示例#1
0
/**
 * WARNING! This callback executes with critical flight control priority every
 * time a gyroscope update happens do NOT put any time consuming calculations
 * in this loop unless they really have to execute with every gyro update
 */
static void stabilizationInnerloopTask()
{
    // watchdog and error handling
    {
#ifdef PIOS_INCLUDE_WDG
        PIOS_WDG_UpdateFlag(PIOS_WDG_STABILIZATION);
#endif
        bool warn  = false;
        bool error = false;
        bool crit  = false;
        // check if outer loop keeps executing
        if (stabSettings.monitor.rateupdates > -64) {
            stabSettings.monitor.rateupdates--;
        }
        if (stabSettings.monitor.rateupdates < -(2 * OUTERLOOP_SKIPCOUNT)) {
            // warning if rate loop skipped more than 2 execution
            warn = true;
        }
        if (stabSettings.monitor.rateupdates < -(4 * OUTERLOOP_SKIPCOUNT)) {
            // critical if rate loop skipped more than 4 executions
            crit = true;
        }
        // check if gyro keeps updating
        if (stabSettings.monitor.gyroupdates < 1) {
            // error if gyro didn't update at all!
            error = true;
        }
        if (stabSettings.monitor.gyroupdates > 1) {
            // warning if we missed a gyro update
            warn = true;
        }
        if (stabSettings.monitor.gyroupdates > 3) {
            // critical if we missed 3 gyro updates
            crit = true;
        }
        stabSettings.monitor.gyroupdates = 0;

        if (crit) {
            AlarmsSet(SYSTEMALARMS_ALARM_STABILIZATION, SYSTEMALARMS_ALARM_CRITICAL);
        } else if (error) {
            AlarmsSet(SYSTEMALARMS_ALARM_STABILIZATION, SYSTEMALARMS_ALARM_ERROR);
        } else if (warn) {
            AlarmsSet(SYSTEMALARMS_ALARM_STABILIZATION, SYSTEMALARMS_ALARM_WARNING);
        } else {
            AlarmsClear(SYSTEMALARMS_ALARM_STABILIZATION);
        }
    }


    RateDesiredData rateDesired;
    ActuatorDesiredData actuator;
    StabilizationStatusInnerLoopData enabled;
    FlightStatusControlChainData cchain;

    RateDesiredGet(&rateDesired);
    ActuatorDesiredGet(&actuator);
    StabilizationStatusInnerLoopGet(&enabled);
    FlightStatusControlChainGet(&cchain);
    float *rate = &rateDesired.Roll;
    float *actuatorDesiredAxis = &actuator.Roll;
    int t;
    float dT;
    dT = PIOS_DELTATIME_GetAverageSeconds(&timeval);

    for (t = 0; t < AXES; t++) {
        bool reinit = (cast_struct_to_array(enabled, enabled.Roll)[t] != previous_mode[t]);
        previous_mode[t] = cast_struct_to_array(enabled, enabled.Roll)[t];

        if (t < STABILIZATIONSTATUS_INNERLOOP_THRUST) {
            if (reinit) {
                stabSettings.innerPids[t].iAccumulator = 0;
            }
            switch (cast_struct_to_array(enabled, enabled.Roll)[t]) {
            case STABILIZATIONSTATUS_INNERLOOP_VIRTUALFLYBAR:
                stabilization_virtual_flybar(gyro_filtered[t], rate[t], &actuatorDesiredAxis[t], dT, reinit, t, &stabSettings.settings);
                break;
            case STABILIZATIONSTATUS_INNERLOOP_RELAYTUNING:
                rate[t] = boundf(rate[t],
                                 -cast_struct_to_array(stabSettings.stabBank.MaximumRate, stabSettings.stabBank.MaximumRate.Roll)[t],
                                 cast_struct_to_array(stabSettings.stabBank.MaximumRate, stabSettings.stabBank.MaximumRate.Roll)[t]
                                 );
                stabilization_relay_rate(rate[t] - gyro_filtered[t], &actuatorDesiredAxis[t], t, reinit);
                break;
            case STABILIZATIONSTATUS_INNERLOOP_AXISLOCK:
                if (fabsf(rate[t]) > stabSettings.settings.MaxAxisLockRate) {
                    // While getting strong commands act like rate mode
                    axis_lock_accum[t] = 0;
                } else {
                    // For weaker commands or no command simply attitude lock (almost) on no gyro change
                    axis_lock_accum[t] += (rate[t] - gyro_filtered[t]) * dT;
                    axis_lock_accum[t]  = boundf(axis_lock_accum[t], -stabSettings.settings.MaxAxisLock, stabSettings.settings.MaxAxisLock);
                    rate[t] = axis_lock_accum[t] * stabSettings.settings.AxisLockKp;
                }
            // IMPORTANT: deliberately no "break;" here, execution continues with regular RATE control loop to avoid code duplication!
            // keep order as it is, RATE must follow!
            case STABILIZATIONSTATUS_INNERLOOP_RATE:
                // limit rate to maximum configured limits (once here instead of 5 times in outer loop)
                rate[t] = boundf(rate[t],
                                 -cast_struct_to_array(stabSettings.stabBank.MaximumRate, stabSettings.stabBank.MaximumRate.Roll)[t],
                                 cast_struct_to_array(stabSettings.stabBank.MaximumRate, stabSettings.stabBank.MaximumRate.Roll)[t]
                                 );
                actuatorDesiredAxis[t] = pid_apply_setpoint(&stabSettings.innerPids[t], speedScaleFactor, rate[t], gyro_filtered[t], dT);
                break;
            case STABILIZATIONSTATUS_INNERLOOP_DIRECT:
            default:
                actuatorDesiredAxis[t] = rate[t];
                break;
            }
        } else {
            switch (cast_struct_to_array(enabled, enabled.Roll)[t]) {
            case STABILIZATIONSTATUS_INNERLOOP_CRUISECONTROL:
                actuatorDesiredAxis[t] = cruisecontrol_apply_factor(rate[t]);
                break;
            case STABILIZATIONSTATUS_INNERLOOP_DIRECT:
            default:
                actuatorDesiredAxis[t] = rate[t];
                break;
            }
        }

