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Acceleration extrapolated position #10

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Merged
QuentinTorg merged 4 commits into from
Dec 25, 2015
Merged

Acceleration extrapolated position #10

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a798aba
Fixed Compilation Issue
QuentinTorg Dec 6, 2015
388a619
Added acceleration based position extrapolation
QuentinTorg Dec 6, 2015
42d4a25
Added a lot of comments
QuentinTorg Dec 18, 2015
e096389
Merge branch 'master' into Acceleration-Extrapolated-Position
QuentinTorg Dec 25, 2015
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105 changes: 68 additions & 37 deletions EncoderMod.h
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Original file line number Diff line number Diff line change
Expand Up @@ -68,6 +68,8 @@ typedef struct {
float rate;
float rate1;
float rate2;
float previousRate;
float accel;
bool lastRateTimer;
} Encoder_internal_state_t;

Expand Down Expand Up @@ -100,6 +102,8 @@ class Encoder
encoder.rate = 0;
encoder.rate1 = 0;
encoder.rate2 = 0;
encoder.previousRate = 0;
encoder.accel = 0;
encoder.lastRateTimer = 0;
if (DIRECT_PIN_READ(encoder.pin1_register, encoder.pin1_bitmask)) s |= 1;
if (DIRECT_PIN_READ(encoder.pin2_register, encoder.pin2_bitmask)) s |= 2;
Expand Down Expand Up @@ -139,16 +143,17 @@ class Encoder
}
float lastRate = encoder.rate;
float elapsedTime = encoder.stepTime;
float lastAccel = encoder.accel;
interrupts();
float extrapolation = lastRate * elapsedTime;
if (extrapolation > 1) {
float extrapolatedPosition = lastRate * elapsedTime + 0.5 * lastAccel * elapsedTime * elapsedTime;
if (extrapolatedPosition > 1) {
return (1 / elapsedTime);
}
else if (extrapolation < -1) {
else if (extrapolatedPosition < -1) {
return (-1 / elapsedTime);
}
else {
return (lastRate);
return (lastRate + lastAccel * elapsedTime);
}
}
inline float extrapolate() {
Expand All @@ -161,16 +166,19 @@ class Encoder
}
float lastRate = encoder.rate;
int32_t lastPosition = encoder.position;
float extrapolation = encoder.stepTime;
float extrapolatedPosition = encoder.stepTime;
float lastAccel = encoder.accel;
interrupts();
extrapolation *= lastRate;
if (extrapolation > 1) {
extrapolation = 1;
extrapolatedPosition = lastRate * extrapolatedPosition + 0.5 * lastAccel * extrapolatedPosition * extrapolatedPosition;
if (extrapolatedPosition > 1) {
return (lastPosition + 1);
}
else if (extrapolation < -1) {
extrapolation = -1;
else if (extrapolatedPosition < -1) {
return (lastPosition - 1);
}
else {
return (extrapolatedPosition + lastPosition);
}
return (extrapolation + lastPosition);
}
#else
inline int32_t read() {
Expand All @@ -181,17 +189,30 @@ class Encoder
encoder.position = p;
}
inline float stepRate() {
return ((extrapolate() - encoder.position) / encoder.stepTime);
float extrapolatedPosition = encoder.rate * encoder.stepTime + 0.5 * encoder.accel * encoder.stepTime * encoder.stepTime;

if (extrapolatedPosition > 1) {
return (1 / encoder.stepTime);
}
else if (extrapolatedPosition < -1) {
return (-1 / encoder.stepTime);
}
else {
return (encoder.rate + encoder.accel * encoder.stepTime)
}

