Armin Sulzmann

Duo duplex drive-by-wire computer system

Abstract The integration of drive-by-wire systems into the future generations of vehicles requires a reliable and safe processing of the drivers input requests. Many approaches presented in the last years apply specialised control units as well as communication systems not available in high quantities. This results in cost-intensive systems and increasing developmental periods, which proves to be harmful in the highly competitive automotive sector. Therefore, this article describes a safety relevant controller composed of commercial-off-the-shelf components designed for automotive applications. The article explains the hardware structure consisting of four electronic control units (ECU), connected via the controller area network, constituting a duo duplex system. To stop the communication of faulty ECUs an additional hardware unit is included in the controller system—the so-called BUSPWR block. Beside the hardware a detailed description of the redundancy management is given, which is the software operating the redundant controller. Safety relevant software components have to meet requirements of high software quality standards. For this reason the last part of the article concentrates on the software development process and its supporting tool chain. The application of automated code generation for safety relevant drive-by-wire systems is discussed in detail.

Robots go automotive - the SPARC approach

This paper introduces a new concept for advanced driver assistance by means of a redundant architecture including all system components spanning from environment perception to vehicle controllers. The first part of this paper is an overview of the project framework and the research platforms. After that the elements of the architecture themselves will be described. The use of sensors and the fusion of their outputs will be presented. Different controllers will be used depending on the scenarios around the vehicle in order to provide a theoric solution. This solution will be downsized after that with a dynamic vehicle model to the feasible safe motion vectors. This list of motion vectors will be compared to the drivers command and will lead to the choose of his/her command or an other safe motion vector if the driver does not react convenient to the situation. The final part describes some preliminary results and concludes towards future work and research issues.

Redundancy Management for Drive-by-Wire Computer Systems

The integration of drive-by-wire systems into the future generations of vehicles requires a reliable and safe processing of the driver’s input requests. Many approaches presented in the last years apply specialized control units as well as communication systems not available in high quantities. This results in cost-intensive systems and increasing developmental periods, which proves to be harmful in the highly competitive automotive sector. Therefore this article describes a safety relevant control system composed of commercial-off-the-shelf (COTS) components designed for automotive applications. The paper explains the hardware structure consisting of four electronic control units (ECU), connected via CAN, which constitute a duo duplex system. Furthermore a detailed description of the redundancy management is given, which is the software operating the redundant computer system. Safety relevant software components have to meet requirements of high software quality standards. For this reason the last part of the paper concentrates on the software development process and its supporting tool chain. The application of automated code generation for safety relevant drive-by-wire systems is discussed in detail.

Improvement of the driving safety using a predictive vehicle dynamical model

This paper introduces a new concept for advanced driver assistance, which uses a predictive dynamical model of the vehicle in order to define the limits of the safe command for the vehicle. The first part of this document explains the needs of such predictive vehicle state models. Then the second part will describe the vehicle model based on transfer functions. Finally the use of this model will be explained on the last part and the possible extensions of the current methods will be pointed out.

Predictive curve anticipation

Parallel to assistant systems reacting to the close vehicle environment, it is necessary to provide a system, which can anticipate the road dynamics like stopping points or curves with small radius [1]. Indeed the vehicle safety is not only performed by looking for the current instant, but also by monitoring the speed and getting the possibility to decrease it in advance by taking into account the vehicle dynamics. In this paper, predictive curve anticipation will be described from sensors point of view and vehicle dynamics computation point of view. Its main task is to look at the curve ahead the vehicle by using both telematic platform with GPS and camera. The maximal safe speed for each point ahead will be defined by computing the maximal lateral force acceptable for the tires. From this maximal speed, the maximal safe acceleration will be extracted depending on the distance and the braking rate of the vehicle. Unfortunately if a crossing section appears ahead the vehicle, some doubts about the way chosen will be legitimated, and a Bayesian approach will be used to estimate which road will be taken and modulate correctly the speed.

Enhancing Reliability of Drive-by-Wire Control Units by Fault Compensation using Data Fusion

As future drive-by-wire systems have no mechanical fallback level, the increased safety requirements need to be met by software-based solutions. The task of the software is to provide services in the field of fault detection and compensation as well as control of redundant hardware structures. Particularly the implementation of fault detection and error correction avoids fatal output of drive-by-wire control units caused by erroneous input signals. This article describes the implementation of a module compensating faults in the input signals of a vehicle function, which controls the longitudinal dynamics of a truck. The error correction is achieved by means of data fusion. Sensing units consisting of the sensor as well as the preprocessing unit often are provided by external suppliers. In some cases information regarding the characteristics of their output data written on the CAN bus is not available. In order to avoid the time-consuming and costly acquisition of this information a method is presented allowing for the estimation of the data quality. This approach is based on the analysis of the time response, the information content and the estimation of the measurement noise variance of the CAN-data. The quality measures are incorporated in a fuzzy-weighted aggregation of the signals and a subsequent filtering with an information filter. This article describes how data fusion can be used profitably for the error compensation of fault-tolerant control systems. The estimation method of data characteristics introduced in this paper allows for a substitution of the erroneous signals with a marginal loss in quality. Additionally in the fault free case an improvement of the data quality regarding noise and dynamics can be achieved.

Software Architecture of Drive-by-Wire Computer Systems

Abstract Computer systems applied to drive-by-wire vehicles without mechanical backup have to meet high demands for reliability. In this article a software architecture designed for these systems is introduced. The so-called system management integrates the components of a fault-tolerant control system (FTCS) with the software operating the redundant hardware structure. Firstly the paper gives an overview of the system management. To offer insights into its realisation the second part concentrates on the fault compensation unit of the FTCS. It applies data fusion techniques using the redundant input information of the drive-by-wire system to compensate signal failures.