Subversion Repositories FlightCtrl

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/************************************************************************/

/* Flight Attitude                                                      */

/************************************************************************/

#include <stdlib.h>

#include <avr/io.h>

#include "attitude.h"

#include "dongfangMath.h"

// For scope debugging only!

#include "rc.h"

// where our main data flow comes from.

#include "analog.h"

#include "configuration.h"

#include "output.h"

// Some calculations are performed depending on some stick related things.

#include "controlMixer.h"

// For Servo_On / Off

// #include "timer2.h"

#define CHECK_MIN_MAX(value, min, max) {if(value < min) value = min; else if(value > max) value = max;}

/*

 * Gyro readings, as read from the analog module. It would have been nice to flow

 * them around between the different calculations as a struct or array (doing

 * things functionally without side effects) but this is shorter and probably

 * faster too.

 * The variables are overwritten at each attitude calculation invocation - the values

 * are not preserved or reused.

 */

int16_t rate_ATT[2], yawRate;

// With different (less) filtering

int16_t rate_PID[2];

int16_t differential[2];

/*

 * Gyro readings, after performing "axis coupling" - that is, the transfomation

 * of rotation rates from the airframe-local coordinate system to a ground-fixed

 * coordinate system. If axis copling is disabled, the gyro readings will be

 * copied into these directly.

 * These are global for the same pragmatic reason as with the gyro readings.

 * The variables are overwritten at each attitude calculation invocation - the values

 * are not preserved or reused.

 */

int16_t ACRate[2], ACYawRate;

/*

 * Gyro integrals. These are the rotation angles of the airframe compared to the

 * horizontal plane, yaw relative to yaw at start.

 */

int32_t angle[2], yawAngleDiff;

int readingHeight = 0;

// Yaw angle and compass stuff.

// This is updated/written from MM3. Negative angle indicates invalid data.

int16_t compassHeading = -1;

// This is NOT updated from MM3. Negative angle indicates invalid data.

int16_t compassCourse = -1;

// The difference between the above 2 (heading - course) on a -180..179 degree interval.

// Not necessary. Never read anywhere.

// int16_t compassOffCourse = 0;

uint8_t updateCompassCourse = 0;

uint8_t compassCalState = 0;

uint16_t ignoreCompassTimer = 500;

int32_t yawGyroHeading; // Yaw Gyro Integral supported by compass

int16_t yawGyroDrift;

#define PITCHROLLOVER180 (GYRO_DEG_FACTOR_PITCHROLL * 180L)

#define PITCHROLLOVER360 (GYRO_DEG_FACTOR_PITCHROLL * 360L)

#define YAWOVER360       (GYRO_DEG_FACTOR_YAW * 360L)

int16_t correctionSum[2] = { 0, 0 };

// For NaviCTRL use.

int16_t averageAcc[2] = { 0, 0 }, averageAccCount = 0;

/*

 * Experiment: Compensating for dynamic-induced gyro biasing.

 */

int16_t driftComp[2] = { 0, 0 }, driftCompYaw = 0;

// int16_t savedDynamicOffsetPitch = 0, savedDynamicOffsetRoll = 0;

// int32_t dynamicCalPitch, dynamicCalRoll, dynamicCalYaw;

// int16_t dynamicCalCount;

/************************************************************************

 * Set inclination angles from the acc. sensor data.                    

 * If acc. sensors are not used, set to zero.                          

 * TODO: One could use inverse sine to calculate the angles more        

 * accurately, but since: 1) the angles are rather small at times when

 * it makes sense to set the integrals (standing on ground, or flying at  

 * constant speed, and 2) at small angles a, sin(a) ~= constant * a,    

 * it is hardly worth the trouble.                                      

 ************************************************************************/

int32_t getAngleEstimateFromAcc(uint8_t axis) {

        return GYRO_ACC_FACTOR * (int32_t)filteredAcc[axis];

}

void setStaticAttitudeAngles(void) {

#ifdef ATTITUDE_USE_ACC_SENSORS

        angle[PITCH] = getAngleEstimateFromAcc(PITCH);

        angle[ROLL] = getAngleEstimateFromAcc(ROLL);

#else

        angle[PITCH] = angle[ROLL] = 0;

#endif

}

/************************************************************************

 * Neutral Readings                                                    

 ************************************************************************/

void attitude_setNeutral(void) {

        // Servo_Off(); // disable servo output. TODO: Why bother? The servos are going to make a jerk anyway.

        dynamicParams.AxisCoupling1 = dynamicParams.AxisCoupling2 = 0;

        driftComp[PITCH] = driftComp[ROLL] = yawGyroDrift = driftCompYaw = 0;

        correctionSum[PITCH] = correctionSum[ROLL] = 0;

        // Calibrate hardware.

        analog_calibrate();

        // reset gyro integrals to acc guessing

        setStaticAttitudeAngles();

        yawAngleDiff = 0;

        // update compass course to current heading

        compassCourse = compassHeading;

        // Inititialize YawGyroIntegral value with current compass heading

        yawGyroHeading = (int32_t) compassHeading * GYRO_DEG_FACTOR_YAW;

        // Servo_On(); //enable servo output

}

/************************************************************************

 * Get sensor data from the analog module, and release the ADC          

 * TODO: Ultimately, the analog module could do this (instead of dumping

 * the values into variables).

