New generation of steering systems keep intelligent vehicles on the road

Steering systems have evolved from the rack and pinion manual setup through hydraulically assisted steering to fully electronic power steering – with increasing amounts of intelligence being added to support semi-autonomous features such as lane assist, and ultimately the fully autonomous vehicle.

One of the leaders in the field is Nexteer which, in January 2018 delivered its 50 millionth electric power steering (EPS) system. “Many people may not realize that our EPS systems are a gateway technology that enables advanced driver-assistance features, such as lane-keeping, park assist, active return to center, traffic jam assist and more,” said Steve Spicer, Vice President of the global EPS product line. “ADAS-compatible EPS systems will ultimately help pave the way for even more advanced safety features in semi and fully autonomous driving.”

Automotive Industries (AI) asked Jeff Zuraski, Executive Director of Future Engineering at Nexteer Automotive, what Nexteer’s advanced steering technology suite offers car manufacturers.

Zuraski: It offers a good combination of features for mixed mode vehicles. Vehicles that can be driven normally, and with a mixed mode of manual and autonomous or fully autonomous. When the vehicle is in fully autonomous mode there is more interior room as the wheel is moved forward and stowed. The wheel can be stationary, reducing distraction, when steer by wire is part of the package. Nexteer’s system is “highly available” and keeps working even if a subcomponent fails. This is important when the driver has not been in the loop and needs some seconds to re-enter the driving task. And lastly, the transition between driving modes, particularly going back to manual driving is managed. This means the system  ensures the driver is ready to take back control before it hands over the steering.

AI: Have these technologies enhanced the functionality of the steering wheel? How important is a feature such as the stowable steering column?

Zuraski: To expand a bit more on my previous answer, the steering wheel could be a conventional one or perhaps shaped differently. Steering wheel styling is a task for the vehicle OEM and the supplier of the steering wheel. Nexteer currently makes all the components between the steering wheel and road wheel, but not the steering wheels themselves. A stationary steering wheel – such as Nexteer Quiet Wheel™ Steering – offers more comfort and control options during autonomous driving mode and redefines the “behind the wheel” experience.

AI: What are some of the advanced steering applications Nexteer has developed that lead to a richer end-user experience?

Zuraski: We have developed steering actuator building block functions that support vehicle-level features. An example would be position control, which is in the electric steering actuator system, and can be used for automatic parking or lane centering assist. It accepts a path command from another subsystem on the vehicle and the two systems work together to achieve the vehicle level feature. Ultimately, Nexteer’s advanced steering technologies mean enhanced comfort, control and safety features for the driver’s end-user experience.

AI: What are the cyber security solutions in Nexteer’s steering technology suite?

Zuraski: First, we work with our customers to support their vehicle level cyber security strategies and architectures. We offer our customers integrated, multi-layer cyber security at a steering system level for maximum protection. Our cyber security technologies consist of specifically designed hardware modules on the semi-conductor level, as well as a multi-layered cryptographic software structure, that identifies and authorizes information and command flow between the steering system and other in-vehicle or external controllers. So, cyber-secure steering technologies become even more important when you think about how vehicles are adopting more advanced electronics to enable automated driving, as well as internet connectivity and V2X communication.

AI: How do OEMs integrate these security features – what kind of building blocks are needed in terms of software and hardware?

Zuraski: It varies by customer. Some form of hardware encryption is normally needed, so hardware selection well in advance of application is a must. We have open, ongoing dialog with our global customers to make sure solutions are ready when needed.

AI: Nexteer’s strength lies in the fact that all technologies are developed in-house (from design to delivery) for agile delivery and customer vehicle development customization – how instrumental has this approach been in the company’s success?

Zuraski: Owning the entire process under one global roof has given us a competitive advantage in terms of the opportunities to participate earlier in the process of multiple ADAS steering applications with customers. In-house ownership also benefits our customers in that we are able to be more agile, responsive and build-in value and quality from start to finish.

AI: Tell us about Nexteer’s relationships with OEMs – such as Continental and WABCO. How have these helped in developing new technologies?

Zuraski: Nexteer’s JV with Continental, “CNXMotion” allows for new features to be developed that involve coordination between lateral and longitudinal control or – said another way – integrated steering and braking. Our collaboration is also accelerating R&D activities for both parent companies. Our WABCO partnership has resulted in expanded output of Magnetic Torque Overlay – what we call MTO, so it could be applied to commercial vehicles. Before this collaboration ¾ ton pickups where the largest vehicles with MTO. It accepts an electrical control signal as an input, which can be used to achieve ADAS features found in passenger vehicles. These ADAS features can reduce driver fatigue, enhance safety, comfort and control – which can be especially important for drivers of bigger trucks and for those drivers sharing the road with these commercial vehicles.

EPS in numbers

• Nexteer EPS systems can improve energy efficiency by up to 6% and reduce CO2 emissions by up to 8 grams per kilometer
• Fuel saved by the 50 million EPS units would fill 7,500 Olympic swimming pools or 40 billion 16-ounce water bottles
• A standard Nexteer EPS system requires about 4.3 million lines of code
• Nexteer’s Steer-by-Wire system requires about 13.5 million lines of code
• Compare this to a mere 400,000 lines of code in the first space shuttle!