Subversion Repositories FlightCtrl

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Copyright (c) 04.2007 Holger Buss
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#include <stdlib.h>
#include <avr/io.h>
#include "eeprom.h"
#include "flight.h"
#include "output.h"

// Only for debug. Remove.
//#include "analog.h"
//#include "rc.h"

// Necessary for external control and motor test
#include "uart0.h"

// for scope debugging
// #include "rc.h"

#include "twimaster.h"
#include "attitude.h"
#include "controlMixer.h"
#include "commands.h"
#ifdef USE_MK3MAG
#include "gps.h"
#endif

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

/*
 * These are no longer maintained, just left at 0. The original implementation just summed the acc.
 * value to them every 2 ms. No filtering or anything. Just a case for an eventual overflow?? Hey???
 */
// int16_t naviAccPitch = 0, naviAccRoll = 0, naviCntAcc = 0;

uint8_t gyroPFactor, gyroIFactor;       // the PD factors for the attitude control
uint8_t yawPFactor, yawIFactor; // the PD factors for the yaw control

// Some integral weight constant...
uint16_t Ki = 10300 / 33;
uint8_t RequiredMotors = 0;

// No support for altitude control right now.
// int16_t SetPointHeight = 0;

/************************************************************************/
/*  Filter for motor value smoothing (necessary???)                     */
/************************************************************************/
int16_t motorFilter(int16_t newvalue, int16_t oldvalue) {
  switch(dynamicParams.UserParams[5]) {
  case 0:
    return newvalue;
  case 1:
    return (oldvalue + newvalue) / 2;  
  case 2:
    if(newvalue > oldvalue)
      return (1 * (int16_t)oldvalue + newvalue) / 2;  //mean of old and new
    else       
      return newvalue - (oldvalue - newvalue) * 1; // 2 * new - old
  case 3:
    if(newvalue < oldvalue)
      return (1 * (int16_t)oldvalue + newvalue) / 2;  //mean of old and new
    else       
      return newvalue - (oldvalue - newvalue) * 1; // 2 * new - old
  default: return newvalue;
  }
}

/************************************************************************/
/*  Neutral Readings                                                    */
/************************************************************************/
void flight_setNeutral() {
  MKFlags |= MKFLAG_CALIBRATE;

  // not really used here any more.
  dynamicParams.KalmanK = -1;
  dynamicParams.KalmanMaxDrift = 0;
  dynamicParams.KalmanMaxFusion = 32;

  controlMixer_initVariables();
}

void setFlightParameters(uint8_t _Ki, uint8_t _gyroPFactor, uint8_t _gyroIFactor, uint8_t _yawPFactor, uint8_t _yawIFactor) {
  Ki = 10300 / _Ki;
  gyroPFactor = _gyroPFactor;
  gyroIFactor = _gyroIFactor;
  yawPFactor = _yawPFactor;
  yawIFactor = _yawIFactor;
}

void setNormalFlightParameters(void) {
  setFlightParameters(dynamicParams.IFactor + 1,
                      dynamicParams.GyroP + 10,
                      staticParams.GlobalConfig & CFG_HEADING_HOLD ? 0 : dynamicParams.GyroI,
                      dynamicParams.GyroP + 10,
                      dynamicParams.UserParams[6]
                      );
}

void setStableFlightParameters(void) {
  setFlightParameters(33, 90, 120, 90, 120);
}


/************************************************************************/
/*  Main Flight Control                                                 */
/************************************************************************/
void flight_control(void) {
  int16_t tmp_int;
    // Mixer Fractions that are combined for Motor Control
  int16_t yawTerm, throttleTerm, term[2];

  // PID controller variables
  int16_t PDPart[2], PDPartYaw, PPart[2];
  static int32_t IPart[2] = {0,0};
  //  static int32_t yawControlRate = 0;

