Reinhard Seyer

Robust partitioning for reliable real-time systems

Summary form only given. Mechatronic systems request for high reliability, especially in the context of time where mostly hard real-time capabilities are mandatory. May be even stronger requirements regard the robustness against software failures and interdependences from erroneous tasks to others. We propose the concept of robust partitioning for reliable real-time embedded systems. The concept consists of two parts, memory space protection and time protection. Memory protection is realized by already existing hardware and software mechanisms. For realizing temporal protection, a two-step timer interrupt system realizing an imprecise computation concept is proposed: if the execution of a module exceeds a certain time limit before the deadline, the first timer interrupt is triggered and a backup routine is started to produce an imprecise result in the remaining time until the second timer expires. This time protection concept shows significant advantages as compared to classical approaches for single, parallel and distributed systems. We give an extended introduction into the concept and discussed first attempts for its realization.

Reliable event-triggered systems for mechatronic applications

Mechatronic systems most often require hard real-time behaviour of the controlling system. The standard solution for this kind of application is based on the time-triggered approach, and for certain circumstances the schedulability is provable. In contrast, this paper introduces an approach using some hardware enhancements that allow first to substitute the time-triggered system by an event-triggered system but conserving the reliability, second to enhance the event-triggered system by a two-level reaction system while conserving the hard real-time capabilities and third to combine tasks to improve even the worst-case behaviour. This results in a hard-time-but-weak-logic reaction system when computing time is tide but maintains full processing capabilities and therefore exact reaction values for all reactions whenever possible. This meets the goal of creating an event-triggered and reliable system approach. Combining two or more events to more than one combination will improve the theoretical schedulability of the system too, especially in the case when configurable computing elements are used.

Supporting the hard real-time requirements of mechatronic systems by 2-level interrupt service management

Mechatronic systems often require hard real-time behaviour of the controlling system. The standard solution for this kind of application is based on the time-triggered approach, and for certain circumstances the schedulability is provable. In contrast to this, the approach in this paper introduces some hardware enhancements that allow first to substitute the time-triggered system by an event-triggered system and second to enhance the event-triggered system by a two-level reaction system while conserving the hard real-time capabilities. This results in a hard-time-but-weak-logic reaction system when computing time is tide but maintains full processing capabilities and therefore exact reaction values for all reactions whenever possible. Combining two or more events will improve the theoretical schedulability of the system too.