Autonomous vehicles

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DRIVING THE FUTURE: AUTONOMOUS VEHICLES

Self-drive cars use a host of new technology to present a novel concept of travel for road users

SELF-DRIVING PIONEERS

DID YOU KNOW? Mainstream autonomous cars are closer than you think: Volvo wants to release a fully self-driven vehicle by 2017

All aboard the road train

A further development on the self-drive principle for a single car has already been implemented on a series of vehicles, allowing them to travel autonomously and in tandem as a group. The concept was an idea borne from the ‘SARTRE’ project, which stands for Safe Road Trains for the Environment. Pioneered by Swedish manufacturer Volvo and a group of technological partners, their system uses an array of radar, camera and laser sensors linked together by wireless technology to allow autonomous vehicles to travel together in a train-like platoon. At the front of the platoon is a dedicated lead vehicle – driven by a professional driver, which is followed autonomously by the trailing vehicles. This is all being done in a bid to reduce the number of accidents caused every year by driver fatigue.

The technology has already proved plausible after tests were carried out over 200 kilometres (124 miles) of road near Barcelona, Spain, in May 2012, with three cars automatically following a truck driven by a human being. The road train successfully melded autonomous technologies with car-to-car ‘communication’ to ensure the three self-driven vehicles remained in line throughout the whole test – and crucially, with no collisions.

Volvo’s SARTRE project in action on a public road

Self-driving trucks

Family cars aren’t the only vehicles currently receiving the autonomous treatment. Mercedes is developing the self-drive concept for its fl eet of heavyhaulage trucks. And, different to the realms of pioneering software of a Google car, Mercedes is simply evolving some of the tech already found in their new luxury saloons instead. Cruise control, lane assist, auto braking and stability control – all available on the Stuttgart company’s new S-Class – has been synced to a radar on its MercedesBenz Future Truck 2025 prototype, which scans the road ahead by up to 250 meters (820 feet) and communicates with the established systems to keep the lorry moving safely, without input from a driver. Developers say the system will drive more economically than a human, saving fuel, while increasing productivity as the vehicle will be able to travel for longer periods than what daily driver limits will currently allow.

Self-drive technology could revolutionise truck transport The cars of tomorrow won’t need steering wheels, an accelerator or a brake pedal; they’re autonomous and don’t require any human input. What’s more is that they are already on the road, with car company Volvo unleashing 100 of them on public roads of Gothenburg, Sweden, in a two-year project.

An autonomous (known as ‘self-drive’) vehicle works mainly thanks to a wealth of on-board radars, sensors and cameras that continuously ‘read’ the car’s surroundings to build a picture of the road ahead. While radars and sensors monitor everything from the proximity of other cars on the road to the whereabouts of cyclists and pedestrians, a forward-facing camera interprets highway instructions from road signs and traffi c lights. All of this information is continuously fed to the vehicle’s on-board computer, which uses the data to action appropriate inputs into the car’s speed and trajectory within milliseconds. Meanwhile, advanced GPS technology is constantly used to clinically navigate the vehicle along a precise route.

An autonomous vehicle prototype, otherwise known a self-driving car, looks fairly similar to a contemporary human-driven vehicle. Built-in sensors dotted around the car emit frequencies that bounce back off objects – much in the same way parking sensors work on executive saloons now – to provide a rationale of how close things such as curbs, pedestrians and other vehicles are to the self-driving car. The processing computer and GPS system are stored out of sight, leaving the roof-mounted LIDAR (Light Detection and Ranging) as the only discerning differentiation from the norm.

This rotating camera sends out lasers and uses the refl ected light to effectively build a 3D picture of the car’s position within the current environment. The information received from these ‘bounced’ light rays is sent to the main on-board computer. In the cabin, an occupant is treated to a screen showing the route, plus there’s an emergency stop button that will immediately pull the car over if needed.

Although technology giant Google has led the way in terms of evolving self-drive technology, automotive manufacturers such as BMW and Nissan have placed considerable resources for research and development into the technology of their own autonomous vehicles. These test vehicles tend to be adapted versions of current human-driven vehicles and as soon as a person touches any of the foot pedals or steering

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wheel, the system immediately cedes control back to the driver.