  // Removed. Too complicated, and apparently not necessary with MEMS gyros anyway.
  // static int32_t IntegralGyroPitchError = 0, IntegralGyroRollError = 0;
  // static int32_t CorrectionPitch, CorrectionRoll;

  static uint16_t emergencyFlightTime;
  static int8_t debugDataTimer = 1;

  // High resolution motor values for smoothing of PID motor outputs
  static int16_t motorFilters[MAX_MOTORS];

  uint8_t i, axis;

  controlMixer_update();

  // Fire the main flight attitude calculation, including integration of angles.
  calculateFlightAttitude();

  throttleTerm = controlThrottle;
  // This check removed. Is done on a per-motor basis, after output matrix multiplication.
  if(throttleTerm < staticParams.MinThrottle + 10) throttleTerm = staticParams.MinThrottle + 10;
  else if(throttleTerm > staticParams.MaxThrottle - 20) throttleTerm = (staticParams.MaxThrottle - 20);

  /************************************************************************/
  /* RC-signal is bad                                                     */
  /* This part could be abstracted, as having yet another control input   */
  /* to the control mixer: An emergency autopilot control.                */
  /************************************************************************/

  if(controlMixer_getSignalQuality() <= SIGNAL_BAD) {           // the rc-frame signal is not reveived or noisy
    RED_ON;
    beepRCAlarm();
   
    if(emergencyFlightTime) {
      // continue emergency flight
      emergencyFlightTime--;
      if(isFlying > 256) {                    
        // We're probably still flying. Descend slowly.
        throttleTerm = staticParams.EmergencyGas;  // Set emergency throttle
        MKFlags |= (MKFLAG_EMERGENCY_LANDING);     // Set flag for emergency landing
        setStableFlightParameters();
      } else {
        MKFlags &= ~(MKFLAG_MOTOR_RUN);            // Probably not flying, and bad R/C signal. Kill motors.
      }
    } else {
      // end emergency flight (just cut the motors???)
      MKFlags &= ~(MKFLAG_MOTOR_RUN | MKFLAG_EMERGENCY_LANDING);
    }
  } else {
    // signal is acceptable
    if(controlMixer_getSignalQuality() > SIGNAL_BAD) {
      // Reset emergency landing control variables.
      MKFlags &= ~(MKFLAG_EMERGENCY_LANDING);  // clear flag for emergency landing
      // The time is in whole seconds.
      emergencyFlightTime = (uint16_t)staticParams.EmergencyGasDuration * 488;
    }

    // If some throttle is given, and the motor-run flag is on, increase the probability that we are flying.
    if(throttleTerm > 40 && (MKFlags & MKFLAG_MOTOR_RUN)) {
      // increment flight-time counter until overflow.
      if(isFlying != 0xFFFF) isFlying++;
    } else
      /*
       * When standing on the ground, do not apply I controls and zero the yaw stick.
       * Probably to avoid integration effects that will cause the copter to spin
       * or flip when taking off.
       */
      if(isFlying < 256) {
        IPart[PITCH] = IPart[ROLL] = 0;
        // TODO: Don't stomp on other modules' variables!!!
        // controlYaw = 0;
        PDPartYaw = 0; // instead.
        if(isFlying == 250) {
          // HC_setGround();
          updateCompassCourse = 1;
          yawAngleDiff = 0;
        }
      } else {
            // Set fly flag. TODO: Hmmm what can we trust - the isFlying counter or the flag?
            // Answer: The counter. The flag is not read from anywhere anyway... except the NC maybe.
            MKFlags |= (MKFLAG_FLY);
      }

        commands_handleCommands();

    // if(controlMixer_getSignalQuality() >= SIGNAL_GOOD) {
    setNormalFlightParameters();
    // }
  } // end else (not bad signal case)
  // end part1a: 750-800 usec.
  /*
   * Looping the H&I way basically is just a matter of turning off attitude angle measurement
   * by integration (because 300 deg/s gyros are too slow) and turning down the throttle.
   * This is the throttle part.
   */
  if(looping) {
    if(throttleTerm > staticParams.LoopGasLimit) throttleTerm = staticParams.LoopGasLimit;
  }
 
