ZF’s new fully active chassis system, sMOTION, reduces inconvenient car body movements caused by potholes, bumps or curves.
The advantages of highly automated and autonomous driving of the future are a reality today, vehicle occupants can work or relax undisturbed while traveling. In addition to increasing comfort, sMOTION takes handling and safety to a new level.
An intelligent actuator actively controls individual wheels, adapting piston compression and rebound for each traveling situation and road condition. sMOTION also offers vehicle manufacturers modular scalability as well as component dimensions and interfaces, making it easy to tailor and integrate the system into vehicle designs.
“When it comes to the development of highly automated and autonomous driving, the chassis plays a key role,” says Dr. Holger Klein, head of the Car Chassis Technology Division at ZF. “Because by the time the autopilot takes over the wheel, all passengers want to be completely relaxed and unaware of the vehicle’s movement, regardless of what is happening on the road. Our sMOTION fully active chassis system can fulfill this desire.”
With ZF’s intelligent sMOTION shock absorbers, it is possible to eliminate almost all annoying motion and vibration from the roadway surface. “Passengers have the sensation of floating serenely over bumps and hollows,” says Dr. Klein. ZF’s innovation not only eliminates shocks caused by large potholes or unevenness but is equally effective against the pitching forward or back during deceleration and acceleration or the rolling and tilting when cornering or changing lanes.
The special feature of the sMOTION system is a very compact, external electric-motor pump unit with integrated electronics, which works as a bi-directional actuator on each wheel. This actuator can actively raise and lower the piston rod and subsequently each wheel individually, a function that is unique in today’s market.
sMOTION also features a second unique technology: a separate hydraulic control path. This feature compensates for higher-frequency bumps caused by minor unevenness in the road surface, such as manhole covers, transverse joints, rough asphalt or gravel.
The innovative spirit of sMOTION is also prominent in terms of sensor technology and networking. The necessary vertical dynamic data can be recorded either directly on the actuator units or via sensors in the vehicle. This information comes together in a central control unit that controls the actuators. The integrated electronics of the actuator serve to activate the electric motor, pump and CDC valves in such a way that the greatest possible calm prevails in the car body.
Transferred to the cloud, the shock absorber data can be used to inform vehicles following behind, or even specialist agencies, about dangerous road surface damage. In addition, sMOTION is perfectly prepared for networking via ZF’s cubiX system. This is an integrating, modular and scalable control algorithm that coordinates all active and semi-active actuators in the car. This means sMOTION can operate in conjunction with ZF’s electric power steering, integrated brake control (IBC), rear axle steering (AKC) and the electric axle drive system (eVD).