idle_thread.cpp

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/**
 * @file    idle_thread.cpp
 * @brief   Idle Air Control valve thread.
 *
 * This thread looks at current RPM and decides if it should increase or decrease IAC duty cycle.
 * This file has the hardware & scheduling logic, desired idle level lives separately.
 *
 *
 * @date May 23, 2013
 * @author Andrey Belomutskiy, (c) 2012-2022
 */
 
#include "pch.h"
 
#if EFI_IDLE_CONTROL
#include "idle_thread.h"
#include "idle_hardware.h"
 
#include "dc_motors.h"
 
#if EFI_TUNER_STUDIO
#include "stepper.h"
#endif
 
using enum idle_mode_e;
 
IIdleController::TargetInfo IdleController::getTargetRpm(float clt) {
    targetRpmByClt = interpolate2d(clt, config->cltIdleRpmBins, config->cltIdleRpm);
 
  // FIXME: this is running as "RPM target" not "RPM bump" [ie adding to the CLT rpm target]
    // idle air Bump for AC
    // Why do we bump based on button not based on actual A/C relay state?
    // Because AC output has a delay to allow idle bump to happen first, so that the airflow increase gets a head start on the load increase
    // alternator duty cycle has a similar logic
    targetRpmAc = engine->module<AcController>().unmock().acButtonState ? engineConfiguration->acIdleRpmTarget : 0;
 
    float target = (targetRpmByClt < targetRpmAc) ? targetRpmAc : targetRpmByClt;
    float rpmUpperLimit = engineConfiguration->idlePidRpmUpperLimit;
    float entryRpm = target + rpmUpperLimit;
 
  // Higher exit than entry to add some hysteresis to avoid bouncing around upper threshold
    float exitRpm = target + 1.5 * rpmUpperLimit;
 
    // Ramp the target down from the transition RPM to normal over a few seconds
  if (engineConfiguration->idleReturnTargetRamp) {
        // Ramp the target down from the transition RPM to normal over a few seconds
        float timeSinceIdleEntry = m_timeInIdlePhase.getElapsedSeconds();
        target += interpolateClamped(
            0, rpmUpperLimit,
            engineConfiguration->idleReturnTargetRampDuration, 0,
            timeSinceIdleEntry
        );
    }
 
    idleTarget = target;
    idleEntryRpm = entryRpm;
    idleExitRpm = exitRpm;
    return { target, entryRpm, exitRpm };
}
 
IIdleController::Phase IdleController::determinePhase(float rpm, IIdleController::TargetInfo targetRpm, SensorResult tps, float vss, float crankingTaperFraction) {
#if EFI_SHAFT_POSITION_INPUT
    if (!engine->rpmCalculator.isRunning()) {
        return Phase::Cranking;
    }
    badTps = !tps;
 
    if (badTps) {
        // If the TPS has failed, assume the engine is running
        return Phase::Running;
    }
 
    // if throttle pressed, we're out of the idle corner
    if (tps.Value > engineConfiguration->idlePidDeactivationTpsThreshold) {
        return Phase::Running;
    }
 
    // If rpm too high (but throttle not pressed), we're coasting
    // ALSO, if still in the cranking taper, disable coasting
  if (rpm > targetRpm.IdleExitRpm) {
        looksLikeCoasting = true;
    } else if (rpm < targetRpm.IdleEntryRpm) {
        looksLikeCoasting = false;
    }
 
    looksLikeCrankToIdle = crankingTaperFraction < 1;
    if (looksLikeCoasting && !looksLikeCrankToIdle) {
        return Phase::Coasting;
    }
 
    // If the vehicle is moving too quickly, disable CL idle
    auto maxVss = engineConfiguration->maxIdleVss;
    looksLikeRunning = maxVss != 0 && vss > maxVss;
    if (looksLikeRunning) {
        return Phase::Running;
    }
 
    // If still in the cranking taper, disable closed loop idle
    if (looksLikeCrankToIdle) {
        return Phase::CrankToIdleTaper;
    }
#endif // EFI_SHAFT_POSITION_INPUT
 
    // If we are entering idle, and the PID settings are aggressive, it's good to make a soft entry upon entering closed loop
    if (m_crankTaperEndTime == 0.0f) {
        m_crankTaperEndTime = engine->fuelComputer.running.timeSinceCrankingInSecs;
        m_idleTimingSoftEntryEndTime = m_crankTaperEndTime + engineConfiguration->idleTimingSoftEntryTime;
    }
 