 * The rate variable end up in a range of about [-1024, 1023].

 *************************************************************************/

void getAnalogData(void) {

        uint8_t axis;

        for (axis = PITCH; axis <= ROLL; axis++) {

                rate_PID[axis] = gyro_PID[axis] / HIRES_GYRO_INTEGRATION_FACTOR + driftComp[axis];

                rate_ATT[axis] = gyro_ATT[axis] / HIRES_GYRO_INTEGRATION_FACTOR + driftComp[axis];

                differential[axis] = gyroD[axis];

                averageAcc[axis] += acc[axis];

        }

        averageAccCount++;

        yawRate = yawGyro + driftCompYaw;

        // We are done reading variables from the analog module.

        // Interrupt-driven sensor reading may restart.

        analogDataReady = 0;

        analog_start();

}

/*

 * This is the standard flight-style coordinate system transformation

 * (from airframe-local axes to a ground-based system). For some reason

 * the MK uses a left-hand coordinate system. The tranformation has been

 * changed accordingly.

 */

void trigAxisCoupling(void) {

        int16_t cospitch = int_cos(angle[PITCH]);

        int16_t cosroll = int_cos(angle[ROLL]);

        int16_t sinroll = int_sin(angle[ROLL]);

        ACRate[PITCH] = (((int32_t) rate_ATT[PITCH] * cosroll - (int32_t) yawRate

                    * sinroll) >> MATH_UNIT_FACTOR_LOG);

        ACRate[ROLL] = rate_ATT[ROLL] +

          (((((int32_t)rate_ATT[PITCH] * sinroll + (int32_t)yawRate * cosroll)

              >> MATH_UNIT_FACTOR_LOG)

              * int_tan(angle[PITCH])) >> MATH_UNIT_FACTOR_LOG);

        ACYawRate = ((int32_t) rate_ATT[PITCH] * sinroll) / cospitch

                        + ((int32_t) yawRate * cosroll) / cospitch;

}

// 480 usec with axis coupling - almost no time without.

void integrate(void) {

        // First, perform axis coupling. If disabled xxxRate is just copied to ACxxxRate.

        uint8_t axis;

        if (!looping && (staticParams.GlobalConfig & CFG_AXIS_COUPLING_ACTIVE)) {

                // The rotary rate limiter bit is abused for selecting axis coupling algorithm instead.

                trigAxisCoupling();

        } else {

                ACRate[PITCH] = rate_ATT[PITCH];

                ACRate[ROLL] = rate_ATT[ROLL];

                ACYawRate = yawRate;

        }

        /*

         * Yaw

         * Calculate yaw gyro integral (~ to rotation angle)

         * Limit yawGyroHeading proportional to 0 deg to 360 deg

         */

        yawGyroHeading += ACYawRate;

        yawAngleDiff += yawRate;

        if (yawGyroHeading >= YAWOVER360) {

                yawGyroHeading -= YAWOVER360; // 360 deg. wrap

        } else if (yawGyroHeading < 0) {

                yawGyroHeading += YAWOVER360;

        }

        /*

         * Pitch axis integration and range boundary wrap.

         */

        for (axis = PITCH; axis <= ROLL; axis++) {

                angle[axis] += ACRate[axis];

                if (angle[axis] > PITCHROLLOVER180) {

                        angle[axis] -= PITCHROLLOVER360;

                } else if (angle[axis] <= -PITCHROLLOVER180) {

                        angle[axis] += PITCHROLLOVER360;

                }

        }

}

/************************************************************************

 * A kind of 0'th order integral correction, that corrects the integrals

 * directly. This is the "gyroAccFactor" stuff in the original code.

 * There is (there) also a drift compensation

 * - it corrects the differential of the integral = the gyro offsets.

 * That should only be necessary with drifty gyros like ENC-03.

 ************************************************************************/

void correctIntegralsByAcc0thOrder(void) {

        // TODO: Consider changing this to: Only correct when integrals are less than ...., or only correct when angular velocities

        // are less than ....., or reintroduce Kalman.

