void attEstimatePose(void) {
// Fixed point implementation
_Q16 dphi, dtheta, dpsi;
float rate[3];
_Q16 wx, wy, wz;
_Q16 sin_phi, tan_theta, cos_phi, cos_theta, temp;
gyroGetRadXYZ(rate); // 50 us
wx = _Q16ftoi(rate[0]);
wy = _Q16ftoi(rate[1]);
wz = _Q16ftoi(rate[2]);
sin_phi = _Q16sin(PoseQ.qdata.phi);
cos_phi = _Q16cos(PoseQ.qdata.phi);
cos_theta = _Q16cos(PoseQ.qdata.theta);
tan_theta = _Q16tan(PoseQ.qdata.theta);
temp = _Q16mult(wy, sin_phi) + _Q16mult(wz, cos_phi);
dphi = _Q16mult(temp, tan_theta) + wx;
dtheta = _Q16mult(wy, cos_phi) + _Q16neg(_Q16mult(wz, sin_phi));
dpsi = _IQ16div(temp, cos_theta);
PoseQ.qdata.phi += _Q16mult(dphi, samplePeriod);
PoseQ.qdata.theta += _Q16mult(dtheta, samplePeriod);
PoseQ.qdata.psi += _Q16mult(dpsi, samplePeriod);
}
void attSetup(float ts) {
samplePeriod = _Q16ftoi(ts);
// initial values of roll, pitch, and yaw.
PoseQ.qdata.phi = 0;
PoseQ.qdata.theta = 0;
PoseQ.qdata.psi = 0;
}
/*---------------------------------------------------------------------
Function Name: Controller_Update
Description: Run the attitude controller, should execute at 1KHz
Set motor values
Inputs: None
Returns: None
-----------------------------------------------------------------------*/
void Controller_Update(void)
{
// Quaternion attitude error
tQuaternion qerror = qprodconj(AHRSdata.q_est, CmdData.q_cmd);
// New Quaternion Controller from Frazzoli
_Q16 pErr = AHRSdata.p - CmdData.p;
_Q16 qErr = AHRSdata.q - CmdData.q;
_Q16 rErr = AHRSdata.r - CmdData.r;
rollCmd = mult(Gains.Kp_roll,qerror.x);
pitchCmd = mult(Gains.Kp_pitch,qerror.y);
yawCmd = mult(Gains.Kp_yaw,qerror.z);
if (qerror.o < 0){
rollCmd = -rollCmd;
pitchCmd = -pitchCmd;
yawCmd = -yawCmd;
}
// Increment Integrators if motor commands are being sent
if (1 == CmdData.AttCmd || 2 == CmdData.AttCmd) {
if (Gains.IntRoll < _Q16ftoi(-1.0)){
Gains.IntRoll = _Q16ftoi(-0.99);
} else if (Gains.IntRoll > _Q16ftoi(1.0)) {
Gains.IntRoll = _Q16ftoi(0.99);
} else {
Gains.IntRoll += mult(rollCmd,Gains.dt);
}
if (Gains.IntPitch < _Q16ftoi(-1.0)){
Gains.IntPitch = _Q16ftoi(-0.99);
} else if (Gains.IntPitch > _Q16ftoi(1.0)) {
Gains.IntPitch = _Q16ftoi(0.99);
} else {
Gains.IntPitch += mult(pitchCmd,Gains.dt);
}
if (Gains.IntYaw < _Q16ftoi(-1.0)){
Gains.IntYaw = _Q16ftoi(-0.99);
} else if (Gains.IntYaw > _Q16ftoi(1.0)) {
Gains.IntYaw = _Q16ftoi(0.99);
} else {
Gains.IntYaw += mult(yawCmd,Gains.dt);
}
} else {
Gains.IntRoll = _Q16ftoi(0.0);
Gains.IntPitch = _Q16ftoi(0.0);
Gains.IntYaw = _Q16ftoi(0.0);
}
rollCmd += mult(Gains.Ki_roll,Gains.IntRoll) - mult(Gains.Kd_roll,pErr);
pitchCmd += mult(Gains.Ki_pitch,Gains.IntPitch) - mult(Gains.Kd_pitch,qErr);
yawCmd += mult(Gains.Ki_yaw,Gains.IntYaw) - mult(Gains.Kd_yaw,rErr);
// End New Quaternion controller
// Form motor commands
_Q16 m1 = -pitchCmd - yawCmd;
_Q16 m2 = -rollCmd + yawCmd;
_Q16 m3 = pitchCmd - yawCmd;
_Q16 m4 = rollCmd + yawCmd;
// DEBUG
//CmdData.throttle = 0;
//CmdData.AttCmd = 1;
// END DEBUG
// Get throttle value
int16_t tmp = (int16_t) CmdData.throttle;
_Q16 throttle = 0;
int16toQ16(&throttle,&tmp); // Throttle between 0.0 and 255.0 here
// DEBUG
//m1 = 0; m2 = 0; m3 = 0; m4 = 0;
if (1 == CmdData.AttCmd || 2 == CmdData.AttCmd) {
/**** PWM motors - take value between 0 and 3685 (converted to 1 <--> 2 ms PWM signal at 490Hz)*/
