Nio and ZF have achieved a milestone in their strategic cooperation by integrating ZF’s steer-by-wire technology into the SkyRide chassis of the new Nio ET9 executive flagship. The start of serial production made the ET9 one of the first production vehicles in the world with steer-by-wire, and it was the first model in China to obtain the Ministry of Industry and Information Technology’s steer-by-wire mass production certification.
The system replaces conventional mechanical steering with fully digital control. By physically decoupling the steering wheel from the road wheels and dynamically adapting the steering behavior to different driving conditions, the partners say that a more precise, more comfortable driving experience with uncompromised safety is achieved.
The steering experience is improved through a variable steering ratio. At low speeds, a lower steering ratio ensures maximum maneuverability, with a maximum of only 0.6 turns of the steering wheel to the right or left. This offers easier operation, especially when parking and maneuvering in confined spaces. At higher speeds, the gear ratio increases to ensure stable straight-line stability and controllability.
Because there is no mechanical connection between the steering and road wheels, multiple safety mechanisms have been integrated. If a component fails, a backup (redundant) system takes control to maintain driving safety.
With the mechanical connection removed, the steer-by-wire system filters vibrations from the road for a more comfortable driving experience. Digital control minimizes the risk of skidding or loss of traction on slippery roads with more precise control.
Nio calls its strategic partnership with ZF established in 2022 a cornerstone of its EU strategy. It is supported by five R&D centers across the continent including at R&D facilities at Oxford in the UK overseen by Danilo Teobaldi, Principal Chief Engineer at Nio.
“At Nio, we’re committed to delivering groundbreaking innovations to our users that redefine the driving experience,” said Teobaldi. “Our collaboration with ZF, a globally recognized leader in high-quality automotive solutions, is a testament to our dedication to the European market and our ambition to set new industry benchmarks with our smart EVs.”
One of ZF’s chassis solutions
ZF is supplying the steer-by-wire hardware and software from its Chassis Solutions Division founded in early 2024. The technology is part of the what the supplier says is its portfolio of pure electronically controlled steering and braking, controlled damping, and cubiX software form the base for software-defined vehicle strategy.
“With our production-ready steer-by-wire steering system, we are launching the era of the software-defined vehicle,” said Dr. Peter Holdmann, Member of the Board of Management at ZF and responsible for the Chassis Solutions Division. “ZF is thus establishing itself as a technology leader in this area and giving car manufacturers such as Nio new freedom in terms of design, comfort, driving functions, and safety.”
In ZF’s steer-by-wire system, a mechatronic actuator between the wheels is the only source of steering power, with no mechanical connection between the steering wheel and gear. Steering commands are issued by a steering wheel actuator in the cockpit taking inputs from a corresponding angle of rotation sensor. An electric drive torque feedback unit recreates the “natural steering feel and feedback from the road” lost by the elimination of the mechanical connection.
The system makes it possible to develop more compact steering wheels that don’t require drivers to change their grip when parking. Steering feel can be adjusted from sporty and direct to comfortable and relaxed. And without a steering column, the driver’s safety is increased in the event of a crash.
ZF says its steer-by-wire technology is ideally suited to electric and automated vehicles. Combined with its AKC mechatronic rear-wheel steering, the supplier says that driving comfort can be improved significantly in electric vehicles with an extended wheelbase.
In addition to Nio, ZF says that a second major global car manufacturer is already using its steer-by-wire technology on an industrial scale, with other customer orders for the system in Europe.
“With a comprehensive product portfolio consisting of hardware and software with solutions for vehicle motion control in vertical, lateral, and longitudinal dynamics, we provide our customers with system expertise from a single source,” concluded Holdmann. “In this way, we are actively shaping the transformation towards the software-defined vehicle.”
ET9 launched at Nio Day
The ET9 was officially launched in December at Nio Day 2024 held in Guangzhou on the 10th anniversary of Nio’s founding. Over 22,000 people joined the event, the largest attendance in the history of Nio Day.
The smart electric executive flagship starts at 788,000 RMB (about $108,600), with a limited edition of 999 units of the First Edition available for sale at 818,000 RMB ($112,700). Delivery starts in China in March.
“The ET9 is the result of Nio’s decade-long continuous investment in R&D, and it is also a testament to Nio’s journey alongside global automotive industry innovators,” said William Li, Founder, Chairman, and CEO of Nio. “Over the past ten years, Nio has grown together with our users and friends, walking hand in hand. Through continuous technological innovation, we have brought high-quality smart electric vehicle products to our users. Through the ongoing deployment of charging and battery swapping infrastructure, we have provided users with more convenient and efficient charging services.”
Nio says that the ET9 integrates 12 Full Stack self-developed technologies, a result of over 53 billion RMB ($7.3 billion) in continuous R&D investment over ten years, and it includes several world-first innovative technologies and 1083 patents. This technical underpinning brings nine “unprecedented flagship experiences” to users.
One of the “world firsts” for the ET9 is the integration of three major technologies in its SkyRide smart EV chassis suite of the ZF steer-by-wire as well as rear-wheel steering and “fully active” suspension. Its hydraulic active suspension for the first time integrates the shock absorber with an active suspension electric drive unit, allowing it to adapt to an ultra-large range of transient adjustment capabilities for stiffness, damping, and height to create a comfortable driving experience.
The front and rear lights create an industry-leading 2-m² light carpet to welcome users as they approach the car. The combination of Sky Island and Executive Bridge divides the cabin into four exclusive spaces to offer comfort and privacy in both business travel and personal use scenarios.
Each seat has ultra-wide 582-mm seat cushions, nearly 2 m² of heating, and a 16-point hot stone massage function, providing every passenger with a “first-class air travel experience.” The class-exclusive double-sided relaxation mode enables occupants to recline and stretch out in comfort.
The Executive Bridge features a 360°-adjustable table, making it easy to read, work, present, and organize items. Its integrated smart electric refrigerator, Smart Safebox, and rear control panel that can be flipped up and down combine to make the ET9 a mobile meeting room intended to set new standards for executive flagships.
Nio says the ET9 has China’s first comprehensively self-developed smart system architecture. Relying on its four core advantages of ultra-high computing power, high-performance data communication, energy management, and security redundancy, the 900-V system is said to be the leading digital architecture in the industry.
The car’s SkyOS is said to be a world-first full-domain operating system covering multiple functions such as vehicle control, intelligent driving, cockpit, and mobile internet. For the “ultimate digital experience,” it fully embraces AI technology characterized by high bandwidth, low latency, large computing power; heterogeneous hardware; cross-domain integration; flexible continuous evolution; high reliability; and information security.
“In the next decade, we will serve global users through our three brands, further the popularization of smart electric vehicles, and help promote the global transition to electric vehicles and continue the work toward our mission of Blue Sky Coming,” concluded Li.
Firefly, Nio’s third brand (Onvo is the other), was also officially launched at Nio Day 2024.
