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JSBSim: revised arrestor wire handling.

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Change the arrestor wire handling as follows;

- expose property to indicate when arrestor wire has been snagged: /fdm/jsbsim/systems/hook/arrestor-wire-engaged-hook
- add property to allow the model to request that the wire is released: /fdm/jsbsim/systems/hook/tailhook-release-cmd. This permits an overspeed approach to catch the wire and then drop it.
This commit is contained in:
Richard Harrison 2018-01-04 03:53:40 +01:00
parent 2f84be16f9
commit 97c1b34fa5
2 changed files with 41 additions and 29 deletions
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66
src/FDM/JSBSim/JSBSim.cxx
View file

@ -155,7 +155,7 @@ std::map<std::string,int> FGJSBsim::TURBULENCE_TYPE_NAMES;
static FGTurbulenceSeverityTable TurbulenceSeverityTable;
FGJSBsim::FGJSBsim( double dt )
: FGInterface(dt), got_wire(false)
: FGInterface(dt)
{
bool result;
if( TURBULENCE_TYPE_NAMES.empty() ) {
@ -335,7 +335,9 @@ FGJSBsim::FGJSBsim( double dt )
ab_brake_engaged = fgGetNode("/autopilot/autobrake/engaged", true);
ab_brake_left_pct = fgGetNode("/autopilot/autobrake/brake-left-output", true);
ab_brake_right_pct = fgGetNode("/autopilot/autobrake/brake-right-output", true);
arrestor_wire_engaged_hook = fgGetNode("/fdm/jsbsim/systems/hook/arrestor-wire-engaged-hook", true);
release_hook = fgGetNode("/fdm/jsbsim/systems/hook/tailhook-release-cmd", true);
altitude = fgGetNode("/position/altitude-ft");
temperature = fgGetNode("/environment/temperature-degc",true);
pressure = fgGetNode("/environment/pressure-inhg",true);
@ -1456,8 +1458,7 @@ void FGJSBsim::update_external_forces(double t_off)
FGColumnVector3 hook_tip_body = hook_root_body;
hook_tip_body(1) -= hook_length * cos_fi;
hook_tip_body(3) += hook_length * sin_fi;
if (!got_wire) {
if (!arrestor_wire_engaged_hook->getBoolValue()) {
double contact[3];
double ground_normal[3];
double ground_vel[3];
@ -1513,31 +1514,40 @@ void FGJSBsim::update_external_forces(double t_off)
}
}
} else {
FGColumnVector3 hook_root_vel = Propagate->GetVel() + (Tb2l * (Propagate->GetPQR() * hook_root_body));
double wire_ends_ec[2][3];
double wire_vel_ec[2][3];
get_wire_ends_ft(t_off, wire_ends_ec, wire_vel_ec);
FGColumnVector3 wire_vel_1 = Tec2l * FGColumnVector3(wire_vel_ec[0][0], wire_vel_ec[0][1], wire_vel_ec[0][2]);
FGColumnVector3 wire_vel_2 = Tec2l * FGColumnVector3(wire_vel_ec[1][0], wire_vel_ec[1][1], wire_vel_ec[1][2]);
FGColumnVector3 rel_vel = hook_root_vel - (wire_vel_1 + wire_vel_2) / 2;
if (rel_vel.Magnitude() < 3) {
got_wire = false;
if (release_hook->getBoolValue()) {
release_wire();
fgSetDouble("/fdm/jsbsim/external_reactions/hook/magnitude", 0.0);
arrestor_wire_engaged_hook->setBoolValue(false);
release_hook->setBoolValue(false);
} else {
FGColumnVector3 wire_end1_body = Tl2b * Location.LocationToLocal(FGColumnVector3(wire_ends_ec[0][0], wire_ends_ec[0][1], wire_ends_ec[0][2])) - hook_root_body;
FGColumnVector3 wire_end2_body = Tl2b * Location.LocationToLocal(FGColumnVector3(wire_ends_ec[1][0], wire_ends_ec[1][1], wire_ends_ec[1][2])) - hook_root_body;
