esp-fc

#include "Control/Controller.h"
#include "Utils/Math.hpp"
#include <algorithm>

namespace Espfc::Control {

Controller::Controller(Model& model): _model(model), _rates{} {}

int Controller::begin()
{
  _rates.begin(_model.config.input);
  _speedFilter.begin(FilterConfig(FILTER_BIQUAD, 10), _model.state.loopTimer.rate);

  constexpr float FAULT_DECAY_TAU = 2.5f; // seconds, independent of loop rate
  _faultDecay =
      1.f - 1.f / (_model.state.loopTimer.rate * FAULT_DECAY_TAU); // ~= exp(-dt / FAULT_DECAY_TAU) for dt << tau

  beginInnerLoop(AXIS_ROLL);
  beginInnerLoop(AXIS_PITCH);
  beginInnerLoop(AXIS_YAW);
  beginOuterLoop(AXIS_ROLL);
  beginOuterLoop(AXIS_PITCH);
  beginAltHold();

  return 1;
}

int FAST_CODE_ATTR Controller::update()
{
  uint32_t startTime = 0;
  if (_model.config.debug.mode == DEBUG_PIDLOOP)
  {
    startTime = micros();
    _model.state.debug[0] = startTime - _model.state.loopTimer.last;
  }

  {
    Utils::Stats::Measure measure(_model.state.stats, COUNTER_OUTER_PID);
    resetIterm();
    switch (_model.config.mixer.type)
    {
      case FC_MIXER_GIMBAL:
        outerLoopRobot();
        break;

      default:
        outerLoop();
        break;
    }
  }

  {
    Utils::Stats::Measure measure(_model.state.stats, COUNTER_INNER_PID);
    switch (_model.config.mixer.type)
    {
      case FC_MIXER_GIMBAL:
        innerLoopRobot();
        break;

      default:
        innerLoop();
        break;
    }
  }

  if (_model.config.debug.mode == DEBUG_PIDLOOP)
  {
    _model.state.debug[2] = micros() - startTime;
  }

  return 1;
}

void Controller::outerLoopRobot()
{
  const float speedScale = 2.f;
  const float gyroScale = 0.1f;
  const float speed = _speedFilter.update(_model.state.output.ch[AXIS_PITCH] * speedScale +
                                          _model.state.gyro.adc[AXIS_PITCH] * gyroScale);
  float angle = 0;
  const auto& input = _model.state.input;
  const auto& levelConf = _model.config.level;

  if (true || _model.isModeActive(MODE_ANGLE))
  {
    angle = input.ch[AXIS_PITCH] * Utils::toRad(levelConf.angleLimit);
  }
  else
  {
    angle = _model.state.outerPid[AXIS_PITCH].update(input.ch[AXIS_PITCH], speed) * Utils::toRad(levelConf.rateLimit);
  }
  _model.state.setpoint.angle.set(AXIS_PITCH, angle);
  _model.state.setpoint.rate[AXIS_YAW] = input.ch[AXIS_YAW] * Utils::toRad(levelConf.rateLimit);

  if (_model.config.debug.mode == DEBUG_ANGLERATE)
  {
    _model.state.debug[0] = speed * 1000;
    _model.state.debug[1] = lrintf(Utils::toDeg(angle) * 10);
  }
}

void Controller::innerLoopRobot()
{
  // VectorFloat v(0.f, 0.f, 1.f);
  // v.rotate(_model.state.attitude.quaternion);
  // const float angle = acos(v.z);

  const auto& attitude = _model.state.attitude;
  const auto& setpoint = _model.state.setpoint;

  auto& output = _model.state.output;
  auto& innerPid = _model.state.innerPid;

  const float angle = std::max(abs(attitude.euler[AXIS_PITCH]), abs(attitude.euler[AXIS_ROLL]));
  const bool stabilize = angle < Utils::toRad(_model.config.level.angleLimit);
  if (stabilize)
  {
    output.ch[AXIS_PITCH] = innerPid[AXIS_PITCH].update(setpoint.angle[AXIS_PITCH], attitude.euler[AXIS_PITCH]);
    output.ch[AXIS_YAW] = innerPid[AXIS_YAW].update(setpoint.rate[AXIS_YAW], _model.state.gyro.adc[AXIS_YAW]);
  }
  else
  {
    resetIterm();
    output.ch[AXIS_PITCH] = 0.f;
    output.ch[AXIS_YAW] = 0.f;
  }

