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 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);
}
void UART2_ProcessSpektrumData( )
{
// PROCESS Spektrum receiver data -- see http://www.desertrc.com/spektrum_protocol.htm for protocol
// Determine what to do with received character
uint8_t i;
int16_t scaleInt;
_Q16 tmpQ16, scaleQ16, scale2Q16;
// Data is 14 bytes long
for( i=0; i<14; i+=2)
{
uint16_t rcdata = spektrumData[i] << 8; // MSB
rcdata += spektrumData[i+1]; // LSB
#ifdef DSMX
// 11-bit data mode
uint16_t cmddata = (int16_t) (rcdata & 0b0000011111111111); // get last 11 bits
uint8_t channel = rcdata >> 11; // get 5 first bits
scaleQ16 = num1024;
scale2Q16 = num2048;
scaleInt = 8;
#else
// 10-bit data mode
uint16_t cmddata = (int16_t) (rcdata & 0b0000001111111111); // get last 10 bits
uint8_t channel = rcdata >> 10; // get 6 first bits
scaleQ16 = num512;
scale2Q16 = num1024;
scaleInt = 4;
#endif
switch(channel){ // process channel data
case 0:
RCdata.ch0 = cmddata;
break;
case 1:
int16toQ16(&tmpQ16,&cmddata);
tmpQ16 -= scaleQ16;
RCdata.ch1 = _IQ16div(tmpQ16,scale2Q16);
break;
case 2:
int16toQ16(&tmpQ16,&cmddata);
tmpQ16 -= scaleQ16;
RCdata.ch2 = _IQ16div(tmpQ16,scale2Q16);
break;
case 3:
int16toQ16(&tmpQ16,&cmddata);
tmpQ16 -= scaleQ16;
RCdata.ch3 = _IQ16div(tmpQ16,scaleQ16);
break;
case 4:
RCdata.ch4 = cmddata;
break;
case 5:
RCdata.ch5 = cmddata;
break;
case 6:
RCdata.ch6 = cmddata;
break;
default:
break;
} // End switch channel
} // End for each data byte
// manual mode
if (RCdata.ch4 > 600) {
CmdData.AttCmd = 1;
//Debug: Scaling throttle down 2 times
//CmdData.throttle = RCdata.ch0/(scaleInt*2); // RCdata is between 0 and 1023, this will be approximately between 0 and 255
//Normal throttle
CmdData.throttle = RCdata.ch0/(scaleInt); // RCdata is between 0 and 1023, this will be approximately between 0 and 255
_Q16 halfRoll = -RCdata.ch1; //mult(RCdata.ch1,num0p5); // this is about -0.6 -> 0.6 which is +/- ~70 degrees
_Q16 halfPitch = RCdata.ch2; //mult(RCdata.ch2,num0p5);
_Q16 cosRoll = _Q16cos(halfRoll);
_Q16 sinRoll = _Q16sin(halfRoll);
_Q16 cosPitch = _Q16cos(halfPitch);
_Q16 sinPitch = _Q16sin(halfPitch);
CmdData.q_cmd.o = mult(cosRoll,cosPitch);
CmdData.q_cmd.x = mult(sinRoll,cosPitch);
CmdData.q_cmd.y = mult(cosRoll,sinPitch);
CmdData.q_cmd.z = -mult(sinRoll,sinPitch);
CmdData.p = CmdData.q = 0;
CmdData.r = mult(RCdata.ch3,num2p0);
// Turn on green LED to signify manual control mode ON
led_on(LED_GREEN);
} else
{
// Turn off green LED to signify manual control mode OFF
led_off(LED_GREEN);
CmdData.AttCmd = 0;
}
}