}
inline float extrapolate() {
float extrapolation = encoder.rate * encoder.stepTime;
if (extrapolation > 1) {
extrapolation = 1;
float extrapolatedPosition = encoder.rate * encoder.stepTime + 0.5 * encoder.accel * encoder.stepTime * encoder.stepTime;
if (extrapolatedPosition > 1) {
return (encoder.position + 1);
}
else if (extrapolation < -1) {
extrapolation = -1;
else if (extrapolatedPosition < -1) {
return (encoder.position - 1);
}
else {
return (extrapolatedPosition + encoder.position);
}
return (extrapolation + encoder.position);
}
#endif
private:
Expand Down Expand Up @@ -344,71 +365,81 @@ class Encoder
arg->state = (state >> 2);
switch (state) {
case 1: case 7: case 8: case 14:
if (arg->position % 2 == 0) {
arg->rate1 = 0.5 / arg->stepTime;
if (arg->lastRateTimer == 0) {
arg->rate2 = 0;
arg->previousRate = arg->rate; // remember previous rate for calculating
if (arg->position % 2 == 0) { // if the previous position was even (0 to 1 step)
arg->rate1 = 0.5 / arg->stepTime; // the 0 to 1 step rate is set to rate1
if (arg->lastRateTimer == 0) { // if the 0 to 1 step was the previous one calculated
arg->rate2 = 0; // then the rate2 step was skipped due to a direction change, so set it to zero
arg->previousRate = 0; // previous rate is also set to zero. there may be a better way but I have yet to think about it
}
arg->lastRateTimer = 0;
arg->lastRateTimer = 0; // remember that rate1 was the last one calculated
}
else {
arg->rate2 = 0.5 / arg->stepTime;
if (arg->lastRateTimer == 1) {
arg->rate1 = 0;
else { // if the previous position was odd (step -1 to 0)
arg->rate2 = 0.5 / arg->stepTime; // the -1 to 0 step rate is set to rate2
if (arg->lastRateTimer == 1) { // if the -1 to 0 step was the previous one calculated
arg->rate1 = 0; // then rate1 step was skipped due to direction change, so it is set to zero
arg->previousRate = 0; // previous rate is also set to zero. there may be a better way but I have yet to think about it
}
arg->lastRateTimer = 1;
arg->lastRateTimer = 1; // remember that rate2 was the last one calculated
}
arg->stepTime = 0;
arg->rate = (arg->rate1 + arg->rate2);
arg->accel = (arg->rate - arg->previousRate) / arg->stepTime;
arg->stepTime = 0;
arg->position++;
return;
case 2: case 4: case 11: case 13:
if (arg->position % 2 != 0) {
arg->rate1 = -0.5 / arg->stepTime;
arg->previousRate = arg->rate;
if (arg->position % 2 != 0) { // if the previous position was odd (1 to 0 step)
arg->rate1 = -0.5 / arg->stepTime; // the 1 to 0 step rate is set to rate1
if (arg->lastRateTimer == 0) {
arg->rate2 = 0;
arg->previousRate = 0;
}
arg->lastRateTimer = 0;
}
else {
else { // if the previous position was even
arg->rate2 = -0.5 / arg->stepTime;
if (arg->lastRateTimer == 1) {
arg->rate1 = 0;
arg->previousRate = 0;
}
arg->lastRateTimer = 1;
}
arg->stepTime = 0;
arg->rate = (arg->rate1 + arg->rate2);
arg->accel = (arg->rate - arg->previousRate) / arg->stepTime;
arg->stepTime = 0;
arg->position--;
return;
case 3: case 12:
arg->previousRate = arg->rate;
if (arg->position % 2 == 0) {
arg->rate1 = 1 / arg->stepTime;
arg->stepTime = 0;
arg->rate2 = arg->rate1;
arg->rate = arg->rate1;
}
else {
arg->rate2 = 1 / arg->stepTime;
arg->stepTime = 0;
arg->rate1 = arg->rate2;
arg->rate = arg->rate2;
}
arg->accel = (arg->rate - arg->previousRate) / arg->stepTime;
arg->stepTime = 0;
arg->position += 2;
return;
case 6: case 9:
arg->previousRate = arg->rate;
if (arg->position % 2 != 0) {
arg->rate1 = -1 / arg->stepTime;
arg->stepTime = 0;
arg->rate2 = arg->rate1;
arg->rate = arg->rate1;
}
else {
arg->rate2 = -1 / arg->stepTime;
arg->stepTime = 0;
arg->rate1 = arg->rate2;
arg->rate = arg->rate2;
}
arg->accel = (arg->rate - arg->previousRate) / arg->stepTime;
arg->stepTime = 0;
arg->position -= 2;
return;
}
Expand Down