The LARA team research subject cover all the technical elements which can lead to a better road transportation system. This research is financed by our two public organisations as well as industrial contracts and contracts with the French state or the European Commission.
The technological agenda concerns all the elements of what is now considered as ITS (Intelligent Transportation System) although we focus on road applications.
While most of our work consists in technological developments, the LARA team is also focused on demonstration activities to present the possibilities of future technologies to the potential users and to the industry. We also insist on technological transfer to speed up the introduction of the new technologies through active cooperation with industry, personnel training and transfer, license agreements and through the creation of start-up companies.
The first step in the design of a control system are sensors and the information we want to extract from them, either for driver assistance or for fully automated guided vehicles. We put aside the internal sensors which are rather well integrated. Internal sensors give information on the host vehicle state, such as its velocity and steering angle information. The necessary information from external sensors (Laser, Radar, image sensors, etc) are of several types:
- localization of the vehicle with respect to the infrastructure using digital maps and GPS plus inertial navigation and landscape feautures; - lateral positioning on the road is obtained by mean of vision (lane markings) or by mean of magnetic, optic or radar devices; - localization of the surrounding vehicles and determination of their behaviour is obtained by a mix of vision, laser or radar; - detection of obstacles other than vehicles: pedestrians, animals, objects on the road etc. that require many types of sensors.
Since INRIA is very involved in image processing, LARA emphasizes the vision technique, particularly stereo-vision, in relation with MIT and ENSMP. A new approach using an evolutionary approach has been developed (the “Fly algorithm”).
The next research problem is the multi-sensor data fusion system consisting of a set of internal and external sensors which information is fused within one data fusion unit. The different sensor processing units deliver processed information about the road geometry (curvature, etc.). They also deliver information about relevant objects detected in the vicinity of the vehicle. The fusion involves, as its name implies, the processing of various information coming from different sensors, apart from providing different coverage, can detect the same object, but with differing accuracy of the parameters (for istance, range and angle) describing that object. This information is complementary, and leads to a measurement of higher integrity, accuracy and confidence. In addition to this, certain sensors may see information “invisible” to other sensors, such as video's ability to locate road markings. This too assists in improving the positioning of objects with respect to the real-world, rather than the subject vehicle.
Since LARA aims at integrating different techniques into real-world vehicles, it is implied into the development of data fusion work packages, i.e. in the CARSENSE project.
The task is to develop a command system designed to execute at best the orders given by either the driver (aided by the system) or the automated driving system. The command system sends orders to the mechanical parts of the vehicles using all the information raised by the sensors. For example, one can imagine a steering system that acts not only on the wheels angle through the steering wheel but also on the brakes of each wheel. This would yield a much more secure behaviour of the vehicle.
The real difficulty with this kind of control comes from the complexity of the dynamic behaviour of the vehicle: response are highly non linear, particularly the response to forces of the tires on various soils. INRIA has a great expertise in these control problems and LARA already demonstrated solutions for automatic driving of platoons of electrical cars. These research is still an active field. We want to enhance the system concerning the speed, the variety of wheel-soil contact. The lateral control problem is also studied, particularly in view of drivers assistance.
Another aspect of command systems is to generate correct trajectories which is another field of expertise for INRIA. These problems deal with obstacle avoidance or with generating complex trajectories in constrained environment (e.g. the parking problem).
The demand of transportation is still growing at a fast rate. Even if some big cities try to limit the use of cars, there must be alternate transportation means, e.g. metro, taxi, bus, etc. The challenge to the community and for the research is to propose plan for the long term and solutions for the integration of the new techniques into the real world. Since the problem of transportation (and particularly of cars) is most acute in cities, this is the place where we concentrate our research effort. Of course some system could be then transposed into medium-sized cities or into the countryside.
There are 4 steps to achieve a good transportation system:
There are several fields where system modelling and management are applied.
Better use of existing infrastructure and vehicles One of the great challenge of automobile industry and of cities administrations in the next years is to integrate cars in a saturated environment (traffic congestion, parking…). Research is currently done on regulation methods such as passage toll, car park toll, users information and multi-modality. This is a very topical theme as illustrated by London toll zone. This implies modelling the traffic in urban areas, modelling the behaviour of drivers and measure by mathematical analysis or on simulations the results of various scenario and eventually optimising parameters (toll, etc.).
Real time infrastructures management is also a problem of resources optimisation but a dynamic one. The question is to control accesses to avoid saturation phenomena which could make fall the performances of the system. Studies should be led on real cases, such as for example a by-pass in Paris area.
With new infrastructures, the problem is to redesign the city transportation system and to measure the improvement linked to another kind of management. Since the space is very rare in central areas, deploying new infrastructures(e.g. tramway) often means replacing part of the existing infrastructures (e.g. roads). This can only properly done when the impact of new infrastructure has been well designed, which means, as for the optimisation of existing infrastructures, measuring, modelling and optimising.
With the automated road, problems to be treated relate primarily to the dimensioning of the infrastructures and the management of these infrastructures. Dimensioning can be approached by techniques of stochastic modelling at the microscopic level or more traditionally by techniques of operational research. LARA already used successfully these techniques for Praxitèle program and account to develop them within the framework of the automated road to provide tools which will make it possible to justify (or to invalidate) the investments.
Communications will obviously play an essential part in ground transportation in a very near future and this is even truer for automated road. Communications are indeed probably essential between close vehicles and between each vehicle and the infrastructure.
The traditional means of communication which are primarily in point-to-point mode or diffusion mode, do not seem adapted to the automated road. It seems that modes in hierarchical networks as for data processing would be better adapted to the problem. INRIA started to work on Ethernet type radio networks and with mobiles i.e. with a dynamic routing (OLSR protocol).
The research is now also focused on the coordination between several vehicles using communication. Already, an experiment has been conducted with 3 vehicles which arrive simultaneously at an intersection. Through communication of their exact position and through simple rules, they have to decide in which order to proceed through the intersection. The nextstep will be to do the same manoeuvre at high speed. Already, theoretical work has been conducted to find how to control the speed of a vehicle to prevent the collision with other intersecting vehicles if we know their speed vector.
Data processing will play an essential part — even critical — for the safety of automated guided vehicles or even for simply secured vehicles. It is thus of primary importance to minimize hardware or software failures and their consequences. For that, it became essential to bring new techniques of programmong and certification. These work are already largely begun with INRIA and with the Ecole des Mines (Language ESTEREL and SynDEx) but the context of the automated road is even more critical than many applications than we try to approach. LARA thus proposes to continue the development of its certification and programming tools ORCCAD and SynDEx in this automobile context i.e. in a very distributed — and thus necessarily redundant — environment.