Semi-autonomous hybrid vehicle trials show fuel, emission savings

The Transport Research Laboratory has unveiled an innovative semi-autonomous vehicle prototype. It offers improvements in environmental performance and safety but also displays some shortcomings. Mike Woof reports.

The UK's Transport Research Laboratory (491 TRL) has been working on an innovative project to develop a prototype vehicle intended to reduce fuel consumption. Based on a Ford Escape hybrid model, TRL's Sentience vehicle uses a combination of mobile communications and mapping technologies to reduce fuel consumption by 5-24 per cent.

According to TRL, introducing this sort of vehicle technology to the vehicle fleet could result in average fuel savings of around 14 per cent. More importantly, it is based on a combination of commercially available systems, many of which are already fitted to upmarket passenger vehicles and which are likely to be introduced to more standard models as the systems become cheaper to produce.

Optimising environmental performance

The product of a 15-month development collaboration between Ricardo, Jaguar-Land Rover (as it was when the partnership was formed), TRL, Ordnance Survey and Orange Business Services, the Sentience vehicle uses GPS and electronic mapping systems in real time, combined with Internet access through mobile communications. The aim of this project has been to provide a vehicle that operates at optimum levels for its environment, reducing fuel consumption and exhaust emissions. The project team estimates that in full production the technology could be added to a hybrid that features commercially available cellphone and GPS location systems for an additional €20. Based on current vehicle development, a production system could be available on the market in just three to four years according to the project team.

The Sentience-equipped hybrid vehicle uses the electronic mapping and GPS technology to identify its location continuously. The vehicle speeds up and slows down by itself as necessary when it recognises road features such as roundabouts, speed bumps, gradients, curves and traffic lights. All the driver has to do is steer, while the vehicle responds to its location data and manages the acceleration and braking. An optimised drive control package is fitted that helps reduce fuel burn even during acceleration. The vehicle also uses regenerative braking to minimise energy losses. In urban operation, the use of this semi-autonomous control offers the chance to operate the vehicle in electric-only mode, which is where most of the fuel and emissions savings will be seen.

Driving the vehicle

The driver of the Sentience vehicle can take manual control at any time, however, to maximise safety in the event of it encountering obstacles. Although the Sentience vehicle could be fitted with technology to provide live traffic data regarding congestion this has not so far been used but the project partners believe it would be comparatively simple to enable. The vehicle has been tested extensively both on TRL's own large test track area, which replicates both urban and highway roads, as well as on actual roads in the UK.

Driving the Sentience vehicle does take some getting used to as the various systems govern speed automatically. The driver steers the vehicle and monitors the situation continuously, ready to brake in the event of unexpected hazards.

System shortcomings

However, there are some serious shortcomings with the Sentience prototype vehicle in its present form and some upgrades would make a significant improvement to its performance. One of the most apparent is what happens when the vehicle loses satellite contact, as it slows down considerably until contact is regained. Given that the vehicle would offer most fuel savings in the urban cycle where canyoning is an issue with GPS technology, a more effective solution needs to be found before such semi-autonomous vehicles can be considered practical. Developments in industries such as agriculture and mining are already pointing the way.

What is notable about the Sentience vehicle is that it could have been considerably safer and more efficient had TRL's development team paid close attention to some of the developments in semi-autonomous and autonomous machines used in the mining sector. Because it relies on low-cost, commercial-grade technology, the Sentience vehicle is considerably less sophisticated than some autonomous and semi-autonomous vehicles used in mining. Two leading heavy equipment manufacturers, US firm Caterpillar and Japanese company Komatsu, have been conducting extensive tests for over 10 years on fleets of autonomous trucks in surface mining, although the trials are still experimental. These are intended to improve safety and efficiency and the machines are guided by GPS technology that is linked to software, with forward scanning radar systems for obstacle detection and as a safety back-up to prevent collisions.

Meanwhile in underground mining, Caterpillar and the Swedish-owned firm Sandvik have developed semi-autonomous machines that are being used in actual production environments. Because of the underground location, these vehicles navigate using scanning lasers rather than GPS equipment and are also equipped with commercially available inertial navigation systems to provide further location accuracy. These underground machines move around predetermined mine areas autonomously and are only operated remotely under human control for loading operations that are too complex to be guided by computer. Interestingly, both the Caterpillar and Sandvik semi-autonomous mining machines benefit from sophisticated software that allow them to 'learn' during operation.

Ready solutions

Accident avoidance technologies are coming to market and an anti-collision system, as now being fitted to some Volvo models, would have been of considerable benefit and would not have been particularly costly. Moreover, as seen on the underground mining machines, commercially available inertial navigation equipment is not particularly expensive but would be invaluable for times when the vehicle loses its GPS satellite connection.

More sophisticated GPS technologies are now commercially available that offer centimetre accuracy and use a combination of the latest US GPS data and the Russian Glonass system. For the moment these satellite positioning systems are costly and are aimed at industry use but the price will fall over time. As with the mining machines, 'learning' software could be fitted to passenger cars as this becomes commercially available.

An over-reliance?

There is a major question mark regarding the safety of the Sentience vehicle, though. While it does respond to the road environment, it is debatable whether the driver will begin to rely too heavily on the vehicle's technology. This is a particular risk in the case of tired drivers. There is evidence that where vehicles require constant and continuous input, the drivers are less likely to fall asleep at the wheel. It was for this reason, for instance, that pioneering aviator Charles Lindbergh requested Ryan to design instability into the Spirit of St Louis monoplane in which he subsequently made his epic 33-hour solo flight across the Atlantic in 1927. Technology has moved forward and there are systems being developed that can recognise driver tiredness and provide warnings to rouse a drowsy driver and prevent accidents, and future production variants of the Sentience vehicle will need this technology. There is also a risk that older drivers may opt for the assistance of Sentience-type vehicles when in fact they should consider giving up driving altogether.

A more positive view

Despite its limitations and shortcomings, the Sentience project could point the way for the future and not just in terms of fuel and emission savings. One notable benefit seen with the semi-autonomous underground mining vehicles is the massive reduction in repair and maintenance bills (as much as 20-25 per cent). Because these vehicles operate at optimum levels under computer control, wear and tear to drivelines and tyres is significantly reduced. Given the way the Sentience prototypes operate, it is highly likely that similar cost savings would be seen. The semi-autonomous mining vehicles also last longer than conventional machines and again, an extended lifespan would be likely for the Sentience vehicle due to its more gentle operation under computer control. As providing raw materials and manufacturing account for up to 20 per cent of the emissions produced by each vehicle, this would in turn reduce its overall environmental footprint. The reduced running costs and extended life would certainly be strong selling points.

Clearly, a more sophisticated system is needed and one that requires greater research into the potential safety implications. Technology is advancing rapidly and the cost of the various systems will continue to decrease, making them more of a marketable solution in the future. Adding technology proven by industry would also help improve on the original concept. Just when a production version of the Sentience vehicle will be commercially viable remains to be seen.