Nexteer and Continental JV CNXMotion innovates brake-to-steer technology for autonomous vehicles

CNXMotion a 50:50 joint-venture between Continental and Nexteer Automotive was established in 2017 to innovate motion control solutions for advanced applications and accelerate R&D activities for the parent companies. Leveraging technology building blocks from its parent companies CNXMotion has announced Brake-to-Steer (BtS) technology, which provides driver safety through an additional layer of directional control for highly automated and autonomous vehicles.

The company says in highly automated vehicle applications, steering systems feature multiple protective layers to ensure the steering safety net is always on. In addition, BtS adds yet another layer by using the electronic brake system to safely steer the vehicle while simultaneously controlling its speed. In a fully autonomous vehicle with no steering wheel present, BtS will negotiate a commanded path until a safe pull-over can be achieved.

Alan Davis, general manager, CNXMotion said: "Perhaps the most critical challenge in highly automated and autonomous driving is ensuring the robustness of system redundancies to keep drivers, passengers and road users safe. CNXMotion's Brake-to-Steer technology offers another steering safety layer for a wide range of automated driving conditions."

The company says its BtS technology offers a cost-effective way for automakers to achieve safety needs by leveraging the vehicle's existing braking and steering systems.

Hiren Desai, head of Strategy, Autonomous Mobility and Safety, Continental North America said: "As we progress toward higher levels of automation in vehicles, secondary and tertiary redundancy becomes crucial in executing successful minimum risk manoeuvres. This helps keep vehicle occupants and road users safe. Cross-domain functionalities such as Brake-to-Steer are enabled by, and housed on, existing hardware, like Continental's MKCx brake-by-wire systems, eliminating the need for additional, costly components."

Robin Milavec, SVP, Executive Board Director, CTO and CSO, Nexteer Automotive said: "While steering traditionally manages the lateral control of a vehicle, Brake-to-Steer enables braking to contribute to lateral control as well. When combined with advanced steering systems like Nexteer's High Availability Electric Power Steering or Steer-by-Wire, Brake-to-Steer gives an additional layer of redundancy - further enhancing the safety net."

How Brake-to-Steer Works
The BtS function resides in the Motion Control System (MCS), which acts as an intermediary between the vehicle's path planner (the automated driving system) and the actuators (steering, brakes and powertrain) to determine the best path forward.

Integrated with a Performance Manager, the vehicle's intended path is compared to the system's ability to steer the vehicle via BtS, while constantly negotiating the safest route ahead.

In the event that BtS needs to engage, BtS reacts in one of three ways: 

1. Continues on the intended path before ultimately moving to the first or second option,

2. Performs a minimum risk manoeuvre, such as slowing and braking to steer the vehicle to the side of the road, or
3. Stops in the lane.

The company says it was originally developed for steering redundancy in Level 4+ autonomy, the feature can be adapted to assist a driver in multiple scenarios for lower levels (Lane Keep, Obstacle Avoidance, etc.) while a driver is still present, following the intentions provided from the driver's steering input.