Although Google began its autonomous vehicle mission by adapting already homologated Toyota and Lexus cars as far back as 2010, its latest prototype is arguably the best yet. So far, it has proved to be markedly safe compared to human-input driving, as driver fatigue or alcohol impairment will play no part in getting from A to B.

To heighten safety even further, Google is experimenting with fl exible windscreens and a front made of foam-like material to protect pedestrians on impact, should the worst happen. These cars have also been limited to a relatively tame 40-kilometre (25-mile)-per-hour top speed while the project is still in the development stage.

However, while the theory of self-drive cars is relatively straightforward – a computer actions an input for a mechanical device to implement – the unpredictability of hazards when driving is the biggest challenge for an autonomous vehicle to overcome. Much like a human having plenty of practice ahead of their driving test, the process for ‘training’ self-drive cars is to evaluate every single possible hazard perception scenario that could arise on the road and input them into the car’s computer for the best course of action to take.

There are further limitations to the technology. Currently, a Google car cannot drive on a road that hasn’t been mapped by the company’s Maps system, so taking a self-drive car for a spin around your newly built suburban housing estate could prove somewhat problematic. Also, sensors on the car currently struggle to pick up on lane markings when roads are wet or covered in snow, making autonomous driving in adverse conditions particularly hazardous.

Companies are seeking to address these shortfalls, with safety drivers currently testing their self-drive vehicles in a variety of situations on the road every day and providing feedback on how to further improve the concept. Google even admits that its self-drive prototype is built with learning and development and not luxury in mind, so their own vehicle is currently bereft of any real creature comforts. However, if the blueprint for an autonomous car proves successful, that could well change and we could soon see motorways packed with moving vehicles where every occupant is kicking back and watching a fi lm, checking emails, or reading How It Works.

The world of a self-drive car

The Google car is a pioneering autonomous vehicle – here’s how it negotiates the environment around it

Position sensor

Located in the wheel hub, these sensors monitor speed and positioning.

Laser scanner

The LIDAR generates a 360-degree view of the environment to within 70m (230ft).

Main computer

The information is processed and actions sent to the relevant inputs, such as steering.

Radar sensors

These monitor moving objects up to 198m (650ft) ahead.

Kill switch

As soon as a ‘driver’ touches any of the foot pedals or steering wheel, autonomous mode is deactivated.

Interior

Occupants have a comfortable seat to sit on and a screen to input the route. Google now plans to build cars without steering wheels or pedals.

Autonomous tech available now

Predictive braking

Available on most modern cars, a radar-controlled Electronic Stability Program (ESP) continuously analyses the traffi c ahead and, if the driver fails to react to the proximity of another object, it automatically stops the car.

Lane assist

This stops a vehicle from drifting between lanes. If the front camera detects the vehicle has unintentionally deviated out of a motorway lane, it’ll input counter-steer at the wheel to ensure the vehicle returns to its lane.

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DID YOU KNOW? An autonomous vehicle builds a 360° picture of its environment, better than human field of vision, which is under 180°

Engine

Similar in principle to a power unit in a conventional car, an engine control unit controls the engine performance.

Radar sensors

Placed at the front and rear, these relay info to the computer to help determine the proximity of other vehicles and objects.

Sensors on all sides

GPS

An evolution of sat-nav technology, this helps position the vehicle and maps a route to a destination.

Front-facing camera

Mounted at the top of the windscreens, these effectively read road signs and traffi c lights, detecting traffi c cones and even lanes.

Processor

This ECU continuously reads the info fed to it by the radars, LIDAR and camera, altering the car’s speed and direction.

LIDAR

The LIDAR sits on top of the car and continuously spins at a rapid pace while emitting light pulses that bounce back off objects to sense and map the surrounding environment.

Forward-facing video camera

This detects conventional road signs, traffi c lights and other highway instructions the LIDAR and radar sensors cannot ‘see.’

Wheels

Driving technology may be vastly different in a Google car, but vehicles still need lightweight alloy wheels and rubber-compound tyres for practical and effi cient motoring over a variety of surfaces.

Active high beam control

Porsche and Volvo have introduced active high beam control, which dips the main headlight beam when sensors detect oncoming traffi c at night. This avoids dazzling other road users with glare from the main beam. This is what a driverless car sees. It utilises laser radar mounted on the roof and in the grill to detect pedestrians, cyclists and other vehicles – and avoid them