Software-Defined Vehicles

The electrification of cars makes all sorts of things possible.


Automobiles long ago stopped being purely mechanical systems. But as more components are electrified — and, in particular, as the drivetrain is electrified — cars are becoming software-defined vehicles.

Some think of such cars as computers on wheels. But as these systems continue to evolve, adding in more assisted and semi-autonomous capabilities, that comparison is looking increasingly simplistic.

“It’s actually not one computer on wheels. It’s a data center on wheels,” said Frank Schirrmeister, senior group director for solution marketing at Cadence. “Within that data center, I have domain-specific compute — not just pure processing, but areas that are NPU-accelerated, areas that are graphics-accelerated, and what have you.”

With most major components being controlled by software, automakers can simplify their product lines while they explore new revenue options. Customers, meanwhile, will have more options and more flexibility in how they buy and equip a car.

Many mostly-mechanical vehicles are still on the road today. In their purest form, the only electrical elements are those things that have to be electrical — typically, the lights and radio. But even with the radio, older controls are mechanical.

Select electrical options have been available for quite a while — electric door-locks and windows, for example. But the guts of the car have remained stubbornly mechanical until the current period, where electric is becoming the future of automobiles, driven by both environmental needs and economics.

The electrified vehicle
Cars can be divided into roughly three components, the drivetrain (or powertrain), the body and suspension, and infotainment. More recently, another category has come into play that doesn’t fit neatly into these other buckets — advanced driver-assist systems (ADAS), which improves the driving experience and adds to the safety of the vehicle.

Fig. 1: A stylized illustration of the many electrified systems within future automobiles. Source: Mentor

Of these, infotainment has been the easiest to electrify, with mechanical radio controls having been long ago replaced by electronic controls. Active suspensions have not replaced mechanical suspensions, but have changed them into a format that can be electrically adjusted. The drivetrain has been the hardest part to fully electrify, but the trend in that direction is unmistakable.

Obviously, some electric cars are already available, and Tesla deals in nothing but electric vehicles. Their acceptance, however, has been limited by the lack of charging options, the time it takes to charge a vehicle, and the distance the car can go on a full battery. As the infrastructure evolves, electric vehicles will be a more palatable choice across the board — and, at some point, likely the only option.

The process of electrification, however, is not merely the replacement of mechanical systems with simple electrical equivalents. Each component comes with a broad range of parameters that can be adjusted by software. Anything from the drive torque to the machine-vision algorithms to the infotainment system can be tuned or reconfigured through software settings.

Automakers see two trends fueling this change. One is the constant need to reduce emissions from vehicles to ever-lower levels. Concerns about the impact of greenhouse gases on the environment have driven regulations that eventually will demand more from cars than can be accomplished with mechanical engines.

While electricity often is generated by means that also cause the release of carbon dioxide, the growing availability of renewable energy means this will improve over time. And, at the very least, it’s a problem for the power plants to solve — no longer one for the automakers.

In addition, people are rethinking how they use cars. Younger people are less likely to want to own a vehicle, particularly when they live in a dense urban setting. As fewer people purchase vehicles, opting instead for public transit or ride-sharing services, revenues for the automakers are starting to dwindle. OEMs are looking for ways to replace those revenues with new sources.

The operating parts of the vehicle
Modern internal-combustion engines have very limited settings that can be controlled by software. “With the internal combustion engine, what you see is what you get,” said Tom Wong, director of marketing for design IP at Cadence. “There’s not a whole lot you can do with the piston or the crankshaft. We don’t have carburetors anymore. We have fuel injection. So what can be controlled electronically is basically the fuel injection system.”

The remainder of the car also has a few electronic options. “Active suspension is somewhat controlled by microcontrollers, and so are your ABS,” Wong said. “When you get to continuously variable transmissions, then you have computer control.”

Software’s role here became all too evident with Volkswagen’s gaming of the emissions systems. It used software to game emissions regulations by detecting when it was likely that a test was occurring, and then changed operation to ensure that the test passed.

Wong noted that, in Formula 1 cars, it’s an entirely different matter. “Everything is electronic, everything is computer-controlled,” he said. “That’s why you look at the steering wheel and all you see is buttons.” But he clarified that many of these capabilities are not likely to make the transition to commercial cars because their impact wouldn’t be strongly felt by the customers, making the cost of them untenable. “As a driver, what do you see? You see fuel economy, you see acceleration, you see a nice temperature control in the car, with adaptive air conditioning. And you have better handling when you manage the active suspension. Beyond that, there’s not a whole lot they can manipulate in real time so that you actually feel a difference.”

By contrast to the current situation, electric vehicles will be — indeed, are already — far more adjustable than their mechanical counterparts. But much of that remains invisible to the user who purchases a car and drives it day-to-day. Many features available in the car, including those that weren’t purchased by the driver, will be in place, waiting only for some electrical signal to turn them on.