        actuatorDesiredAxis[t] = boundf(actuatorDesiredAxis[t], -1.0f, 1.0f);
    }

    actuator.UpdateTime = dT * 1000;

    if (cchain.Stabilization == FLIGHTSTATUS_CONTROLCHAIN_TRUE) {
        ActuatorDesiredSet(&actuator);
    } else {
        // Force all axes to reinitialize when engaged
        for (t = 0; t < AXES; t++) {
            previous_mode[t] = 255;
        }
    }
    {
        uint8_t armed;
        FlightStatusArmedGet(&armed);
        float throttleDesired;
        ManualControlCommandThrottleGet(&throttleDesired);
        if (armed != FLIGHTSTATUS_ARMED_ARMED ||
            ((stabSettings.settings.LowThrottleZeroIntegral == STABILIZATIONSETTINGS_LOWTHROTTLEZEROINTEGRAL_TRUE) && throttleDesired < 0)) {
            // Force all axes to reinitialize when engaged
            for (t = 0; t < AXES; t++) {
                previous_mode[t] = 255;
            }
        }
    }
    PIOS_CALLBACKSCHEDULER_Schedule(callbackHandle, FAILSAFE_TIMEOUT_MS, CALLBACK_UPDATEMODE_LATER);
}
示例#2
0
/**
 * Module task
 */
static void stabilizationTask(void* parameters)
{
	UAVObjEvent ev;
	
	uint32_t timeval = PIOS_DELAY_GetRaw();
	
	ActuatorDesiredData actuatorDesired;
	StabilizationDesiredData stabDesired;
	RateDesiredData rateDesired;
	AttitudeActualData attitudeActual;
	GyrosData gyrosData;
	FlightStatusData flightStatus;

	float *stabDesiredAxis = &stabDesired.Roll;
	float *actuatorDesiredAxis = &actuatorDesired.Roll;
	float *rateDesiredAxis = &rateDesired.Roll;
	float horizonRateFraction = 0.0f;

	// Force refresh of all settings immediately before entering main task loop
	SettingsUpdatedCb((UAVObjEvent *) NULL);
	
	// Settings for system identification
	uint32_t iteration = 0;
	const uint32_t SYSTEM_IDENT_PERIOD = 75;
	uint32_t system_ident_timeval = PIOS_DELAY_GetRaw();

	float dT_filtered = 0;

	// Main task loop
	zero_pids();
	while(1) {
		iteration++;

		PIOS_WDG_UpdateFlag(PIOS_WDG_STABILIZATION);
		
		// Wait until the AttitudeRaw object is updated, if a timeout then go to failsafe
		if (PIOS_Queue_Receive(queue, &ev, FAILSAFE_TIMEOUT_MS) != true)
		{
			AlarmsSet(SYSTEMALARMS_ALARM_STABILIZATION,SYSTEMALARMS_ALARM_WARNING);
			continue;
		}
		
		calculate_pids();

		float dT = PIOS_DELAY_DiffuS(timeval) * 1.0e-6f;
		timeval = PIOS_DELAY_GetRaw();
		