    // No other conditions met, we are idling!
    return Phase::Idling;
}
 
float IdleController::getCrankingTaperFraction(float clt) const {
    float taperDuration = interpolate2d(clt, config->afterCrankingIACtaperDurationBins, config->afterCrankingIACtaperDuration);
    return (float)engine->rpmCalculator.getRevolutionCounterSinceStart() / taperDuration;
}
 
float IdleController::getCrankingOpenLoop(float clt) const {
    return interpolate2d(clt, config->cltCrankingCorrBins, config->cltCrankingCorr);
}
 
percent_t IdleController::getRunningOpenLoop(IIdleController::Phase phase, float rpm, float clt, SensorResult tps) {
    float running = interpolate3d(
        config->cltIdleCorrTable,
        config->rpmIdleCorrBins, m_lastTargetRpm,
        config->cltIdleCorrBins, clt
    );
 
    // Now we bump it by the AC/fan amount if necessary
    if (engine->module<AcController>().unmock().acButtonState && (phase == Phase::Idling || phase == Phase::CrankToIdleTaper)) {
        running += engineConfiguration->acIdleExtraOffset;
    }
 
    running += enginePins.fanRelay.getLogicValue() ? engineConfiguration->fan1ExtraIdle : 0;
    running += enginePins.fanRelay2.getLogicValue() ? engineConfiguration->fan2ExtraIdle : 0;
 
    running += luaAdd;
 
#if EFI_ANTILAG_SYSTEM
if (engine->antilagController.isAntilagCondition) {
    running += engineConfiguration->ALSIdleAdd;
}
#endif /* EFI_ANTILAG_SYSTEM */
 
    // 'dashpot' (hold+decay) logic for coasting->idle
    float tpsForTaper = tps.value_or(0);
    efitimeus_t nowUs = getTimeNowUs();
    if (phase == Phase::Running) {
        lastTimeRunningUs = nowUs;
    }
    // imitate a slow pedal release for TPS taper (to avoid engine stalls)
    if (tpsForTaper <= engineConfiguration->idlePidDeactivationTpsThreshold) {
        // make sure the time is not zero
        float timeSinceRunningPhaseSecs = (nowUs - lastTimeRunningUs + 1) / US_PER_SECOND_F;
        // we shift the time to implement the hold correction (time can be negative)
        float timeSinceRunningAfterHoldSecs = timeSinceRunningPhaseSecs - engineConfiguration->iacByTpsHoldTime;
        // implement the decay correction (from tpsForTaper to 0)
        tpsForTaper = interpolateClamped(0, engineConfiguration->idlePidDeactivationTpsThreshold, engineConfiguration->iacByTpsDecayTime, tpsForTaper, timeSinceRunningAfterHoldSecs);
    }
 
    // Now bump it by the specified amount when the throttle is opened (if configured)
    // nb: invalid tps will make no change, no explicit check required
    iacByTpsTaper = interpolateClamped(
        0, 0,
        engineConfiguration->idlePidDeactivationTpsThreshold, engineConfiguration->iacByTpsTaper,
        tpsForTaper);
 
    running += iacByTpsTaper;
 
    float airTaperRpmUpperLimit = engineConfiguration->idlePidRpmUpperLimit;
    iacByRpmTaper = interpolateClamped(
        engineConfiguration->idlePidRpmUpperLimit, 0,
        airTaperRpmUpperLimit, engineConfiguration->airByRpmTaper,
        rpm);
 
    running += iacByRpmTaper;
 
  // are we clamping open loop part separately? should not we clamp once we have total value?
    return clampPercentValue(running);
}
 
percent_t IdleController::getOpenLoop(Phase phase, float rpm, float clt, SensorResult tps, float crankingTaperFraction) {
    percent_t crankingValvePosition = getCrankingOpenLoop(clt);
 
    isCranking = phase == Phase::Cranking;
    isIdleCoasting = phase == Phase::Coasting || (phase == Phase::Running && engineConfiguration->modeledFlowIdle);
 
    // if we're cranking, nothing more to do.
    if (isCranking) {
        return crankingValvePosition;
    }
 
    // If coasting (and enabled), use the coasting position table instead of normal open loop
    isIacTableForCoasting = engineConfiguration->useIacTableForCoasting && isIdleCoasting;
    if (isIacTableForCoasting) {
        percent_t coastingPosition = interpolate2d(rpm, config->iacCoastingRpmBins, config->iacCoasting);
 
