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added function for delaying brake engagement and release
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@pkerspe
pkerspe committed Aug 2, 2020
1 parent e83b2db commit 1de13b3
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Showing 2 changed files with 103 additions and 19 deletions.
107 changes: 90 additions & 17 deletions src/ESP_FlexyStepper.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -277,6 +277,38 @@ void ESP_FlexyStepper::setBrakePin(byte brakePin, byte activeState)
// configure the IO pins
pinMode(this->brakePin, OUTPUT);
this->deactivateBrake();
_isBrakeConfigured = true;
}
else
{
_isBrakeConfigured = false;
}
}

/**
* set a delay in milliseconds between stopping the stepper motor and engaging the pyhsical brake (trigger the eternal pin configured via setBrakePin() ).
* Default is 0, resulting in immediate triggering of the motor brake once the motor stops moving.
* This value does NOT affect the triggering of the brake in cade of an emergency stop. In this case the brake will always get triggered without delay
*/
void ESP_FlexyStepper::setBrakeEngageDelayMs(unsigned long delay)
{
this->_brakeEngageDelayMs = delay;
}

/**
* set a timeout in milliseconds fter which the brake shall be released once triggered and no motion is performed by the stpper motor.
* By default the value is -1 indicating, that the brake shall never be automatically released, as long as the stepper motor is not moving to a new position.
* Value must be larger than 1 (Even though 1ms delay does probably not make any sense since physical brakes have a delay that is most likely higher than that just to engange)
*/
void ESP_FlexyStepper::setBrakeReleaseDelayMs(signed long delay)
{
if (delay < 0)
{
this->_brakeReleaseDelayMs = -1;
}
else
{
this->_brakeReleaseDelayMs = delay;
}
}

Expand All @@ -285,10 +317,11 @@ void ESP_FlexyStepper::setBrakePin(byte brakePin, byte activeState)
*/
void ESP_FlexyStepper::activateBrake()
{
if (this->brakePin >= 0)
if (this->_isBrakeConfigured)
{
digitalWrite(this->brakePin, (this->brakePinActiveState == ESP_FlexyStepper::ACTIVE_HIGH) ? 1 : 0);
this->_isBrakeActive = true;
this->_timeToEngangeBrake = LONG_MAX;
}
}

Expand All @@ -297,10 +330,12 @@ void ESP_FlexyStepper::activateBrake()
*/
void ESP_FlexyStepper::deactivateBrake()
{
if (this->brakePin >= 0)
if (this->_isBrakeConfigured)
{
digitalWrite(this->brakePin, (this->brakePinActiveState == ESP_FlexyStepper::ACTIVE_HIGH) ? 0 : 1);
this->_isBrakeActive = false;
this->_timeToReleaseBrake = LONG_MAX;
this->_hasMovementOccuredSinceLastBrakeRelease = false;
}
}

Expand Down Expand Up @@ -975,6 +1010,7 @@ void ESP_FlexyStepper::setTargetPositionInSteps(long absolutePositionToMoveToInS
this->isOnWayToHome = false;
this->isOnWayToLimit = false;
targetPosition_InSteps = absolutePositionToMoveToInSteps;
this->firstProcessingAfterTargetReached = true;
}

//
Expand Down Expand Up @@ -1022,8 +1058,8 @@ bool ESP_FlexyStepper::processMovement(void)
directionOfMotion = 0;
targetPosition_InSteps = currentPosition_InSteps;

//activate brake if configured and not active already
if (!this->_isBrakeActive)
//activate brake (if configured) driectly due to emergency stop if not already active
if (this->_isBrakeConfigured && !this->_isBrakeActive)
{
this->activateBrake();
}
Expand All @@ -1035,6 +1071,16 @@ bool ESP_FlexyStepper::processMovement(void)
return (true);
}

//check if delayed brake shall be engaged / released
if (this->_timeToEngangeBrake != LONG_MAX && this->_timeToEngangeBrake <= millis())
{
this->activateBrake();
}
else if (this->_timeToReleaseBrake != LONG_MAX && this->_timeToReleaseBrake <= millis())
{
this->deactivateBrake();
}

long distanceToTarget_Signed;

