weather or unpredictable road surface conditions. Furthermore, electric vehicles are significantly more complex than conventional vehicles due to their numerous interdependent subsystems. This complex testing environment exacerbates the workload for automotive test engineers, who already face challenges due to short development cycles and limited budgets.

To address these issues, Subaru applied NI HIL simulation solutions based on NI PXI products and LabVIEW software to verification tests instead of actual roads. By introducing the HIL system, we were able to eliminate environmental factors before actual vehicle diagnosis and efficiently and thoroughly test vehicle embedded controllers in a virtual environment.

Daisuke Umiguchi, head of Subaru’s electric power unit research and experiment department, stated, “We were able to fully implement a customized HIL system and develop our own software in just one to two weeks using NI PXI products and LabVIEW,” adding, “We were able to reduce purchasing costs to about one-third of the level compared to other companies’ products, and because we were familiar with the LabVIEW environment, we were able to develop our own software at one-sixth the level of outsourcing costs.”

Subaru additionally equipped the system with a controller-driven dynamometer from HORIBA and CarSim vehicle dynamics simulation software from Virtual Mechanics to generate load conditions identical to actual road conditions. This drive system transmits the calculated values to the NI HIL system in real time, creating closed-loop control between the model on the HIL system and the drive system model. Consequently, the HIL interaction system enables the application of appropriate loads to the vehicle throughout the entire testing process.

Subaru plans to use this NI test system for final quality inspection during the final stage of electric vehicle development, and intends to expand its application to all models in the future. Furthermore, by adopting this NI system, it is expected that test time will be reduced by half compared to the existing method.