        // Add A/C offset if the A/C is on during coasting
        if (engine->module<AcController>().unmock().acButtonState) {
            coastingPosition += engineConfiguration->acIdleExtraOffset;
        }
 
        // We return here, bypassing the final interpolation, so we should clamp the value
        // to ensure it's a valid percentage.
        return clampPercentValue(coastingPosition);
    }
 
    percent_t running = getRunningOpenLoop(phase, rpm, clt, tps);
 
    // Interpolate between cranking and running over a short time
    // This clamps once you fall off the end, so no explicit check for >1 required
    return interpolateClamped(0, crankingValvePosition, 1, running, crankingTaperFraction);
}
 
float IdleController::getIdleTimingAdjustment(float rpm) {
    return getIdleTimingAdjustment(rpm, m_lastTargetRpm, m_lastPhase);
}
 
float IdleController::getIdleTimingAdjustment(float rpm, float targetRpm, Phase phase) {
    // if not enabled, do nothing
    if (!engineConfiguration->useIdleTimingPidControl) {
        return 0;
    }
 
    // If not idling, do nothing
    if (phase != Phase::Idling) {
        m_timingPid.reset();
        return 0;
    }
 
    if (engineConfiguration->idleTimingSoftEntryTime > 0.0f) {
        // Use interpolation for correction taper
        m_timingPid.setErrorAmplification(interpolateClamped(m_crankTaperEndTime, 0.0f, m_idleTimingSoftEntryEndTime, 1.0f, engine->fuelComputer.running.timeSinceCrankingInSecs));
    }
 
    if (engineConfiguration->modeledFlowIdle) {
        return m_modeledFlowIdleTiming;
    } else {
        // We're now in the idle mode, and RPM is inside the Timing-PID regulator work zone!
        return m_timingPid.getOutput(targetRpm, rpm, FAST_CALLBACK_PERIOD_MS / 1000.0f);
    }
}
 
static void finishIdleTestIfNeeded() {
    if (engine->timeToStopIdleTest != 0 && getTimeNowUs() > engine->timeToStopIdleTest)
        engine->timeToStopIdleTest = 0;
}
 
/**
 * @return idle valve position percentage for automatic closed loop mode
 */
float IdleController::getClosedLoop(IIdleController::Phase phase, float tpsPos, float rpm, float targetRpm) {
    auto idlePid = getIdlePid();
 
    if (shouldResetPid && !wasResetPid) {
        needReset = idlePid->getIntegration() <= 0 || shouldResetPid;
        // this is not-so valid since we have open loop first for this?
        // we reset only if I-term is negative, because the positive I-term is good - it keeps RPM from dropping too low
        if (needReset) {
            idlePid->reset();
        }
        shouldResetPid = false;
        wasResetPid = true;
    }
 
    // todo: move this to pid_s one day
    industrialWithOverrideIdlePid.antiwindupFreq = engineConfiguration->idle_antiwindupFreq;
    industrialWithOverrideIdlePid.derivativeFilterLoss = engineConfiguration->idle_derivativeFilterLoss;
 
    efitimeus_t nowUs = getTimeNowUs();
 
    isIdleClosedLoop = phase == IIdleController::Phase::Idling;
 
    if (!isIdleClosedLoop) {
        // Don't store old I and D terms if PID doesn't work anymore.
        // Otherwise they will affect the idle position much later, when the throttle is closed.¿
        shouldResetPid = true;
        idleState = TPS_THRESHOLD;
 
        // We aren't idling, so don't apply any correction.  A positive correction could inhibit a return to idle.
        m_lastAutomaticPosition = 0;
        return 0;
    }
 
    bool acToggleJustTouched = engine->module<AcController>().unmock().timeSinceStateChange.getElapsedSeconds() < 0.5f /*second*/;
    // check if within the dead zone
    isInDeadZone = !acToggleJustTouched && std::abs(rpm - targetRpm) <= engineConfiguration->idlePidRpmDeadZone;
    if (isInDeadZone) {
        idleState = RPM_DEAD_ZONE;
        // current RPM is close enough, no need to change anything
        return m_lastAutomaticPosition;
    }
 
    // When rpm < targetRpm, there's a risk of dropping RPM too low - and the engine dies out.
    // So PID reaction should be increased by adding extra percent to PID-error:
    percent_t errorAmpCoef = 1.0f;
    if (rpm < targetRpm) {
        errorAmpCoef += (float)engineConfiguration->pidExtraForLowRpm / PERCENT_MULT;
    }
 
