The Road to Zero Prototypes
ADAS and HMI development are new applications for simulation solutions.
The concept of designing, engineering and manufacturing a new vehicle without physical prototypes is typically viewed as either impractical or mythical. Even as virtual development processes have become increasingly capable, experts maintain that hard prototypes are still needed to validate the fidelity of virtual models.
But “zero prototypes” is more than a slogan at one of the top providers of real-time simulation and driving simulator solutions. For VI-grade, zero prototypes are a crusade.
“We have customer companies that are already building their first physical prototype very, very late in the design cycle,” noted Guido Bairati, VI-grade managing director. “That prototype is really a pre-series production vehicle.”
Bairati believes Darmstadt, Germany-based VI-grade (owned since 2018 by Spectris plc), with its many families of simulation tools, is nearing the threshold of eliminating physical prototypes in vehicle development as well as in ADAS, a fast-growing application. Building a vehicle simulation model allows engineers to do multiple runs offline on the computer. They can identify corner cases, then evaluate those cases on the driving simulator even before the first prototype is built. By doing that, engineers can front-load problems and tackle a lot of development in the last part of the V-model (verification and validation).
“Basically, you do everything earlier — and the earlier you find issues, the easier it is to solve them,” Bairati said in an interview with SAE Media. As soon as hardware components — for example, a steering system, a damper, a camera or lidar — become available, they go into a methodology that integrates Hardware-in-the-Loop (HiL) testing with one of VI-grade’s driving simulators. A full, complete physical prototype is not needed. Instead, engineers work with what Bairati calls a “hybrid prototype” in which some components are represented by software and some are real hardware.
“The driving simulator is becoming basically an integration platform around which all these pieces come together,” he explained. VI-grade customers are seeing different benefits using the latest sim. Volvo, for example, reported a 50% reduction in the development cycle of its latest SUV platform. Ford Motor Co., a major VI-grade customer, claims that tasks that would take a
month to complete at a proving ground can be finished in just one week using simulation technology. “And that does not include the time and cost of building a prototype, shipping it to a proving ground, and sending engineers and drivers to the proving ground.,” Bairati said.
“We try to make simulation an analog to the real world. It’s not a replacement; it’s an enhanced, better way to work,” explained Louis Jamail, supervisor, core methods and simulation/VAE driving simulators, at Ford. He said Ford still validates physically near the end of development, “but if I can get to an 80-percent answer without a prototype it’s probably more consistent. And it’s a win even if we have to spend 20 percent of our time on the prototype.” With Ford’s expanding simulation facilities operating at 100% capacity, Jamail’s group has been moving to incorporate simulation across Ford’s PD landscape “in small steps,” enabling engineers and technicians to more fully understand the tools, he said. “As a former test driver and development engineer, I’m bringing my own 20-plus years of knowledge into the virtual space,” he added.
The potential to slash development time and cost, and streamline the PD process, has ignited the global automotive market for simulation solutions overall. SAE Media counts more than three dozen companies doing business in the driving-simulator space, with VI-grade, AB Dynamics and a few others recognized as the dominant players, according to OEM simulation managers. The driving simulator market alone is forecast to increase by $381 million USD, growing at a CAGR of 5.65%, according to a January 2023 report by Technavio Research. North America is expected to account for 34% of the market's growth during the forecast period.
Challenges to growth include the high cost of validating simulation resulting in increased total cost of ownership (TCO) of simulators, according to experts. VI-grade’s top-of-line DiM250 Dynamic Driving Simulator, a centerpiece of Ford’s simulation work in Dearborn, is a $5 million investment (including building, installation and personnel cost), for example. The process of validation in the automotive simulation sector is limited, particularly for studies that use human factors simulation, according to Technavio. Higher costs of fully validated human-factors Driver-in-the-Loop (DiL) simulators also are expected to rise.
Those potential hurdles, however, aren’t putting off OEMs’ strategic integration of simulation into their vehicle development organizations. Soon after Ford commissioned its new DiM250 in Dearborn, the automaker launched a new VI-grade Compact Simulator, outfitted with a Virtual Test Tracks package, at its Research and Engineering Center in Nanjing, China. The companies are now working on integrating 3D virtual data into the driving simulator that will simulate Ford’s test tracks in Nanjing.
