Carsten Rust

Pr/T-Net Based Seamless Design of Embedded Real-Time Systems

During the last years we have been working towards a complete design method for distributed embedded real-time systems. The main characteristic of the methodology is that within the critical phases of analysis and synthesis the system under development is available in one unique model, that of extended Pr/T-Nets. Among several other reasons we have chosen a high-level Petri Net model in order to benefit from the multitude of analysis and synthesis methods for Petri Nets. Even though the methodology is based upon one common model, it nevertheless supports the modeling of heterogeneous systems using different specification languages. The methodology was introduced and described in several former publications. In this paper we therefore only give a brief overview and afterwards go into details of our recent work, namely the transformation of proper Pr/T-Net-models into synchronous languages, the partitioning of Pr/T-Nets and an OS-integrated execution engine for Pr/T-Nets.

Using mini robots for prototyping intersection management of vehicles

In this paper, an environment for prototyping algorithms for the autonomous intersection management of vehicles is presented. It is based on a colony of Khepera mini robots that cooperate via radio communication to enable a collision-free passing of an intersection. The design of the environment, a simple distributed algorithm, and results from first experiments are described. Compared to other work, multiple robots can pass the intersection simultaneously.

Petri Net Based Design of Reconfigurable Embedded Real-Time Systems

During the last years we have developed a methodology for the design of complex embedded real-time systems. The methodology supports the complete design flow reaching from modeling of embedded systems on a high level of abstraction over simulation and analysis down to the implementation on target platforms. In this paper, we describe our current work, which aims at opening the methodology for dynamically reconfigurable systems. We describe the main ideas for extending our formal model of High-Level Petri Nets in order to capture these systems. Furthermore, we describe our approach for timing analysis of these systems.

A Petri Net Approach for The Design of Dynamically Modifiable Embedded Systems

A Petri net based approach for modeling dynamically modifiable embedded realtime systems is presented. The presented work contributes to the extension of a Petri net based design methodology for distributed embedded systems towards the handling of dynamically modifiable systems. Extensions to the underlying high-level Petri net model are introduced that allow for dynamic modifications of a net at run time.

From high-level Petri nets to SystemC

The paper introduces an approach for realizing high-level Petri net-models in SystemC. The presented approach contributes to an existing methodology for the Petri net-based design of distributed embedded real-time systems. It is intended to be a vehicle for realizing Petri net-components in hardware. The paper describes the use of standard SystemC language constructs to realize the firing of a high-level Petri net, which is assumed to be separated into partitions. The execution includes for instance the execution of single transitions, the handling of conflicting transitions, the realization of transition delays and the communication between Petri net-components realized in different partitions. Besides techniques for realizing these mechanisms, the integration of the code generation into the overall design flow is discussed.

Design of intelligent mechatronical systems with modifiable behaviors

We present and extend an approach for the integration of reinforcement learning methods into Petri net based specifications of autonomous behaviors. The work aims at the design of autonomous mechatronical systems with modifiable adaptive behavior and our extension handles the required modifiability. In order to combine Petri nets and learning methods, we modeled Q-learning - a variant of reinforcement learning - with high-level Petri nets. The result can be integrated into Petri net models of autonomous mechatronical systems. For an evaluation of our approach, we have implemented a realistic application example. It has been evaluated by simulation as well as on a physical system

Integrated Design and Simulation of Hybrid Systems

In this article we present a new approach for the design of hybrid systems composed of discrete and continuous parts. In our approach the system designers can start their specifications with the discrete as well as with the continuous parts. Both paradigms can be used with there own methodology and Tools. There are integration mechanisms for both paradigms. For the integrated simulation C code is generated. The advantages of our approach are demonstrated by modeling all important aspects of a system for building up motorcades. The model includes a discrete part selecting one of the different strategies modeled in the continuous parts. These are strategies for velocity and distance control for vehicles.

From high-level specifications down to software implementations of parallel embedded real-time systems

In this paper we describe a methodology and accompanying tool support for the development of parallel and distributed embedded real-time system software. The presented approach comprises the complete design flow from the modeling of a distributed controller system by means of a high-level graphical language down to the synthesis of executable code for a given target hardware, whereby the implementation is verified to meet hard real-time constraints. The methodology is mainly based upon the tools SEA (system engineering and animation) and CHaRy (the C-LAB Hard Real-Time System).

Petri net based design of a multi-robot scenario - a case study

In the paper, we describe the realization of an application scenario with Khepera minirobots. The scenario is a decentralized intersection management, where several Kheperas move trough two intersecting lanes without collisions. The application is realized based on a Petri net based methodology for the seamless design of distributed embedded real-time systems. Hence, the presented work brings together results from two different research areas: robotic applications and embedded systems design.

Automatic Synthesis of SystemC-Code from Formal Specifications

The paper presents an approach for realizing high-level Petri net models in SystemC. The approach contributes to an existing methodology for the Petri net based design of distributed embedded real-time systems. It is intended to be a vehicle for realizing Petri net components in hardware. The paper describes the use of standard SystemC language constructs to realize the execution of a high-level Petri net, which is assumed to be separated into partitions. Besides techniques for realizing the mechanisms of Petri net execution, the integration of the code generation into the overall design flow is discussed. To demonstrate the effectiveness of our approach we use the inverse discrete cosine transformation (IDCT) that is part of the MPEG-2 algorithm.