  /************************************************************************/
  /*  Yawing                                                              */
  /************************************************************************/
  if(abs(controlYaw) > 4 * staticParams.StickYawP) { // yaw stick is activated
    ignoreCompassTimer = 1000;
    if(!(staticParams.GlobalConfig & CFG_COMPASS_FIX)) {
      updateCompassCourse = 1;
    }
  }
 
  //  yawControlRate = controlYaw;

  // Trim drift of yawAngleDiff with controlYaw.
  // TODO: We want NO feedback of control related stuff to the attitude related stuff.
  // This seems to be used as: Difference desired <--> real heading.
  yawAngleDiff -= controlYaw;
 
  // limit the effect
  CHECK_MIN_MAX(yawAngleDiff, -50000, 50000);
 
  /************************************************************************/
  /* Compass is currently not supported.                                  */
  /************************************************************************/
  if(staticParams.GlobalConfig & (CFG_COMPASS_ACTIVE|CFG_GPS_ACTIVE)) {
    updateCompass();
  }
 
#if defined (USE_NAVICTRL)
  /************************************************************************/
  /* GPS is currently not supported.                                      */
  /************************************************************************/
  if(staticParams.GlobalConfig & CFG_GPS_ACTIVE) {
    GPS_Main();
    MKFlags &= ~(MKFLAG_CALIBRATE | MKFLAG_START);
  } else {
  }
#endif
  // end part 1: 750-800 usec.
  // start part 3: 350 - 400 usec.
#define SENSOR_LIMIT  (4096 * 4)
    /************************************************************************/

    /* Calculate control feedback from angle (gyro integral)                */
    /* and angular velocity (gyro signal)                                   */
    /************************************************************************/
    // The P-part is the P of the PID controller. That's the angle integrals (not rates).
  for (axis=PITCH; axis<=ROLL; axis++) {
    if(looping & ((1<<4)<<axis)) {
      PPart[axis] = 0;
    } else { // TODO: Where do the 44000 come from???
      PPart[axis] = angle[axis] * gyroIFactor / (44000 / CONTROL_SCALING); // P-Part - Proportional to Integral
    }

    /*
     * Now blend in the D-part - proportional to the Differential of the integral = the rate.
     * Read this as: PDPart = PPart + rate_PID * pfactor * CONTROL_SCALING
     * where pfactor is in [0..1].
     */
    PDPart[axis] = PPart[axis] + (int32_t)((int32_t)rate_PID[axis] * gyroPFactor / (256L / CONTROL_SCALING))
      + (differential[axis] * (int16_t)dynamicParams.GyroD) / 16;

    CHECK_MIN_MAX(PDPart[axis], -SENSOR_LIMIT, SENSOR_LIMIT);
  }

  PDPartYaw =
    (int32_t)(yawRate * 2 * (int32_t)yawPFactor) / (256L / CONTROL_SCALING)
  + (int32_t)(yawAngleDiff * yawIFactor) / (2 * (44000 / CONTROL_SCALING));
 
  // limit control feedback
  CHECK_MIN_MAX(PDPartYaw, -SENSOR_LIMIT, SENSOR_LIMIT);
 
  /*
   * Compose throttle term.
   * If a Bl-Ctrl is missing, prevent takeoff.
   */
  if(missingMotor) {
    // if we are in the lift off condition. Hmmmmmm when is throttleTerm == 0 anyway???
    if(isFlying > 1 && isFlying < 50 && throttleTerm > 0)
      isFlying = 1; // keep within lift off condition
    throttleTerm = staticParams.MinThrottle; // reduce gas to min to avoid lift of
  }

  // Scale up to higher resolution. Hmm why is it not (from controlMixer and down) scaled already?
  throttleTerm *= CONTROL_SCALING;

