jsbsim.js/JSBSim/aircraft/p51d/Systems/autothrottle.xml

JSBSim flight dynamics model ported to JavaScript

<?xml version="1.0"?> 

<system name="Autothrottle">

    <!-- INTERFACE PROPERTIES -->
    <property value="0.0">ap/ap_map_hold</property>
    <property>ap/throttle-cmd-norm</property>
    
    <!-- INITIAL GAIN and control VALUES -->

    <property value="0.05"> ap/map-pid-kp </property>
    <property value="0.1"> ap/map-pid-ki </property>
    <property value="0.00625"> ap/map-pid-kd </property>
    <property value="1"> ap/throttle-gain </property>
    <property value="25.0"> ap/lag_constant </property>
    <property value="75"> ap/max_MP </property>

    <!--
    =====================================================

    MANIFOLD PRESSURE CHANNEL 
    
    Implements the RR Merlin engine monifold control system. 

    =====================================================
    -->     

    <!-- Manifold Pressure hold -->

    <channel name="Manifold pressure hold">
    
    
       <!-- deal with corner cases -->
       <switch name="ap/ap_map_trigger">
          <default value="0.0"/>
          
          <!-- disable pid if engine not running -->
          <test value="1.0">  
              propulsion/engine/set-running == 0
          </test>
          
          <!-- disable pid if target-mp < actual mp and butterfly fully closed -->
          <test LOGIC="AND" value="1.0">
             ap/map-error LT 0.0
             fcs/throttle-pos-norm LE 0.001
          </test>
          
          <!-- disable pid if target-mp > actual mp and butterfly fully open -->
          <test logic="AND" value="1.0">
             ap/map-error GT 0.0
             fcs/throttle-pos-norm GT 0.99
          </test>  
       </switch>

        <!--
            The difference between the desired manifold pressure and the actual 
            manifold pressure is determined.
            
            systems/engine/target-mp-inhg is defined and set in the propulsion module
        -->

        <summer name="ap/map-error">
            <input> systems/engine/target-mp-inhg </input> 
            <input> -/engines/engine/mp-inhg </input>
            <clipto>
               <min>-ap/max_MP </min>
               <max> ap/max_MP </max>
            </clipto>
        </summer>

        <!--
           The desired MP is lagged slightly for stability.
        -->

        <lag_filter name="ap/map-error-lag">
            <input> ap/map-error </input>
            <c1> ap/lag_constant </c1>
        </lag_filter>

        <!--
            If the MP autopilot command is ON, then this switch component will
            pass through the MP error (from the previous component). Otherwise, it
            will pass zero.    On this engine it is on by default and is only over riden
            if the automatic system fails.
        -->

        <switch name="ap/map-switch">
            <default value="0.0"/>
            <test value="ap/map-error-lag">
                ap/ap_map_hold == 0
            </test>
        </switch>
        
        <pid name="ap/map-error-pid">
            <input>ap/map-switch</input>
            <kp> ap/map-pid-kp </kp>
            <ki> ap/map-pid-ki </ki>
            <kd> ap/map-pid-kd </kd>
            <trigger> ap/ap_map_trigger </trigger>
        </pid>

        <pure_gain name="ap/throttle-cmd-out">
            <input> ap/map-error-pid </input>
            <gain> ap/throttle-gain </gain>
            <clipto>
              <min> 0</min>
              <max> 1</max>
            </clipto>
            <output>ap/throttle-cmd-norm</output>
        </pure_gain>      

   </channel>
</system>