FGColumnVector3 force_plane_normal = wire_end1_body * wire_end2_body;
force_plane_normal.Normalize();
cos_fi = DotProduct(force_plane_normal, FGColumnVector3(0, 0, 1));
if (cos_fi < 0) cos_fi = -cos_fi;
sin_fi = sqrt(1 - sqr(cos_fi));
fi = atan2(sin_fi, cos_fi) * SG_RADIANS_TO_DEGREES;
fgSetDouble("/fdm/jsbsim/external_reactions/hook/x", -cos_fi);
fgSetDouble("/fdm/jsbsim/external_reactions/hook/y", 0);
fgSetDouble("/fdm/jsbsim/external_reactions/hook/z", sin_fi);
fgSetDouble("/fdm/jsbsim/external_reactions/hook/magnitude", fgGetDouble("/fdm/jsbsim/systems/hook/force"));
FGColumnVector3 hook_root_vel = Propagate->GetVel() + (Tb2l * (Propagate->GetPQR() * hook_root_body));
double wire_ends_ec[2][3];
double wire_vel_ec[2][3];
get_wire_ends_ft(t_off, wire_ends_ec, wire_vel_ec);
FGColumnVector3 wire_vel_1 = Tec2l * FGColumnVector3(wire_vel_ec[0][0], wire_vel_ec[0][1], wire_vel_ec[0][2]);
FGColumnVector3 wire_vel_2 = Tec2l * FGColumnVector3(wire_vel_ec[1][0], wire_vel_ec[1][1], wire_vel_ec[1][2]);
FGColumnVector3 rel_vel = hook_root_vel - (wire_vel_1 + wire_vel_2) / 2;
if (rel_vel.Magnitude() < 3) {
release_wire();
fgSetDouble("/fdm/jsbsim/external_reactions/hook/magnitude", 0.0);
arrestor_wire_engaged_hook->setBoolValue(false);
release_hook->setBoolValue(false);
}
else {
FGColumnVector3 wire_end1_body = Tl2b * Location.LocationToLocal(FGColumnVector3(wire_ends_ec[0][0], wire_ends_ec[0][1], wire_ends_ec[0][2])) - hook_root_body;
FGColumnVector3 wire_end2_body = Tl2b * Location.LocationToLocal(FGColumnVector3(wire_ends_ec[1][0], wire_ends_ec[1][1], wire_ends_ec[1][2])) - hook_root_body;
FGColumnVector3 force_plane_normal = wire_end1_body * wire_end2_body;
force_plane_normal.Normalize();
cos_fi = DotProduct(force_plane_normal, FGColumnVector3(0, 0, 1));
if (cos_fi < 0) cos_fi = -cos_fi;
sin_fi = sqrt(1 - sqr(cos_fi));
fi = atan2(sin_fi, cos_fi) * SG_RADIANS_TO_DEGREES;
fgSetDouble("/fdm/jsbsim/external_reactions/hook/x", -cos_fi);
fgSetDouble("/fdm/jsbsim/external_reactions/hook/y", 0);
fgSetDouble("/fdm/jsbsim/external_reactions/hook/z", sin_fi);
fgSetDouble("/fdm/jsbsim/external_reactions/hook/magnitude", fgGetDouble("/fdm/jsbsim/systems/hook/force"));
}
}
}
@ -1547,7 +1557,7 @@ void FGJSBsim::update_external_forces(double t_off)
hook_area[0][1] = hook_tip(2);
hook_area[0][2] = hook_tip(3);
if (!got_wire) {
if (!arrestor_wire_engaged_hook->getBoolValue()) {
// The previous positions.
hook_area[2][0] = last_hook_root[0];
hook_area[2][1] = last_hook_root[1];
@ -1559,7 +1569,7 @@ void FGJSBsim::update_external_forces(double t_off)
// Check if we caught a wire.
// Returns true if we caught one.
if (caught_wire_ft(t_off, hook_area)) {
got_wire = true;
arrestor_wire_engaged_hook->setBoolValue(true);
}
}

4
src/FDM/JSBSim/JSBSim.hxx
View file

@ -291,6 +291,9 @@ private:
SGPropertyNode_ptr wind_from_east;
SGPropertyNode_ptr wind_from_down;
SGPropertyNode_ptr arrestor_wire_engaged_hook;
SGPropertyNode_ptr release_hook;
SGPropertyNode_ptr slaved;
SGPropertyNode_ptr terrain;
@ -301,7 +304,6 @@ private:
double last_hook_root[3];
JSBSim::FGColumnVector3 hook_root_struct;
double hook_length;
bool got_wire;
bool crashed;