A control theory approach for analyzing the effects of data errors in safety-critical control systems

Computers are increasingly used for implementing control algorithms in safety-critical embedded applications, such as engine control, braking control and flight surface control. Addressing the consequent coupling of control performance with computer related errors, this paper develops a composite computer dependability/control theory methodology for analyzing the effects data errors have on control system dependability. The effect is measured as the resulting control error (defined as the difference between the desired value of a physical properly and its actual value). We use maximum bounds on this measure as the criterion for control system failure (i.e., if the control error exceeds a certain threshold, the system has failed). In this paper we a) present suitable models of computer faults for analysis of control level effects and related analysis methods, and b) apply traditional control theory analysis methods for understanding the effects of data errors on system dependability An automobile slip-control brake-system is used as an example showing the viability of our approach. © 2002 IEEE

A Control Theory Approach for Analyzing the Effects of Data Errors in Safety-Critical Control Systems

Computers are increasingly used for implementing control algorithms in safety-critical embedded applications, such as engine control, braking control and flight surface control. Addressing the consequent coupling of control performance with computer related errors, this paper develops a composite computer dependability/control theory methodology for analyzing the effects data errors have on control system dependability. The effect is measured as the resulting control error (defined as the difference between the desired value of a physical properly and its actual value). We use maximum bounds on this measure as the criterion for control system failure (i.e., if the control error exceeds a certain threshold, the system has failed). In this paper we a) present suitable models of computer faults for analysis of control level effects and related analysis methods, and b) apply traditional control theory analysis methods for understanding the effects of data errors on system dependability An automobile slip-control brake-system is used as an example showing the viability of our approach

Réseau de communication à haut niveau d'intégrité pour des systèmes de commande-contrôle critiques intégrant des nappes de microsystèmes

Vu le développement important des micro-systèmes, leur utilisation sous forme de nappes dans les systèmes de commande-contrôle critiques est incontournable. Cela soulève néanmoins des défis, parmi lesquels la définition d'un système de communication à haut niveau d'intégrité. L'étude que nous avons effectuée sur des réseaux standard montre que les protections classiques à base de codes CRC ne permettent pas d'obtenir le niveau d'intégrité visé. Pour l'atteindre, nous avons proposé une solution originale - fonction de contrôle évolutive - qui tire profit du fait que, pour les systèmes de commande-contrôle envisagés (systèmes à dynamique lente), l'intégrité est à considérer sur un lot de messages et non un seul message. La solution proposée a ensuite été validée via des simulations Matlab-Simulink. Le cas d'étude utilisé est celui de systèmes de commande de vol du futur, en vue de pouvoir commander des nappes de milliers de micro-surfaces tels que des micro-spoilers. ABSTRACT : With the wide development of microsystems, it is likely that they will be massively used in critical control systems. This raises many new challenges, among which the definition of a dependable communication network with high integrity level. The study of standard communication networks and their basic commonly used transmission errors detection techniques based on CRC codes shows that they cannott ensure the required integrity level. To reach this integrity level, we propose an original solution - an evolutive error control function - based on the slowly evolution characteristic of the control systems considered, for which the integrity is considered for a set of consecutive messages and not for a single message. The validation of the proposed solution is based on MATLAB simulation models we have developed. The study case is about the integration of thousands of micro-surfaces such as micro-spoilers in future flight control systems