		// exponential moving averaging (EMA) of dT to reduce jitter; ~200points
		// to have more or less equivalent noise reduction to a normal N point moving averaging:  alpha = 2 / (N + 1)
		// run it only at the beginning for the first samples, to reduce CPU load, and the value should converge to a constant value

		if (iteration < 100) {
			dT_filtered = dT;
		} else if (iteration < 2000) {
			dT_filtered = 0.01f * dT + (1.0f - 0.01f) * dT_filtered;
		} else if (iteration == 2000) {
			gyro_filter_updated = true;
		}

		if (gyro_filter_updated) {
			if (settings.GyroCutoff < 1.0f) {
				gyro_alpha = 0;
			} else {
				gyro_alpha = expf(-2.0f * (float)(M_PI) *
						settings.GyroCutoff * dT_filtered);
			}

			// Compute time constant for vbar decay term
			if (settings.VbarTau < 0.001f) {
				vbar_decay = 0;
			} else {
				vbar_decay = expf(-dT_filtered / settings.VbarTau);
			}

			gyro_filter_updated = false;
		}

		FlightStatusGet(&flightStatus);
		StabilizationDesiredGet(&stabDesired);
		AttitudeActualGet(&attitudeActual);
		GyrosGet(&gyrosData);
		ActuatorDesiredGet(&actuatorDesired);
#if defined(RATEDESIRED_DIAGNOSTICS)
		RateDesiredGet(&rateDesired);
#endif

		struct TrimmedAttitudeSetpoint {
			float Roll;
			float Pitch;
			float Yaw;
		} trimmedAttitudeSetpoint;
		
		// Mux in level trim values, and saturate the trimmed attitude setpoint.
		trimmedAttitudeSetpoint.Roll = bound_min_max(
			stabDesired.Roll + trimAngles.Roll,
			-settings.RollMax + trimAngles.Roll,
			 settings.RollMax + trimAngles.Roll);
		trimmedAttitudeSetpoint.Pitch = bound_min_max(
			stabDesired.Pitch + trimAngles.Pitch,
			-settings.PitchMax + trimAngles.Pitch,
			 settings.PitchMax + trimAngles.Pitch);
		trimmedAttitudeSetpoint.Yaw = stabDesired.Yaw;

		// For horizon mode we need to compute the desire attitude from an unscaled value and apply the
		// trim offset. Also track the stick with the most deflection to choose rate blending.
		horizonRateFraction = 0.0f;
		if (stabDesired.StabilizationMode[ROLL] == STABILIZATIONDESIRED_STABILIZATIONMODE_HORIZON) {
			trimmedAttitudeSetpoint.Roll = bound_min_max(
				stabDesired.Roll * settings.RollMax + trimAngles.Roll,
				-settings.RollMax + trimAngles.Roll,
				 settings.RollMax + trimAngles.Roll);
			horizonRateFraction = fabsf(stabDesired.Roll);
		}
		if (stabDesired.StabilizationMode[PITCH] == STABILIZATIONDESIRED_STABILIZATIONMODE_HORIZON) {
			trimmedAttitudeSetpoint.Pitch = bound_min_max(
				stabDesired.Pitch * settings.PitchMax + trimAngles.Pitch,
				-settings.PitchMax + trimAngles.Pitch,
				 settings.PitchMax + trimAngles.Pitch);
			horizonRateFraction = MAX(horizonRateFraction, fabsf(stabDesired.Pitch));
		}
		if (stabDesired.StabilizationMode[YAW] == STABILIZATIONDESIRED_STABILIZATIONMODE_HORIZON) {
			trimmedAttitudeSetpoint.Yaw = stabDesired.Yaw * settings.YawMax;
			horizonRateFraction = MAX(horizonRateFraction, fabsf(stabDesired.Yaw));
		}

		// For weak leveling mode the attitude setpoint is the trim value (drifts back towards "0")
		if (stabDesired.StabilizationMode[ROLL] == STABILIZATIONDESIRED_STABILIZATIONMODE_WEAKLEVELING) {
			trimmedAttitudeSetpoint.Roll = trimAngles.Roll;
		}
		if (stabDesired.StabilizationMode[PITCH] == STABILIZATIONDESIRED_STABILIZATIONMODE_WEAKLEVELING) {
			trimmedAttitudeSetpoint.Pitch = trimAngles.Pitch;
		}
		if (stabDesired.StabilizationMode[YAW] == STABILIZATIONDESIRED_STABILIZATIONMODE_WEAKLEVELING) {
			trimmedAttitudeSetpoint.Yaw = 0;
		}