int16_t pwmData = 0;
throttle = mult(throttle,num14p45); // multiply throttle by 14.45 to get 0 to 3685 ( assuming throttle is between 0 and 255)
_Q16 motorCmd = m1 + throttle;
_Q16sat(&motorCmd, num3685, 0); // TODO: find lower saturation bound here so motors don't turn off
Q16toint16(&pwmData,&motorCmd);
SETPWM(PWM1,pwmData);
motorCmd = m2 + throttle;
_Q16sat(&motorCmd, num3685, 0); // TODO: find lower saturation bound here so motors don't turn off
Q16toint16(&pwmData,&motorCmd);
SETPWM(PWM2,pwmData);
motorCmd = m3 + throttle;
_Q16sat(&motorCmd, num3685, 0); // TODO: find lower saturation bound here so motors don't turn off
Q16toint16(&pwmData,&motorCmd);
SETPWM(PWM3,pwmData);
motorCmd = m4 + throttle;
_Q16sat(&motorCmd, num3685, 0); // TODO: find lower saturation bound here so motors don't turn off
Q16toint16(&pwmData,&motorCmd);
SETPWM(PWM4,pwmData);
} else if (0 == CmdData.AttCmd) {
// set motor values to off
SETPWM(PWM1,0);
SETPWM(PWM2,0);
SETPWM(PWM3,0);
SETPWM(PWM4,0);
}
}
/*---------------------------------------------------------------------
Function Name: Controller_Init
Description: Initialize all the controller variables
Inputs: None
Returns: None
-----------------------------------------------------------------------*/
void Controller_Init(void)
{
// ESCs
SETPWM(PWM1,0);
SETPWM(PWM2,0);
SETPWM(PWM3,0);
SETPWM(PWM4,0);
CmdData.q_cmd.o = _Q16ftoi(1.0);
CmdData.q_cmd.x = _Q16ftoi(0.0);
CmdData.q_cmd.y = _Q16ftoi(0.0);
CmdData.q_cmd.z = _Q16ftoi(0.0);
CmdData.p = _Q16ftoi(0.0);
CmdData.q = _Q16ftoi(0.0);
CmdData.r = _Q16ftoi(0.0);
CmdData.throttle = 0;
CmdData.AttCmd = 0;
// mQxx default values
// Working gains
/*
Gains.Kp_roll = _Q16ftoi(354.0);
Gains.Ki_roll = _Q16ftoi(0.0);
Gains.Kd_roll = _Q16ftoi(118.0);
Gains.Kp_pitch = _Q16ftoi(354.0);
Gains.Ki_pitch = _Q16ftoi(0.0);
Gains.Kd_pitch = _Q16ftoi(118.0);
Gains.Kp_yaw = _Q16ftoi(0.0);
Gains.Ki_yaw = _Q16ftoi(0.0);
Gains.Kd_yaw = _Q16ftoi(184.0);
Gains.maxang = _Q16ftoi(0.8);
Gains.IntRoll = _Q16ftoi(0.0);
Gains.IntPitch = _Q16ftoi(0.0);
Gains.IntYaw = _Q16ftoi(0.0);
Gains.dt = _Q16ftoi(1.0/1000.0);
*/
Gains.Kp_roll = _Q16ftoi(2000.0);
Gains.Ki_roll = _Q16ftoi(0.0);
Gains.Kd_roll = _Q16ftoi(400.0);
Gains.Kp_pitch = _Q16ftoi(2000.0);
Gains.Ki_pitch = _Q16ftoi(0.0);
Gains.Kd_pitch = _Q16ftoi(400.0);
Gains.Kp_yaw = _Q16ftoi(0.0);
Gains.Ki_yaw = _Q16ftoi(0.0);
Gains.Kd_yaw = _Q16ftoi(184.0);
Gains.maxang = _Q16ftoi(0.8);
Gains.IntRoll = _Q16ftoi(0.0);
Gains.IntPitch = _Q16ftoi(0.0);
Gains.IntYaw = _Q16ftoi(0.0);
Gains.dt = _Q16ftoi(1.0/2000.0);
}
void AHRS_GyroProp(void){
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
// Read raw gyro values from A2D registers, A2D automatically scans inputs at 5KHz
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
SensorData.gyroX = xgyro; SensorData.gyroX -= SensorCal.gyroRawBias;
SensorData.gyroY = ygyro; SensorData.gyroY -= SensorCal.gyroRawBias;
SensorData.gyroZ = zgyro; SensorData.gyroZ -= SensorCal.gyroRawBias;
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
// Gyro scaling, to rad/sec
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
int16toQ16(&AHRSdata.p, &SensorData.gyroX);
AHRSdata.p = -mult( AHRSdata.p, SensorCal.gyroScale);
int16toQ16(&AHRSdata.q, &SensorData.gyroY);