    // if PID was previously reset, we store the time when it turned on back (see errorAmpCoef correction below)
    if (wasResetPid) {
        restoreAfterPidResetTimeUs = nowUs;
        wasResetPid = false;
    }
    // increase the errorAmpCoef slowly to restore the process correctly after the PID reset
    // todo: move restoreAfterPidResetTimeUs to idle?
    efitimeus_t timeSincePidResetUs = nowUs - restoreAfterPidResetTimeUs;
    // todo: add 'pidAfterResetDampingPeriodMs' setting
    errorAmpCoef = interpolateClamped(0, 0, MS2US(/*engineConfiguration->pidAfterResetDampingPeriodMs*/1000), errorAmpCoef, timeSincePidResetUs);
    // If errorAmpCoef > 1.0, then PID thinks that RPM is lower than it is, and controls IAC more aggressively
    idlePid->setErrorAmplification(errorAmpCoef);
 
    percent_t newValue = idlePid->getOutput(targetRpm, rpm, FAST_CALLBACK_PERIOD_MS / 1000.0f);
    idleState = PID_VALUE;
 
    // the state of PID has been changed, so we might reset it now, but only when needed (see idlePidDeactivationTpsThreshold)
    mightResetPid = true;
 
    // Apply PID Multiplier if used
    if (engineConfiguration->useIacPidMultTable) {
        float engineLoad = getFuelingLoad();
        float multCoef = interpolate3d(
            config->iacPidMultTable,
            config->iacPidMultLoadBins, engineLoad,
            config->iacPidMultRpmBins, rpm
        );
        // PID can be completely disabled of multCoef==0, or it just works as usual if multCoef==1
        newValue = interpolateClamped(0, 0, 1, newValue, multCoef);
    }
 
    // Apply PID Deactivation Threshold as a smooth taper for TPS transients.
    // if tps==0 then PID just works as usual, or we completely disable it if tps>=threshold
    // TODO: should we just remove this? It reduces the gain if your zero throttle stop isn't perfect,
    // which could give unstable results.
    newValue = interpolateClamped(0, newValue, engineConfiguration->idlePidDeactivationTpsThreshold, 0, tpsPos);
 
    m_lastAutomaticPosition = newValue;
    return newValue;
}
 
float IdleController::getIdlePosition(float rpm) {
#if EFI_SHAFT_POSITION_INPUT
 
        // Simplify hardware CI: we borrow the idle valve controller as a PWM source for various stimulation tasks
        // The logic in this function is solidly unit tested, so it's not necessary to re-test the particulars on real hardware.
        #ifdef HARDWARE_CI
            return config->cltIdleCorrTable[0][0];
        #endif
 
        bool useModeledFlow = engineConfiguration->modeledFlowIdle;
 
    /*
     * Here we have idle logic thread - actual stepper movement is implemented in a separate
     * working thread see stepper.cpp
     */
        getIdlePid()->iTermMin = engineConfiguration->idlerpmpid_iTermMin;
        getIdlePid()->iTermMax = engineConfiguration->idlerpmpid_iTermMax;
 
        // On failed sensor, use 0 deg C - should give a safe highish idle
        float clt = Sensor::getOrZero(SensorType::Clt);
        auto tps = Sensor::get(SensorType::DriverThrottleIntent);
 
        // Compute the target we're shooting for
        auto targetRpm = getTargetRpm(clt);
        m_lastTargetRpm = targetRpm.ClosedLoopTarget;
 
        // Determine cranking taper (modeled flow does no taper of open loop)
        float crankingTaper = useModeledFlow ? 1 : getCrankingTaperFraction(clt);
 
        // Determine what operation phase we're in - idling or not
        float vehicleSpeed = Sensor::getOrZero(SensorType::VehicleSpeed);
        auto phase = determinePhase(rpm, targetRpm, tps, vehicleSpeed, crankingTaper);
 
        // update TS flag
        isIdling = (phase == Phase::Idling) || (phase == Phase::CrankToIdleTaper);
 
    if (phase != m_lastPhase && phase == Phase::Idling) {
        // Just entered idle, reset timer
            m_timeInIdlePhase.reset();
      }
 
        m_lastPhase = phase;
 
        finishIdleTestIfNeeded();
 
            // Always apply open loop correction
        percent_t iacPosition = getOpenLoop(phase, rpm, clt, tps, crankingTaper);
            baseIdlePosition = iacPosition;
            // Force closed loop operation for modeled flow
            auto idleMode = useModeledFlow ? IM_AUTO : engineConfiguration->idleMode;
 