		// Note we divide by the maximum limit here so the fraction ranges from 0 to 1 depending on
		// how much is requested.
		horizonRateFraction = bound_sym(horizonRateFraction, HORIZON_MODE_MAX_BLEND) / HORIZON_MODE_MAX_BLEND;

		// Calculate the errors in each axis. The local error is used in the following modes:
		//  ATTITUDE, HORIZON, WEAKLEVELING
		float local_attitude_error[3];
		local_attitude_error[0] = trimmedAttitudeSetpoint.Roll - attitudeActual.Roll;
		local_attitude_error[1] = trimmedAttitudeSetpoint.Pitch - attitudeActual.Pitch;
		local_attitude_error[2] = trimmedAttitudeSetpoint.Yaw - attitudeActual.Yaw;
		
		// Wrap yaw error to [-180,180]
		local_attitude_error[2] = circular_modulus_deg(local_attitude_error[2]);

		static float gyro_filtered[3];
		gyro_filtered[0] = gyro_filtered[0] * gyro_alpha + gyrosData.x * (1 - gyro_alpha);
		gyro_filtered[1] = gyro_filtered[1] * gyro_alpha + gyrosData.y * (1 - gyro_alpha);
		gyro_filtered[2] = gyro_filtered[2] * gyro_alpha + gyrosData.z * (1 - gyro_alpha);

		// A flag to track which stabilization mode each axis is in
		static uint8_t previous_mode[MAX_AXES] = {255,255,255};
		bool error = false;

		//Run the selected stabilization algorithm on each axis:
		for(uint8_t i=0; i< MAX_AXES; i++)
		{
			// Check whether this axis mode needs to be reinitialized
			bool reinit = (stabDesired.StabilizationMode[i] != previous_mode[i]);
			// The unscaled input (-1,1)
			float *raw_input = &stabDesired.Roll;
			previous_mode[i] = stabDesired.StabilizationMode[i];
			// Apply the selected control law
			switch(stabDesired.StabilizationMode[i])
			{
				case STABILIZATIONDESIRED_STABILIZATIONMODE_RATE:
					if(reinit)
						pids[PID_GROUP_RATE + i].iAccumulator = 0;

					// Store to rate desired variable for storing to UAVO
					rateDesiredAxis[i] = bound_sym(stabDesiredAxis[i], settings.ManualRate[i]);

					// Compute the inner loop
					actuatorDesiredAxis[i] = pid_apply_setpoint(&pids[PID_GROUP_RATE + i],  rateDesiredAxis[i],  gyro_filtered[i], dT);
					actuatorDesiredAxis[i] = bound_sym(actuatorDesiredAxis[i],1.0f);

					break;

			case STABILIZATIONDESIRED_STABILIZATIONMODE_ACROPLUS:
					// this implementation is based on the Openpilot/Librepilot Acro+ flightmode
					// and our existing rate & MWRate flightmodes
					if(reinit)
							pids[PID_GROUP_RATE + i].iAccumulator = 0;

					// The factor for gyro suppression / mixing raw stick input into the output; scaled by raw stick input
					float factor = fabsf(raw_input[i]) * settings.AcroInsanityFactor / 100;

					// Store to rate desired variable for storing to UAVO
					rateDesiredAxis[i] = bound_sym(raw_input[i] * settings.ManualRate[i], settings.ManualRate[i]);

					// Zero integral for aggressive maneuvers, like it is done for MWRate
					if ((i < 2 && fabsf(gyro_filtered[i]) > 150.0f) ||
											(i == 0 && fabsf(raw_input[i]) > 0.2f)) {
							pids[PID_GROUP_RATE + i].iAccumulator = 0;
							pids[PID_GROUP_RATE + i].i = 0;
							}

					// Compute the inner loop
					actuatorDesiredAxis[i] = pid_apply_setpoint(&pids[PID_GROUP_RATE + i], rateDesiredAxis[i], gyro_filtered[i], dT);
					actuatorDesiredAxis[i] = factor * raw_input[i] + (1.0f - factor) * actuatorDesiredAxis[i];
					actuatorDesiredAxis[i] = bound_sym(actuatorDesiredAxis[i], 1.0f);

					break;
			case STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE:
					if(reinit) {
						pids[PID_GROUP_ATT + i].iAccumulator = 0;
						pids[PID_GROUP_RATE + i].iAccumulator = 0;
					}

					// Compute the outer loop
					rateDesiredAxis[i] = pid_apply(&pids[PID_GROUP_ATT + i], local_attitude_error[i], dT);
					rateDesiredAxis[i] = bound_sym(rateDesiredAxis[i], settings.MaximumRate[i]);