Along with its traditional role in vehicle dynamics work, simulation has found a natural home in ADAS and autonomous vehicle development. Progress Technologies Group, a Japanese engineering services company, recently launched a new VI-grade DiM driving simulator at its new engineering facility, company CEO Nakayama Gakuto announced in a release. He expects the tool to be used to perform both human-factors development and “functional verification of automated driving systems and advanced safety control systems” when integrated into the company’s model-based systems engineering (MBSE) and model-based definition (MBD) technologies.
Changing the development game
“Everyone will tell you how simulation saves cost and development time, and that’s true,” observed Lucas Bruck, a principal research engineer at McMaster University in Ontario, Canada. “But in my view, the most valuable thing about driving simulators is the design flexibility they give you by adding drivability and performance into the mix. They allow you to tackle those things beforehand – a game-changer for things like ADAS, particularly when combined with hardware-in-the-loop,” Bruck told SAE Media.
Driving simulators are “changing the game” in ADAS and AV development by introducing the environmental factors such as weather and an infinite number of real-world driving conditions into the models in a collaborative work environment – without the real-world impediments those conditions pose to engineers.
“Validating ADAS and automated systems, as engineers incorporate more and more AI, is a big application for driving simulators,” according to Sam Abuelsamid, principal research analyst leading Guidehouse Insights' E-Mobility solutions group and former development engineer who worked on ABS, traction control and stability control systems. “In those days we had a suite of test scenarios which was comparatively limited because we knew that ultimately, it came down to the human driver, whom we were trying to assist. But today’s fully-automated systems have to be able to deal with every potential scenario in the real world.”
VI-grade’s simulation solutions for ADAS seamlessly connect control system design, traffic simulation, weather conditions, sensor fusion and the driving simulators, according to Bairati. The onboard sensor array can be modelled into the traffic simulation environment together with the vehicle to verify common SAE Level 2 ADAS functions such as automated emergency braking, adaptive cruise control, and lane departure warning. It also can be hardware tested at the subsystem and system levels.
For ADAS studies, a typical VI-grade Driving Simulator configuration consists of a static or full-motion dynamic simulator (the company says most customers have both to test and tune different types of systems); a cockpit from a real vehicle, which provides realism and immersion of the driving experience, and active safety systems like belts and seat vibrators that give the drivers additional cues. Control systems, sensors and other devices can be added both as SiL or HiL. With HiL, embedded controllers can be tested with actual hardware components –individual and fused sensors, in the case of ADAS—that simulate real world conditions well before the final system is integrated, the company claims.
And highlighting the additional flexibility benefit noted above, the sensor test can be extended to the Driving Simulator via a Sensor Fusion Test, enabling ADAS functionalities, including driver reaction to the test parameters, to be fully and safely evaluated and optimized in the lab environment before running real road tests.
Experts mention another valuable aspect of simulation that’s already underway: training test engineers. They’re the perceptive and practiced individuals who can run five hard laps on the track then tell you the damping rate needs to be increased by a fraction of an Ns/m. Driving simulator training sessions enable test engineers to correlate how the feel of the vehicle changes when the parameters are changed. “Give them experience – and they can train the software as well,” Abuelsamid asserted.
Human factors design is another application that’s growing for driving simulators, due to the importance of HMI development for occupant safety, comfort and convenience. Driving simulators are being used to optimize HMI design, improving the vehicle-to-driver communication, ensuring the driver remains engaged in the driving task and playing a role in designing vehicle interiors that enhance the driving and transportation experience.
Zero prototypes are a worthy goal for vehicle development teams, and for the companies who provide solutions toward that goal. “Do I believe in ‘zero prototypes’? No,” said virtual simulation and testing expert Bruck of McMaster University. “I say that because I worked 10 years in the industry. But I do think that a drastic reduction of prototypes is achievable.” he said.