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1910 - 1
/************************************************************************/
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/* Flight Attitude                                                      */
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/************************************************************************/
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#include <stdlib.h>
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#include <avr/io.h>
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#include "attitude.h"
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#include "dongfangMath.h"
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11
// For scope debugging only!
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#include "rc.h"
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// where our main data flow comes from.
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#include "analog.h"
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17
#include "configuration.h"
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#include "output.h"
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// Some calculations are performed depending on some stick related things.
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#include "controlMixer.h"
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// For Servo_On / Off
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// #include "timer2.h"
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#define CHECK_MIN_MAX(value, min, max) {if(value < min) value = min; else if(value > max) value = max;}
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/*
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 * Gyro readings, as read from the analog module. It would have been nice to flow
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 * them around between the different calculations as a struct or array (doing
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 * things functionally without side effects) but this is shorter and probably
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 * faster too.
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 * The variables are overwritten at each attitude calculation invocation - the values
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 * are not preserved or reused.
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 */
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int16_t rate_ATT[2], yawRate;
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// With different (less) filtering
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int16_t rate_PID[2];
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int16_t differential[3];
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/*
1922 - 43
 * Gyro integrals. These are the rotation angles of the airframe compared to the
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 * horizontal plane, yaw relative to yaw at start. Not really used for anything else
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 * than diagnostics.
1910 - 46
 */
1927 - 47
int32_t angle[3];
1910 - 48
 
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/*
1922 - 50
 * Error integrals. Stick is always positive. Gyro is configurable positive or negative.
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 * These represent the deviation of the attitude angle from the desired on each axis.
1910 - 52
 */
1922 - 53
int32_t error[3];
1910 - 54
 
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int32_t yawGyroHeading; // Yaw Gyro Integral supported by compass
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int16_t correctionSum[2] = { 0, 0 };
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// For NaviCTRL use.
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int16_t averageAcc[2] = { 0, 0 }, averageAccCount = 0;
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/*
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 * Experiment: Compensating for dynamic-induced gyro biasing.
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 */
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int16_t driftComp[2] = { 0, 0 }, driftCompYaw = 0;
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// int16_t savedDynamicOffsetPitch = 0, savedDynamicOffsetRoll = 0;
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// int32_t dynamicCalPitch, dynamicCalRoll, dynamicCalYaw;
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// int16_t dynamicCalCount;
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/************************************************************************
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 * Set inclination angles from the acc. sensor data.                    
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 * If acc. sensors are not used, set to zero.                          
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 * TODO: One could use inverse sine to calculate the angles more        
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 * accurately, but since: 1) the angles are rather small at times when
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 * it makes sense to set the integrals (standing on ground, or flying at  
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 * constant speed, and 2) at small angles a, sin(a) ~= constant * a,    
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 * it is hardly worth the trouble.                                      
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 ************************************************************************/
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80
int32_t getAngleEstimateFromAcc(uint8_t axis) {
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  return GYRO_ACC_FACTOR * (int32_t) filteredAcc[axis];
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}
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84
void setStaticAttitudeAngles(void) {
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#ifdef ATTITUDE_USE_ACC_SENSORS
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  angle[PITCH] = getAngleEstimateFromAcc(PITCH);
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  angle[ROLL] = getAngleEstimateFromAcc(ROLL);
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#else
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  angle[PITCH] = angle[ROLL] = 0;
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#endif
91
}
92
 
93
/************************************************************************
94
 * Neutral Readings                                                    
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 ************************************************************************/
96
void attitude_setNeutral(void) {
97
  // Servo_Off(); // disable servo output. TODO: Why bother? The servos are going to make a jerk anyway.
1926 - 98
  driftComp[PITCH] = driftComp[ROLL];
1910 - 99
  correctionSum[PITCH] = correctionSum[ROLL] = 0;
100
 
101
  // Calibrate hardware.
102
  analog_calibrate();
103
 
104
  // reset gyro integrals to acc guessing
105
  setStaticAttitudeAngles();
106
 
107
  // Inititialize YawGyroIntegral value with current compass heading
1927 - 108
  angle[YAW] = 0;
1910 - 109
 
110
  // Servo_On(); //enable servo output
111
}
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113
/************************************************************************
114
 * Get sensor data from the analog module, and release the ADC          
115
 * TODO: Ultimately, the analog module could do this (instead of dumping
116
 * the values into variables).
117
 * The rate variable end up in a range of about [-1024, 1023].
118
 *************************************************************************/
119
void getAnalogData(void) {
120
  uint8_t axis;
121
 
122
  for (axis = PITCH; axis <= ROLL; axis++) {
123
    rate_PID[axis] = gyro_PID[axis] + driftComp[axis];
124
    rate_ATT[axis] = gyro_ATT[axis] + driftComp[axis];
125
    differential[axis] = gyroD[axis];
126
    averageAcc[axis] += acc[axis];
127
  }
128
 