					// Compute the inner loop
					actuatorDesiredAxis[i] = pid_apply_setpoint(&pids[PID_GROUP_RATE + i],  rateDesiredAxis[i],  gyro_filtered[i], dT);
					actuatorDesiredAxis[i] = bound_sym(actuatorDesiredAxis[i],1.0f);

					break;

				case STABILIZATIONDESIRED_STABILIZATIONMODE_VIRTUALBAR:
					// Store for debugging output
					rateDesiredAxis[i] = stabDesiredAxis[i];

					// Run a virtual flybar stabilization algorithm on this axis
					stabilization_virtual_flybar(gyro_filtered[i], rateDesiredAxis[i], &actuatorDesiredAxis[i], dT, reinit, i, &pids[PID_GROUP_VBAR + i], &settings);

					break;
				case STABILIZATIONDESIRED_STABILIZATIONMODE_WEAKLEVELING:
				{
					if (reinit)
						pids[PID_GROUP_RATE + i].iAccumulator = 0;

					float weak_leveling = local_attitude_error[i] * weak_leveling_kp;
					weak_leveling = bound_sym(weak_leveling, weak_leveling_max);

					// Compute desired rate as input biased towards leveling
					rateDesiredAxis[i] = stabDesiredAxis[i] + weak_leveling;
					actuatorDesiredAxis[i] = pid_apply_setpoint(&pids[PID_GROUP_RATE + i],  rateDesiredAxis[i],  gyro_filtered[i], dT);
					actuatorDesiredAxis[i] = bound_sym(actuatorDesiredAxis[i],1.0f);

					break;
				}
				case STABILIZATIONDESIRED_STABILIZATIONMODE_AXISLOCK:
					if (reinit)
						pids[PID_GROUP_RATE + i].iAccumulator = 0;

					if (fabsf(stabDesiredAxis[i]) > max_axislock_rate) {
						// While getting strong commands act like rate mode
						rateDesiredAxis[i] = bound_sym(stabDesiredAxis[i], settings.ManualRate[i]);

						// Reset accumulator
						axis_lock_accum[i] = 0;
					} else {
						// For weaker commands or no command simply lock (almost) on no gyro change
						axis_lock_accum[i] += (stabDesiredAxis[i] - gyro_filtered[i]) * dT;
						axis_lock_accum[i] = bound_sym(axis_lock_accum[i], max_axis_lock);

						// Compute the inner loop
						float tmpRateDesired = pid_apply(&pids[PID_GROUP_ATT + i], axis_lock_accum[i], dT);
						rateDesiredAxis[i] = bound_sym(tmpRateDesired, settings.MaximumRate[i]);
					}

					actuatorDesiredAxis[i] = pid_apply_setpoint(&pids[PID_GROUP_RATE + i],  rateDesiredAxis[i],  gyro_filtered[i], dT);
					actuatorDesiredAxis[i] = bound_sym(actuatorDesiredAxis[i],1.0f);

					break;

				case STABILIZATIONDESIRED_STABILIZATIONMODE_HORIZON:
					if(reinit) {
						pids[PID_GROUP_RATE + i].iAccumulator = 0;
					}

					// Do not allow outer loop integral to wind up in this mode since the controller
					// is often disengaged.
					pids[PID_GROUP_ATT + i].iAccumulator = 0;

					// Compute the outer loop for the attitude control
					float rateDesiredAttitude = pid_apply(&pids[PID_GROUP_ATT + i], local_attitude_error[i], dT);
					// Compute the desire rate for a rate control
					float rateDesiredRate = raw_input[i] * settings.ManualRate[i];

					// Blend from one rate to another. The maximum of all stick positions is used for the
					// amount so that when one axis goes completely to rate the other one does too. This
					// prevents doing flips while one axis tries to stay in attitude mode.
					rateDesiredAxis[i] = rateDesiredAttitude * (1.0f-horizonRateFraction) + rateDesiredRate * horizonRateFraction;
					rateDesiredAxis[i] = bound_sym(rateDesiredAxis[i], settings.ManualRate[i]);

					// Compute the inner loop
					actuatorDesiredAxis[i] = pid_apply_setpoint(&pids[PID_GROUP_RATE + i],  rateDesiredAxis[i],  gyro_filtered[i], dT);
					actuatorDesiredAxis[i] = bound_sym(actuatorDesiredAxis[i],1.0f);

					break;

				case STABILIZATIONDESIRED_STABILIZATIONMODE_MWRATE:
				{
					if(reinit) {
						pids[PID_GROUP_MWR + i].iAccumulator = 0;
					}

					/*
					 Conversion from MultiWii PID settings to our units.
						Kp = Kp_mw * 4 / 80 / 500
						Kd = Kd_mw * looptime * 1e-6 * 4 * 3 / 32 / 500
						Ki = Ki_mw * 4 / 125 / 64 / (looptime * 1e-6) / 500