  if (_model.config.debug.mode == DEBUG_ANGLERATE)
  {
    _model.state.debug[2] = lrintf(Utils::toDeg(attitude.euler[AXIS_PITCH]) * 10);
    _model.state.debug[3] = lrintf(output.ch[AXIS_PITCH] * 1000);
  }
}

void FAST_CODE_ATTR Controller::outerLoop()
{
  // Roll/Pitch rates control
  if (_model.isModeActive(MODE_ANGLE))
  {
    for (size_t i = 0; i < AXIS_COUNT_RP; i++)
    {
      const float angleSetpoint = Utils::toRad(_model.config.level.angleLimit) * _model.state.input.ch[i];
      _model.state.setpoint.rate[i] = _model.state.outerPid[i].update(angleSetpoint, _model.state.attitude.euler[i]);
      // disable fterm in angle mode
      _model.state.innerPid[i].fScale = 0.f;
    }
  }
  else
  {
    for (size_t i = 0; i < AXIS_COUNT_RP; i++)
    {
      _model.state.setpoint.rate[i] = calculateSetpointRate(i, _model.state.input.ch[i]);
    }
  }

  // Yaw rates control
  _model.state.setpoint.rate[AXIS_YAW] = calculateSetpointRate(AXIS_YAW, _model.state.input.ch[AXIS_YAW]);

  // thrust control
  if (_model.isModeActive(MODE_ALTHOLD))
  {
    _model.state.setpoint.rate[AXIS_THRUST] = calcualteAltHoldSetpoint();
  }
  else
  {
    _model.state.setpoint.rate[AXIS_THRUST] = _model.state.input.ch[AXIS_THRUST];
  }

  // debug
  if (_model.config.debug.mode == DEBUG_ANGLERATE)
  {
    for (size_t i = 0; i < AXIS_COUNT_RPY; ++i)
    {
      _model.state.debug[i] = lrintf(Utils::toDeg(_model.state.setpoint.rate[i]));
    }
  }
}

void FAST_CODE_ATTR Controller::innerLoop()
{
  // Roll/Pitch/Yaw rates control
  const float tpaFactor = getTpaFactor();
  const auto& setpoint = _model.state.setpoint;
  const auto& altitude = _model.state.altitude;

  auto& innerPid = _model.state.innerPid;
  auto& output = _model.state.output;

  for (size_t i = 0; i < AXIS_COUNT_RPY; ++i)
  {
    output.ch[i] = innerPid[i].update(setpoint.rate[i], _model.state.gyro.adc[i]) * tpaFactor;
  }

  updateFaultIntegral();

  // thrust control
  if (_model.isModeActive(MODE_ALTHOLD))
  {
    output.ch[AXIS_THRUST] = innerPid[AXIS_THRUST].update(setpoint.rate[AXIS_THRUST], altitude.vario);
  }
  else
  {
    innerPid[AXIS_THRUST].update(0, altitude.vario);
    // follow iTerm from rc input for smooth mid-air transition
    innerPid[AXIS_THRUST].iTerm = _model.state.input.ch[AXIS_THRUST];
    output.ch[AXIS_THRUST] = setpoint.rate[AXIS_THRUST];
  }

  if (_model.config.debug.mode == DEBUG_STACK)
  {
    _model.state.debug[0] = std::clamp(lrintf(setpoint.rate[AXIS_THRUST] * 1000.0f), -3000l, 3000l);    // hi mem
    _model.state.debug[1] = std::clamp(lrintf(altitude.vario * 1000.0f), -30000l, 30000l);              // lo mem
    _model.state.debug[2] = std::clamp(lrintf(altitude.height * 100.0f), -30000l, 30000l);              // curr
    _model.state.debug[3] = std::clamp(lrintf(innerPid[AXIS_THRUST].error * 1000.0f), -30000l, 30000l); // p
    _model.state.debug[4] = std::clamp(lrintf(innerPid[AXIS_THRUST].pTerm * 1000.0f), -3000l, 3000l);
    _model.state.debug[5] = std::clamp(lrintf(innerPid[AXIS_THRUST].iTerm * 1000.0f), -3000l, 3000l);
    _model.state.debug[6] = std::clamp(lrintf(innerPid[AXIS_THRUST].dTerm * 1000.0f), -3000l, 3000l);
    _model.state.debug[7] = std::clamp(lrintf(innerPid[AXIS_THRUST].fTerm * 1000.0f), -3000l, 3000l);
  }

