Through its investment in Rivian, Volkswagen is changing the hardware design of its cars by thinking outside the box.

For example, the company is eliminating the growing number of control boxes, a key shortcoming of typical domain architectures. In the domain approach commonly used by traditional automakers, each functional element of the vehicle, whether it is the powertrain, safety system or infotainment system, is managed by its own domain controller.

In modern cars handling increasingly complex tasks, these domains lead to redundant connections from power to electronic control units (ECUs) and cumbersome wiring that stretches to all four corners of the vehicle. Whether powered by electricity or gasoline, a traditional brand's car may have as many as 150 separate ECUs.

Model of traditional manufacturers

"The old model of traditional manufacturers is, if you want an active suspension system, add a box," said Kyle Lobo, director of electrical systems at Rivian. "You want fancier headlights? Add another box."

"Our approach is, no, let's create these regional controllers and then expand them to feature sets," Lobo said.

Rivian's three-zone architecture (East, West, and South) connects nodes that are physically close but independent of the functions they provide. The zones are connected to each other and to a central computing node via Fast Ethernet, which reduces latency. Lobo uses Rivian's adaptive suspension as an example: The South zone connects to the rear drive components, and the West zone connects to the adjacent front suspension. The suspensions are then networked via a bus.

"This is different from what traditional OEMs do, where there is one suspension controller and everything is connected to it," Lobo said.

The approach reduces cost, mass, and manufacturing complexity, and can make repairs easier and less expensive. Compared to first-generation Rivians, the zoned architecture reduces the number of electronic control units (ECUs) from 17 to seven more powerful units, including controllers for infotainment, autonomous driving, motor drive units, and battery management. The architecture saves 1.6 miles of internal wiring and 44 pounds of weight, and is said to reduce material costs by 20% and carbon emissions by 15%.

That approach requires the kind of vertical integration that Rivian excels at, company engineers say: developing sophisticated software and hardware in-house from the start of a new design, rather than contracting from hundreds of independent suppliers. It's a strategy favored by Chinese manufacturers like Tesla and BYD because they can yield design and manufacturing efficiencies, and the profits that come with them, that have plagued traditional automakers. It's another big challenge for companies like Volkswagen, Toyota or GM, whose empires are built on relationships with global suppliers large and small and the parts they develop: electronics from Bosch or transmissions from ZF.

Just as important, Rivian's scalable system allows for comprehensive over-the-air updates - not just for infotainment or comfort, but also for performance, safety, advanced driver assistance systems (ADAS) or subscription services.

"One thing we often hear from customers is that they feel like they're getting a new car every month, and that's what we're working on," including the ongoing development of AI features and voice control, says Vivek Surya, Rivian's director of product management.

Rivian said that "software-defined car" may be the new industry slogan, but it is ultimately an inadequate descriptor.

"Internally, we call it a 'software-updatable vehicle' rather than a software-defined vehicle. Because that's where the real magic is."

Source: Content compiled from IEEE

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