AHRSdata.q = mult( AHRSdata.q, SensorCal.gyroScale );
int16toQ16(&AHRSdata.r, &SensorData.gyroZ);
AHRSdata.r = mult( AHRSdata.r, SensorCal.gyroScale );
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
// Initial gyro bias calculation
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
if( SensorCal.biasCountGyro < SensorCal.biasTotalGyro){
// Do some blank reads to clear any garbage in the initial transient
if(--SensorCal.blankReadsGyro > 0)
return;
SensorCal.pBias += AHRSdata.p;
SensorCal.qBias += AHRSdata.q;
SensorCal.rBias += AHRSdata.r;
led_on(LED_RED);
if( ++SensorCal.biasCountGyro == SensorCal.biasTotalGyro ){
_Q16 tmp = _Q16ftoi(1.0 / ((float)SensorCal.biasTotalGyro ));
SensorCal.pBias = mult( SensorCal.pBias, tmp);
SensorCal.qBias = mult( SensorCal.qBias, tmp);
SensorCal.rBias = mult( SensorCal.rBias, tmp);
led_off(LED_RED);
led_off(LED_GREEN);
}
// TODO: Initialize q_est to q_meas
return;
}
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
// Gyro bias correction
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
AHRSdata.p -= SensorCal.pBias;
AHRSdata.q -= SensorCal.qBias;
AHRSdata.r -= SensorCal.rBias;
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
// Gyro propagation
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
AHRSdata.q_est.o -= mult( mult(AHRSdata.q_est.x,AHRSdata.p) + mult(AHRSdata.q_est.y,AHRSdata.q) + mult(AHRSdata.q_est.z,AHRSdata.r) , SensorCal.gyroPropDT);
AHRSdata.q_est.x += mult( mult(AHRSdata.q_est.o,AHRSdata.p) - mult(AHRSdata.q_est.z,AHRSdata.q) + mult(AHRSdata.q_est.y,AHRSdata.r) , SensorCal.gyroPropDT);
AHRSdata.q_est.y += mult( mult(AHRSdata.q_est.z,AHRSdata.p) + mult(AHRSdata.q_est.o,AHRSdata.q) - mult(AHRSdata.q_est.x,AHRSdata.r) , SensorCal.gyroPropDT);
AHRSdata.q_est.z += mult( mult(AHRSdata.q_est.x,AHRSdata.q) - mult(AHRSdata.q_est.y,AHRSdata.p) + mult(AHRSdata.q_est.o,AHRSdata.r) , SensorCal.gyroPropDT);
// Run the attitude control after propogating gyros
loop.AttCtl = 1;
}
// Initialize
void AHRS_init(void){
// Setup calibration struct
SensorCal.biasCountGyro = 0;
SensorCal.biasTotalGyro = 2000;
SensorCal.blankReadsGyro = 200;
SensorCal.biasCountAcc = 0;
SensorCal.biasTotalAcc = 2000;
SensorCal.blankReadsAcc = 200;
SensorCal.pBias = _Q16ftoi(0.0);
SensorCal.qBias = _Q16ftoi(0.0);
SensorCal.rBias = _Q16ftoi(0.0);
// Initialize attitude
AHRSdata.q_est.o = _Q16ftoi(1.0);
AHRSdata.q_est.x = _Q16ftoi(0.0);
AHRSdata.q_est.y = _Q16ftoi(0.0);
AHRSdata.q_est.z = _Q16ftoi(0.0);
AHRSdata.q_meas.o = _Q16ftoi(1.0);
AHRSdata.q_meas.x = _Q16ftoi(0.0);
AHRSdata.q_meas.y = _Q16ftoi(0.0);
AHRSdata.q_meas.z = _Q16ftoi(0.0);
// Parameters
SensorCal.gyroRawBias = 512; // Mid-range value for 10-bit A2D
SensorCal.accelRawBias= 500; // Mid-range value for 10-bit A2D (adjusted manually)
SensorCal.gyroScale = _Q16ftoi(PI/180.0 / 1024.0 * 3.3 / 0.0033 * 1.5 ); // Based on 10-bit A2D and gyro sensitivity of 3.3mV / deg/s with fudge factor
SensorCal.gyroPropDT = _Q16ftoi(0.001 / 2.0);
SensorCal.accelScale = _Q16ftoi( 3.3 / 1024.0 / 0.200 ); // at 6g resolution, sensitivity is 200mV/g
SensorCal.acc_window_min = _Q16ftoi(0.5);
SensorCal.acc_window_max = _Q16ftoi(1.5);
SensorCal.axBias = _Q16ftoi(0.0);
SensorCal.ayBias = _Q16ftoi(0.0);
SensorCal.azBias = _Q16ftoi(0.0);