        // Well actually the Z axis acc. check is not so silly.

        uint8_t axis;

        int32_t temp;

        if (!looping && acc[Z] >= -dynamicParams.UserParams[7] && acc[Z]

                        <= dynamicParams.UserParams[7]) {

                DebugOut.Digital[0] |= DEBUG_ACC0THORDER;

                uint8_t permilleAcc = staticParams.GyroAccFactor; // NOTE!!! The meaning of this value has changed!!

                uint8_t debugFullWeight = 1;

                int32_t accDerived;

                if ((controlYaw < -64) || (controlYaw > 64)) { // reduce further if yaw stick is active

                        permilleAcc /= 2;

                        debugFullWeight = 0;

                }

                if ((maxControl[PITCH] > 64) || (maxControl[ROLL] > 64)) { // reduce effect during stick commands

                        permilleAcc /= 2;

                        debugFullWeight = 0;

                }

                if (debugFullWeight)

                        DebugOut.Digital[1] |= DEBUG_ACC0THORDER;

                else

                        DebugOut.Digital[1] &= ~DEBUG_ACC0THORDER;

                /*

                 * Add to each sum: The amount by which the angle is changed just below.

                 */

                for (axis = PITCH; axis <= ROLL; axis++) {

                        accDerived = getAngleEstimateFromAcc(axis);

                        DebugOut.Analog[9 + axis] = (10 * accDerived) / GYRO_DEG_FACTOR_PITCHROLL;

                        // 1000 * the correction amount that will be added to the gyro angle in next line.

                        temp = angle[axis]; //(permilleAcc * (accDerived - angle[axis])) / 1000;

                        angle[axis] = ((int32_t) (1000L - permilleAcc) * temp

                                        + (int32_t) permilleAcc * accDerived) / 1000L;

                        correctionSum[axis] += angle[axis] - temp;

                }

        } else {

                DebugOut.Digital[0] &= ~DEBUG_ACC0THORDER;

                DebugOut.Digital[1] &= ~DEBUG_ACC0THORDER;

                DebugOut.Analog[9] = 0;

                DebugOut.Analog[10] = 0;

                DebugOut.Analog[16] = 0;

                DebugOut.Analog[17] = 0;

                // experiment: Kill drift compensation updates when not flying smooth.

                correctionSum[PITCH] = correctionSum[ROLL] = 0;

        }

}

/************************************************************************

 * This is an attempt to correct not the error in the angle integrals

 * (that happens in correctIntegralsByAcc0thOrder above) but rather the

 * cause of it: Gyro drift, vibration and rounding errors.

 * All the corrections made in correctIntegralsByAcc0thOrder over

 * DRIFTCORRECTION_TIME cycles are summed up. This number is

 * then divided by DRIFTCORRECTION_TIME to get the approx.

 * correction that should have been applied to each iteration to fix

 * the error. This is then added to the dynamic offsets.

 ************************************************************************/

// 2 times / sec. = 488/2

#define DRIFTCORRECTION_TIME 256L

void driftCorrection(void) {

        static int16_t timer = DRIFTCORRECTION_TIME;

        int16_t deltaCorrection;

        uint8_t axis;

        if (!--timer) {

                timer = DRIFTCORRECTION_TIME;

                for (axis = PITCH; axis <= ROLL; axis++) {

                        // Take the sum of corrections applied, add it to delta

                        deltaCorrection = (correctionSum[axis] + DRIFTCORRECTION_TIME / 2) / DRIFTCORRECTION_TIME;

                        // Add the delta to the compensation. So positive delta means, gyro should have higher value.

                        driftComp[axis] += deltaCorrection / staticParams.GyroAccTrim;

                        CHECK_MIN_MAX(driftComp[axis], -staticParams.DriftComp, staticParams.DriftComp);

                        // DebugOut.Analog[11 + axis] = correctionSum[axis];

            DebugOut.Analog[16 + axis] = correctionSum[axis];

                        DebugOut.Analog[18 + axis] = deltaCorrection / staticParams.GyroAccTrim;

                        DebugOut.Analog[28 + axis] = driftComp[axis];

                        correctionSum[axis] = 0;

                }

        }

}

/************************************************************************

 * Main procedure.

 ************************************************************************/

void calculateFlightAttitude(void) {

        // part1: 550 usec.

        // part1a: 550 usec.

