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Fix and improve PID loops (#14373)

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- Windup guarding was missing. The kludge in place of windup guard is removed. D term filter calculations are simplified to require fewer `float` calculations. Sign change for D term output to make debugging output clearer.
- Use "no overshoot" for bed PID tuning.
This commit is contained in:
mikeshub 2019-06-22 16:52:56 -05:00 committed by Scott Lahteine
parent 17778d1c2a
commit 1db7013e3b
1 changed files with 39 additions and 44 deletions
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71
Marlin/src/module/temperature.cpp
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@ -350,11 +350,13 @@ temp_range_t Temperature::temp_range[HOTENDS] = ARRAY_BY_HOTENDS(sensor_heater_0
PID_t tune_pid = { 0, 0, 0 };
float max = 0, min = 10000;
const bool isbed = (heater < 0);
#if HAS_PID_FOR_BOTH
#define GHV(B,H) (heater < 0 ? (B) : (H))
#define SHV(B,H) do{ if (heater < 0) temp_bed.soft_pwm_amount = B; else temp_hotend[heater].soft_pwm_amount = H; }while(0)
#define ONHEATINGSTART() (heater < 0 ? printerEventLEDs.onBedHeatingStart() : printerEventLEDs.onHotendHeatingStart())
#define ONHEATING(S,C,T) do{ if (heater < 0) printerEventLEDs.onBedHeating(S,C,T); else printerEventLEDs.onHotendHeating(S,C,T); }while(0)
#define GHV(B,H) (isbed ? (B) : (H))
#define SHV(B,H) do{ if (isbed) temp_bed.soft_pwm_amount = B; else temp_hotend[heater].soft_pwm_amount = H; }while(0)
#define ONHEATINGSTART() (isbed ? printerEventLEDs.onBedHeatingStart() : printerEventLEDs.onHotendHeatingStart())
#define ONHEATING(S,C,T) (isbed ? printerEventLEDs.onBedHeating(S,C,T) : printerEventLEDs.onHotendHeating(S,C,T))
#elif ENABLED(PIDTEMPBED)
#define GHV(B,H) B
#define SHV(B,H) (temp_bed.soft_pwm_amount = B)
@ -370,7 +372,7 @@ temp_range_t Temperature::temp_range[HOTENDS] = ARRAY_BY_HOTENDS(sensor_heater_0
#if WATCH_BED || WATCH_HOTENDS
#define HAS_TP_BED BOTH(THERMAL_PROTECTION_BED, PIDTEMPBED)
#if HAS_TP_BED && BOTH(THERMAL_PROTECTION_HOTENDS, PIDTEMP)
#define GTV(B,H) (heater < 0 ? (B) : (H))
#define GTV(B,H) (isbed ? (B) : (H))
#elif HAS_TP_BED
#define GTV(B,H) (B)
#else
@ -456,11 +458,13 @@ temp_range_t Temperature::temp_range[HOTENDS] = ARRAY_BY_HOTENDS(sensor_heater_0
SERIAL_ECHOPAIR(MSG_BIAS, bias, MSG_D, d, MSG_T_MIN, min, MSG_T_MAX, max);
if (cycles > 2) {
float Ku = (4.0f * d) / (float(M_PI) * (max - min) * 0.5f),
Tu = ((float)(t_low + t_high) * 0.001f);
tune_pid.Kp = 0.6f * Ku;
const float Ku = (4.0f * d) / (float(M_PI) * (max - min) * 0.5f),
Tu = float(t_low + t_high) * 0.001f,
pf = isbed ? 0.2f : 0.6f,
df = isbed ? 1.0f / 3.0f : 1.0f / 8.0f;
tune_pid.Kp = Ku * pf;
tune_pid.Kd = tune_pid.Kp * Tu * df;
tune_pid.Ki = 2 * tune_pid.Kp / Tu;
tune_pid.Kd = tune_pid.Kp * Tu * 0.125f;
SERIAL_ECHOPAIR(MSG_KU, Ku, MSG_TU, Tu);
SERIAL_ECHOLNPGM("\n" MSG_CLASSIC_PID);
SERIAL_ECHOLNPAIR(MSG_KP, tune_pid.Kp, MSG_KI, tune_pid.Ki, MSG_KD, tune_pid.Kd);
@ -496,7 +500,7 @@ temp_range_t Temperature::temp_range[HOTENDS] = ARRAY_BY_HOTENDS(sensor_heater_0
// Report heater states every 2 seconds
if (ELAPSED(ms, next_temp_ms)) {
#if HAS_TEMP_SENSOR
print_heater_states(heater >= 0 ? heater : active_extruder);
print_heater_states(isbed ? active_extruder : heater);
SERIAL_EOL();
#endif
next_temp_ms = ms + 2000UL;
@ -507,9 +511,9 @@ temp_range_t Temperature::temp_range[HOTENDS] = ARRAY_BY_HOTENDS(sensor_heater_0
#if WATCH_BED && WATCH_HOTENDS
true
#elif WATCH_HOTENDS
heater >= 0
!isbed
#else
heater < 0
isbed
#endif
) {
if (!heated) { // If not yet reached target...
