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SITL: improved single-motor tailsitter plane

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give larger control surfaces and take account of thrust airflow over
control surfaces
This commit is contained in:
Andrew Tridgell 2017-04-17 14:23:15 +10:00
parent 6b6ad6ddf2
commit 92f060bdef
2 changed files with 32 additions and 10 deletions
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40
libraries/SITL/SIM_Plane.cpp
View File

@ -98,9 +98,23 @@ float Plane::dragCoeff(float alpha) const
} }
// Torque calculation function // Torque calculation function
Vector3f Plane::getTorque(float inputAileron, float inputElevator, float inputRudder, const Vector3f &force) const Vector3f Plane::getTorque(float inputAileron, float inputElevator, float inputRudder, float inputThrust, const Vector3f &force) const
{ {
const float alpha = angle_of_attack; float alpha = angle_of_attack;
//calculate aerodynamic torque
float effective_airspeed = airspeed;
if (tailsitter) {
/*
tailsitters get airspeed from prop-wash
*/
effective_airspeed += inputThrust * 20;
// reduce effective angle of attack as thrust increases
alpha *= constrain_float(1 - inputThrust, 0, 1);
}
const float s = coefficient.s; const float s = coefficient.s;
const float c = coefficient.c; const float c = coefficient.c;
const float b = coefficient.b; const float b = coefficient.b;
@ -129,10 +143,9 @@ Vector3f Plane::getTorque(float inputAileron, float inputElevator, float inputRu
double q = gyro.y; double q = gyro.y;
double r = gyro.z; double r = gyro.z;
//calculate aerodynamic torque double qbar = 1.0/2.0*rho*pow(effective_airspeed,2)*s; //Calculate dynamic pressure
double qbar = 1.0/2.0*rho*pow(airspeed,2)*s; //Calculate dynamic pressure
double la, na, ma; double la, na, ma;
if (is_zero(airspeed)) if (is_zero(effective_airspeed))
{ {
la = 0; la = 0;
ma = 0; ma = 0;
@ -140,9 +153,9 @@ Vector3f Plane::getTorque(float inputAileron, float inputElevator, float inputRu
} }
else else
{ {
la = qbar*b*(c_l_0 + c_l_b*beta + c_l_p*b*p/(2*airspeed) + c_l_r*b*r/(2*airspeed) + c_l_deltaa*inputAileron + c_l_deltar*inputRudder); la = qbar*b*(c_l_0 + c_l_b*beta + c_l_p*b*p/(2*effective_airspeed) + c_l_r*b*r/(2*effective_airspeed) + c_l_deltaa*inputAileron + c_l_deltar*inputRudder);
ma = qbar*c*(c_m_0 + c_m_a*alpha + c_m_q*c*q/(2*airspeed) + c_m_deltae*inputElevator); ma = qbar*c*(c_m_0 + c_m_a*alpha + c_m_q*c*q/(2*effective_airspeed) + c_m_deltae*inputElevator);
na = qbar*b*(c_n_0 + c_n_b*beta + c_n_p*b*p/(2*airspeed) + c_n_r*b*r/(2*airspeed) + c_n_deltaa*inputAileron + c_n_deltar*inputRudder); na = qbar*b*(c_n_0 + c_n_b*beta + c_n_p*b*p/(2*effective_airspeed) + c_n_r*b*r/(2*effective_airspeed) + c_n_deltaa*inputAileron + c_n_deltar*inputRudder);
} }
@ -254,9 +267,18 @@ void Plane::calculate_forces(const struct sitl_input &input, Vector3f &rot_accel
// calculate angle of attack // calculate angle of attack
angle_of_attack = atan2f(velocity_air_bf.z, velocity_air_bf.x); angle_of_attack = atan2f(velocity_air_bf.z, velocity_air_bf.x);
beta = atan2f(velocity_air_bf.y,velocity_air_bf.x); beta = atan2f(velocity_air_bf.y,velocity_air_bf.x);
if (tailsitter) {
/*
tailsitters get 4x the control surfaces
*/
aileron *= 4;
elevator *= 4;
rudder *= 4;
}
Vector3f force = getForce(aileron, elevator, rudder); Vector3f force = getForce(aileron, elevator, rudder);
rot_accel = getTorque(aileron, elevator, rudder, force); rot_accel = getTorque(aileron, elevator, rudder, thrust, force);
// simulate engine RPM // simulate engine RPM
rpm1 = thrust * 7000; rpm1 = thrust * 7000;

2
libraries/SITL/SIM_Plane.h
View File

@ -104,7 +104,7 @@ protected:
float liftCoeff(float alpha) const; float liftCoeff(float alpha) const;
float dragCoeff(float alpha) const; float dragCoeff(float alpha) const;
Vector3f getForce(float inputAileron, float inputElevator, float inputRudder) const; Vector3f getForce(float inputAileron, float inputElevator, float inputRudder) const;
Vector3f getTorque(float inputAileron, float inputElevator, float inputRudder, const Vector3f &force) const; Vector3f getTorque(float inputAileron, float inputElevator, float inputRudder, float inputThrust, const Vector3f &force) const;
void calculate_forces(const struct sitl_input &input, Vector3f &rot_accel, Vector3f &body_accel); void calculate_forces(const struct sitl_input &input, Vector3f &rot_accel, Vector3f &body_accel);
}; };