Jacek Tkacz

FORMAL REASONING IN LOGIC DESIGN OF RECONFIGURABLE CONTROLLERS

The rigorous digital design of embedded Reconfigurable Logic Controller starts from hierarchical concurrent state machine model (HCSM), which has been formally derived from modular control interpreted Petri net. The colored tokens, arcs, places and transitions distinguish nested State Machine Modules. Colored coordination places, called doubles facilitate effective and flexible Petri net state encoding. The rule based on a textual logic description of the Petri net is accepted by the hardware description language VHDL and easily mapped into Field Programmable Gate Array macrocells. Several combinatorial procedures in formal digital design of logic controller are supported by formal reasoning in the monotone Gentzen calculus.

Logic design of structured configurable controllers

The paper is concentrated on behavioral and structural specification of reconfigurable logic controllers (RLC). The initial description is given as a hierarchical modular control interpreted Petri net. On the abstract level of the logic synthesis specification is written in propositional sequent language. Rapid modeling and synthesis in FPGA can be done directly from expressions, written in the hardware description language, for example in VHDL.

Design of Reconfigurable Logic Controllers

This bookpresents the original concepts and modern techniques for specification, synthesis, optimisation and implementation of parallel logical control devices. It deals with essential problems of reconfigurable control systems like dependability, modularity and portability. Reconfigurable systems require a wider variety of design and verification options than the application-specific integrated circuits. The book presents a comprehensive selection of possible design techniques. The diversity of the modelling approaches covers Petri nets, state machines and activity diagrams. The preferences of the presented optimization and synthesis methods are not limited to increasing of the efficiency of resource use. One of the biggest advantages of the presented methods is the platform independence, the FPGA devices and single board computers are some of the examples of possible platforms. These issues and problems are illustrated with practical cases of complete control systems. If you expect a new look at the reconfigurable systems designing process or need ideas for improving the quality of the project, this book is a good choice.g process or need ideas for improving the quality of the project, this book is a good choice.

Dual Simulation of Application Specific Logic Controllers Based on Petri Nets

The paper describes a new method of verification of the application specific logic controllers designed with use of Petri net. The method is oriented on behavioral simulation of post synthesis models. Two different method of logic synthesis are preformed for the same control algorithm described as Petri net. Then, obtained HDL models are used for dual simulation with result comparison. It allows to detect ambiguous construct in designed control algorithm.

Role of UML Modelling in Discrete Controller Design

The paper presents an application of UML technology in a discrete system development process. In the process at the analysis stage UML diagrams are fundamental tool. The outcome of this stage is a basis for formal models exploited at the design stage, where the design is symbolically verified and treated as a rule-based system. Two formal models of good graphical appeal are proposed: Petri nets and statechart diagrams. Both are heavily using Boolean expressions what makes that design can easily be implemented in modern programmable structures.

Unit testing-based approach for reconfigurable logic controllers verification

The paper presents unit testing-based approach to FPGA design in-circuit verification. Presented methodology is dedicated to modular reconfigurable logic controllers, but other ip-cores and systems can be verified as well. The speed and reproducibility of tests is key for rapid system prototyping, where the quality and reliability of the system is significance. Typically FPGA are programmed by means single (full) bitstream. Specific devices are able to be reconfigured partially. Usually the partial reconfiguration is a part of the design functionality. It enables the minimization of used resources or provides specific functionality like system adaptation. The paper presents the use of the partial reconfiguration as a toll for the designer. The unit testing approach well know form software engineering was adopted to modular logic controllers development. The simulation process results waveform files, the waveform can be used for synthesizable test bench generation.

Petri nets SM-cover based on heuristic coloring algorithm

In the paper, coloring heuristic algorithm of interpreted Petri nets is presented. Coloring is used to determine the State Machines (SM) subnets. The present algorithm reduces the Petri net in order to reduce the computational complexity and finds one of its possible State Machines cover. The proposed algorithm uses elements of interpretation of Petri nets. The obtained result may not be the best, but it is sufficient for use in rapid prototyping of logic controllers. Found SM-cover will be also used in the development of algorithms for decomposition, and modular synthesis and implementation of parallel logic controllers. Correctness developed heuristic algorithm was verified using Gentzen formal reasoning system.

Dual synthesis of Petri net based dependable logic controllers for safety critical systems

In the paper, implementation of application specific logic controller for safety critical systems by means of Petri nets is described. The solution is based on duplicated main control unit and results comparison from both units. The design process of algorithm with use of Petri net is common for both unit. The hardware duplication is obtained during dual synthesis process. This process uses two different logic synthesis methods to obtain two different architectures for both control units. Such design flow simplify the process of realization of safety critical logic controllers.

GENTZEN SYSTEM CALCULUS IMPLEMENTATION FOR SYMBOLIC MINIMALIZATION OF COMPLICATED LOGICAL EXPRESSIONS

Abstract The paper presents a practical application of Gentzen theorem proving system by means of an experimental computer tool, for the purpose of logic expressions normalization into the form similar to the Horn clauses. The initial expressions are described as complicated nested condition rules in general rule-based form “IF THEN”. Additionally the paper describes a particular kind of logic algorithms optimization and some possibilities of increasing of efficiency of the presented application, for the normalizing a great number of symbolic expressions.

Modeling and implementation of concurrent logic controllers with use of Petri nets, LSMs, and sequent calculus

The paper presentes the method of modeling and implementation of concurrent controllers. Concurrent controllers are specified by Petri nets. Then Petri nets are decomposed using symbolic deduction method of analysis. Formal methods like sequent calculus system with considered elements of Thelens algorithm have been used here. As a result, linked state machines (LSMs) are received. Each FSM is implemented using methods of structural decomposition during process of logic synthesis. The method of multiple encoding of microinstruction has been applied. It leads to decreased number of Boolean function realized by combinational part of FSM. The additional decoder could be implemented with the use of memory blocks.