SensorCal.K_AttFilter = _Q16ftoi(0.025); // Default value, may be overwritten by SensorPacket
}
void AHRS_AccMagCorrect(void)
{
// Quit if the biases are still being calculated
if( SensorCal.biasCountGyro < SensorCal.biasTotalGyro)
return;
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
// Read raw accel values from A2D registers, A2D automatically scans inputs at 5KHz
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
SensorData.accX = xaccel; SensorData.accX -= SensorCal.accelRawBias;
SensorData.accY = yaccel; SensorData.accY -= SensorCal.accelRawBias;
SensorData.accZ = zaccel; SensorData.accZ -= SensorCal.accelRawBias;
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
// Accel scaling, to g
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
int16toQ16(&AHRSdata.ax, &SensorData.accX);
AHRSdata.ax = -mult( AHRSdata.ax, SensorCal.accelScale);
int16toQ16(&AHRSdata.ay, &SensorData.accY);
AHRSdata.ay = mult( AHRSdata.ay, SensorCal.accelScale );
int16toQ16(&AHRSdata.az, &SensorData.accZ);
AHRSdata.az = -mult( AHRSdata.az, SensorCal.accelScale );
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
// Initial acc bias calculation
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
if( SensorCal.biasCountAcc < SensorCal.biasTotalAcc){
// Do some blank reads to clear any garbage in the initial transient
if(--SensorCal.blankReadsAcc > 0)
return;
SensorCal.axBias += AHRSdata.ax;
SensorCal.ayBias += AHRSdata.ay;
SensorCal.azBias += AHRSdata.az;
led_on(LED_RED);
if( ++SensorCal.biasCountAcc == SensorCal.biasTotalAcc ){
_Q16 tmp = _Q16ftoi(1.0 / ((float)SensorCal.biasTotalAcc ));
SensorCal.axBias = mult( SensorCal.axBias, tmp);
SensorCal.ayBias = mult( SensorCal.ayBias, tmp);
SensorCal.azBias = mult( SensorCal.azBias, tmp);
led_off(LED_RED);
led_off(LED_GREEN);
}
return;
}
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
// Acc bias correction
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
AHRSdata.ax = AHRSdata.ax - SensorCal.axBias;
AHRSdata.ay = AHRSdata.ay - SensorCal.ayBias;
AHRSdata.az = AHRSdata.az - SensorCal.azBias;
_Q16 ax = AHRSdata.ax;
_Q16 ay = AHRSdata.ay;
_Q16 az = AHRSdata.az;
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
// Maneuver detector, do not use accels during fast movement
// $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
// TODO: Check angular rates
// Roll and pitch calculation, assumes accelerometer units are 10000*g
// Normalize the acceleration vector to length 1
_Q16 root = _Q16sqrt( mult(ax,ax) + mult(ay,ay) + mult(az,az));
// TODO: Make sure we're around 1g
if( root < SensorCal.acc_window_min || root > SensorCal.acc_window_max){
return;
}
// Normalize
ax = _IQ16div(ax, root);
ay = _IQ16div(ay, root);
az = _IQ16div(az, root);
// Too close to singularity (due to numerical precision limits)
if( ax > num0p998 || -ax > num0p998 )
return;
root = _Q16sqrt( mult(ay,ay) + mult(az,az));
if(root < num0p0001 )
root = num0p0001;
// Calculate sin/cos of roll and pitch
_Q16 sinR = - _IQ16div(ay,root);
_Q16 cosR = - _IQ16div(az,root);
_Q16 sinP = ax;
_Q16 cosP = -( mult(ay,sinR) + mult(az,cosR) );
// Calculate half-angles
_Q16 cosR2 = _Q16sqrt( mult( num1p0 + cosR , num0p5 ));
if(cosR2 < num0p0001 )
cosR2 = num0p0001;
_Q16 sinR2 = mult(_IQ16div( sinR , cosR2) , num0p5 ); // WARNING: This step is numerically ill-behaved!
