Fully digital steering:
The steer-by-wire system Space Drive 3 Add-On paves the way to an autonomous future
The next generation of the "by-wire" Space Drive driving and steering system - Space Drive 3 AddOn - marks the entry into series production and is an important key technology for autonomous driving. In addition, the technology acts as an important interface for data transfer with a view to maximum active safety.
Call up a car via app, name your destination and be chauffeured to work. That still sounds like science fiction. But the use of self-driving vehicles could become reality in just a few years. The new generation of the digital driving and steering system Space Drive provides an important key technology for transmitting the signals of the sensors and the driving automation safely to the road via electronic signals - without a mechanical connection to the actuators. At the same time, important data on vehicle and road conditions can be fed back. This is an important interface when it comes to making the technology for the future of autonomous driving safe and sustainable. Ultimately, the driver will be replaced by the computer and sensors in autonomous driving. The steering is another active sensor that transmits the driving experience in the form of data.
The basis for this development was laid by PARAVAN GmbH with founder and managing director Roland Arnold, who developed the technology - originally for vehicle adaptation in the field of mobility for the disabled. Space Drive has road approval according to ECE-R13 (brake) and ECE-R79 (steering). In the meantime, the system has been in use for almost 20 years, with over 9,000 systems installed and over one billion kilometres driven on public roads. The special feature: in the field of mobility for the disabled, redundancy or fail-safety - fail operational - is the most important development goal. In this area, the fallback level has always been the system and not the human being, because in an emergency, the handicapped driver cannot intervene.
Steer-by-wire system Space Drive ready for series production
Since 2018, the joint venture Schaeffler Paravan Technologie GmbH & Co KG has been developing the next generation of the innovative steering system, marking the next step: Space Drive 3 AddOn stands for entry into series production. To this end, it is to comply with the standards and norms of the automotive industry and support the homologation of new vehicles to be developed. The redundant system relies on a consistent safety concept for vehicles with functional safety relevance, developed according to the ASPICE process, and fulfils the highest requirements according to the ISO 26262 safety standard. Automobile manufacturers benefit from maximum scalability with the greatest possible scope for model- and vehicle-specific customisation. An important milestone on the way to steer-by-wire in large-scale production - both for road vehicles and for people movers or vehicle solutions for operation on private industrial sites, for example ports, logistics centres or airports.
The AUTOSAR-based system also enables a direct connection to the vehicle electronics as well as communication and network architecture. An enormous added value with regard to the integration of already existing driver assistance systems. Space Drive 3 AddOn is designed for small series production and is the basis for the future integrated large series solution. The control unit and software provide an important platform for further development.
Mechatronic solutions for more comfort and safety
The development is complemented by a hand wheel actuator (HWA) with force feedback module, which replaces the classic steering wheel with a mechanical steering column with mechatronic actuators. This allows for optimisation of the installation space and enables completely new interior concepts - for example, by stowing the steering wheel in the console, which will play an important role especially in (partially) autonomous driving. In addition, the system enables the suppression of unwanted disturbances, such as strong impacts from the road, as well as the realisation of new driving dynamics functions through a variable steering ratio. The modular and scalable design allows the system to be adapted for different vehicle classes and applications. In combination with the Space Drive steer-by-wire system from Schaeffler Paravan and mechatronic actuators on the steering gear, Schaeffler is developing an intelligent front axle steering system (iFWS).
Development approach From Track to Road
Racing is traditionally considered a development accelerator. The engineers are using this approach to further develop Space Drive - under the toughest conditions and in a demanding environment, such as the DTM. The technology carriers used here manage entirely without a mechanical connection between the Force Feedback steering unit and the steering gear. Since 2019, the Space Drive System has been approved by the German Motor Sports Federation (DMSB), and since 2020 it has been firmly anchored in the regulations of the DTM, among others. In this environment, the Schaeffler Paravan technology carriers are tested by a wide range of development drivers, including Markus Winkelhock, Bernd Schneider, Maximilian Götz or Maximilian Buhk, or in the rally field - where the loads are even significantly higher - by European Rally Champion Armin Schwarz.
In addition to DTM, ADAC GT 4 Germany, GTC Race or in the field of rallying, the technology carriers were already used in 2020 (GT4) and 2021 (GT3) at the ADAC Total 24h Nürburgring. It is important to the Schaeffler Paravan engineers that the development has a common thread. That is why, in addition to the GT3 technology carriers, tests are also being carried out with the GT4 vehicles, which are clearly closer to series production, as well as with road cars. Although the sporting successes are not the main focus, they are an important indicator of the reliability and resilience of the system. The highlight in 2021 was the first podium finish of a Space Drive vehicle already in the first DTM season at the finale at the Norisring.
Especially when used in motorsport, many new, data-driven development approaches arise in terms of steering parameters. It is about recording and analysing road conditions and feeding them back to the Advanced Driver Assistance System (ADAS). An important and central feature of data generation is to increase the driving safety and reliability of future autonomous driving systems. The data generated in the Force Feedback steering unit can not only provide the steering angle, but also, for example, information on the condition of the road surface (grip level) to the control unit.
So using Space Drive is not just about developing a new technology: it's about breaking with 125 years of automotive history, because the steering of the future is digital!