void hoverRollCntrl(void)
{
int16_t rollNavDeflection;
union longww gyroRollFeedback;
if (state_flags._.pitch_feedback)
{
if (settings._.AileronNavigation && state_flags._.GPS_steering)
{
rollNavDeflection = (tofinish_line > hover.HoverNavMaxPitchRadius/2) ? navigate_determine_deflection('h') : 0;
}
else
{
rollNavDeflection = 0;
}
gyroRollFeedback.WW = __builtin_mulus(hoverrollkd , omegaAccum[1]);
}
else
{
rollNavDeflection = 0;
gyroRollFeedback.WW = 0;
}
roll_control = rollNavDeflection -(int32_t)gyroRollFeedback._.W1;
}
void helicalTurnCntrl(void)
{
union longww accum;
int16_t pitchAdjustAngleOfAttack;
int16_t rollErrorVector[3];
int16_t rtlkick;
int16_t desiredPitch;
int16_t steeringInput;
int16_t desiredTiltVector[3];
int16_t desiredRotationRateGyro[3];
uint16_t airSpeed;
union longww desiredTilt;
int16_t desiredPitchVector[2];
int16_t desiredPerpendicularPitchVector[2];
int16_t actualPitchVector[2];
int16_t pitchDot;
int16_t pitchCross;
int16_t pitchError;
int16_t pitchEarthBodyProjection[2];
int16_t angleOfAttack;
#ifdef TestGains
state_flags._.GPS_steering = 0; // turn off navigation
state_flags._.pitch_feedback = 1; // turn on stabilization
airSpeed = 981; // for testing purposes, an airspeed is needed
#else
airSpeed = air_speed_3DIMU;
if (airSpeed < TURN_CALC_MINIMUM_AIRSPEED) airSpeed = TURN_CALC_MINIMUM_AIRSPEED;
#endif
// determine the desired turn rate as the sum of navigation and fly by wire.
// this allows the pilot to override navigation if needed.
steeringInput = 0 ; // just in case no airframe type is specified or radio is off
if (udb_flags._.radio_on == 1)
{
#if ( (AIRFRAME_TYPE == AIRFRAME_STANDARD) || (AIRFRAME_TYPE == AIRFRAME_GLIDER) )
if (AILERON_INPUT_CHANNEL != CHANNEL_UNUSED) // compiler is smart about this
{
steeringInput = udb_pwIn[ AILERON_INPUT_CHANNEL ] - udb_pwTrim[ AILERON_INPUT_CHANNEL ];
steeringInput = REVERSE_IF_NEEDED(AILERON_CHANNEL_REVERSED, steeringInput);
}
else if (RUDDER_INPUT_CHANNEL != CHANNEL_UNUSED)
{
steeringInput = udb_pwIn[ RUDDER_INPUT_CHANNEL ] - udb_pwTrim[ RUDDER_INPUT_CHANNEL ];
steeringInput = REVERSE_IF_NEEDED(RUDDER_CHANNEL_REVERSED, steeringInput);
}
else
{
steeringInput = 0;
}
#endif // AIRFRAME_STANDARD
#if (AIRFRAME_TYPE == AIRFRAME_VTAIL)
// use aileron channel if it is available, otherwise use rudder
if (AILERON_INPUT_CHANNEL != CHANNEL_UNUSED) // compiler is smart about this
{
steeringInput = udb_pwIn[AILERON_INPUT_CHANNEL] - udb_pwTrim[AILERON_INPUT_CHANNEL];
steeringInput = REVERSE_IF_NEEDED(AILERON_CHANNEL_REVERSED, steeringInput);
}
else if (RUDDER_INPUT_CHANNEL != CHANNEL_UNUSED)
{
// unmix the Vtail
int16_t rudderInput = REVERSE_IF_NEEDED(RUDDER_CHANNEL_REVERSED, (udb_pwIn[ RUDDER_INPUT_CHANNEL] - udb_pwTrim[RUDDER_INPUT_CHANNEL]));
int16_t elevatorInput = REVERSE_IF_NEEDED(ELEVATOR_CHANNEL_REVERSED, (udb_pwIn[ ELEVATOR_INPUT_CHANNEL] - udb_pwTrim[ELEVATOR_INPUT_CHANNEL]));
steeringInput = (-rudderInput + elevatorInput);
}
else
{
steeringInput = 0;
}
#endif // AIRFRAME_VTAIL
#if (AIRFRAME_TYPE == AIRFRAME_DELTA)
// delta wing must have an aileron input, so use that
// unmix the elevons
int16_t aileronInput = REVERSE_IF_NEEDED(AILERON_CHANNEL_REVERSED, (udb_pwIn[AILERON_INPUT_CHANNEL] - udb_pwTrim[AILERON_INPUT_CHANNEL]));
int16_t elevatorInput = REVERSE_IF_NEEDED(ELEVATOR_CHANNEL_REVERSED, (udb_pwIn[ELEVATOR_INPUT_CHANNEL] - udb_pwTrim[ELEVATOR_INPUT_CHANNEL]));
steeringInput = REVERSE_IF_NEEDED(ELEVON_VTAIL_SURFACES_REVERSED, ((elevatorInput - aileronInput)));
#endif // AIRFRAME_DELTA
}
if (steeringInput > MAX_INPUT) steeringInput = MAX_INPUT;
if (steeringInput < - MAX_INPUT) steeringInput = - MAX_INPUT;
// note that total steering is the sum of pilot input and waypoint navigation,
// so that the pilot always has some say in the matter