129
  differential[YAW] = gyroD[YAW];
130
 
131
  averageAccCount++;
132
  yawRate = yawGyro + driftCompYaw;
133
 
134
  // We are done reading variables from the analog module.
135
  // Interrupt-driven sensor reading may restart.
136
  analogDataReady = 0;
137
  analog_start();
138
}
139
 
140
void integrate(void) {
141
  // First, perform axis coupling. If disabled xxxRate is just copied to ACxxxRate.
142
  uint8_t axis;
143
 
1927 - 144
    // TODO: Multiply on a factor on control. Wont work without...
1910 - 145
  if (staticParams.GlobalConfig & CFG_AXIS_COUPLING_ACTIVE) {
2024 - 146
    error[PITCH] += control[CONTROL_ELEVATOR] + (staticParams.servoDirections & 1 ? rate_ATT[PITCH] : -rate_ATT[PITCH]);
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    error[ROLL]  += control[CONTROL_AILERONS] + (staticParams.servoDirections & 2 ? rate_ATT[ROLL]  : -rate_ATT[ROLL]);
148
    error[YAW]   += control[CONTROL_RUDDER]   + (staticParams.servoDirections & 4 ? yawRate : -yawRate);
1927 - 149
 
150
    angle[PITCH] += rate_ATT[PITCH];
2024 - 151
    angle[ROLL]  += rate_ATT[ROLL];
152
    angle[YAW] += yawRate;
1927 - 153
} else {
2024 - 154
    error[PITCH] += control[CONTROL_ELEVATOR] + (staticParams.servoDirections & SERVO_DIRECTION_ELEVATOR ? rate_ATT[PITCH] : -rate_ATT[PITCH]);
155
    error[ROLL]  += control[CONTROL_AILERONS] + (staticParams.servoDirections & SERVO_DIRECTION_AILERONS ? rate_ATT[ROLL]  : -rate_ATT[ROLL]);
156
    error[YAW]   += control[CONTROL_RUDDER]   + (staticParams.servoDirections & SERVO_DIRECTION_RUDDER ? yawRate : -yawRate);
1927 - 157
    angle[PITCH] += rate_ATT[PITCH];
2024 - 158
    angle[ROLL]  += rate_ATT[ROLL];
159
    angle[YAW] += yawRate;
1910 - 160
  }
161
 
1927 - 162
// TODO: Configurable.
163
#define ERRORLIMIT 1000
164
for (axis=PITCH; axis<=YAW; axis++) {
1922 - 165
  if (error[axis] > ERRORLIMIT) {
166
        error[axis] = ERRORLIMIT;
167
    } else if (angle[axis] <= -ERRORLIMIT) {
168
        angle[axis] = -ERRORLIMIT;
169
    }
1927 - 170
}
1922 - 171
 
1910 - 172
  /*
173
   * Pitch axis integration and range boundary wrap.
174
   */
175
  for (axis = PITCH; axis <= ROLL; axis++) {
1922 - 176
    angle[axis] += rate_ATT[axis];
1910 - 177
    if (angle[axis] > PITCHROLLOVER180) {
178
      angle[axis] -= PITCHROLLOVER360;
179
    } else if (angle[axis] <= -PITCHROLLOVER180) {
180
      angle[axis] += PITCHROLLOVER360;
181
    }
182
  }
1927 - 183
 
184
    /*
185
     * Yaw
186
     * Calculate yaw gyro integral (~ to rotation angle)
187
     * Limit yawGyroHeading proportional to 0 deg to 360 deg
188
     */
189
    if (angle[YAW] >= YAWOVER360) {
190
        angle[YAW] -= YAWOVER360; // 360 deg. wrap
191
    } else if (angle[YAW] < 0) {
192
        angle[YAW] += YAWOVER360;
193
    }
194
 
1910 - 195
}
196
 
197
/************************************************************************
198
 * A kind of 0'th order integral correction, that corrects the integrals
199
 * directly. This is the "gyroAccFactor" stuff in the original code.
200
 * There is (there) also a drift compensation
201
 * - it corrects the differential of the integral = the gyro offsets.
202
 * That should only be necessary with drifty gyros like ENC-03.
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 ************************************************************************/
204
void correctIntegralsByAcc0thOrder(void) {
205
  // TODO: Consider changing this to: Only correct when integrals are less than ...., or only correct when angular velocities
206
  // are less than ....., or reintroduce Kalman.
207
  // Well actually the Z axis acc. check is not so silly.
208
  uint8_t axis;
209
  int32_t temp;
2024 - 210
  if (acc[Z] >= -staticParams.zerothOrderGyroCorrectionZAccLimit && acc[Z]
1910 - 211
      <= dynamicParams.UserParams[7]) {
212
    DebugOut.Digital[0] |= DEBUG_ACC0THORDER;
213
 