						These values will just be approximate and should help
						you get started.
					*/

					// The unscaled input (-1,1) - note in MW this is from (-500,500)
					float *raw_input = &stabDesired.Roll;

					// dynamic PIDs are scaled both by throttle and stick position
					float scale = (i == 0 || i == 1) ? mwrate_settings.RollPitchRate : mwrate_settings.YawRate;
					float pid_scale = (100.0f - scale * fabsf(raw_input[i])) / 100.0f;
					float dynP8 = pids[PID_GROUP_MWR + i].p * pid_scale;
					float dynD8 = pids[PID_GROUP_MWR + i].d * pid_scale;
					// these terms are used by the integral loop this proportional term is scaled by throttle (this is different than MW
					// that does not apply scale 
					float cfgP8 = pids[PID_GROUP_MWR + i].p;
					float cfgI8 = pids[PID_GROUP_MWR + i].i;

					// Dynamically adjust PID settings
					struct pid mw_pid;
					mw_pid.p = 0;      // use zero Kp here because of strange setpoint. applied later.
					mw_pid.d = dynD8;
					mw_pid.i = cfgI8;
					mw_pid.iLim = pids[PID_GROUP_MWR + i].iLim;
					mw_pid.iAccumulator = pids[PID_GROUP_MWR + i].iAccumulator;
					mw_pid.lastErr = pids[PID_GROUP_MWR + i].lastErr;
					mw_pid.lastDer = pids[PID_GROUP_MWR + i].lastDer;

					// Zero integral for aggressive maneuvers
 					if ((i < 2 && fabsf(gyro_filtered[i]) > 150.0f) ||
 					    (i == 0 && fabsf(raw_input[i]) > 0.2f)) {
						mw_pid.iAccumulator = 0;
						mw_pid.i = 0;
					}

					// Apply controller as if we want zero change, then add stick input afterwards
					actuatorDesiredAxis[i] = pid_apply_setpoint(&mw_pid,  raw_input[i] / cfgP8,  gyro_filtered[i], dT);
					actuatorDesiredAxis[i] += raw_input[i];             // apply input
					actuatorDesiredAxis[i] -= dynP8 * gyro_filtered[i]; // apply Kp term
					actuatorDesiredAxis[i] = bound_sym(actuatorDesiredAxis[i],1.0f);

					// Store PID accumulators for next cycle
					pids[PID_GROUP_MWR + i].iAccumulator = mw_pid.iAccumulator;
					pids[PID_GROUP_MWR + i].lastErr = mw_pid.lastErr;
					pids[PID_GROUP_MWR + i].lastDer = mw_pid.lastDer;
				}
					break;
				case STABILIZATIONDESIRED_STABILIZATIONMODE_SYSTEMIDENT:
					if(reinit) {
						pids[PID_GROUP_ATT + i].iAccumulator = 0;
						pids[PID_GROUP_RATE + i].iAccumulator = 0;
					}

					static uint32_t ident_iteration = 0;
					static float ident_offsets[3] = {0};

					if (PIOS_DELAY_DiffuS(system_ident_timeval) / 1000.0f > SYSTEM_IDENT_PERIOD && SystemIdentHandle()) {
						ident_iteration++;
						system_ident_timeval = PIOS_DELAY_GetRaw();

						SystemIdentData systemIdent;
						SystemIdentGet(&systemIdent);

						const float SCALE_BIAS = 7.1f;
						float roll_scale = expf(SCALE_BIAS - systemIdent.Beta[SYSTEMIDENT_BETA_ROLL]);
						float pitch_scale = expf(SCALE_BIAS - systemIdent.Beta[SYSTEMIDENT_BETA_PITCH]);
						float yaw_scale = expf(SCALE_BIAS - systemIdent.Beta[SYSTEMIDENT_BETA_YAW]);

						if (roll_scale > 0.25f)
							roll_scale = 0.25f;
						if (pitch_scale > 0.25f)
							pitch_scale = 0.25f;
						if (yaw_scale > 0.25f)
							yaw_scale = 0.2f;