  // debug
  if (_model.config.debug.mode == DEBUG_ITERM_RELAX)
  {
    _model.state.debug[0] = lrintf(Utils::toDeg(innerPid[AXIS_ROLL].itermRelaxBase));
    _model.state.debug[1] = lrintf(innerPid[AXIS_ROLL].itermRelaxFactor * 100.0f);
    _model.state.debug[2] = lrintf(Utils::toDeg(innerPid[AXIS_ROLL].iTermError));
    _model.state.debug[3] = lrintf(innerPid[AXIS_ROLL].iTerm * 1000.0f);
  }
}

void Controller::updateFaultIntegral()
{
  if (_model.state.runaway.status == RunawayProtectionStatus::RUNAWAY_STATUS_MONITORING)
  {
    const auto& innerPid = _model.state.innerPid;
    const auto& threshold = Utils::toRad(80.f); // 80 degrees
    bool kill = false;
    for (size_t i = 0; i < AXIS_COUNT_RPY; ++i)
    {
      _model.state.runaway.axisFault[i] += innerPid[i].error * innerPid[i].dt;
      _model.state.runaway.axisFault[i] *= _faultDecay;
      if (std::fabs(_model.state.runaway.axisFault[i]) > threshold)
      {
        kill = true;
      }
    }
    if (kill)
    {
      _model.state.runaway.status = RunawayProtectionStatus::RUNAWAY_STATUS_KILL;
      _model.disarm(DISARM_REASON_RUNAWAY_TAKEOFF);
    }
  }
}

float Controller::calcualteAltHoldSetpoint() const
{
  float thrust = _model.state.input.ch[AXIS_THRUST];

  // if(_model.isThrottleLow()) thrust = 0.0f; // stick below min check, no command

  thrust = Utils::deadband(thrust, 0.1f); // +/- 12.5% deadband

  return Utils::map3(thrust, -1.f, 0.f, 1.f, -2.0f, 0.f, 4.f); // climb rate 5ms, descend rate 2 m/s
}

float Controller::getTpaFactor() const
{
  if (_model.config.controller.tpaScale == 0) return 1.f;
  float t = std::clamp<float>(_model.state.input.us[AXIS_THRUST], _model.config.controller.tpaBreakpoint, 2000.f);
  return Utils::map(t, (float)_model.config.controller.tpaBreakpoint, 2000.f, 1.f,
                    1.f - ((float)_model.config.controller.tpaScale * 0.01f));
}

void Controller::resetIterm()
{
  if (!_model.isModeActive(MODE_ARMED) // when not armed
      || (!_model.isAirModeActive() && _model.config.iterm.lowThrottleZeroIterm &&
          _model.isThrottleLow()) // on low throttle (not in air mode)
  )
  {
    for (size_t i = 0; i < AXIS_COUNT_RPY; i++)
    {
      _model.state.innerPid[i].resetIterm();
      _model.state.outerPid[i].resetIterm();
    }
  }
  if (!_model.isModeActive(MODE_ARMED))
  {
    //_model.state.innerPid[AXIS_THRUST].resetIterm();
  }
}

float Controller::calculateSetpointRate(int axis, float input) const
{
  if (axis == AXIS_YAW) input *= -1.f;
  return _rates.getSetpoint(axis, input);
}

void Controller::beginInnerLoop(size_t axis)
{
  const int pidFilterRate = _model.state.loopTimer.rate;
  float pidScale[] = {1.f, 1.f, 1.f};
  if (_model.config.mixer.type == FC_MIXER_GIMBAL)
  {
    pidScale[AXIS_YAW] = 0.2f;   // ROBOT
    pidScale[AXIS_PITCH] = 20.f; // ROBOT
  }

  const auto& pc = _model.config.pid[axis];
  const auto& dtermConf = _model.config.dterm;

