wideband/firmware/heater_control.cpp

142 lines
3.6 KiB
C++

#include "heater_control.h"
#include "wideband_config.h"
#include "ch.h"
#include "hal.h"
#include "fault.h"
#include "pwm.h"
#include "sampling.h"
#include "pid.h"
// 400khz / 1024 = 390hz PWM
Pwm heaterPwm(PWMD1, 0, 400'000, 1024);
enum class HeaterState
{
Preheat,
WarmupRamp,
ClosedLoop,
Stopped,
};
int timeCounter = HEATER_PREHEAT_TIME / HEATER_CONTROL_PERIOD;
float rampDuty = 0.5f;
static HeaterState GetNextState(HeaterState state, float sensorEsr)
{
switch (state)
{
case HeaterState::Preheat:
timeCounter--;
// If preheat timeout, or sensor is already hot (engine running?)
if (timeCounter <= 0 || sensorEsr < HEATER_CLOSED_LOOP_THRESHOLD_ESR)
{
// If enough time has elapsed, start the ramp
// Start the ramp at 50% duty - ~6-7 volts
rampDuty = 0.5f;
// Next phase times out at 15 seconds
timeCounter = HEATER_WARMUP_TIMEOUT / HEATER_CONTROL_PERIOD;
return HeaterState::WarmupRamp;
}
// Stay in preheat - wait for time to elapse
break;
case HeaterState::WarmupRamp:
if (sensorEsr < HEATER_CLOSED_LOOP_THRESHOLD_ESR)
{
return HeaterState::ClosedLoop;
}
else if (timeCounter == 0)
{
setFault(Fault::SensorDidntHeat);
return HeaterState::Stopped;
}
timeCounter--;
break;
case HeaterState::ClosedLoop:
if (sensorEsr < HEATER_OVERHEAT_ESR)
{
setFault(Fault::SensorOverheat);
return HeaterState::Stopped;
}
else if (sensorEsr > HEATER_UNDERHEAT_ESR)
{
setFault(Fault::SensorUnderheat);
return HeaterState::Stopped;
}
break;
case HeaterState::Stopped: break;
}
return state;
}
static Pid heaterPid(0.003f, 0.01f, 1, HEATER_CONTROL_PERIOD);
static float GetDutyForState(HeaterState state, float heaterEsr)
{
switch (state)
{
case HeaterState::Preheat: return 0.04f;
case HeaterState::WarmupRamp:
if (rampDuty < 0.75f)
{
// 0.4 volt per second, divided by battery voltage and update rate
rampDuty += ((0.4f / 14) / HEATER_CONTROL_PERIOD);
}
return rampDuty;
case HeaterState::ClosedLoop:
// Negated because lower resistance -> hotter
return -heaterPid.GetOutput(HEATER_TARGET_ESR, heaterEsr);
case HeaterState::Stopped:
// Something has gone wrong, return 0.
return 0;
}
// should be unreachable
return 0;
}
static HeaterState state = HeaterState::Preheat;
static THD_WORKING_AREA(waHeaterThread, 256);
static void HeaterThread(void*)
{
while (true)
{
// Read sensor state
float heaterEsr = GetSensorInternalResistance();
// Run the state machine
state = GetNextState(state, heaterEsr);
float duty = GetDutyForState(state, heaterEsr);
// Pipe the output to the heater driver
heaterPwm.SetDuty(duty);
// Loop at ~20hz
chThdSleepMilliseconds(HEATER_CONTROL_PERIOD);
}
}
void StartHeaterControl()
{
heaterPwm.Start();
heaterPwm.SetDuty(0);
chThdCreateStatic(waHeaterThread, sizeof(waHeaterThread), NORMALPRIO + 1, HeaterThread, nullptr);
}
bool IsRunningClosedLoop()
{
return state == HeaterState::ClosedLoop;
}