The active steering system features an electric motor mounted on top of the hydraulic steering gear.Earlier this month, Volvo Trucks North America took another step in driver assist systems by introducing Volvo Dynamic Steering (VDS) on its VNL and VNR for next model year.
You might not have driven with VDS yet – and may have only heard about it last week – but I’m almost certain you’ve seen it in action.
Volvo’s electrically assisted hydraulic steering, which debuted in Europe for the 2014 model year, was in use by two reversing Volvo FM trucks while Jean Claude Van Damme did the splits between them. That viral video has been viewed more than 93 million times since Volvo Trucks uploaded it to YouTube in November 2013.
The VDS system itself is fairly straightforward. An electric motor mounted on top of the hydraulic steering gear compensates for up to 9 feet of torque in the steering column – the equivalent of having a third hand on the wheel – while also reducing vibration and offering directional stability.
It makes driving a little easier and a lot more comfortable for the 82% of drivers that report suffering some kind of muscular strain on the road by lessening the driver’s steering efforts by up to 85% at low speeds. Volvo said testing has shown that VDS has the potential to cut muscular strain by up to 30% and for some specific motions, muscular strain can be reduced up to 70%.
VDS is a passive steering system in that it does not steer the truck by itself. It’s simply a layer of assistance for the driver. In the event of a system failure, the system reverts to its hydraulic system and works like it normally would without the VDS bolt-on.
I was able to take VDS for a couple of quick spins – once in a VNR and once in a VNL sleeper – at Volvo’s Dublin, Va., Customer Center.
Each truck was equipped with a switch to turn the system on and off for comparative driving but production models won’t be selectable and VDS will always be active.
The truck felt more nimble, and the steering lighter, through a series of aggressive low-speed S-turns with VDS turned on. Sawing left and right on the wheel without the system, the truck felt sluggish and heavy. Bringing the truck up to speed, the feel of wheel tightens up and offers a more traditional feel and response.
Sliding the front wheel off a soft shoulder, the VDS system filters most of the impact from slipping off the road out of steering column and it takes less physical input to steer the tractor back onto the road, practically eliminating overcorrection. Lessening the impact of the drop off the road is also significant. The drop tends to jar the driver, causing them to lurch with the truck and put even more steering input into the incident, making a bad situation a little worse. Of course the cab still rocks from the dip, but VDS prevents much of that impact from transferring into the driver’s hands.
Over a patch of rumble strips, with VDS inactive, there’s a fist-numbing violent shake in the wheel as the truck skates across the bumps. With VDS enabled – over the same strips at the same 35 mph – the wheel barely moves. Input from multiple vehicle sensors – at over 2,000 times per second – determines the appropriate steering response, so the system reacts practically immediately as driving conditions change.
A Return-to-Center feature enables the steering wheel to automatically return to the center position when the truck is in motion, making it easier to reverse the vehicle and maneuver in tight areas.
A self-learning system, VDS can compensate for road crowning and crosswinds by recognizing when the driver is consistently holding the wheel with a left or right bias to offset it. The system will input steering torque in the needed direction, taking some of the strain off the driver. For example, if you’re diving deep into a long curve – or fighting a strong flat-state crosswind – the system recognizes that the driver is having to offset those forces and does it for them.
Volvo’s Virginia-made tractor is already among the safest on the road. When you add layers of new technology – like Volvo Active Driver Assist platform (VADA) 2.0 and the optional VDS – it not only offers additional safety, it also makes for a more comfortable, car-like driving experience.