            // If TPS is working and automatic mode enabled, add any closed loop correction
            if (tps.Valid && idleMode == IM_AUTO) {
                if (useModeledFlow && phase != Phase::Idling) {
                    auto idlePid = getIdlePid();
                    idlePid->reset();
                }
                auto closedLoop = getClosedLoop(phase, tps.Value, rpm, targetRpm.ClosedLoopTarget);
                idleClosedLoop = closedLoop;
                iacPosition += closedLoop;
            } else {
              isIdleClosedLoop = false;
            }
 
            iacPosition = clampPercentValue(iacPosition);
 
// todo: while is below disabled for unit tests?
#if EFI_TUNER_STUDIO && (EFI_PROD_CODE || EFI_SIMULATOR)
 
            // see also tsOutputChannels->idlePosition
            getIdlePid()->postState(engine->outputChannels.idleStatus);
 
 
        extern StepperMotor iacMotor;
        engine->outputChannels.idleStepperTargetPosition = iacMotor.getTargetPosition();
#endif /* EFI_TUNER_STUDIO */
        if (useModeledFlow && phase != Phase::Cranking) {
            float totalAirmass = 0.01 * iacPosition * engineConfiguration->idleMaximumAirmass;
            idleTargetAirmass = totalAirmass;
 
            bool shouldAdjustTiming = engineConfiguration->useIdleTimingPidControl && phase == Phase::Idling;
 
            // extract hiqh frequency content to be handled by timing
            float timingAirmass = shouldAdjustTiming ? m_timingHpf.filter(totalAirmass) : 0;
 
            // Convert from airmass delta -> timing
            m_modeledFlowIdleTiming = interpolate2d(timingAirmass, engineConfiguration->airmassToTimingBins, engineConfiguration->airmassToTimingValues);
 
            // Handle the residual low frequency content with airflow
            float idleAirmass = totalAirmass - timingAirmass;
            float airflowKgPerH = 3.6 * 0.001 * idleAirmass * rpm / 60 * engineConfiguration->cylindersCount / 2;
            idleTargetFlow = airflowKgPerH;
 
            // Convert from desired flow -> idle valve position
            float idlePos = interpolate2d(
                airflowKgPerH,
                engineConfiguration->idleFlowEstimateFlow,
                engineConfiguration->idleFlowEstimatePosition
            );
 
            iacPosition = idlePos;
        }
 
        currentIdlePosition = iacPosition;
 
    bool acActive = engine->module<AcController>().unmock().acButtonState;
    bool fan1Active = enginePins.fanRelay.getLogicValue();
    bool fan2Active = enginePins.fanRelay2.getLogicValue();
    updateLtit(rpm, clt, acActive, fan1Active, fan2Active, getIdlePid()->getIntegration());
 
        return iacPosition;
#else
        return 0;
#endif // EFI_SHAFT_POSITION_INPUT
 
}
 
void IdleController::onFastCallback() {
#if EFI_SHAFT_POSITION_INPUT
    float position = getIdlePosition(engine->triggerCentral.instantRpm.getInstantRpm());
    applyIACposition(position);
    // huh: why not onIgnitionStateChanged?
    engine->m_ltit.checkIfShouldSave();
#endif // EFI_SHAFT_POSITION_INPUT
}
 
void IdleController::onEngineStop() {
    getIdlePid()->reset();
}
 
void IdleController::onConfigurationChange(engine_configuration_s const * previousConfiguration) {
#if ! EFI_UNIT_TEST
    shouldResetPid = !previousConfiguration || !getIdlePid()->isSame(&previousConfiguration->idleRpmPid);
#endif
}
 
void IdleController::init() {
    shouldResetPid = false;
    mightResetPid = false;
    wasResetPid = false;
    m_timingPid.initPidClass(&engineConfiguration->idleTimingPid);
    m_timingHpf.configureHighpass(20, 1);
    getIdlePid()->initPidClass(&engineConfiguration->idleRpmPid);
    engine->m_ltit.loadLtitFromConfig();
}
 
void IdleController::updateLtit(float rpm, float clt, bool acActive, bool fan1Active, bool fan2Active, float idleIntegral) {
    if (engineConfiguration->ltitEnabled) {
        engine->m_ltit.update(rpm, clt, acActive, fan1Active, fan2Active, idleIntegral);
    }
}
 
void IdleController::onIgnitionStateChanged(bool ignitionOn) {
    engine->m_ltit.onIgnitionStateChanged(ignitionOn);
}
 
#endif /* EFI_IDLE_CONTROL */