Synthesis of Discrete-Event Controllers Based on the Signal Environment

In this paper, we present the integration of controller synthesis techniques in the SIGNAL environmentthrough the description of a tool dedicated to the incrementalconstruction of reactive controllers. The plant is specifiedin SIGNAL and the control synthesis is performed ona logical abstraction of this program, named polynomial dynamicalsystem (PDS) over ℤ/3ℤ{−1,0,+1}. The control of the plant is performedby restricting the controllable input values with respect tothe control objectives. These restrictions are obtained by incorporatingnew algebraic equations into the initial system. This theorysets the basis for the verification and the controller synthesistool, SIGNAL. Moreover, we present a tool developedaround the SIGNAL environment allowing the visualizationof the synthesized controller by an interactive simulation ofthe controlled system. In a first stage, the user specifies in SIGNAL both the physical model and the control objectivesto be ensured. A second stage is performed by the SIGNAL compiler which translates the initial SIGNAL programinto a PDS, and the control objectives in terms of polynomialrelations/operations. The controller is then synthesized using SIGNAL. The result is a controller coded by a polynomialand then by a Ternary Decision Diagram (TDD). Finally, in a thirdstage, the obtained controller and some simulation processesare automatically included in the initial SIGNAL program.It is then sufficient for the user to compile the resulting SIGNAL program which generates executable code ready for simulation.Different academic examples are used to illustrate the applicationof the tool.