  /*
   * Compose yaw term.
   * The yaw term is limited: Absolute value is max. = the throttle term / 2.
   * However, at low throttle the yaw term is limited to a fixed value,
   * and at high throttle it is limited by the throttle reserve (the difference
   * between current throttle and maximum throttle).
   */
#define MIN_YAWGAS (40 * CONTROL_SCALING)  // yaw also below this gas value
  yawTerm = PDPartYaw - controlYaw * CONTROL_SCALING;
  // Limit yawTerm
  DebugOut.Digital[0] &= ~DEBUG_CLIP;
  if(throttleTerm > MIN_YAWGAS) {
    if (yawTerm < -throttleTerm/2) {
      DebugOut.Digital[0] |= DEBUG_CLIP;
      yawTerm = -throttleTerm/2;
    } else if (yawTerm > throttleTerm/2) {
      DebugOut.Digital[0] |= DEBUG_CLIP;
      yawTerm = throttleTerm/2;
    }
    //CHECK_MIN_MAX(yawTerm, - (throttleTerm / 2), (throttleTerm / 2));
  } else {
    if (yawTerm < -MIN_YAWGAS/2) {
      DebugOut.Digital[0] |= DEBUG_CLIP;
      yawTerm = -MIN_YAWGAS/2;
    } else if (yawTerm > MIN_YAWGAS/2) {
      DebugOut.Digital[0] |= DEBUG_CLIP;
      yawTerm = MIN_YAWGAS/2;
    }
    //CHECK_MIN_MAX(yawTerm, - (MIN_YAWGAS / 2), (MIN_YAWGAS / 2));
  }

  // FIXME: Throttle may exceed maxThrottle (there is no check no more).
  tmp_int = staticParams.MaxThrottle * CONTROL_SCALING;
  if (yawTerm < -(tmp_int - throttleTerm)) {
    yawTerm = -(tmp_int - throttleTerm);
    DebugOut.Digital[0] |= DEBUG_CLIP;
  } else if (yawTerm > (tmp_int - throttleTerm)) {
    yawTerm = (tmp_int - throttleTerm);
    DebugOut.Digital[0] |= DEBUG_CLIP;
  }
  // CHECK_MIN_MAX(yawTerm, -(tmp_int - throttleTerm), (tmp_int - throttleTerm));
  DebugOut.Digital[1] &= ~DEBUG_CLIP;
  for (axis=PITCH; axis<=ROLL; axis++) {  
    /*
     * Compose pitch and roll terms. This is finally where the sticks come into play.
     */
    if(gyroIFactor) {
      // Integration mode: Integrate (angle - stick) = the difference between angle and stick pos.
      // That means: Holding the stick a little forward will, at constant flight attitude, cause this to grow (decline??) over time.
      // TODO: Find out why this seems to be proportional to stick position - not integrating it at all.
      IPart[axis] += PPart[axis] - control[axis]; // Integrate difference between P part (the angle) and the stick pos.
    } else {
      // "HH" mode: Integrate (rate - stick) = the difference between rotation rate and stick pos.
      // To keep up with a full stick PDPart should be about 156...
      IPart[axis] += PDPart[axis] - control[axis]; // With gyroIFactor == 0, PDPart is really just a D-part. Integrate D-part (the rot. rate) and the stick pos.
    }

    tmp_int = (int32_t)((int32_t) dynamicParams.DynamicStability * (int32_t) (throttleTerm + abs(yawTerm) / 2)) / 64;

    // TODO: From which planet comes the 16000?
    CHECK_MIN_MAX(IPart[axis], -(CONTROL_SCALING * 16000L), (CONTROL_SCALING * 16000L));
    // Add (P, D) parts minus stick pos. to the scaled-down I part.
    term[axis] = PDPart[axis] - control[axis] + IPart[axis] / Ki;    // PID-controller for pitch

