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"

#include "uart0.h"

// Necessary for external control and motor test

#include "twimaster.h"

#include "attitude.h"

#include "controlMixer.h"

#include "commands.h"

#include "heightControl.h"

#ifdef USE_MK3MAG

#include "mk3mag.h"

#include "compassControl.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 * These are no longer maintained, just left at 0.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

uint8_t invKi = 64;

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

/*  Filter for motor value smoothing (necessary???)                     */

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

int16_t motorFilter(int16_t newvalue, int16_t oldvalue) {

  switch (staticParams.motorSmoothing) {

  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 _invKi, uint8_t _gyroPFactor,

    uint8_t _gyroIFactor, uint8_t _yawPFactor, uint8_t _yawIFactor) {

  invKi = _invKi;

  gyroPFactor = _gyroPFactor;

  gyroIFactor = _gyroIFactor;

  yawPFactor = _yawPFactor;

  yawIFactor = _yawIFactor;

}

void setNormalFlightParameters(void) {

  setFlightParameters(

                      staticParams.IFactor,

                      dynamicParams.gyroP,

                      staticParams.bitConfig & CFG_HEADING_HOLD ? 0 : dynamicParams.gyroI,

                      dynamicParams.gyroP,

                      staticParams.yawIFactor

                      );

}

void setStableFlightParameters(void) {

  setFlightParameters(0, 90, 120, 90, 120);

}

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

/*  Main Flight Control                                                 */

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

void flight_control(void) {

  uint16_t tmp_int;

  // Mixer Fractions that are combined for Motor Control

  int16_t yawTerm, throttleTerm, term[2];

  // PID controller variables

  int16_t PDPart;

  static int32_t IPart[2] = {0, 0};

  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;

  throttleTerm = controls[CONTROL_THROTTLE];

  // 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

    if (controlMixer_didReceiveSignal) beepRCAlarm();  // Only make alarm if a control signal was received before the signal loss.

    if (emergencyFlightTime) {

      // continue emergency flight

      emergencyFlightTime--;

      if (isFlying > 256) {

        // We're probably still flying. Descend slowly.

        throttleTerm = staticParams.emergencyThrottle; // Set emergency throttle

        MKFlags |= (MKFLAG_EMERGENCY_FLIGHT); // 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_FLIGHT);

    }

  } else {

    // signal is acceptable

    if (controlMixer_getSignalQuality() > SIGNAL_BAD) {

      // Reset emergency landing control variables.

      MKFlags &= ~(MKFLAG_EMERGENCY_FLIGHT); // clear flag for emergency landing

      // The time is in whole seconds.

      if (staticParams.emergencyFlightDuration > (65535-F_MAINLOOP)/F_MAINLOOP)

        emergencyFlightTime = 0xffff;

      else

        emergencyFlightTime = (uint16_t)staticParams.emergencyFlightDuration * F_MAINLOOP;

    }

    // 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;

        if (isFlying == 250) {

          HC_setGround();

#ifdef USE_MK3MAG

          attitude_resetHeadingToMagnetic();

          compass_setTakeoffHeading(heading);

#endif

          // Set target heading to the one just gotten off compass.

          // targetHeading = heading;

        }

   } 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();

    setNormalFlightParameters();

  } // end else (not bad signal case)

  // end part 1: 750-800 usec.

  // start part 3: 350 - 400 usec.

#define YAW_I_LIMIT (45L * GYRO_DEG_FACTOR_YAW)

  // This is where control affects the target heading. It also (later) directly controls yaw.

  headingError -= controls[CONTROL_YAW];

  debugOut.analog[28] = headingError / 100;

  if (headingError < -YAW_I_LIMIT) headingError = -YAW_I_LIMIT;

  if (headingError > YAW_I_LIMIT) headingError = YAW_I_LIMIT;

  PDPart =  (int32_t)(headingError * yawIFactor) / (GYRO_DEG_FACTOR_YAW << 4);

  // Ehhhhh here is something with desired yaw rate, not?? Ahh OK it gets added in later on.