_Q16 cosP2 = _Q16sqrt( mult( num1p0 + cosP , num0p5 ));
if(cosP2 < num0p0001 )
cosP2 = num0p0001;
_Q16 sinP2 = mult(_IQ16div( sinP , cosP2) , num0p5 ); // WARNING: This step is numerically ill-behaved!
// Too close to singularity (due to numerical precision limits)
if( mult(cosR2,cosR2) + mult(sinR2,sinR2) > num1p1 || mult(cosP2,cosP2) + mult(sinP2,sinP2) > num1p1 )
return;
// Yaw calculation
// Normalize the magnetometer vector to length 1
/* magx = (float)AHRSdata.magY;
magy = -(float)AHRSdata.magX;
magz = (float)AHRSdata.magZ;
// Todo: magx*magx can be done in fixed pt
root = sqrt( magx*magx + magy*magy + magz*magz );
magx /= root;
magy /= root;
magz /= root;
yaw = atan2(-cosR*magy - sinR*magz , cosP*magx+sinP*sinR*magy-sinP*cosR*magz);
yaw += PI;
if(yaw > PI){
yaw -= 2*PI;
}
sinY2 = sin(yaw/2.0);
cosY2 = cos(yaw/2.0);
*/
_Q16 cosY2 = _Q16ftoi(1.0);
_Q16 sinY2 = 0;
// Finally get quaternion
tQuaternion qroll,qpitch,qyaw;
qyaw.o = cosY2; qyaw.x = 0; qyaw.y = 0; qyaw.z = sinY2;
qpitch.o = cosP2; qpitch.x = 0; qpitch.y = sinP2; qpitch.z = 0;
qroll.o = cosR2; qroll.x = sinR2; qroll.y = 0; qroll.z = 0;
AHRSdata.q_meas = qprod(qyaw,qpitch);
AHRSdata.q_meas = qprod(AHRSdata.q_meas, qroll);
// Check if flipped from last measurement
if( mult(AHRSdata.q_meas.x,AHRSdata.q_est.x) + mult(AHRSdata.q_meas.y,AHRSdata.q_est.y) + mult(AHRSdata.q_meas.z,AHRSdata.q_est.z) + mult(AHRSdata.q_meas.o,AHRSdata.q_est.o) < 0 )
{
AHRSdata.q_meas.o = - AHRSdata.q_meas.o;
AHRSdata.q_meas.x = - AHRSdata.q_meas.x;
AHRSdata.q_meas.y = - AHRSdata.q_meas.y;
AHRSdata.q_meas.z = - AHRSdata.q_meas.z;
}
// Gyro bias estimation
// Make the correction
AHRSdata.q_est.o -= mult(AHRSdata.q_est.o-AHRSdata.q_meas.o, SensorCal.K_AttFilter);
AHRSdata.q_est.x -= mult(AHRSdata.q_est.x-AHRSdata.q_meas.x, SensorCal.K_AttFilter);
AHRSdata.q_est.y -= mult(AHRSdata.q_est.y-AHRSdata.q_meas.y, SensorCal.K_AttFilter);
AHRSdata.q_est.z -= mult(AHRSdata.q_est.z-AHRSdata.q_meas.z, SensorCal.K_AttFilter);
}
