Can you develop a vehicle that can drive both cooperatively, that is, in a column with others, and autonomously? This is the central question of the research programme i-Cave, which started in 2015. Now, five years later, the answer is affirmative. This does not mean that there are no longer any hindrances or questions. For example, how do you set up the computer systems, and is it safe for cars to drive autonomously on public roads?
Self-driving vehicles hold great promise, but for 'normal traffic' the introduction of autonomous vehicles is still some way off. In the i-CAVE program, scientists, companies and governments joined forces five years ago to develop a vehicle that can drive autonomously on closed roads as well as cooperatively on public roads.
In the case of autonomous driving, the vehicles use information they collect themselves. If they partially or entirely obtain their information via other vehicles, then this is called cooperative driving.
"Originally, we sought a combination of cooperative and autonomous driving", says project leader Henk Nijmeijer, professor of Dynamics and Control at the department of Mechanical Engineering. "In the case of autonomous driving, the vehicles, or more accurately the algorithms that control the vehicles, use information they collect themselves. If they partially or entirely obtain their information via other vehicles, then this is called cooperative driving. In that case, the information improves the collective behaviour, which, amongst other things, improves the traffic flow. However, this does require the vehicles to communicate with each other via a wireless connection."
The research proposal was aimed at various aspects of autonomous and cooperative driving. Apart from safety, logistics and sensor technology, psychological and social aspects were also considered. All of these subjects were integrated later in the project.
safety
First, the research in the area of safety. That focused not just on avoiding errors in the software or the cars' observation system and, consequently, on preventing accidents due to these errors, says Nijmeijer. "It is also intended to increase the acceptance of cooperative and autonomous driving cars. If people feel unsafe, or if fellow road users do not trust these cars, then this will delay their introduction."
And this is where we come up against the practical limitations. Nijmeijer: "On public roads, driving in columns, also referred to as platooning, can be done safely, but that is definitely not yet the case for autonomous driving. For the time being, that can only be done in a controlled environment, such as a test location or a parking area, and not in the centre of a town because the traffic situation there is too complex."
Twizy
The researchers tested the operation of the developed algorithms in a number of vehicles at a test site in Eindhoven. Since last year, their small Renault Twizys at the location have been capable of driving in a column with an interval of no more than 0.3 seconds and following each other in bends. By way of comparison: the Dutch government advises an interval of 2 seconds and on the busy A2 motorway that is 0.9 to 1 seconds. The Renaults follow the leading car with the help of Cooperative Adaptive Cruise Control (CACC), which makes use of WiFi, radar, GPS and cameras.
COVID-19 regrettably disrupted plans for live demonstrations. The research incurred delays, and no physical meetings took place. "Fortunately, we could still carry out various tests thanks to the relentless efforts of the researchers and partners", says Nijmeier.
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About i-Cave
I-Cave (the acronym for integrated Cooperative Automated Vehicle) is a programme from Eindhoven University of Technology with support from a wide range of other parties. It was awarded four million euros in funding via the NWO Perspectief programme. Industry contributed more than one million euros.
To celebrate the succesful conclusion of i-Cave a symposium was held on November 4, 2021. At the event a book was presented, in which the researchers talk in detail about their research and the results.
Merging in a column
Challenges still remain for cooperative driving too. For example, how can other road users merge in while a column of lorries that are driving close to each other goes past?
Nijmeijer: "We have designed algorithms which facilitate that and consequently stimulate social behaviour: the lorries in a column make room for vehicles that want to merge in. It is an improvement on the current situation where lorries driven by people are often quite close to each other, so it is difficult for cars to merge in."
At present, driving in platoons is only possible if there is a driver in all of the participating vehicles: "We cannot yet guarantee that the system is always free of errors and so we must have a driver in each vehicle for the sake of safety. The computers can control the speed, and the distance between the vehicles but detecting mistakes is still something that only humans can do."
However, steps are being made in that area: "These include the improved flow of traffic and a reduced use of fuel for lorries, which accelerate and brake in a controlled manner and ride in each other's slipstream. Also, driving is less tiring, which could eventually lead to changes in the Driving Time Decree, which determines the maximum period of time a lorry driver may sit behind the wheel." But the Netherlands Vehicle Authority (RDW) would need to approve the technology: "The standards for this are largely still lacking."
Gaining people's trust
Then there is the research into psychological and social factors. More than fifteen researchers have been involved in this. Debargha Dey was the first to gain a doctorate studying this aspect of i-Cave. He mainly examined the fellow road users of autonomously driving vehicles: "What does a pedestrian or cyclist need to be able to trust the behaviour of such a vehicle if there is no driver and a lack of eye contact?"
Dey concluded