    /*
     * Apply "dynamic stability" - that is: Limit pitch and roll terms to a growing function of throttle and yaw(!).
     * The higher the dynamic stability parameter, the wider the bounds. 64 seems to be a kind of unity
     * (max. pitch or roll term is the throttle value).
     * TODO: Why a growing function of yaw?
     */
    if (term[axis] < -tmp_int) {
      DebugOut.Digital[1] |= DEBUG_CLIP;
    } else if (term[axis] > tmp_int) {
      DebugOut.Digital[1] |= DEBUG_CLIP;
    }
    CHECK_MIN_MAX(term[axis], -tmp_int, tmp_int);
  }
  // end part 3: 350 - 400 usec.

  // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  // Universal Mixer
  // Each (pitch, roll, throttle, yaw) term is in the range [0..255 * CONTROL_SCALING].
  // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  DebugOut.Analog[12] = term[PITCH];
  DebugOut.Analog[13] = term[ROLL];
  DebugOut.Analog[14] = yawTerm;
  DebugOut.Analog[15] = throttleTerm;

  for(i = 0; i < MAX_MOTORS; i++) {
    int16_t tmp;
    if (MKFlags & MKFLAG_MOTOR_RUN && Mixer.Motor[i][MIX_THROTTLE] > 0) {
      tmp = ((int32_t) throttleTerm * Mixer.Motor[i][MIX_THROTTLE]) / 64L;
      tmp += ((int32_t) term[PITCH] * Mixer.Motor[i][MIX_PITCH]) / 64L;
      tmp += ((int32_t) term[ROLL] * Mixer.Motor[i][MIX_ROLL]) / 64L;
      tmp += ((int32_t) yawTerm * Mixer.Motor[i][MIX_YAW]) / 64L;
      motorFilters[i] = motorFilter(tmp, motorFilters[i]);
      // Now we scale back down to a 0..255 range.
      tmp = motorFilters[i] / MOTOR_SCALING;

      // So this was the THIRD time a throttle was limited. But should the limitation
      // apply to the common throttle signal (the one used for setting the "power" of
      // all motors together) or should it limit the throttle set for each motor,
      // including mix components of pitch, roll and yaw? I think only the common
      // throttle should be limited.
      // --> WRONG. This caused motors to stall completely in tight maneuvers.
      // Apply to individual signals instead.
      CHECK_MIN_MAX(tmp, 8, 255);
      motor[i].SetPoint = tmp;
    }
    else if (motorTestActive) {
      motor[i].SetPoint = motorTest[i];
    } else {
      motor[i].SetPoint = 0;
    }
    if (i < 4)
      DebugOut.Analog[22+i] = motor[i].SetPoint;
  }
  I2C_Start(TWI_STATE_MOTOR_TX);
 
  // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  // Debugging
  // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  if(!(--debugDataTimer)) {
    debugDataTimer = 24; // update debug outputs at 488 / 24 = 20.3 Hz.
    DebugOut.Analog[0]  = (10 * angle[PITCH]) / GYRO_DEG_FACTOR_PITCHROLL; // in 0.1 deg
    DebugOut.Analog[1]  = (10 * angle[ROLL]) / GYRO_DEG_FACTOR_PITCHROLL; // in 0.1 deg
    DebugOut.Analog[2]  = yawGyroHeading / GYRO_DEG_FACTOR_YAW;

    /*
    DebugOut.Analog[23] = (yawRate * 2 * (int32_t)yawPFactor) / (256L / CONTROL_SCALING);
    DebugOut.Analog[24] = controlYaw;
    DebugOut.Analog[25] = yawAngleDiff / 100L;
    DebugOut.Analog[26] = accNoisePeak[PITCH];
    DebugOut.Analog[27] = accNoisePeak[ROLL];
    DebugOut.Analog[30] = gyroNoisePeak[PITCH];
    DebugOut.Analog[31] = gyroNoisePeak[ROLL];
    */
  }
}