        // part1b: 60 usec.

        getAnalogData();

        // end part1b

        integrate();

        // end part1a

        DebugOut.Analog[6] = ACRate[PITCH];

        DebugOut.Analog[7] = ACRate[ROLL];

        DebugOut.Analog[8] = ACYawRate;

        DebugOut.Analog[3] = rate_PID[PITCH];

        DebugOut.Analog[4] = rate_PID[ROLL];

        DebugOut.Analog[5] = yawRate;

#ifdef ATTITUDE_USE_ACC_SENSORS

        correctIntegralsByAcc0thOrder();

        driftCorrection();

#endif

        // end part1

}

void updateCompass(void) {

        int16_t w, v, r, correction, error;

        if (compassCalState && !(MKFlags & MKFLAG_MOTOR_RUN)) {

                if (controlMixer_testCompassCalState()) {

                        compassCalState++;

                        if (compassCalState < 5)

                                beepNumber(compassCalState);

                        else

                                beep(1000);

                }

        } else {

                // get maximum attitude angle

                w = abs(angle[PITCH] / 512);

                v = abs(angle[ROLL] / 512);

                if (v > w)

                        w = v;

                correction = w / 8 + 1;

                // calculate the deviation of the yaw gyro heading and the compass heading

                if (compassHeading < 0)

                        error = 0; // disable yaw drift compensation if compass heading is undefined

                else if (abs(yawRate) > 128) { // spinning fast

                        error = 0;

                } else {

                        // compassHeading - yawGyroHeading, on a -180..179 deg interval.

                        error = ((540 + compassHeading - (yawGyroHeading / GYRO_DEG_FACTOR_YAW))

                                        % 360) - 180;

                }

                if (!ignoreCompassTimer && w < 25) {

                        yawGyroDrift += error;

                        // Basically this gets set if we are in "fix" mode, and when starting.

                        if (updateCompassCourse) {

                                beep(200);

                                yawGyroHeading = (int32_t) compassHeading * GYRO_DEG_FACTOR_YAW;

                                compassCourse = compassHeading; //(int16_t)(yawGyroHeading / GYRO_DEG_FACTOR_YAW);

                                updateCompassCourse = 0;

                        }

                }

                yawGyroHeading += (error * 8) / correction;

                /*

                 w = (w * dynamicParams.CompassYawEffect) / 32;

                 w = dynamicParams.CompassYawEffect - w;

                 */

                w = dynamicParams.CompassYawEffect - (w * dynamicParams.CompassYawEffect)

                                / 32;

                // As readable formula:

                // w = dynamicParams.CompassYawEffect * (1-w/32);

                if (w >= 0) { // maxAttitudeAngle < 32

                        if (!ignoreCompassTimer) {

                                v = 64 + (maxControl[PITCH] + maxControl[ROLL]) / 8;

                                // yawGyroHeading - compassCourse on a -180..179 degree interval.

                                r

                                                = ((540 + yawGyroHeading / GYRO_DEG_FACTOR_YAW - compassCourse)

                                                                % 360) - 180;

                                v = (r * w) / v; // align to compass course

                                // limit yaw rate

                                w = 3 * dynamicParams.CompassYawEffect;

                                if (v > w)

                                        v = w;

                                else if (v < -w)

                                        v = -w;

                                yawAngleDiff += v;

                        } else { // wait a while

                                ignoreCompassTimer--;

                        }

                } else { // ignore compass at extreme attitudes for a while

                        ignoreCompassTimer = 500;

                }

        }

}

/*

 * This is part of an experiment to measure average sensor offsets caused by motor vibration,

 * and to compensate them away. It brings about some improvement, but no miracles.

 * As long as the left stick is kept in the start-motors position, the dynamic compensation

 * will measure the effect of vibration, to use for later compensation. So, one should keep

 * the stick in the start-motors position for a few seconds, till all motors run (at the wrong

 * speed unfortunately... must find a better way)

 */

/*

 void attitude_startDynamicCalibration(void) {

 dynamicCalPitch = dynamicCalRoll = dynamicCalYaw = dynamicCalCount = 0;

 savedDynamicOffsetPitch = savedDynamicOffsetRoll = 1000;

 }

 void attitude_continueDynamicCalibration(void) {

 // measure dynamic offset now...

 dynamicCalPitch += hiResPitchGyro;

 dynamicCalRoll += hiResRollGyro;

 dynamicCalYaw += rawYawGyroSum;

 dynamicCalCount++;

 // Param6: Manual mode. The offsets are taken from Param7 and Param8.

 if (dynamicParams.UserParam6 || 1) { // currently always enabled.

 // manual mode

 driftCompPitch = dynamicParams.UserParam7 - 128;

 driftCompRoll = dynamicParams.UserParam8 - 128;

 } else {

 // use the sampled value (does not seem to work so well....)

 driftCompPitch = savedDynamicOffsetPitch = -dynamicCalPitch / dynamicCalCount;

 driftCompRoll = savedDynamicOffsetRoll = -dynamicCalRoll / dynamicCalCount;

 driftCompYaw = -dynamicCalYaw / dynamicCalCount;

 }

 // keep resetting these meanwhile, to avoid accumulating errors.

 setStaticAttitudeIntegrals();

 yawAngle = 0;

 }

 */