Renault "Next Two"

Autonomous and connected driving

Developing electronics Systems for the vehicles of tomorrow 

The "Next Two” prototype is Renault’s vision of an autonomous car, which is likely to be launched in 2020 and is based on the electric production model, the Renault Zoé. The very first driver assistance systems were wired, but recent rapid advances in the field of electronics have made it possible to introduce completely new in-car connectivity functions, even in medium-sized models. The requirement was to develop a reliable system at a price suitable for volume production. Bertrandt was responsible for designing and implementing the software for the central control unit.

Based on assistance systems

The "Next Two” prototype can detect its environment using sensors that have been added to the basic version of the Zoé. The long-range radar sensor in the front bumper identifies the vehicles ahead, their speed and other obstacles over a distance of up to 200 metres. An infrared camera on the windscreen detects the road markings and helps to position the vehicle in its lane. The direct environment is evaluated by ultrasonic sensors all around the car. These are sensor models that are close to production readiness and have already been used in driver assistance systems. This means that they meet the requirements for cost-effectiveness.

Switching to autonomous driving

The driver can activate automated driving mode manually, if the car is on a motorway where there are no pedestrians or cyclists. The top speed is currently restricted to 30 km/h and the system will not make any automatic lane changes. These restrictions are designed to represent a traffic jam on a motorway or a city ring road. In autonomous mode, the driver can take over control again at any time. The "Next Two” will also suggest to the driver that it switches to autonomous mode if the conditions are right.

Short development times

Bertrandt designed and developed the software for the central control unit in the autonomous drive function. The overall development process focused on three functions: longitudinal guidance, lateral guidance and the control strategy. Bertrandt based the longitudinal guidance function, which is responsible for acceleration and deceleration, on an existing radar-based adaptive cruise control system and added braking and stopping functions to it. This allows the vehicle’s speed to be adapted depending on the road conditions, in particular by restricting the acceleration permitted on bends. One of the challenges involved using and integrating production components, most importantly the engine control units. These were not designed for use in an autonomous system, which meant that a particularly complex control function had to be developed.

The lateral guidance function is responsible for the vehicle’s electric steering. In this area, Bertrandt had full responsibility for the control algorithm. The aim was to develop a robust strategy which was not sensitive to brief interruptions or a temporary lack of sensor data. The overall control system, which brings together all the car’s control strategies, was defined using finite state machines. Particular attention was paid to developing the transitions between the states to ensure a smooth and flowing driving style. A fault management system and emergency functions were put in place for all three functions in order to ensure the safety of the car in all driving states and situations.

Despite the complexity of the system, the development of these functions took only nine months. The engineers provided services covering the entire V-model from the specifications to the functional testing on the road. The software was developed as a model-based design using Matlab Simulink. The concept phase required an MiL (modelin-the-loop) simulation environment to evaluate the dynamic driving style.

All the integration and validation phases were kept short by using an HiL rapid prototyping toolkit. Since the prototype was first built, a number of functions have been developed further. These include the lateral guidance function which will form the basis for the new lane departure warning system in the Renault’s latest models.

In brief

Electronics development

  • Body and interdisciplinary activities
  • Interior and exterior equipment
  • Chassis
  • Architecture
  • Electronics, electrics
  • Cost, quality and competitive analyses
  • Project management
  • Supplier management