Infiniti's Direct Adaptive Steering is a steer-by-wire system used on the Infiniti Q50, the world's first production vehicle to use steer-by-wire technology. Steer-by-wire means that normally the steering wheel has no physical connection to the steering rack, instead the steering is controlled by sensors that detect steering wheel movement and convert that into an electrical signal that is sent down a wire to the steering rack while at the same time an actuator generates feedback so that the steering wheel feels natural. When the signal hits the steering rack it turns the wheels the appropriate amount.
Potential advantages to the system include less maintenance and lower weight, while also allowing easy handling customizability. Direct Adaptive Steering can also reduce the need for constant steering corrections caused by uneven roads, while eliminating the direct connection between the steering wheel and the tires removes most of the vibration from the steering wheel. These combine to make driving more comfortable and less tiring.
The Direct Adaptive Steering system is fully redundant with three independent electronic control units (or ECUs) working together and monitoring each other. There is also still a direct connection between the steering wheel and steering rack, however there is a clutch between the two that remains disengaged unless a problem with the system is detected. When the clutch engages the system behaves just like a normal steering system, allowing the car to remain under control.