Citation
Hilding Elmqvist. "Synchronous Control and State Machines in Modelica". Talk or presentation, 27, November, 2012.

Abstract
The scope of Modelica has been extended from a language primarily intended for physical systems modeling to modeling of complete systems by allowing the modeling of control systems and by enabling automatic code generation for embedded systems. Much focus has been given to safe constructs and intuitive and well-defined semantics. The presentation will describe the fundamental synchronous language primitives introduced for increased correctness of control systems implementation. The approach is based on associating clocks to the variable types. Special operators are needed when accessing variables of another clock. This enables clock inference and increased correctness of the code since many more checks can be done during translation. Furthermore, the sampling period of a clocked partition needs to be defined only at one place (either in absolute time or relatively to other clocked partitions). The principles of partitioning a system model into different clocks (continuous, periodic, non-periodic, multi-rate) will be explained. The new language elements follow the synchronous approach. They are based on the clock calculus and inference system of Lucid Synchrone. However, the Modelica approach also uses multi-rate periodic clocks based on rational arithmetic and also non-periodic and event based clocks are supported. Parallel and hierarchical state machines will be introduced including submodels within states. The supporting Modelica library will also be introduced.

Electronic downloads

• dreams-elmqvist-nov-2012.pdf · application/download · 329 kbytes

• HTML

  Hilding Elmqvist. <a
  href="http://chess.eecs.berkeley.edu/pubs/956.html"
  ><i>Synchronous Control and State Machines in
  Modelica</i></a>, Talk or presentation,  27,
  November, 2012.

• Plain text

  Hilding Elmqvist. "Synchronous Control and State
  Machines in Modelica". Talk or presentation,  27,
  November, 2012.

• BibTeX

  @presentation{Elmqvist12_SynchronousControlStateMachinesInModelica,
      author = {Hilding Elmqvist},
      title = {Synchronous Control and State Machines in Modelica},
      day = {27},
      month = {November},
      year = {2012},
      abstract = {The scope of Modelica has been extended from a
                language primarily intended for physical systems
                modeling to modeling of complete systems by
                allowing the modeling of control systems and by
                enabling automatic code generation for embedded
                systems. Much focus has been given to safe
                constructs and intuitive and well-defined
                semantics. The presentation will describe the
                fundamental synchronous language primitives
                introduced for increased correctness of control
                systems implementation. The approach is based on
                associating clocks to the variable types. Special
                operators are needed when accessing variables of
                another clock. This enables clock inference and
                increased correctness of the code since many more
                checks can be done during translation.
                Furthermore, the sampling period of a clocked
                partition needs to be defined only at one place
                (either in absolute time or relatively to other
                clocked partitions). The principles of
                partitioning a system model into different clocks
                (continuous, periodic, non-periodic, multi-rate)
                will be explained. The new language elements
                follow the synchronous approach. They are based on
                the clock calculus and inference system of Lucid
                Synchrone. However, the Modelica approach also
                uses multi-rate periodic clocks based on rational
                arithmetic and also non-periodic and event based
                clocks are supported. Parallel and hierarchical
                state machines will be introduced including
                submodels within states. The supporting Modelica
                library will also be introduced. },
      URL = {http://chess.eecs.berkeley.edu/pubs/956.html}
  }
  

Posted by David Broman on 13 Dec 2012.
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