2024 - 214
    uint8_t permilleAcc = staticParams.zerothOrderGyroCorrectionFactorx1000;
1910 - 215
    uint8_t debugFullWeight = 1;
216
    int32_t accDerived;
217
 
218
    if ((control[YAW] < -64) || (control[YAW] > 64)) { // reduce further if yaw stick is active
219
      permilleAcc /= 2;
220
      debugFullWeight = 0;
221
    }
222
 
223
    if ((maxControl[PITCH] > 64) || (maxControl[ROLL] > 64)) { // reduce effect during stick commands. Replace by controlActivity.
224
      permilleAcc /= 2;
225
      debugFullWeight = 0;
226
    }
227
 
228
    if (debugFullWeight)
229
      DebugOut.Digital[1] |= DEBUG_ACC0THORDER;
230
    else
231
      DebugOut.Digital[1] &= ~DEBUG_ACC0THORDER;
232
 
233
    /*
234
     * Add to each sum: The amount by which the angle is changed just below.
235
     */
236
    for (axis = PITCH; axis <= ROLL; axis++) {
237
      accDerived = getAngleEstimateFromAcc(axis);
238
      // DebugOut.Analog[9 + axis] = (10 * accDerived) / GYRO_DEG_FACTOR_PITCHROLL;
239
 
240
      // 1000 * the correction amount that will be added to the gyro angle in next line.
241
      temp = angle[axis]; //(permilleAcc * (accDerived - angle[axis])) / 1000;
242
      angle[axis] = ((int32_t) (1000L - permilleAcc) * temp
243
          + (int32_t) permilleAcc * accDerived) / 1000L;
244
      correctionSum[axis] += angle[axis] - temp;
245
    }
246
  } else {
247
    DebugOut.Digital[0] &= ~DEBUG_ACC0THORDER;
248
    DebugOut.Digital[1] &= ~DEBUG_ACC0THORDER;
249
    // DebugOut.Analog[9] = 0;
250
    // DebugOut.Analog[10] = 0;
251
 
252
    DebugOut.Analog[16] = 0;
253
    DebugOut.Analog[17] = 0;
254
    // experiment: Kill drift compensation updates when not flying smooth.
255
    correctionSum[PITCH] = correctionSum[ROLL] = 0;
256
  }
257
}
258
 
259
/************************************************************************
260
 * This is an attempt to correct not the error in the angle integrals
261
 * (that happens in correctIntegralsByAcc0thOrder above) but rather the
262
 * cause of it: Gyro drift, vibration and rounding errors.
263
 * All the corrections made in correctIntegralsByAcc0thOrder over
264
 * DRIFTCORRECTION_TIME cycles are summed up. This number is
265
 * then divided by DRIFTCORRECTION_TIME to get the approx.
266
 * correction that should have been applied to each iteration to fix
267
 * the error. This is then added to the dynamic offsets.
268
 ************************************************************************/
269
// 2 times / sec. = 488/2
270
#define DRIFTCORRECTION_TIME 256L
271
void driftCorrection(void) {
272
  static int16_t timer = DRIFTCORRECTION_TIME;
273
  int16_t deltaCorrection;
274
  int16_t round;
275
  uint8_t axis;
276
 
277
  if (!--timer) {
278
    timer = DRIFTCORRECTION_TIME;
279
    for (axis = PITCH; axis <= ROLL; axis++) {
280
      // Take the sum of corrections applied, add it to delta
281
      if (correctionSum[axis] >=0)
282
        round = DRIFTCORRECTION_TIME / 2;
283
      else
284
        round = -DRIFTCORRECTION_TIME / 2;
285
      deltaCorrection = (correctionSum[axis] + round) / DRIFTCORRECTION_TIME;
286
      // Add the delta to the compensation. So positive delta means, gyro should have higher value.
2024 - 287
      driftComp[axis] += deltaCorrection / staticParams.secondOrderGyroCorrectionDivisor;
288
      CHECK_MIN_MAX(driftComp[axis], -staticParams.secondOrderGyroCorrectionLimit, staticParams.secondOrderGyroCorrectionLimit);
1910 - 289
      // DebugOut.Analog[11 + axis] = correctionSum[axis];
290
      DebugOut.Analog[16 + axis] = correctionSum[axis];
291
      DebugOut.Analog[28 + axis] = driftComp[axis];
292
 
293
      correctionSum[axis] = 0;
294
    }
295
  }
296
}
297
 
298
/************************************************************************
299
 * Main procedure.
300
 ************************************************************************/
301
void calculateFlightAttitude(void) {
302
  getAnalogData();
303
  integrate();
304
 
305
  DebugOut.Analog[3] = rate_PID[PITCH];
306
  DebugOut.Analog[4] = rate_PID[ROLL];
307
  DebugOut.Analog[5] = yawRate;
308
 
309
#ifdef ATTITUDE_USE_ACC_SENSORS
310
  correctIntegralsByAcc0thOrder();
311
  driftCorrection();
312
#endif
313
}