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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Copyright (c) 04.2007 Holger Buss
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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 readings
        // rate_ATT[PITCH] = rate_ATT[ROLL] = yawRate = 0;

        // 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] + driftComp[axis])
                                / HIRES_GYRO_INTEGRATION_FACTOR;
                rate_ATT[axis] = (gyro_ATT[axis] + driftComp[axis])
                                / HIRES_GYRO_INTEGRATION_FACTOR;
                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]);
        int16_t tanpitch = int_tan(angle[PITCH]);
#define ANTIOVF 512
        ACRate[PITCH] = ((int32_t) rate_ATT[PITCH] * cosroll - (int32_t) yawRate
                        * sinroll) / (int32_t) MATH_UNIT_FACTOR;
        ACRate[ROLL] = rate_ATT[ROLL] + (((int32_t) rate_ATT[PITCH] * sinroll
                        / ANTIOVF * tanpitch + (int32_t) yawRate * int_cos(angle[ROLL]) / ANTIOVF
                        * tanpitch) / ((int32_t) MATH_UNIT_FACTOR / ANTIOVF * MATH_UNIT_FACTOR));
        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 correction;
        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.
                        correction = angle[axis]; //(permilleAcc * (accDerived - angle[axis])) / 1000;
                        angle[axis] = ((int32_t) (1000L - permilleAcc) * angle[axis]
                                        + (int32_t) permilleAcc * accDerived) / 1000L;
                        correctionSum[axis] += angle[axis] - correction;
                        DebugOut.Analog[16 + axis] = angle[axis] - correction;
                }
        } 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] * HIRES_GYRO_INTEGRATION_FACTOR
                                        + 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[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;
 }
 */