This can provide carmakers with enormous efficiencies. They can deliver the same drivetrain on every car, relying on quick software updates to enable the purchased features. “The physical properties that are required to put those vehicles and power trains together will become more standardized,” said Doug Burcicki, director for IESD automotive market development at Mentor, a Siemens Business. “Instead of having 8 or 9 platforms that support 30 or 40 different vehicle variants globally, you’ll see OEMs having about 3. And the majority of those platforms will be based on common components, with only wheelbase and width as the main variations.”

Many of the ADAS features finding their way into cars today are more algorithmically intense. They include:

  • Adaptive cruise control
  • Lane departure warning
  • Blind-spot detection
  • Electronic or camera-based “mirrors”
  • The availability of a 360° view
  • Automatic parking
  • Road-noise cancellation

They may even venture into the surreal. As Wong described it, once one can manipulate sounds for suppressing road noise, you can play other tricks like having the speakers make it sound, when slamming a light, clanky door, as if it were a heavy, high-cost door. The door itself hasn’t changed, but the driver feels like he or she has a higher-end vehicle based upon the sound of the closing door.

Going the software route instead of using hardware chips does involve some tradeoffs, though. “An IC with the required features will add value if it’s small, monitors itself, and has low noise,” said Gene Warzecha, executive director of the automotive business unit at Maxim Integrated. “However, the IC development cycle is one to two years, so it is difficult to know what the right combination of features will be. The winning roadmap needs to provide small, safe and quiet solutions and guess what the future needs of the customer will be. On the other hand, additional software content also implies a large SoC, which means more power. Furthermore, SoC suppliers are able to offset some of their own power by going to the latest process geometry and lowest possible supply voltage. In contrast to the guessing game that is needed for sensor/module solutions, the winning SoC power roadmap pushes the limits of the architecture and process capabilities.”

Staying up to date
Accompanying all of these capabilities will be a rich communications channel that sends operational data up to the cloud and facilitates the downloading of entertainment and driver-assist services. That raises the importance of security. “Over-the-air (OTA) updates and reliability of the ADAS system are the two highest security priorities that we have seen,” said Jason Oberg, co-founder and CTO of Tortuga Logic.

That communication channel also will be important for providing software updates in a way that’s not possible today in most cars. “With an internal combustion engine, there’s not a lot of stuff you can tweak after it leaves the factory,” said Wong.

With an electric drivetrain, updates may fix bugs and provide plug security patches, fine-tune operational parameters, and allow feature upgrades or “rental” of temporary features. The fine tuning may be based upon analytics gathered from an entire fleet of vehicles.

“Today you would get almost 10% more efficiency or range on your battery charge than you got three years ago,” said Burcicki. “That’s been done through continuous over-the-air updates on a regular basis from Tesla, because they analyze all the data coming back from all the vehicles on the road. And they modify the algorithms controlling how the battery pack is charging and discharging. Every time they do that, they get better at it, and everyone’s vehicle on the road has more range than it did when they bought it.” Tesla even extended the battery life of vehicles in range of an approaching hurricane to assist with efforts to flee.

Data management will become a more important aspect of how vehicles are managed and developed. “The [traditional] on-premise development cycle focused on ‘model years’ in the past, but is now transforming and utilizing agile methodologies that will drive continuous software development,” said Simon Rance, head of marketing at ClioSoft. “This will result in software being deployed to the vehicle long after it has left the factory. This transformation is similar to one we saw from cellular phones to smartphones. Smartphone development demands agile methodologies, which require robust design data management.”

Meanwhile, “rented” features make possible new revenue streams that can’t be tapped today. “We have heard in the popular press for a long time that Gen Zs are not buying cars,” said Wong. This has the industry concerned that revenues may fall. “Carmakers are looking at this as a way to make more money, so they will want to have the car equipped with multiple options.”

Burcicki amplified that point. “No OEM is going to make money on an autonomous vehicle anytime soon, but they still have investors and stockholders that they are beholden to,” he said. “Any CEO who wants to be around to see autonomous cars has to be profitable between now and then. So they’re trying to figure out technologies they can leverage now and how they can benefit from them, even though the true payoff might be over a decade away.”

Renting features will create new opportunities. Burcicki noted the possible example of a “ludicrous mode,” where for some period of time the car can be tuned to perform more like a racecar for playing on the racetrack over the weekend. Or it might be the opposite. “If your son or daughter is taking your car out and you want to limit the performance that they can get out of the vehicle, you could do that using a software switch,” said Aileen Ryan, senior director of strategy in Mentor’s UltraSoc business unit. “This would be a temporary thing, because when can you get in your car tomorrow morning you want the car to be back to the way you want to drive it.”

The mechanical analogy here would be to ship every internal-combustion vehicle with a V8 engine in it, with only some of the pistons activated. A four-cylinder car would merely leave four of the cylinders unused. And if the driver were going on a vacation and needed extra power to tow a trailer, they could “rent” the other four cylinders for the week, shutting them back down when finished. What’s impractical mechanically becomes tenable electrically.

