Automotive industry expands use of Hardware-In-The-Loop (HIL) simulation for Electric Vehicle (EV) and Advanced Driver Assist Systems (ADAS).
National Instruments (NI) is expanding the scope for electric vehicle (EV) powertrain component validation using hardware-in-the-loop (HIL) testing and simulation.
The move comes about as government regulations mandating lower emissions and higher efficiency are on the increase, which places more pressure on the automotive supply chain to get EVs on to market as quickly as possible. For powertrain test engineers, the move to EVs represents new and constantly evolving technologies with rapidly changing test requirements on aggressive schedules.
HIL vs fixed function
With the fast evolution of technology to support EV development, engineers can no longer efficiently rely on fixed function test platforms that require extensive modifications with each technology iteration.
With its HIL platform, NI is equipping engineers with the ability to modify and extend test systems more quickly and efficiently than they can with traditional fixed-function test systems delivered by turnkey vendors. This approach can help accelerate time to market through the flexibility to scale system performance and change the I/O mix as often as necessary in response to rapidly changing test requirements.
NI HIL systems are built according to a reference test architecture based on best practices observed by participants in the automotive industry. The EV reference architecture optimises the HIL test of powertrain power electronics like the traction inverter, DC/DC converter and charger by providing standard starting points for integrating high-fidelity power electronics and plant models, mapping and signal conditioning I/O, emulating sensors and loads, inserting faults, sequencing tests and reporting results.
The NI reference architecture for EV test and NI’s investments in workflow integration better optimise HIL testing for fast moving new technology with quickly changing requirements. The flexible user-defined systems help validation teams keep up with the breakneck pace of innovation in the automotive industry by helping them cut test development time and increase test coverage.
High-performance EV HIL systems require coordination from multiple vendors so NI has worked with companies like OPAL-RT, with its advanced eHS electrical solver and electric machine library, to help ensure seamless high-fidelity model integration. Seamless integration of OPAL-RT models with the test system can help reduce test development times while increasing result resolution, helping customers achieve shorter design cycles and gaining better insights from test data.
According to Jean Belanger of OPAL-RT, this collaborative approach is key to the development of an end-to-end architecture covering the full HIL automotive spectrum, providing an economical, modular and scalable system.
“The collaboration facilitates the development of FPGA-based electrical solvers on popular NI hardware platforms, such as PXI and CompactRIO, which enables us to maintain our focus on cutting-edge HIL technologies,” he says.
The collaborative approach taken in HIL testing development also extends to other industry participants such as MathWorks for model integration using Simulink and ETAS for pre-configuration expertise.
The notion of Hardware-in-the-Loop relies on the ability to have a simulation and test system into which prototype as well as production hardware can be simply plugged so that real hardware can be fully tested in virtual environments.
The joint venture with ETAS has resulted in ETAS NI Systems, which combines ETAS’ expertise in developing and integrating HIL systems with NI’s software-defined platform and comprehensive I/O capabilities.
The pre-integrated systems will be able to be quickly configured from a common infrastructure to meet each customer’s specific needs, and being built on the NI platform means the added ability to economically change the tester over time to keep pace with technology changes.
As well as EV testing, the joint venture will examine the validation of the operation of ADAS in vehicles. ADAS has proven to be a notoriously difficult system to test in all possible input variations through a long list of test scenarios. This list continues to expand with each new consumer-driven innovation, forcing automotive OEMs and their suppliers to determine how to perform repeatable, real-world testing.
On top of this is the complexity introduced with the electrified powertrain, consisting of the motor, inverter and battery. With each component experiencing significant innovation to improve efficiency and the driving experience, the testing demands are constantly changing.
By employing simulation techniques, hardware-in-the-loop (HIL) systems provide an efficient, repeatable and viable method that engineers can apply to accomplish their exact test needs while minimising costly and potentially dangerous road testing. Historically, these needs have been met with custom, closed test systems designed from the ground up for each unique set of customer requirements or put together by internal test teams that have to integrate components from several different test vendors.
By adding ADAS to its test coverage, NI and ETAS are addressing an important part of automotive development that is part of the UN remit for improved road safety and also paving the way for the future of autonomous road transport.
Radar for ADAS
Automotive radar is essential to vehicle safety for current advanced driver assistance systems (ADAS) and future autonomous driving. It’s one of the most widely used sensing technologies because it’s robust and readily available. The massive automotive industry shift towards 79 GHz radar has reduced the cost of radar-based safety features such as autonomous emergency braking (AEB) and rear cross-traffic alert (RCTA).
The main advantage of 79 GHz radar sensors is the 4 GHz bandwidth, which significantly improves resolution and accuracy for both range and velocity. A tradeoff, however, is a larger set of test challenges, as the additional bandwidth means more data. This requires additional processing capabilities and an increase in test scenarios as more objects are discernible. With the simulation capabilities of the Vehicle Radar Test System (VRTS) developed by NI, engineers can work to improve their test to more confidently address these challenges.
“4 GHz is more than just larger bandwidth and extra scenarios,” says Oliver Poos, Radar Test Engineer at Noffz Technologies. “It provides added room for error on the test, so reliability and repeatability are increasingly important to guarantee safety.”
NI’s new VRTS is capable of simulating two objects per angle with a highly repeatable radar cross section (RCS). The RCS makes the simulated obstacle appropriate for both validation and production test. As part of the overall NI platform, the VRTS benefits from the flexibility, scalability and cost-effectiveness of the company’s software-defined systems, helping the user create more precise test scenarios and achieve lower test setup times. Finally, the VRTS is both cost- and space-optimised for large production deployments.