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Prevent ItermAccel and windup to clash with each other

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This commit is contained in:
borisbstyle 2017-01-30 09:21:07 +01:00
parent 12a6d2f848
commit cf04294f70
4 changed files with 12 additions and 9 deletions
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1
src/main/fc/cli.c
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@ -702,6 +702,7 @@ const clivalue_t valueTable[] = {
{ "pid_at_min_throttle", VAR_UINT8 | PROFILE_VALUE | MODE_LOOKUP, &masterConfig.profile[0].pidProfile.pidAtMinThrottle, .config.lookup = { TABLE_OFF_ON } },
{ "anti_gravity_threshold", VAR_UINT16 | PROFILE_VALUE, &masterConfig.profile[0].pidProfile.itermThrottleThreshold, .config.minmax = {20, 1000 } },
{ "anti_gravity_gain", VAR_FLOAT | PROFILE_VALUE, &masterConfig.profile[0].pidProfile.itermAcceleratorGain, .config.minmax = {1, 30 } },
{ "anti_gravity_rate_max", VAR_UINT16 | PROFILE_VALUE, &masterConfig.profile[0].pidProfile.itermAcceleratorRateLimit, .config.minmax = {0, 2000 } },
{ "setpoint_relax_ratio", VAR_UINT8 | PROFILE_VALUE, &masterConfig.profile[0].pidProfile.setpointRelaxRatio, .config.minmax = {0, 100 } },
{ "dterm_setpoint_weight", VAR_UINT8 | PROFILE_VALUE, &masterConfig.profile[0].pidProfile.dtermSetpointWeight, .config.minmax = {0, 255 } },
{ "yaw_accel_limit", VAR_FLOAT | PROFILE_VALUE, &masterConfig.profile[0].pidProfile.yawRateAccelLimit, .config.minmax = {0.1f, 50.0f } },

1
src/main/fc/config.c
View file

@ -184,6 +184,7 @@ static void resetPidProfile(pidProfile_t *pidProfile)
pidProfile->rateAccelLimit = 0.0f;
pidProfile->itermThrottleThreshold = 300;
pidProfile->itermAcceleratorGain = 3.0f;
pidProfile->itermAcceleratorRateLimit = 80;
}
void resetProfile(profile_t *profile)

16
src/main/flight/pid.c
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@ -148,7 +148,7 @@ void pidInitFilters(const pidProfile_t *pidProfile)
}
static float Kp[3], Ki[3], Kd[3], c[3], maxVelocity[3], relaxFactor[3];
static float levelGain, horizonGain, horizonTransition, ITermWindupPoint, ITermWindupPointInv;
static float levelGain, horizonGain, horizonTransition, ITermWindupPoint, ITermWindupPointInv, itermAcceleratorRateLimit;
void pidInitConfig(const pidProfile_t *pidProfile) {
for(int axis = FD_ROLL; axis <= FD_YAW; axis++) {
@ -165,6 +165,7 @@ void pidInitConfig(const pidProfile_t *pidProfile) {
maxVelocity[FD_YAW] = pidProfile->yawRateAccelLimit * 1000 * dT;
ITermWindupPoint = (float)pidProfile->itermWindupPointPercent / 100.0f;
ITermWindupPointInv = 1.0f - ITermWindupPoint;
itermAcceleratorRateLimit = (float)pidProfile->itermAcceleratorRateLimit;
}
static float calcHorizonLevelStrength(void) {
@ -216,6 +217,8 @@ void pidController(const pidProfile_t *pidProfile, const rollAndPitchTrims_t *an
static float previousSetpoint[3];
const float motorMixRange = getMotorMixRange();
// Dynamic ki component to gradually scale back integration when above windup point
float dynKi = MIN((1.0f - motorMixRange) / ITermWindupPointInv, 1.0f);
// ----------PID controller----------
for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
@ -247,13 +250,10 @@ void pidController(const pidProfile_t *pidProfile, const rollAndPitchTrims_t *an
float ITerm = previousGyroIf[axis];
if (motorMixRange < 1.0f) {
// Only increase ITerm if motor output is not saturated and errorRate exceeds noise threshold
float ITermDelta = Ki[axis] * errorRate * dT;
// gradually scale back integration when above windup point
if (motorMixRange > ITermWindupPoint) {
ITermDelta *= (1.0f - motorMixRange) / ITermWindupPointInv;
} else {
ITermDelta *= itermAccelerator;
}
// Iterm will only be accelerated below steady rate threshold
if (ABS(currentPidSetpoint) < itermAcceleratorRateLimit)
dynKi *= itermAccelerator;
float ITermDelta = Ki[axis] * errorRate * dT * dynKi;
ITerm += ITermDelta;
// also limit maximum integrator value to prevent windup
ITerm = constrainf(ITerm, -250.0f, 250.0f);

3
src/main/flight/pid.h
View file

@ -76,8 +76,9 @@ typedef struct pidProfile_s {
uint8_t levelSensitivity; // Angle mode sensitivity reflected in degrees assuming user using full stick
// Betaflight PID controller parameters
uint16_t itermThrottleThreshold; // max allowed throttle delta before errorGyroReset in ms
uint16_t itermThrottleThreshold; // max allowed throttle delta before iterm accelerated in ms
float itermAcceleratorGain; // Iterm Accelerator Gain when itermThrottlethreshold is hit
uint16_t itermAcceleratorRateLimit; // Setpointrate limit for iterm accelerator to operate within
uint8_t setpointRelaxRatio; // Setpoint weight relaxation effect
uint8_t dtermSetpointWeight; // Setpoint weight for Dterm (0= measurement, 1= full error, 1 > agressive derivative)
float yawRateAccelLimit; // yaw accel limiter for deg/sec/ms