The ZF “Advanced Urban Vehicle” concept car shows what mobility of the future will look like in cities.
Radishes are growing on the dashboard like in a vegetable garden; you could also plant a bonsai tree there and then drive it around. Earlier this year, Rinspeed, the creative Swiss manufacturer of future vehicles, presented this concept car, called “Oasis”. The most interesting feature: the small garden integrated behind the windshield. The slogan for this: “‘Home and garden’ is now ‘car and garden’.” This is not a PR stunt, but a serious vision of cars becoming spaces to live. A living room on wheels, with swivel chairs, a sideboard, a television, and a wooden floor. Or an office on wheels: when the driver chooses to let the computer take control of the vehicle, the steering wheel can be converted into a folding table that they can connect a tablet or keyboard to. The passengers should feel at home in the vehicle, and be able to relax or do some work there. A vehicle for individualists. And yet something which can be considered “off-the-shelf” is under the body of the “Oasis”: the Intelligent Rolling Chassis (IRC) supplied by ZF, which handles everything that has to do with braking, driving, and steering. ZF calls the underlying prototype the Advanced Urban Vehicle (AUV), and sees it as a customizable universal platform for electric urban transportation in the future.
Universal platform for tomorrow’s urban transportation
ZF is taking a new approach with a straightforward modular system and a prototype chassis whose components all come from a single source. If technical systems such as the Advanced Urban Vehicle are developed cooperatively and networked intelligently, synergies can be achieved, says Gerhard Gumpoltsberger, Head of Innovation Management and Testing at ZF Friedrichshafen. For example, braking is said to be more efficient when it is connected with electric drives.
This can also optimize one-pedal driving: Simply taking your foot off the accelerator creates a sufficient braking effect for many traffic situations without also having to step on the brake pedal. “We can offer all the elements in one concept, from the drive to the steering system to the braking system, and network them by wire,” says developer Gumpoltsberger. “By wire”: this is what engineers say when they replace mechanical connections with cable connections. A well-known example is steer-by-wire, where steering columns are no longer used, and steering commands are instead sent to the electric motor via sensors and cables. This offers advantages in, among other things, the areas of installation space, assembly, and crash behavior.
ZF sees great potential in this high-tech system. It is expensive to buy parts and components individually from different suppliers and synchronize them into the single functioning system that an automobile is. “Development costs for automobile manufacturers could be significantly reduced with the IRC,” says Gerhard Gumpoltsberger. The manufacturers’ platform strategies themselves show that this strategy could succeed. The Golf VII, introduced in 2012, was the first model on the market using the new modular transverse matrix (MQB). Now several VW models use this as a basis. Other manufacturers are taking similar actions.
Complete solution with customization potential
The platform concept from ZF can be modified by automobile manufacturers. Many different body types and interior concepts are possible thanks to the largely flat base of the chassis, which ZF colorfully refers to as a “skateboard”. The design incorporates a twist-beam rear axle with two integrated 40 kW electric motors placed close to the wheels. Each motor is housed in an aluminum housing together with a single-speed transmission unit. The automobile manufacturer has free rein with regard to body design.
Small two-seat sports cars and family cars for the city are conceivable, as are robot taxis or vehicles for package delivery companies. And they will all benefit from the greatest advantage the Advanced Urban Vehicle offers: its extremely wide steering angle. “Thanks to intelligent mechanics, the angle is 75°. A steering angle of 40° is normal with front-drive axles”, says Gumpoltsberger. The design of the double-wishbone independent suspension, the central mechanical element for this wide steering angle, is particularly innovative. “The full steering angle looks very impressive,” says Gumpoltsberger. Yet the resulting maneuverability is highly unusual. “You can turn inside of a soccer goal.”
The biggest advantage is maneuverability: “This is a great advantage for city traffic, where vehicles sometimes have to maneuver in highly confined spaces.” Not only in parking spaces, but also in narrow streets and alleys, construction sites and loading areas. This would surely be any package deliveryman’s dream as well.
Networked systems are also essential for sharp turning maneuvers. Torque vectoring – the monitoring of the driving force on the wheels and its variable distribution – is a technology used in other vehicles to improve driving stability, for example. In the case of the AUV, steering is optimized by two electric motors mounted on the rear axle close to the wheels. This system distributes the majority of the driving force to the right rear wheel when turning into a parking space to the left of the vehicle at the maximum steering angle, and vice versa.
On the move with zero-emission robot taxis
ZF believes automobiles will still be driving on city streets in the future. “However, the number of vehicles will decrease slightly,” says ZF researcher Gumpoltsberger. “There are studies which predict that the number of cars in the future can be reduced by a factor of 5 to 10 if robot taxis are used.”
He considers such vehicles “the most attractive form of transportation”. These automobiles will no longer be owned by the individuals using them. “Yet individuality will remain, since you will be the one who determines the start and end of a trip.” Robot taxis without human drivers which are booked via an app or bot are still a topic for the future, says Gumpoltsberger, “but we are preparing for this future.”