Trucks will automatically swerve to avoid collision
The ‘uncrashable truck’ has come a step closer as ZF has revealed an Evasive Maneuver Assist (EMA) system, which it has developed in conjunction with braking system specialist Wabco.
The system is designed to help articulated trucks avoid rear-end collisions in situations where the now-mandatory Advanced Emergency Braking System (AEBS) alone cannot respond fast enough to prevent a crash.
Showcased on ZF’s first Safety Truck 2016, EMA is expected to be available on production vehicles in around two years’ time.
The system uses advanced sensors working in conjunction with ZF’s electrohydraulic ReAX power-steering. It can calculate whether the truck has sufficient ‘stopping power’ to come to a standstill before it hits a detected obstruction on the highway ahead, which may not be the case if the road surface is very slippery or the obstacle comes to light suddenly around a bend or over the brow of a hill.
If the driver initiates a swerve manoeuvre in such a situation, then the system automatically applies the optimum steering and braking inputs to retain stability, avoid the collision and prevent vehicle rollover.
EMA combines technologies from ZF and Wabco, including ZF’s electrohydraulic ReAX power steering system and Wabco’s Electronic Braking System (EBS), Advanced Emergency Braking, Electronic Stability Control (ESC) and vehicle dynamics control systems.
The control logic of Wabco’s automatic AEBS OnGuardActive emergency braking system defines when to activate the EMA installed in an in-house ADAS control unit.
OnGuardActive has three operational levels. In Level One the system detects an obstacle in the road ahead and activates visual and acoustic alerts. In Level Two, the system generates haptic signals to the driver (by, for example, vibrating the seat) and commences moderate deceleration by up to 3 M/S2, and at Level Three the system activates the maximum possible emergency braking effort until the vehicle stops.
EMA will detect the driver making a sudden steering input in response to the warnings at OnGuardActive’s Level One and assume automated control. The software constantly calculates the optimal evasion route and adjusts the steering angle accordingly. The software algorithm continuously monitors and compares the calculated and actual steering trajectory.
The integrated roll-over protection function in the EMA is adapted for such extreme driving situations. This function is integrated into the ESC system and the lateral acceleration sensor through networking and is a feature in the ZF Innovation Truck 2016.
The driver can override the EMA at any time during the autonomous evasive manoeuvre by simply taking control of the steering wheel, brakes or throttle.
ZF has also shown a second ZF Innovation Truck fitted with a Highway Driver Assist program which can help protect against the often very severe consequences resulting from lack of attention, distraction or a few seconds of microsleep.
The system warns the driver that the truck is unintentionally moving out of the lane and at the same time actively and independently keeps the vehicle in the lane. It simultaneously automatically maintains a safe distance from the vehicles in front at any speed, which in this case also includes stop and go functionality.
Key to this solution is the combination of sensors: a camera sensor mounted on the front windshield accurately monitors road markings (S-Cam), and a radar sensor (AC1000) measures distance. The latter provides a broader field of view at low speeds while offering long range detection at higher speeds.
Additional ZF networking efforts involve combinations of the brakes and TraXon Hybrid automatic transmission system, including the predictive shifting strategy PreVision GPS, along with the ReAX steering system. If lane markings are missing from a stretch of road, it can predict where they should be and act accordingly.