						switch(ident_iteration & 0x07) {
							case 0:
								ident_offsets[0] = 0;
								ident_offsets[1] = 0;
								ident_offsets[2] = yaw_scale;
								break;
							case 1:
								ident_offsets[0] = roll_scale;
								ident_offsets[1] = 0;
								ident_offsets[2] = 0;
								break;
							case 2:
								ident_offsets[0] = 0;
								ident_offsets[1] = 0;
								ident_offsets[2] = -yaw_scale;
								break;
							case 3:
								ident_offsets[0] = -roll_scale;
								ident_offsets[1] = 0;
								ident_offsets[2] = 0;
								break;
							case 4:
								ident_offsets[0] = 0;
								ident_offsets[1] = 0;
								ident_offsets[2] = yaw_scale;
								break;
							case 5:
								ident_offsets[0] = 0;
								ident_offsets[1] = pitch_scale;
								ident_offsets[2] = 0;
								break;
							case 6:
								ident_offsets[0] = 0;
								ident_offsets[1] = 0;
								ident_offsets[2] = -yaw_scale;
								break;
							case 7:
								ident_offsets[0] = 0;
								ident_offsets[1] = -pitch_scale;
								ident_offsets[2] = 0;
								break;
						}
					}

					if (i == ROLL || i == PITCH) {
						// Compute the outer loop
						rateDesiredAxis[i] = pid_apply(&pids[PID_GROUP_ATT + i], local_attitude_error[i], dT);
						rateDesiredAxis[i] = bound_sym(rateDesiredAxis[i], settings.MaximumRate[i]);

						// Compute the inner loop
						actuatorDesiredAxis[i] = pid_apply_setpoint(&pids[PID_GROUP_RATE + i],  rateDesiredAxis[i],  gyro_filtered[i], dT);
						actuatorDesiredAxis[i] += ident_offsets[i];
						actuatorDesiredAxis[i] = bound_sym(actuatorDesiredAxis[i],1.0f);
					} else {
						// Get the desired rate. yaw is always in rate mode in system ident.
						rateDesiredAxis[i] = bound_sym(stabDesiredAxis[i], settings.ManualRate[i]);

						// Compute the inner loop only for yaw
						actuatorDesiredAxis[i] = pid_apply_setpoint(&pids[PID_GROUP_RATE + i],  rateDesiredAxis[i],  gyro_filtered[i], dT);
						actuatorDesiredAxis[i] += ident_offsets[i];
						actuatorDesiredAxis[i] = bound_sym(actuatorDesiredAxis[i],1.0f);						
					}

					break;

				case STABILIZATIONDESIRED_STABILIZATIONMODE_COORDINATEDFLIGHT:
					switch (i) {
						case YAW:
							if (reinit) {
								pids[PID_COORDINATED_FLIGHT_YAW].iAccumulator = 0;
								pids[PID_RATE_YAW].iAccumulator = 0;
								axis_lock_accum[YAW] = 0;
							}

							//If we are not in roll attitude mode, trigger an error
							if (stabDesired.StabilizationMode[ROLL] != STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE)
							{
								error = true;
								break ;
							}

							if (fabsf(stabDesired.Yaw) < COORDINATED_FLIGHT_MAX_YAW_THRESHOLD) { //If yaw is within the deadband...
								if (fabsf(stabDesired.Roll) > COORDINATED_FLIGHT_MIN_ROLL_THRESHOLD) { // We're requesting more roll than the threshold
									float accelsDataY;
									AccelsyGet(&accelsDataY);

									//Reset integral if we have changed roll to opposite direction from rudder. This implies that we have changed desired turning direction.
									if ((stabDesired.Roll > 0 && actuatorDesiredAxis[YAW] < 0) ||
											(stabDesired.Roll < 0 && actuatorDesiredAxis[YAW] > 0)){
										pids[PID_COORDINATED_FLIGHT_YAW].iAccumulator = 0;
									}

									// Coordinate flight can simply be seen as ensuring that there is no lateral acceleration in the
									// body frame. As such, we use the (noisy) accelerometer data as our measurement. Ideally, at
									// some point in the future we will estimate acceleration and then we can use the estimated value
									// instead of the measured value.
									float errorSlip = -accelsDataY;

									float command = pid_apply(&pids[PID_COORDINATED_FLIGHT_YAW], errorSlip, dT);
									actuatorDesiredAxis[YAW] = bound_sym(command ,1.0);

									// Reset axis-lock integrals
									pids[PID_RATE_YAW].iAccumulator = 0;
									axis_lock_accum[YAW] = 0;
								} else if (fabsf(stabDesired.Roll) <= COORDINATED_FLIGHT_MIN_ROLL_THRESHOLD) { // We're requesting less roll than the threshold
									// Axis lock on no gyro change
									axis_lock_accum[YAW] += (0 - gyro_filtered[YAW]) * dT;

									rateDesiredAxis[YAW] = pid_apply(&pids[PID_ATT_YAW], axis_lock_accum[YAW], dT);
									rateDesiredAxis[YAW] = bound_sym(rateDesiredAxis[YAW], settings.MaximumRate[YAW]);

									actuatorDesiredAxis[YAW] = pid_apply_setpoint(&pids[PID_RATE_YAW],  rateDesiredAxis[YAW],  gyro_filtered[YAW], dT);
									actuatorDesiredAxis[YAW] = bound_sym(actuatorDesiredAxis[YAW],1.0f);

