This project was launched with the aim of modifying and equipping a production vehicle so that it can be used as a test platform for innovative control system functions. To enable automated operation, a drive-by-wire kit was installed in the vehicle. It makes it possible to drive defined and reproducible manoeuvres and thus systematically analyse the implemented AI-based control algorithms. In addition, the AFM utilises the advantages of semi-active suspension technology, making it a suitable test platform for vertical dynamic control applications. Another area of research is the interpretation of the vehicle's environment for the control of vehicle dynamics. With the help of various perception sensors and advanced machine learning methods (AI-based), the driving environment is processed and recorded in real time. This information is in turn integrated into the algorithms for chassis control and estimating the system status.
The vehicle is equipped with a large number of sensors to record the status and internal sensor values as well as environmental variables such as road conditions and the environmental scenario. The vehicle sensors are recorded synchronously on a rapid control prototyping system. For certain research projects, the collected data is uploaded to a cloud system that enables centralised and cross-vehicle control methods. The extensive measuring equipment transforms the vehicle into a powerful data collector that enables the development of new methods for condition estimation. For a simulative analysis with a digital twin, a true-to-the-original vehicle model is required. For this purpose, a multi-domain multi-body system (MBS) vehicle model was implemented in Modelica.
Components in the AFM
The AFM is equipped with the following sensors and powerful CPU and GPU systems:
Complete drive-by-wire kit (DBW) The drive-by-wire (DBW) kit enables steering, acceleration and braking to be controlled in real time, allowing the vehicle to be driven automatically. The system is seamlessly integrated into the vehicle electronics and the communication network and enables control of all standard actuators.
Powerful Rapid Control Prototyping (RCP) system The RCP system is a powerful platform that is optimised for use in vehicles. The system offers numerous interfaces for information transfer, e.g. several CAN and Ethernet connections as well as a multi-I/O card for generating and measuring analogue and digital signals. All control algorithms used to control the DBW kit run on this system. Centralised data logging with a cloud connection also takes place here.
Multi GPU supported AI computing platform The seven environment cameras and the two lidar sensors are connected to the powerful AI computing platform (GPU-based) to process their outputs (3D stereo, lane/sign/object recognition,...) and to record the data.
State-of-the-art perimeter camera system A total of seven high-resolution cameras (GMSL - RCCB) are mounted on the roof rack, which record the 360° environment fully synchronised in full resolution.
High-resolution lidar sensors Two 360° lidar sensors are mounted on the roof rack at the front of the vehicle to scan the surroundings and correlate the information with other sensors, e.g. the cameras or the radar.
Radar sensor system Up to three radar sensors are integrated into the front of the vehicle, which transmit the radar signatures to the AI computing platform, where seamless object detection and tracking is performed.
Customised semi-active damper control system The controlled semi-active dampers regulate the forces that influence the bodywork and wheel load fluctuations.
Non-contact road weather sensor The high-precision optical sensor continuously scans the road surface and records various parameters such as the surface temperature or the height of the water film.
High-precision IMU/GNSS system A high-precision 6D inertial measurement unit (IMU) is installed near the centre of gravity to record all parts of the vehicle's movement. Two roof antennas enable the combined use of the global navigation satellite system (GNSS).
Real-time measurement of drive torque and steering force via strain gauges A calibrated system of strain gauges is installed on the drive shafts and track rods. This allows drive torques and track rod forces to be measured during driving manoeuvres.
Optical speed sensor The optical sensor scans the road surface to measure the speed of the vehicle relative to the carriageway. Both the longitudinal and lateral speed can be precisely determined. These measurements are used to calculate the vehicle's slip angle.
Mobile internet access (4G) The vehicle network can be accessed via an LTE connection for changing controller parameters during runtime and remote monitoring of test drives. It is also possible to upload data in real time and connect to cloud-based applications.
Mobile base station for dGPS reception To increase the accuracy of the GPS measurements, a mobile differential GPS base station (dGPS) supplies correction data to the IMU/GNSS platform in the vehicle.
Intelligent power supply system (PDS) The PDS manages the power supply for all additional electrical components in the vehicle. Due to the large number of sensors and actuators installed, their power supply must be intelligently controlled.
As part of the AI For Mobility project, a hybrid production vehicle was chosen as the base platform as it has a fully wired vehicle architecture. As most prototype vehicles have the disadvantage that they are not road-legal, they can only be used on closed-off test sites. The AFM has a special road licence for certain operating modes and therefore has a wider range of possible applications in experiments on the public road network.
Contact
Dr. Jonathan Brembeck
Head of department
German Aerospace Center (DLR)
Institute for Vehicle Concepts
Vehicle System Dynamics and Control
Münchener Straße 20, 82234 Oberpfaffenhofen-Wessling
