Wolfgang Fengler

Electronic System Design Automation Using High Level Petri Nets

A design and implementation methodology for system specification, modelling and implementation using a special kind of high level Petri nets is described. Electronic system design automation tools are used to generate synthesizable VHDL code from a Petri net model. For the design of large systems with regular structures the use of coloured Petri nets will improve the handling and flexibility. Two design examples illustrate the described methodology.

Model-driven development and multiprocessor implementation of a dynamic control algorithm for nanopositioning and nanomeasuring machines

Abstract This article presents a computationally intensive adaptive trajectory tracking control algorithm for dynamic control of nanopositioning and nanomeasuring machines. To realize the required high sample rate of the control algorithm, an embedded multiprocessor architecture has been chosen as development target. The model-oriented development approach studied here aims to narrow the gap between the control system design environment MATLAB/Simulink® and the actual distributed implementation on the custom platform by introducing a custom code generation target intending the utilization of automatic code generation facilities.

GPU vs FPGA: Example Application on White Light Interferometry

High performance image processing applications area challenging field when targeting embedded processing. Field programmable gate arrays (FPGA) receive a growing interest as implementation platforms, but these solutions have to compete with the state of the art in image processing, which is codefined by graphics processing units (GPU). This paper provides a case study which analyzes the potential of embedded or hybrid implementation on FPGA and GPU for image stack processing in a white light interferometry (WLI) application.

LiSARD: LabVIEW Integrated Softcore Architecture for Reconfigurable Devices

The development of industrial control and measurement systems is often based on modular commercial off the-shelf hardware. Lately, for these platforms reconfigurable I/O modules with field-programmable gate arrays (FPGA) have gained significance, since they allow the implementation of data processing functionality very close to the data acquisition interfaces. However, algorithm complexity and floating-point support are limited by FGPA resources and design methods. This contribution presents an application specific configurable DSP soft core architecture built around a scalable double precision floating-point arithmetic/logic unit. The core can be seamlessly utilized as a functional component in Lab VIEW based FPGA designs. A small case study shows the performance of an example application implemented on the presented core in comparison to other embedded architectures.

Design of Embedded Control Systems Using Hybrid Petri Nets

The paper describes the challenges of modeling embedded hybrid control systems at a higher abstraction level. It discusses the problems of modeling and analyzing such systems and suggests the use of hybrid Petri nets and time interval Petri nets. Modeling an exemplary embedded control system with a special hybrid Petri net class using an object-oriented modeling and simulation tool and the extension of hybrid Petri nets with the concept of time intervals for analyzing time constraints shows the potential of this approach.

Advanced Assertion-Based Design for Mixed-Signal Verification

Functional and formal verification are important methodologies for complex mixed-signal design validation. However the industry is still verifying such systems by pure simulation. This process lacks on error localization and formal verifications methods. This is the existing verification gap between the analog and digital blocks within a mixed-signal system. Our approach improves the verification process by creating temporal properties named mixed-signal assertions which are described by a combination of digital assertions and analog properties. The proposed method is a new assertion-based verification flow for designing mixed-signal circuits. The effectiveness of the approach is demonstrated on a Σ/Δ-converter.

Development of real-time system specifications through the refinement of duration interval Petri nets

This paper aims at the development of an engineering technique for the construction of systems through the refinement of duration interval transitions. The theoretical system model is based on so-called interval time Petri nets. Duration interval transitions turn out to be a syntactical abbreviation for a certain structure of interval time Petri nets. The kind of refinement technique preserves the safety property and guarantees that the refined system behaves neither slower nor faster than the unrefined one. The application of our approach lies in the development of time correct system specifications.

Integrated system development process for high-precision motion control systems

A cost-efficient way to achieve high-accuracy motion control is the utilization of complex control algorithms. Hence advanced motion control constitutes a class of real-time applications, for which the technical feasibility strongly depends on the achievable execution performance on the embedded processing platform. The presented modular controller structure defines a set of advanced control algorithms able minimize the tracking error, even for friction affected kinematics. Transferring the controller design to an implementation-oriented modelling level focuses on minimizing the processing latency in order to realize the required high sample rate. The utilization or even the custom development of a parallel platform becomes inevitable, which is why it is necessary to integrate both, control and embedded platform development processes. The presented process includes controller design, platform mapping and architecture optimization to address the challenge of tailoring an application-specific modular embedded processing platform already on the modelling level before interfacing state-of-the-art tool chains.

Modeling of complex automation systems using colored State Charts

The design of complex distributed automation systems often presents great challenges due to the size and number of components which have to work in parallel to one another in real time. This paper discusses some of the problems of designing such systems. The use of colored dynamic state diagrams for the modeling of complex real-time systems is suggested as a possible solution. This type of diagram is based on State Charts, the well-known and generally applied description technique included as one variation in the unified modeling language. Colored State Charts harness two techniques: the modelling technique well accepted by engineers, and high level Petri nets with their outstanding powers of description. By coloring State Charts, the behaviour of several objects or processes can be modelled simultaneously in a single figure. The colored state diagrams contain a variety of resources to facilitate clear and unequivocal representation of the composition of a number of simple state diagrams. They also have additional mechanisms for mapping the dependencies and relationships between individual objects. Via transformation into colored Petri nets, they make formal verification possible. Their usability is shown in a modelled reference example.

Extending the Modeling Efficiency of the UML Activity Diagram for the Design of Distributed Systems

The design of complex distributed embedded systems often presents great challenges because of the large number and dimensions of their components. This research paper discusses some of the problems of designing such systems. The use of Colored Dynamic Activity Diagrams for modeling complex real-time systems is suggested as a possible solution. The Colored Activity Diagrams bridge a gap between modeling technique and description power of High Level Petri nets. By coloring Activity Diagrams the behavior of several objects or processes can be modeled in a single diagram. They also have additional mechanisms for mapping dependences and relationships between individual objects. The color is a property which supports the intended transformation into the High Level Petri Nets allowing further the formal verification of the whole system. The usability of the method is shown in a modeled reference example.