Ziele Untersuchung
mit Columbo Integrität von
Datenbanken Interaktion und
Portierbarkeit Ergonomie der
Schnittstellen

Angebot Produkte Projekt Beratung

Mittel Analytik Modellierung Sprachen Algebra Logik Hardware Denken Kreativität

Zusammenhänge Gesellschaft Wirtschaft Branche Firma


Quellcodebibliothek Statistik Leitseite products/sources/formale Sprachen/VDM/VDMRT/ChessWayRT/ (Wiener Entwicklungsmethode ^©) Datei vom 13.4.2020 mit Größe 2 kB

Quelle Wheel.vdmrt Sprache: VDM

% Wheel.vdmrt

\subsubsection{Closing the feedback loop -- the \texttt{Wheel} class}

The \texttt{Wheel} class is used to close the feedback loop in the environment model.
It computes the new acceleration, speed and angular position, whenever the
\texttt{evaluate} operation is called by the environment.

\begin{vdm_al}
class Wheel

values
  -- maximum angular acceleration is 20 pi rad/sec^2
  MAX_ACC : real = 62.8318531

instance variables
  -- the logical name of the wheel
  mName : seq of char;

  -- link to the environment
  mEnvironment : Environment;

  -- last evaluated at time step
  last : nat := 0;

  -- current angular acceleration
  public acc : real := 0.0;

  -- current angular speed
  public speed : real := 0.0;

  -- current angular position
  public position : real := 0.0

operations
  -- constructor for the wheel class
  public Wheel: seq of char * Environment ==> Wheel
  Wheel (pname, penv) == ( mName := pname; mEnvironment := penv);

  private isActuated: () ==> bool
  isActuated () ==
    return mEnvironment.getValue(mName^"_ACTUATED") = 1;

  private getPWM: () ==> real
  getPWM () ==
    return mEnvironment.getValue(mName^"_PWM");

  public evaluate: () ==> ()
  evaluate () ==
    ( dcl pwm       : real := if isActuated()
                              then getPWM()
                              else 0.0,
          old_acc   : real := acc,
          old_speed : real := speed,
          now       : nat  := time;
      -- compute the amount of time passed
      def dt = (now - last) / World`SIM_RESOLUTION in
        ( -- update the current wheel acceleration
          acc := MAX_ACC * pwm;
          -- update the wheel angular speed (Euler)
          speed := speed + 0.5 * dt * (old_acc + acc);
          -- update the wheel angular positiom (Euler)
          position := position + 0.5 * dt * (old_speed + speed);
          -- remember when we where executed
          last := now )  )

end Wheel
\end{vdm_al}

The \texttt{evaluate} operation first checks whether the \texttt{Wheel} is
actuated by the controller (it may be running in \texttt{<FREERUNNING>} mode).
If the motor is \texttt{<ACTUATED>}, then it will retrieve the current PWM
value from the environment, which has been set by the controller.
As a simple abstraction, the direct drive motor is considered ideal and a
simple linear response is created. The new acceleration is computed by
multiplying the PWM value with the maximum angular acceleration
of the motor. The angular speed and position are computed by integration
and double integration respectively, using the well-known Euler algorithm.

quality90%

¤ Dauer der Verarbeitung: 0.0 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.