Reimagining the HMI for SAE Level 4 autonomous cars
ZF's engineering team had been building a physical control knob — the Centronic, later called MMA (Multimodal Armrest). The knob could change its rotational resistance in real time according to the UI — for eg. volume up/down will have low resistance, drive mode changes will have more resistance.
Centronic ACP demonstrator — the MRF knob, gear selector, and ambient light surface paired with the UI tablet
At Level 4, the old automotive HMI constraints disappear. You can look at the screen, lean back, use both hands. The UI has to be effective to show the hardware capabilities.
The question handed to our team was: what does the software experience look like?
10 months
Case study
Workshop · 3 days
"The outer ring of the Centronic changes resistance depending on where you are in the interface. You don't just see the menu — you feel the edge of it. That was the core idea: the knob knows what it's controlling." — Interaction model principle, ZF Centronic, 2019
Where the industry went
The haptic rotary control we prototyped in 2019 is now showing up everywhere. BMW's iDrive in the i7, the Mercedes S-Class center console, Volkswagen's Golf — all moving toward physical controls with variable feedback, after a decade of touchscreen-only cabins.
Euro NCAP's 2026 mandate requires physical volume and navigation controls — exactly the case we were making internally. ZF productized the Centronic MRF technology under the name HaptiX.
None of these can be attributed directly to this project — supply chain documentation doesn't work that way. But the direction we argued for in 2019 is now industry standard in 2024.