									// Reset coordinated-flight integral
									pids[PID_COORDINATED_FLIGHT_YAW].iAccumulator = 0;
								}
							} else { //... yaw is outside the deadband. Pass the manual input directly to the actuator.
								actuatorDesiredAxis[YAW] = bound_sym(stabDesiredAxis[YAW], 1.0);

								// Reset all integrals
								pids[PID_COORDINATED_FLIGHT_YAW].iAccumulator = 0;
								pids[PID_RATE_YAW].iAccumulator = 0;
								axis_lock_accum[YAW] = 0;
							}
							break;
						case ROLL:
						case PITCH:
						default:
							//Coordinated Flight has no effect in these modes. Trigger a configuration error.
							error = true;
							break;
					}

					break;

				case STABILIZATIONDESIRED_STABILIZATIONMODE_POI:
					// The sanity check enforces this is only selectable for Yaw
					// for a gimbal you can select pitch too.
					if(reinit) {
						pids[PID_GROUP_ATT + i].iAccumulator = 0;
						pids[PID_GROUP_RATE + i].iAccumulator = 0;
					}

					float error;
					float angle;
					if (CameraDesiredHandle()) {
						switch(i) {
						case PITCH:
							CameraDesiredDeclinationGet(&angle);
							error = circular_modulus_deg(angle - attitudeActual.Pitch);
							break;
						case ROLL:
						{
							uint8_t roll_fraction = 0;
#ifdef GIMBAL
							if (BrushlessGimbalSettingsHandle()) {
								BrushlessGimbalSettingsRollFractionGet(&roll_fraction);
							}
#endif /* GIMBAL */

							// For ROLL POI mode we track the FC roll angle (scaled) to
							// allow keeping some motion
							CameraDesiredRollGet(&angle);
							angle *= roll_fraction / 100.0f;
							error = circular_modulus_deg(angle - attitudeActual.Roll);
						}
							break;
						case YAW:
							CameraDesiredBearingGet(&angle);
							error = circular_modulus_deg(angle - attitudeActual.Yaw);
							break;
						default:
							error = true;
						}
					} else
						error = true;

					// Compute the outer loop
					rateDesiredAxis[i] = pid_apply(&pids[PID_GROUP_ATT + i], error, dT);
					rateDesiredAxis[i] = bound_sym(rateDesiredAxis[i], settings.PoiMaximumRate[i]);

					// Compute the inner loop
					actuatorDesiredAxis[i] = pid_apply_setpoint(&pids[PID_GROUP_RATE + i],  rateDesiredAxis[i],  gyro_filtered[i], dT);
					actuatorDesiredAxis[i] = bound_sym(actuatorDesiredAxis[i],1.0f);

					break;
				case STABILIZATIONDESIRED_STABILIZATIONMODE_NONE:
					actuatorDesiredAxis[i] = bound_sym(stabDesiredAxis[i],1.0f);
					break;
				default:
					error = true;
					break;
			}
		}

		if (settings.VbarPiroComp == STABILIZATIONSETTINGS_VBARPIROCOMP_TRUE)
			stabilization_virtual_flybar_pirocomp(gyro_filtered[2], dT);

#if defined(RATEDESIRED_DIAGNOSTICS)
		RateDesiredSet(&rateDesired);
#endif

		// Save dT
		actuatorDesired.UpdateTime = dT * 1000;
		actuatorDesired.Throttle = stabDesired.Throttle;

		if(flightStatus.FlightMode != FLIGHTSTATUS_FLIGHTMODE_MANUAL) {
			ActuatorDesiredSet(&actuatorDesired);
		} else {
			// Force all axes to reinitialize when engaged
			for(uint8_t i=0; i< MAX_AXES; i++)
				previous_mode[i] = 255;
		}

		if(flightStatus.Armed != FLIGHTSTATUS_ARMED_ARMED ||
		   (lowThrottleZeroIntegral && stabDesired.Throttle < 0))
		{
			// Force all axes to reinitialize when engaged
			for(uint8_t i=0; i< MAX_AXES; i++)
				previous_mode[i] = 255;
		}

		// Clear or set alarms.  Done like this to prevent toggling each cycle
		// and hammering system alarms
		if (error)
			AlarmsSet(SYSTEMALARMS_ALARM_STABILIZATION,SYSTEMALARMS_ALARM_ERROR);
		else
			AlarmsClear(SYSTEMALARMS_ALARM_STABILIZATION);
	}
}