accum.WW = __builtin_mulsu(steeringInput, turngainfbw) /(2*MAX_INPUT);
if ((settings._.AileronNavigation || settings._.RudderNavigation) && state_flags._.GPS_steering)
{
accum.WW +=(int32_t) navigate_determine_deflection('t');
}
if (accum.WW >(int32_t) 2*(int32_t) RMAX - 1) accum.WW =(int32_t) 2*(int32_t) RMAX - 1;
if (accum.WW < -(int32_t) 2*(int32_t) RMAX + 1) accum.WW = -(int32_t) 2*(int32_t) RMAX + 1;
desiredTurnRateRadians = accum._.W0;
// compute the desired tilt from desired turn rate and air speed
// range for acceleration is plus minus 4 times gravity
// range for turning rate is plus minus 4 radians per second
// desiredTilt is the ratio(-rmat[6]/rmat[8]), times RMAX/2 required for the turn
// desiredTilt = desiredTurnRate * airSpeed / gravity
// desiredTilt = RMAX/2*"real desired tilt"
// desiredTurnRate = RMAX/2*"real desired turn rate", desired turn rate in radians per second
// airSpeed is air speed centimeters per second
// gravity is 981 centimeters per second per second
desiredTilt.WW = - __builtin_mulsu(desiredTurnRateRadians, airSpeed);
desiredTilt.WW /= GRAVITYCMSECSEC;
// limit the lateral acceleration to +- 4 times gravity, total wing loading approximately 4.12 times gravity
if (desiredTilt.WW > (int32_t)2 * (int32_t)RMAX - 1)
{
desiredTilt.WW = (int32_t)2 * (int32_t)RMAX - 1;
accum.WW = __builtin_mulsu(-desiredTilt._.W0, GRAVITYCMSECSEC);
accum.WW /= airSpeed;
desiredTurnRateRadians = accum._.W0;
}
else if (desiredTilt.WW < -(int32_t)2 * (int32_t)RMAX + 1)
{
desiredTilt.WW = -(int32_t)2 * (int32_t)RMAX + 1;
accum.WW = __builtin_mulsu(-desiredTilt._.W0, GRAVITYCMSECSEC);
accum.WW /= airSpeed;
desiredTurnRateRadians = accum._.W0;
}
// Compute the amount of lift needed to perform the desired turn
// Tests show that the best estimate of lift is obtained using
// actual values of rmat[6] and rmat[8], and the commanded value of their ratio
estimatedLift = wingLift(rmat[6], rmat[8], desiredTilt._.W0);
// compute angle of attack and elevator trim based on relative wing loading.
// relative wing loading is the ratio of wing loading divided by the stall wing loading, as a function of air speed
// both angle of attack and trim are computed by a linear approximation as a function of relative loading:
// y = (2m)*(x/2) + b, y is either angle of attack or elevator trim.
// x is relative wing loading. (x/2 is computed instead of x)
// 2m and b are determined from values of angle of attack and trim at stall speed, normal and inverted.
// b = (y_normal + y_inverted) / 2.
// 2m = (y_normal - y_inverted).
// If airspeed is greater than stall speed, compute angle of attack and elevator trim,
// otherwise set AoA and trim to zero.
if (air_speed_3DIMU > STALL_SPEED_CM_SEC)
{
// compute "x/2", the relative wing loading
relativeLoading = relativeWingLoading(estimatedLift, air_speed_3DIMU);
// multiply x/2 by 2m for angle of attack
accum.WW = __builtin_mulss(AOA_SLOPE, relativeLoading);
// add mx to b
angleOfAttack = AOA_OFFSET + accum._.W1;
// project angle of attack into the earth frame
accum.WW =(__builtin_mulss(angleOfAttack, rmat[8])) << 2;
pitchAdjustAngleOfAttack = accum._.W1;
// similarly, compute elevator trim
accum.WW = __builtin_mulss(ELEVATOR_TRIM_SLOPE, relativeLoading);
elevatorLoadingTrim = ELEVATOR_TRIM_OFFSET + accum._.W1;
}
else
{
angleOfAttack = 0;
pitchAdjustAngleOfAttack = 0;
elevatorLoadingTrim = 0;
}
// SetAofA(angleOfAttack); // removed by helicalTurns
// convert desired turn rate from radians/second to gyro units
accum.WW = (((int32_t)desiredTurnRateRadians) << 4); // desired turn rate in radians times 16 to provide resolution for the divide to follow
accum.WW = accum.WW / RADSTOGYRO; // at this point accum._.W0 has 2 times the required gyro signal for the turn.