Driving within Europe provides other opportunities. “In Europe, we have the ability to drive across borders, and when we do that, there are potentially different legislative situations,” noted Ryan. “Different speed limits, for example, can kick in when you cross the border. This means being able to automatically understand, ‘Oh, I was in France five minutes ago, but now I’m in Germany, and therefore I can either use some additional features or I may not use some features because I’m in a different legal jurisdiction.’”

In other cases, this can enable after-sales feature upgrades. “A car buyer may not want to turn on all available options,” Wong explained. “You can buy a car without automatic emergency braking, but the hardware is capable of doing that already. Maybe six months down the line they will send you an email and say, ‘Well, for $500, we can enable the automatic emergency braking. Are you interested?’”

The infotainment system is probably the biggest likely source of income. “A base model vehicle may have the same infotainment system as every other vehicle, but you may have the opportunity for software upgrades to have higher fidelity sound, additional speakers within the vehicle, or more tuned speakers, or surround-sound in the vehicle,” Wong said. Even more promising would be entertainment rentals for the back seat. Regardless of what is purchased, the automaker gets a cut as the toll taker.

“Those over-the-air updates and that incremental revenue stream that they’re generating after they sell a vehicle are the number one objective via software for many of these companies,” Burcicki said.

One wrinkle in the whole update notion is how these updates will interact with functional-safety considerations. “There’s a big open question regarding how these updates affect functional safety,” said Kurt Shuler, vice president of marketing at Arteris IP. “Is it practical to completely redo the safety analysis for each update?”

This represents an area that will need attention before this all comes to fruition.

The need for security
Having such a conduit for communication raises the specter of hackers, and such attacks are all too famous (picture a Jeep in a ditch). “OTA has a broad set of security requirements, since updates are pushed from a cloud infrastructure into the automobile itself, and protecting this data in flight is important,” said Tortuga Logic’s Oberg. “However, it is common that OTA carries security down to the hardware level to ensure updates are securely loaded at the endpoint. ”Security will be essential not only to ensure that communications are safe, but to protect the integrity of the vehicle. Any code being downloaded must be checked to ensure it comes from a legitimate source. That includes any settings that might change. You don’t want “ludicrous mode” to suddenly engage mysteriously while you’re on the highway with your foot on the accelerator behind a semi-trailer.

“When I have to upgrade an ECU or update an operating system, that that can take some time,” said Chris Clark, solutions architect for automotive software and security at Synopsys. “We have to perform sanity and validation checks. But what is my key infrastructure? Can I validate that the software is indeed intended for this particular vehicle? I may need to do a key update, which may take some time if I don’t have dedicated processors in the vehicle to generate large keys.”

But those capabilities are likely to improve over time. “As we see organizations move to centralized computing, more powerful computing platforms, or virtualization, then that story changes,” Clark said. “Now it can do hot-swap. I can validate and rollback much more quickly.”

This also raises the question of when these updates should occur. Will they be restricted to when the car is in park? Turned all the way off? Perhaps overnight? Computer operating systems tend to be updated by the OS makers at the convenience of the OS makers, and hopefully data is not lost in the process. That would not work for a vehicle.

There’s also the question of what happens if an update fails to install. Failover becomes important so that a previous version remains intact. It may even be necessary to keep that previous version while the new version runs. If a bug is later found in the new version, then it may be necessary to revert to the previous version until a new — and improved — update is available.

There is a close connection between security and safety. “For ADAS systems, many of these security requirements are intertwined with functional safety,” said Oberg. “It is paramount that an ADAS system behave as expected, whether it is an unanticipated environmental effect or malicious intent from an adversary.”

These considerations aren’t merely being discussed by the industry. Organizations are actively defining standards and regulations. A new standard, ISO 21434, is in development as a security-related companion to the well-known safety standard ISO 26262. There are also two proposed UN regulations, one for cybersecurity and one for OTA updates. Such documents will be important in guiding how communications security evolves in vehicles.

There’s one additional very practical communications concern. What happens with the vehicle if it goes out of cellular range? There are vast regions not covered by cellular service, and with 5G, it’s not at all clear that these gaps will be remedied. So what happens to the vehicle if communication ceases? There was one notable example of a rental car that tracked the driver through the cell connection. At the point where the driver left the coverage area, the car simply stopped and could not be restarted.

Such situations might be considered rare corner cases for urban dwellers, but for rural residents, it’s a daily reality. Future automobiles will need to balance the need for communication with the need to keep running when communication isn’t possible.

Ultimately, the use of software will forever alter the automotive business. OEMs will be able to achieve higher efficiency while opening new revenue streams. Drivers will experience much more flexibility, and the vehicle will remain configurable long after the purchase is complete. The ability to configure a vehicle both during manufacturing and operation will completely change the experience of building or owning a vehicle.


Douglas Wallace says:

Unlocking new and better features in a car one already owns by paying for upgrades in SW could be a new revenue stream for auto makers.

As long as we don’t have 737 Max issues with software doing dangerous things in ironically vain attempts to make us safer.

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