On December 3, 2020, CNXMotion launched the "Brake-to-Steer" (BtS) technology, using the technology modules built by its parent company Nexteer Automotive Systems and Continental, which is a highly automated and automatic Driving vehicles provide an additional layer of direction control to enhance driver safety technology.
In highly autonomous vehicle applications, the performance of the steering system is protected by multiple layers to ensure that the steering safety network is always on. In addition, BtS uses an electronic braking system to control the speed of the vehicle while achieving safe steering, adding an extra layer of protection to the steering safety network. In fully autonomous vehicles without a steering wheel, BtS will continue to interactively negotiate route instructions until the vehicle stops safely.
"In highly automated and autonomous driving, the most critical challenge may be how to ensure the robustness of system redundancy to ensure the safety of drivers, passengers and road users.” explained Alan Davis, general manager of CNXMotion, “BtS of CNXMotion Braking and steering technology provides an extra layer of steering safety for a wide range of autonomous driving scenarios."
CNXMotion's BtS technology uses the vehicle's existing braking and steering systems to meet safety requirements, providing automakers with cost-effective safety solutions.
"As we continue to move toward a high degree of vehicle automation, dual and triple redundancy are essential to successfully implement the minimum risk strategy, which will ensure the safety of drivers, passengers and road users." Continental North America Strategy, Automated Travel and Safety The person in charge Hiren Desai said, “Cross-domain coordination functions like BtS brake steering will be deployed in existing hardware, such as Continental’s MKCx brake-by-wire system, which eliminates the worry of adding additional expensive components.”
"Traditionally, the steering system manages the lateral control of the vehicle, and the BtS brake steering system allows braking to also participate in the lateral control." said Robin Milavec, vice president, executive director, chief technology officer and chief strategy officer of Nexteer Automotive Systems. "When the brake steering is combined with advanced steering systems such as Nexteer's high availability EPS or steer-by-wire, it can provide an extra layer of redundancy to further increase safety."
How the brake steering works
The BtS brake steering function exists in the motion control system, which acts as an intermediary between the vehicle path planner (automatic driving system) and the actuators (steering, brakes and powertrain) to determine the best forward route.
After being integrated with the vehicle performance manager, the vehicle's expected path will be continuously verified by the BtS and the system for its steering capability, and at the same time, it will continue to interact and negotiate to obtain the safest route forward.
If BtS needs to intervene, it will respond in one of three ways:
1. Before finally choosing the first or second option, continue on the expected route, 2. Perform the least risky maneuvers, such as slowing and braking to turn the vehicle to the side of the road, or 3. Stop in the lane. This function was originally developed for the steering redundancy of autonomous driving above level 4, and it is also suitable for low-level automatic driving assistance functions (such as lane keeping, obstacle avoidance, etc.) that mainly focus on the driver's steering intention in different scenarios.