Added ability to dynamically change thruster location via property

[hitchcock9307]

In vehicle's such as tiltrotors the rotor must be both translated (i.e. x_position = cos(theta)*rotor_height + base_x) and rotated, only the pitch-angle-rad is exposed via property and prevents scripting a tilt-rotor adequately.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 15 lines in your changes are missing coverage. Please review.

Project coverage is 24.95%. Comparing base (3c7582e) to head (ccac57f).
Report is 1 commits behind head on master.

Files	Patch %	Lines
src/models/propulsion/FGThruster.cpp	0.00%	12 Missing ⚠️
src/models/propulsion/FGForce.h	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1073      +/-   ##
==========================================
- Coverage   24.97%   24.95%   -0.03%     
==========================================
  Files         168      168              
  Lines       18057    18072      +15     
==========================================
  Hits         4510     4510              
- Misses      13547    13562      +15     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[seanmcleod]

I kicked off the build and test checks. No need to worry about the MacOSX-14 error about not finding Julia.

[hitchcock9307]

Thanks! Anything else I have to do to get this through? Coverage? I intend to contribute documentation and code in the future to this project so I would like to become familiar with your processes. Thanks!

[bcoconni]

Hi @hitchcock9307,

I'd suggest you also add properties for FGForce::GetActingLocation[XYZ] and FGForce::SetActingLocation[XYZ] to implement your feature request in the same way than FGPropeller does:

jsbsim/src/models/propulsion/FGPropeller.cpp

Lines 269 to 271 in 3c7582e

	double factor = Sense * P_Factor * angle / tangentialVel;
	SetActingLocationY( GetLocationY() + factor * localAeroVel(eW));
	SetActingLocationZ( GetLocationZ() + factor * localAeroVel(eV));

The idea is that you would have a reference point (that is named base_x in your original post) that never changes and that it would be the acting point that would be modified. This would give something like:

  property_name = base_property_name + "/x-reference-position";
  PropertyManager->Tie(property_name.c_str(), (FGForce*)this, &FGForce::GetLocationX);
  property_name = base_property_name + "/y-reference-position";
  PropertyManager->Tie(property_name.c_str(), (FGForce*)this, &FGForce::GetLocationY);
  property_name = base_property_name + "/z-reference-position";
  PropertyManager->Tie(property_name.c_str(), (FGForce*)this, &FGForce::GetLocationZ);
  property_name = base_property_name + "/x-position";
  PropertyManager->Tie(property_name.c_str(), (FGForce*)this, &FGForce::GetActingLocationX, &FGForce::SetActingLocationX);
  property_name = base_property_name + "/y-position";
  PropertyManager->Tie(property_name.c_str(), (FGForce*)this, &FGForce::GetActingLocationY, &FGForce::SetActingLocationY);
  property_name = base_property_name + "/z-position";
  PropertyManager->Tie(property_name.c_str(), (FGForce*)this, &FGForce::GetActingLocationZ, &FGForce::SetActingLocationZ);

This would allow to use your formula x_position = cos(theta)*rotor_height + base_x without the need to hardcode base_x in your FCS.

<function name="rotor1/tilt-command-x">
  <sum>
    <property>propulsion/engine[0]/x-reference-position</property>
    <product>
      <property>propulsion/engine[0]/rotor-height-in</property>
      <cos>
        <property>propulsion/engine[0]/pitch-angle-rad</property>
      </cos>
    </product>
  </sum>
  <output>propulsion/engine[0]/x-position</output>
</function>

Note that for this code to compile, you'd need to change the signature of the methods FGForce::SetActingLocation[XYZ] in src/models/propulsion/FGForce.h:

-  inline double SetActingLocationX(double x) {vActingXYZn(eX) = x; return x;}
+  inline void SetActingLocationX(double x) {vActingXYZn(eX) = x; }
-  inline double SetActingLocationY(double y) {vActingXYZn(eY) = y; return y;}
+  inline void SetActingLocationY(double y) {vActingXYZn(eY) = y; }
-  inline double SetActingLocationZ(double z) {vActingXYZn(eZ) = z; return z;}
+  inline void SetActingLocationZ(double z) {vActingXYZn(eZ) = z; }

[hitchcock9307]

Excellent recommendation, that will help clean up the XML implementation; changed.

[bcoconni]

Looks good to me.