//check if limit switch flag is active
Expand Down Expand Up @@ -1079,10 +1125,10 @@ bool ESP_FlexyStepper::processMovement(void)
{
this->_homeReachedCallback();
}
//activate brake since we reached the final position
if (!this->_isBrakeActive)
//activate brake (or schedule activation) since we reached the final position
if (this->_isBrakeConfigured && !this->_isBrakeActive)
{
this->activateBrake();
this->triggerBrakeIfNeededOrSetTimeout();
}
return true;
}
Expand All @@ -1093,14 +1139,15 @@ bool ESP_FlexyStepper::processMovement(void)
(this->disallowedDirection == 1 && distanceToTarget_Signed > 0) ||
(this->disallowedDirection == -1 && distanceToTarget_Signed < 0))
{
//limit switch is acitve and movement in request direction is not allowed
currentStepPeriod_InUS = 0.0;
nextStepPeriod_InUS = 0.0;
directionOfMotion = 0;
targetPosition_InSteps = currentPosition_InSteps;
//activate brake since we reached the final position
if (!this->_isBrakeActive)
//activate brake (or schedule activation) since limit is active for requested direction
if (this->_isBrakeConfigured && !this->_isBrakeActive)
{
this->activateBrake();
this->triggerBrakeIfNeededOrSetTimeout();
}
return true;
}
Expand Down Expand Up @@ -1139,10 +1186,10 @@ bool ESP_FlexyStepper::processMovement(void)
else
{
this->lastStepDirectionBeforeLimitSwitchTrigger = 0;
//activate brake since we reached the final position
if (!this->_isBrakeActive)
//activate brake since motor is stopped
if (this->_isBrakeConfigured && !this->_isBrakeActive && this->_hasMovementOccuredSinceLastBrakeRelease)
{
this->activateBrake();
this->triggerBrakeIfNeededOrSetTimeout();
}
return (true);
}
Expand All @@ -1156,8 +1203,8 @@ bool ESP_FlexyStepper::processMovement(void)
if (periodSinceLastStep_InUS < (unsigned long)nextStepPeriod_InUS)
return (false);

//deactivate brake if configured and active
if (this->_isBrakeActive)
//we have to move, so deactivate brake (if configured at all) immediately
if (this->_isBrakeConfigured && this->_isBrakeActive)
{
this->deactivateBrake();
}
Expand All @@ -1178,6 +1225,8 @@ bool ESP_FlexyStepper::processMovement(void)
// return the step line low
digitalWrite(stepPin, LOW);

this->_hasMovementOccuredSinceLastBrakeRelease = true;

// check if the move has reached its final target position, return true if all
// done
if (currentPosition_InSteps == targetPosition_InSteps)
Expand All @@ -1198,9 +1247,9 @@ bool ESP_FlexyStepper::processMovement(void)
this->_targetPositionReachedCallback();
}
//activate brake since we reached the final position
if (!this->_isBrakeActive)
if (this->_isBrakeConfigured && !this->_isBrakeActive)
{
this->activateBrake();
this->triggerBrakeIfNeededOrSetTimeout();
}
}
return (true);
Expand All @@ -1209,6 +1258,30 @@ bool ESP_FlexyStepper::processMovement(void)
return (false);
}

/**
* internal helper to determine if brake shall be acitvated (if configured at all) or if a delay needs to be set
*/
void ESP_FlexyStepper::triggerBrakeIfNeededOrSetTimeout()
{
//check if break is already set or a timeout has already beend set
if (this->_isBrakeConfigured && !this->_isBrakeActive && this->_timeToEngangeBrake == LONG_MAX)
{
if (this->_brakeReleaseDelayMs > 0 && this->_hasMovementOccuredSinceLastBrakeRelease)
{
this->_timeToReleaseBrake = millis() + this->_brakeReleaseDelayMs;
}

if (this->_brakeEngageDelayMs == 0)
{
this->activateBrake();
}
else
{
this->_timeToEngangeBrake = millis() + this->_brakeEngageDelayMs;
}
}
}

// Get the current velocity of the motor in steps/second. This functions is
// updated while it accelerates up and down in speed. This is not the desired
// speed, but the speed the motor should be moving at the time the function is
Expand Down
15 changes: 13 additions & 2 deletions src/ESP_FlexyStepper.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,7 @@ class ESP_FlexyStepper

//IO setup and helper / debugging functions
void connectToPins(byte stepPinNumber, byte directionPinNumber);
void setBrakePin(byte brakePin, byte activeState = 1);
void setBrakePin(byte brakePin, byte activeState = ESP_FlexyStepper::ACTIVE_HIGH);
long getTaskStackHighWaterMark(void);
void clearLimitSwitchActive(void);
bool motionComplete();
Expand Down Expand Up @@ -98,6 +98,9 @@ class ESP_FlexyStepper
void setDirectionToHome(signed char directionTowardHome);
void setLimitSwitchActive(byte limitSwitchType);

void setBrakeEngageDelayMs(unsigned long);
void setBrakeReleaseDelayMs(signed long);

float getCurrentVelocityInStepsPerSecond();
float getCurrentVelocityInRevolutionsPerSecond();
float getCurrentVelocityInMillimetersPerSecond(void);
Expand Down Expand Up @@ -157,10 +160,18 @@ class ESP_FlexyStepper
static void taskRunner(void *parameter);

void DeterminePeriodOfNextStep();
void triggerBrakeIfNeededOrSetTimeout(void);

byte stepPin;
byte brakePin;
byte brakePin = -1;
byte brakePinActiveState = ACTIVE_HIGH;
unsigned long _brakeEngageDelayMs = 0;
signed long _brakeReleaseDelayMs = -1;
unsigned long _timeToEngangeBrake = LONG_MAX;
unsigned long _timeToReleaseBrake = LONG_MAX;
bool _isBrakeConfigured = false;
bool _hasMovementOccuredSinceLastBrakeRelease = true;

byte directionPin;
bool _isBrakeActive = false;
float stepsPerMillimeter;
Expand Down

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