  PDPart += (int32_t)(yawRate * yawPFactor) /  (GYRO_DEG_FACTOR_YAW >> 5);

  /*

   * 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 = PDPart - controls[CONTROL_YAW] * 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;

    }

  } 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;

    }

  }

  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;

  }

  debugOut.digital[1] &= ~DEBUG_CLIP;

  tmp_int = ((uint16_t)dynamicParams.dynamicStability * ((uint16_t)throttleTerm + abs(yawTerm) / 2)) >> 6;

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

  /* 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++) {

    int16_t iDiff;

    iDiff = PDPart = attitude[axis] * gyroIFactor / (GYRO_DEG_FACTOR_PITCHROLL << 3);

    PDPart += (int32_t)rate_PID[axis] * gyroPFactor / (GYRO_DEG_FACTOR_PITCHROLL >> 4);

    PDPart += (differential[axis] * (int16_t) dynamicParams.gyroD) / 16;

    // In acc. mode the I part is summed only from the attitude (IFaktor) angle minus stick.

    // In HH mode, the I part is summed from P and D of gyros minus stick.

    if (gyroIFactor) {

      IPart[axis] += iDiff - controls[axis]; // With gyroIFactor == 0, PDPart is really just a D-part. Integrate D-part (the rot. rate) and the stick pos.

    } else {

      IPart[axis] += PDPart - controls[axis]; // With gyroIFactor == 0, PDPart is really just a D-part. Integrate D-part (the rot. rate) and the stick pos.

    }

    // With normal Ki, limit effect to +/- 205 (of 1024!!!)

    if (IPart[axis] < -64000) {

      IPart[axis] = -64000;

      debugOut.digital[1] |= DEBUG_FLIGHTCLIP;

    } else if (IPart[axis] > 64000) {

      IPart[axis] = 64000;

      debugOut.digital[1] |= DEBUG_FLIGHTCLIP;

    }

    term[axis] = PDPart - controls[axis] + ((int32_t)IPart[axis] * invKi) >> 14;

        term[axis] += (dynamicParams.levelCorrection[axis] - 128);

        /*

     * 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;

    }

  }

  // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  // Universal Mixer

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

  // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  debugOut.analog[3]  = rate_ATT[PITCH];

  debugOut.analog[4]  = rate_ATT[ROLL];

  debugOut.analog[5]  = yawRate;

  debugOut.analog[6]  = filteredAcc[PITCH];

  debugOut.analog[7]  = filteredAcc[ROLL];

  debugOut.analog[8]  = filteredAcc[Z];

  debugOut.analog[13] = term[PITCH];

  debugOut.analog[14] = term[ROLL];

  debugOut.analog[15] = yawTerm;

  debugOut.analog[16] = throttleTerm;

  for (i = 0; i < MAX_MOTORS; i++) {

    int32_t tmp;

    uint8_t throttle;

    tmp = (int32_t)throttleTerm * mixerMatrix.motor[i][MIX_THROTTLE];

    tmp += (int32_t)term[PITCH] * mixerMatrix.motor[i][MIX_PITCH];

    tmp += (int32_t)term[ROLL] * mixerMatrix.motor[i][MIX_ROLL];

    tmp += (int32_t)yawTerm * mixerMatrix.motor[i][MIX_YAW];

    tmp = tmp >> 6;

    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, 1, 255);

    throttle = tmp;

    // if (i < 4) debugOut.analog[22 + i] = throttle;

    if ((MKFlags & MKFLAG_MOTOR_RUN) && mixerMatrix.motor[i][MIX_THROTTLE] > 0) {

      motor[i].throttle = throttle;

    } else if (motorTestActive) {

      motor[i].throttle = motorTest[i];

    } else {

      motor[i].throttle = 0;

    }

  }

  I2C_Start(TWI_STATE_MOTOR_TX);

  // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  // Debugging

  // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  if (!(--debugDataTimer)) {

    debugDataTimer = 24; // update debug outputs at 488 / 24 = 20.3 Hz.

    debugOut.analog[0] = attitude[PITCH] / (GYRO_DEG_FACTOR_PITCHROLL/10); // in 0.1 deg

    debugOut.analog[1] = attitude[ROLL]  / (GYRO_DEG_FACTOR_PITCHROLL/10); // in 0.1 deg

    debugOut.analog[2] = heading / GYRO_DEG_FACTOR_YAW;

  }

}