@ -569,7 +573,7 @@ temp_range_t Temperature::temp_range[HOTENDS] = ARRAY_BY_HOTENDS(sensor_heater_0
// Use the result? (As with "M303 U1")
if (set_result) {
#if HAS_PID_FOR_BOTH
if (heater < 0) _SET_BED_PID(); else _SET_EXTRUDER_PID();
if (isbed) _SET_BED_PID(); else _SET_EXTRUDER_PID();
#elif ENABLED(PIDTEMP)
_SET_EXTRUDER_PID();
#else
@ -805,9 +809,7 @@ float Temperature::get_pid_output(const int8_t e) {
static float temp_iState[HOTENDS] = { 0 },
temp_dState[HOTENDS] = { 0 };
static bool pid_reset[HOTENDS] = { false };
float pid_error = temp_hotend[HOTEND_INDEX].target - temp_hotend[HOTEND_INDEX].current;
work_pid[HOTEND_INDEX].Kd = PID_K2 * PID_PARAM(Kd, HOTEND_INDEX) * (temp_hotend[HOTEND_INDEX].current - temp_dState[HOTEND_INDEX]) + float(PID_K1) * work_pid[HOTEND_INDEX].Kd;
temp_dState[HOTEND_INDEX] = temp_hotend[HOTEND_INDEX].current;
const float pid_error = temp_hotend[HOTEND_INDEX].target - temp_hotend[HOTEND_INDEX].current;
if (temp_hotend[HOTEND_INDEX].target == 0
|| pid_error < -(PID_FUNCTIONAL_RANGE)
@ -825,13 +827,17 @@ float Temperature::get_pid_output(const int8_t e) {
else {
if (pid_reset[HOTEND_INDEX]) {
temp_iState[HOTEND_INDEX] = 0.0;
work_pid[HOTEND_INDEX].Kd = 0.0;
pid_reset[HOTEND_INDEX] = false;
}
temp_iState[HOTEND_INDEX] += pid_error;
work_pid[HOTEND_INDEX].Kd = work_pid[HOTEND_INDEX].Kd + PID_K2 * (PID_PARAM(Kd, HOTEND_INDEX) * (temp_dState[HOTEND_INDEX] - temp_hotend[HOTEND_INDEX].current) - work_pid[HOTEND_INDEX].Kd);
const float max_power_over_i_gain = (float)PID_MAX / PID_PARAM(Ki, HOTEND_INDEX);
temp_iState[HOTEND_INDEX] = constrain(temp_iState[HOTEND_INDEX] + pid_error, 0, max_power_over_i_gain);
work_pid[HOTEND_INDEX].Kp = PID_PARAM(Kp, HOTEND_INDEX) * pid_error;
work_pid[HOTEND_INDEX].Ki = PID_PARAM(Ki, HOTEND_INDEX) * temp_iState[HOTEND_INDEX];
pid_output = work_pid[HOTEND_INDEX].Kp + work_pid[HOTEND_INDEX].Ki - work_pid[HOTEND_INDEX].Kd;
pid_output = work_pid[HOTEND_INDEX].Kp + work_pid[HOTEND_INDEX].Ki + work_pid[HOTEND_INDEX].Kd;
#if ENABLED(PID_EXTRUSION_SCALING)
work_pid[HOTEND_INDEX].Kc = 0;
@ -850,15 +856,9 @@ float Temperature::get_pid_output(const int8_t e) {
}
#endif // PID_EXTRUSION_SCALING
if (pid_output > PID_MAX) {
if (pid_error > 0) temp_iState[HOTEND_INDEX] -= pid_error; // conditional un-integration
pid_output = PID_MAX;
}
else if (pid_output < 0) {
if (pid_error < 0) temp_iState[HOTEND_INDEX] -= pid_error; // conditional un-integration
pid_output = 0;
}
pid_output = constrain(pid_output, 0, PID_MAX);
}
temp_dState[HOTEND_INDEX] = temp_hotend[HOTEND_INDEX].current;
#else // PID_OPENLOOP
@ -908,23 +908,18 @@ float Temperature::get_pid_output(const int8_t e) {
static PID_t work_pid = { 0 };
static float temp_iState = 0, temp_dState = 0;
float pid_error = temp_bed.target - temp_bed.current;
temp_iState += pid_error;
const float max_power_over_i_gain = (float)MAX_BED_POWER / temp_bed.pid.Ki,
pid_error = temp_bed.target - temp_bed.current;
temp_iState = constrain(temp_iState + pid_error, 0, max_power_over_i_gain);
work_pid.Kp = temp_bed.pid.Kp * pid_error;
work_pid.Ki = temp_bed.pid.Ki * temp_iState;
work_pid.Kd = PID_K2 * temp_bed.pid.Kd * (temp_bed.current - temp_dState) + PID_K1 * work_pid.Kd;
work_pid.Kd = work_pid.Kd + PID_K2 * (temp_bed.pid.Kd * (temp_dState - temp_bed.current) - work_pid.Kd);
temp_dState = temp_bed.current;
float pid_output = work_pid.Kp + work_pid.Ki - work_pid.Kd;
if (pid_output > MAX_BED_POWER) {
if (pid_error > 0) temp_iState -= pid_error; // conditional un-integration
pid_output = MAX_BED_POWER;
}
else if (pid_output < 0) {
if (pid_error < 0) temp_iState -= pid_error; // conditional un-integration
pid_output = 0;
}
const float pid_output = constrain(work_pid.Kp + work_pid.Ki + work_pid.Kd, 0, MAX_BED_POWER);
#else // PID_OPENLOOP