  auto& pid = _model.state.innerPid[axis];
  pid.Kp = (float)pc.P * PTERM_SCALE * pidScale[axis];
  pid.Ki = (float)pc.I * ITERM_SCALE * pidScale[axis];
  pid.Kd = (float)pc.D * DTERM_SCALE * pidScale[axis];
  pid.Kf = (float)pc.F * FTERM_SCALE * pidScale[axis];
  pid.iLimitLow = -_model.config.iterm.limit * 0.01f;
  pid.iLimitHigh = _model.config.iterm.limit * 0.01f;
  pid.oLimitLow = -0.66f;
  pid.oLimitHigh = 0.66f;
  pid.rate = pidFilterRate;
  pid.dtermNotchFilter.begin(dtermConf.notchFilter, pidFilterRate);
  if (dtermConf.dynLpfFilter.cutoff > 0)
  {
    pid.dtermFilter.begin(FilterConfig((FilterType)dtermConf.filter.type, dtermConf.dynLpfFilter.cutoff),
                          pidFilterRate);
  }
  else
  {
    pid.dtermFilter.begin(dtermConf.filter, pidFilterRate);
  }
  pid.dtermFilter2.begin(dtermConf.filter2, pidFilterRate);
  pid.ftermFilter.begin(_model.config.input.filterDerivative, pidFilterRate);
  pid.itermRelaxFilter.begin(FilterConfig(FILTER_PT1, _model.config.iterm.relaxCutoff), pidFilterRate);
  if (axis == AXIS_YAW)
  {
    pid.itermRelax = (_model.config.iterm.relax == ITERM_RELAX_RPY || _model.config.iterm.relax == ITERM_RELAX_RPY_INC)
                         ? _model.config.iterm.relax
                         : ITERM_RELAX_OFF;
    pid.ptermFilter.begin(_model.config.yaw.filter, pidFilterRate);
  }
  else
  {
    pid.itermRelax = _model.config.iterm.relax;
  }
  pid.begin();
}

void Controller::beginOuterLoop(size_t axis)
{
  const int pidFilterRate = _model.state.loopTimer.rate;
  const auto& pc = _model.config.pid[FC_PID_LEVEL];

  auto& pid = _model.state.outerPid[axis];
  pid.Kp = (float)pc.P * LEVEL_PTERM_SCALE;
  pid.Ki = (float)pc.I * LEVEL_ITERM_SCALE;
  pid.Kd = (float)pc.D * LEVEL_DTERM_SCALE;
  pid.Kf = (float)pc.F * LEVEL_FTERM_SCALE;
  pid.iLimitHigh = Utils::toRad(_model.config.level.rateLimit * 0.1f);
  pid.iLimitLow = -pid.iLimitHigh;
  pid.oLimitHigh = Utils::toRad(_model.config.level.rateLimit);
  pid.oLimitLow = -pid.oLimitHigh;
  pid.rate = pidFilterRate;
  pid.ptermFilter.begin(_model.config.level.ptermFilter, pidFilterRate);
  // pid.iLimit = 0.3f; // ROBOT
  // pid.oLimit = 1.f;  // ROBOT
  pid.begin();
}

void Controller::beginAltHold()
{
  float itermCenter = std::clamp((int)_model.config.altHold.itermCenter, 10, 60) * 0.01f;
  float itermRange = itermCenter * std::clamp((int)_model.config.altHold.itermRange, 10, 60) * 0.01f;
  const auto& pc = _model.config.pid[FC_PID_VEL];

  auto& pid = _model.state.innerPid[AXIS_THRUST];
  pid.Kp = (float)pc.P * VEL_PTERM_SCALE;
  pid.Ki = (float)pc.I * VEL_ITERM_SCALE;
  pid.Kd = (float)pc.D * VEL_DTERM_SCALE;
  pid.Kf = (float)pc.F * VEL_FTERM_SCALE;
  pid.iLimitLow = -1.0f + 2.0f * (itermCenter - itermRange);
  pid.iLimitHigh = -1.0f + 2.0f * (itermCenter + itermRange);
  pid.iReset = pid.iLimitLow;
  pid.rate = _model.state.loopTimer.rate;
  pid.dtermFilter.begin(FilterConfig(FILTER_PT1, 10), _model.state.loopTimer.rate);
  pid.ftermDerivative = false;
  pid.begin();
}

} // namespace Espfc::Control