// compute desired rotation rate vector in body frame, scaling is same as gyro signal
VectorScale(3, desiredRotationRateGyro, &rmat[6], accum._.W0); // this operation has side effect of dividing by 2
// compute desired rotation rate vector in body frame, scaling is in RMAX/2*radians/sec
VectorScale(3, desiredRotationRateRadians, &rmat[6], desiredTurnRateRadians); // this produces half of what we want
VectorAdd(3, desiredRotationRateRadians, desiredRotationRateRadians, desiredRotationRateRadians); // double
// incorporate roll into desired tilt vector
desiredTiltVector[0] = desiredTilt._.W0;
desiredTiltVector[1] = 0;
desiredTiltVector[2] = RMAX/2; // the divide by 2 is to account for the RMAX/2 scaling in both tilt and rotation rate
vector3_normalize(desiredTiltVector, desiredTiltVector); // make sure tilt vector has magnitude RMAX
// incorporate pitch into desired tilt vector
// compute return to launch pitch down kick for unpowered RTL
if (!udb_flags._.radio_on && state_flags._.GPS_steering)
{
rtlkick = RTLKICK;
}
else
{
rtlkick = 0;
}
// Compute Matt's glider pitch adjustment
#if (GLIDE_AIRSPEED_CONTROL == 1)
fractional aspd_pitch_adj = gliding_airspeed_pitch_adjust();
#endif
// Compute total desired pitch
#if (GLIDE_AIRSPEED_CONTROL == 1)
desiredPitch = - rtlkick + aspd_pitch_adj + pitchAltitudeAdjust;
#else
desiredPitch = - rtlkick + pitchAltitudeAdjust;
#endif
// Adjustment for inverted flight
if (!canStabilizeInverted() || !desired_behavior._.inverted)
{
// normal flight
desiredTiltVector[1] = - desiredPitch - pitchAdjustAngleOfAttack;
}
else
{
// inverted flight
desiredTiltVector[0] = - desiredTiltVector[0];
desiredTiltVector[1] = - desiredPitch - pitchAdjustAngleOfAttack - INVNPITCH; // only one of the adjustments is not zero
desiredTiltVector[2] = - desiredTiltVector[2];
}
vector3_normalize(desiredTiltVector, desiredTiltVector); // make sure tilt vector has magnitude RMAX
// compute roll error
VectorCross(rollErrorVector, &rmat[6], desiredTiltVector); // compute tilt orientation error
if (VectorDotProduct(3, &rmat[6], desiredTiltVector) < 0) // more than 90 degree error
{
vector3_normalize(rollErrorVector, rollErrorVector); // for more than 90 degrees, make the tilt error vector parallel to desired axis, with magnitude RMAX
}
tiltError[1] = rollErrorVector[1];
// compute pitch error
// start by computing the projection of earth frame pitch error to body frame
pitchEarthBodyProjection[0] = rmat[6];
pitchEarthBodyProjection[1] = rmat[8];
// normalize the projection vector and compute the cosine of the actual pitch as a side effect
actualPitchVector[1] =(int16_t) vector2_normalize(pitchEarthBodyProjection, pitchEarthBodyProjection);
// complete the actual pitch vector
actualPitchVector[0] = rmat[7];
// compute the desired pitch vector
desiredPitchVector[0] = - desiredPitch;
desiredPitchVector[1] = RMAX;
vector2_normalize(desiredPitchVector, desiredPitchVector);
// rotate desired pitch vector by 90 degrees to be able to compute cross product using VectorDot
desiredPerpendicularPitchVector[0] = desiredPitchVector[1];
desiredPerpendicularPitchVector[1] = - desiredPitchVector[0];
// compute pitchDot, the dot product of actual and desired pitch vector
// (the 2* that appears in several of the following expressions is a result of the Q2.14 format)
pitchDot = 2*VectorDotProduct(2, actualPitchVector, desiredPitchVector);
// compute pitchCross, the cross product of the actual and desired pitch vector
pitchCross = 2*VectorDotProduct(2, actualPitchVector, desiredPerpendicularPitchVector);
if (pitchDot > 0)
{
pitchError = pitchCross;
}
else
{
if (pitchCross > 0)
{
pitchError = RMAX;
}
else
{
pitchError = - RMAX;
}
}
// multiply the normalized rmat[6], rmat[8] vector by the pitch error
VectorScale(2, pitchEarthBodyProjection, pitchEarthBodyProjection, pitchError);
tiltError[0] = 2*pitchEarthBodyProjection[1];
tiltError[2] = - 2*pitchEarthBodyProjection[0];
// compute the rotation rate error vector
VectorSubtract(3, rotationRateError, omegaAccum, desiredRotationRateGyro);
}