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Emergency steering assist

TRW Automotive (USA) has demonstrated its Emergency Steering Assist (ESA) system on a prototype vehicle at an event at the Hockenheimring speedway in Germany. The ESA helps support the driver in a situation, when an evasive steering maneuver is initiated.

Emergency Steering Assist systems will be introduced soon (Photo: TRW Automotive)

THE ESA IS A NEXT STEP IN COLLISION AVOIDANCE. It applies an additional steering torque during the maneuver and assists the driver in lateral vehicle guidance. For example, if you swerve to avoid an obstacle, the system will calculate the optimal trajectory around it and additional steering torque will be applied to help to follow the trajectory and stabilize the car. The driver remains in control of the vehicle and can override the system at all times.
The demonstrated ESA integrates data from TRW's video camera and radar sensors to provide an accurate and real-time image of the road ahead, with a CAN interface to the electrically powered steering (EPS) system. The automotive supplier has developed the system together with the Technical University of Dortmund (Germany). The company anticipates that the technology will be ready for production in 2017 for 2018 model year applications.

Competitor Continental has launched its ContiGuard ESA system already in 2010. Two years later, Nissan has presented the idea of a self-developed assistant, which steers in emergency situations by its own. TRW develops since some years driver assist systems, which are based on radar and video camera systems. The company has developed advanced driver assistance (ADAS) technology since the early 1970s and launched its first production radar in 2002 on the VW Phaeton and first video camera in 2008 on the Lancia Delta. Since then, TRW has fitted radars to vehicles including the Bentley Continental, VW Passat, and Citroen C4 Picasso, and cameras to vehicles including the Nissan Qashqai, Jeep Cherokee, Chrysler 200, Chevrolet Silverado, Hyundai i40, and Iveco Daily vans. ZF (Germany) is interested to acquire TRW Automotive, to form an automotive supplier enterprise, which is competitive with the market leaders.

The Japanese carmaker’s crash-avoidance system, the Autonomous Emergency Steering System, applies automatic braking and automatic steering in situations where a collision is eminent due to the driver’s delayed reaction. This system uses information provided by the front-mounted radar and camera, the two left- and right-rear radars, and finally the five laser scanners that have been placed strategically around the vehicle. When the system identifies a problem ahead that requires immediate braking, it checks for obstacles in front, alongside, and behind the vehicle, then shows the driver where they ought to steer.

Nissan has given no indication when or where the mentioned assist system might first appear. It will automatically steer the vehicle if its sensors and cameras decide that it’s too late for the driver to avoid a collision. Nissan said its system is advanced enough to not swerve into oncoming traffic or an adjacent vehicle when performing an autonomous maneuver. If swerving to avoid a frontal collision would mean veering into oncoming traffic, the system will keep the car on track regardless, but will attempt to mitigate the collision by applying the brakes beforehand.

Sensors help the chassis “to see”

"Many of the systems in use today are restricted to intervening in the longitudinal dynamics, Emergency Steer Assist is the lateral dynamics complement to Emergency Brake Assist", said Dr. Peter Laier from Continental. "If the driver of a vehicle traveling at high speed has gone beyond the last possible point where braking would have an effect, it may still be possible to avoid an accident through steering, or by taking evasive action. This possibility is not yet being actively incorporated into driving safety." ESA can now help drivers to steer past an obstacle. It does this by accessing the technologies, which are already integrated into many vehicles. The lower the road surface friction coefficient, due to rain or snow for example, the greater the gap between the 'braking' or the 'evasion' options. This means that evasive action is still a possibility long after there is no more hope of avoiding the accident by emergency braking alone.

Emergency Steering Assist systems will be introduced soon (Photo: TRW Automotive)

Before the ESA can be performed, it is essential that the vehicle is fitted with sensors for monitoring the road as far ahead as possible. "The more reliable and detailed a picture of other road users and of the road itself can be gained, the more effectively Emergency Steer Assist can assist the driver to decide, for example, whether to take evasive action by steering to the left or the right when suddenly coming up against the tail of a motorway traffic jam", said Bernd Hartmann, Chassis Systems Advanced Engineering manager in the Chassis & Safety Division. The first stage will employ radar sensors similar to those currently in production for Adaptive Cruise Control (ACC). The advanced engineering department is also working on combining the video images from camera systems, like those already in series production for Intelligent Headlamp Control, with the radar signals. In this way, the chassis will learn to 'see' so that the vehicle's safety systems are given early warning of an imminent hazard situation.

Assist systems will be demanded

Of course, after fusing radar and camera data, the results are given via CAN-based in-vehicle networks also to other ECUs (electronic control unit). Andrew Whydell from TRW stated: "ADAS has and will continue to be a focal point for the automotive industry as governments and industry bodies strive to reduce road fatalities worldwide. For example, the European New Car Assessment Program (Euro NCAP) and the Insurance Institute for Highway Safety (IIHS) have this year introduced active safety criteria into their assessment programs, which can be met with forward-looking radar and video camera sensors. We are demonstrating our leading technologies within these systems today."

From 2014, Euro NCAP has introduced automatic emergency braking (AEB) and lane departure warning (LDW) into its ratings scheme, and in North America, the IIHS has made fitment of forward collision warning (FCW) or AEB a requirement to receive its "Top Safety Pick +" consumer safety award. Going forward, from 2016 Euro NCAP will also introduce pedestrian AEB into its assessment program and is considering additional tests for other vulnerable road users including cyclists in future updates.

Whydell continued: "TRW has broad experience in radar and video camera systems and we anticipate exponential growth in these technologies over the next decade. We are now implementing our third and fourth generation sensor systems, which not only help to address the more immediate industry requirements, but also play a fundamental role in enabling semi- and automated driving.” He added: "As we move towards cars that allow the driver to take their hands off the wheel for periods of time, we'll start to see additional sensors being fitted to monitor 360° around the vehicle and also the driver's attention level. The systems will need to allow time for a distracted driver to be able to retake control of the vehicle. Radar sensors will therefore require a wider field of view at shorter range, combined with an overall longer range detection capability. Next generation video camera sensors will likely have lenses which can extend the range for detecting vehicles to 250 m and beyond for highway driving, while also allowing you to see what is happening close to the vehicle when maneuvering at low speed.

In some dangerous situations, a targeted evasive maneuver offers a chance to prevent a crash even if the driver has no time left for emergency braking. The ESA function assists the driver in these critical driving situations and helps to keep the vehicle stable. This is made possible by interaction between ESC, the electric steering, and driver assistance sensors. If the driver decides to take evasive action, Emergency Steer Assist calculates in milliseconds what line the optimum evasive maneuver could follow, termed the vehicle movement trajectory. To ensure that the vehicle remains stable, the evasive action is supported by a smooth steering movement.

All the electronics, which is necessary to make Emergency Steer Assist a reality is already installed in series production vehicles. Radar and video sensors work reliably in driver assistance systems. All new vehicles registered in Germany are now equipped with Electronic Stability Control (ESC) and this will be made mandatory for all new vehicles by end of 2014. ESC is also required in the USA for all new cars, SUVs, pickups, and minivans. ESA links together all the useful data from the existing systems. Because the necessary components are already present in many vehicles, manufacturers could implement ESA relatively inexpensively.