According to Mitja Schulz, senior vice president and general manager for commercial steering systems at ZF TRW, the former is designed to keep trucks in lane and at a safe distance from the vehicle in front.
Meanwhile, Dr Christian Wiehen, chief technology officer at Wabco, explains that the EMA system automatically steers tractor-trailers around hazardous situations, so helping to prevent rear-end collisions.
Both have been introduced for the first time in the prototype ZF Innovation Truck 2016 vehicle and are expected to be available in 2018.
Schulz says the new technologies represent the next level of active safety beyond the now mandatory AEBS (advanced emergency braking systems) and LDW (lane departure warning) systems.
HDA and EMA, he says, use advanced sensors (front-facing camera and wide-angle radar) and intelligent control units to drive braking and steering – with HDA managing the brakes and TraXon Hybrid automatic transmission (including the predictive shifting strategy PreVision GPS), while EMA takes control of the steering wheel via ZF’s electrohydraulic ReAX power steering system.
The assistant function detects if the AEBS or driver braking is sufficient to enable a stop, directing truck and trailer safely toward an open lane or hard shoulder, even at full speed.
“Our innovative function simultaneously evades, brakes and stabilises automatically at all speeds, with any load in the semi-trailer truck and with any type of semi-trailer,” states Schulz.
“This function helps to avoid rear-end collisions. It helps us to come one step closer toward our overriding target, Vision Zero.”
Schulz makes the point that with sudden manual avoidance manoeuvres, there is always the risk that the driver underplays or overplays the steering required – potentially making dangerous crash situations far worse.
In operation, the control logic of Wabco’s automatic OnGuardActive emergency braking system defines when to activate the EMA installed in the ADAS control unit.
At Level 1, the system warns the driver acoustically and visually, while Level 2 generates haptic signals, moderately decelerating the vehicle, and Level 3 initiates an emergency stop with roll-over protection.
The steering system interprets a sudden pulling of the steering wheel at Level 1 as a command to start EMA, with the system software constantly calculating the optimal evasion route and automatically adjusting the steering angle to match calculated versus actual steering trajectories.
“Evasive Manoeuvre Assist demonstrates Wabco’s and ZF’s leadership in developing innovative safety technologies for commercial vehicles,” comments Wabco’s Dr Wiehen, adding that it is yet another development on the way to automated driving.
Incidentally, ZF’s Schulz adds that the HDA control unit also has another important feature. “If the markings are missing on one side of the road, the system ... calculates them,” he says.
“We can have the HDA ready for volume production in approximately two years... By then, it will be absolutely realistic for it to meet all requirements needed for truck platooning.”