With roads getting
more and more congested every day all across the world, and with available
technology, there is only so much we do to close in every inch of the gap we
can. Congestion isn’t always referring to moving traffic; it can also be found
on bridges, alleys, narrow roads and most importantly parking spaces.
In countries
where population is high and space in negligible, maneuverability is key. Cars
can only turn as much as the turning radius will let it. The smaller the
turning radius the better it is to maneuver in slow moving traffic. It all
depends on how long the car is and the camber and angle at which the front axle
will let the front wheels turn. Problem is that modern cars can go to almost
45-60 degree of full lock on either way of steering and with camber adjusting
systems you can get a smaller radius. But now ZF has invented a new type of
axle that does more than that.
ZF has made a
concept ZF Smart Urban Vehicle. The concept car which is powered by
electricity, ZF says that it us “a starting point from which concepts for
future urban mobility”.
The ZF Smart
Urban Vehicle has a clever front axle, an electric powered rear axle and a lot
more clever gizmos. The front axle turns to 75 degrees of steering angle lock
which enormously increases the agility and maneuverability of the car. The
electric motors are mounted close to the wheel instead of a differential which
eliminates any loss of energy. Because all it has to do now is turn the wheels
directly and not some pinions in the differential to make the wheels go round.
The power comes from a traction battery. The ZF semi-independent rear
suspension with electric Twist Beam (eTB) sends 54bhp to each of the wheels through
the electric motors. 1,400Nm of torque is sent to the axle directly and a
maximum rev of 21,000 rpm. ZF claims the car will do a top speed of 150kmph.
In cohesion
with the torque vectoring system and the front axle that turns to 75 degree
angle, making U-turns is a peach turning through 180 degrees, is possible with
no difficulty on a standard two-lane road is what ZF has said. This will also
make it much easier to park cars in extremely tighter spots.
Apart from
the front and rear axles and the electric powertrain, the car has more clever
gizmos to make driving safer, easier and even more practical.
The
advantages of the new front-axle concept come to the fore in combination with
the Smart Parking Assist driver assistance function implemented in the Smart
Urban Vehicle. The system assists the driver not only in recognizing suitable
parking spaces, but can also park the vehicle fully automatically in parallel
or perpendicular spaces. The parking aid obtains its information from twelve
ultrasound sensors and two infrared sensors on the vehicle's front-end,
rear-end, and flanks; these sensors help find a suitable parking space. The
control electronics process the information and control all the systems
involved in the parking function – for instance, the electric drive and the
required steering angle of the electric power steering. The driver can interact
with the vehicle during the process through the display in the cockpit or
trigger the parking function once they exit the vehicle by using an application
on a mobile device. The Smart Urban Vehicle then automatically searches the
surroundings at walking pace for a suitable gap and automatically initiates the
parking process.
“When
implementing the concept, we weren't only looking at the benefits for the driver,”
explains Harald Naunheimer. “If passenger cars in future park without a driver,
parking space can also be used more effectively. As such the door opening
angles would no longer need to be taken into account in
the parking
garage – thus making the parking spaces smaller. All of which also takes the
pressure off cities because the freed-up space can then be used productively as
additional living and working areas.”
The
cloud-based ZF PreVision Cloud Assist driver assistance function provides
maximum range and driving safety in the Smart Urban Vehicle. Unlike purely
GPS-based systems, the ZF study not only takes into account geometry data and
information on the permissible top speed, but also stores data in the cloud on
the vehicle position, currently driven speed, and lateral and longitudinal
acceleration for every journey. If the driver follows the same route again, the
system calculates the optimum speed for
an
approaching bend on the basis of these empirical data and actual vehicle data.
The assistance function then throttles back the torque early on before entering
the bend, to the point where the bend can be negotiated without any mechanical
braking. All of which not only protects the vehicle's battery and braking
system, but also provides greater safety particularly on blind corners.
The driver is
kept informed at all times about the intervention of PreVision Cloud Assist:
The multifunction steering wheel, which ZF uses in the Smart Urban Vehicle,
features an OLED display in the steering wheel rim in the driver's direct field
of view. This display shows, for instance, how much drive torque the driver assistance
system throttles back before entering the bend – or provides again after the
bend.
The driver,
however, remains in direct contact with the Smart Urban Vehicle using HOD. The
capacitive system covers the entire steering wheel and detects whether the
driver is holding the steering wheel. The electronic control unit built into
the steering wheel converts the identified state into a digital signal and
sends this to the vehicle via the LIN (Local Interconnect Network). Depending
on the situation, this alerts the driver or activates the available assistance
systems.
“With the
hands-on detection, we are creating the basis for assistance and automated driving
functions which reduce the driver's workload – such as in urban traffic, which
is characterized by strenuous stop-and-go phases during rush-hour periods,” explains
Dr. Alois Seewald, Technical Director of Integrated Active & Passive Safety
Technologies at ZF TRW. These assistance functions automatically maintain, for
instance, a sufficient distance to the vehicle ahead or reliably initiate
braking as required. “Thus we can improve active safety – even if the driver does
not have their hands on the steering wheel.”
Source: ZF