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DDA: have an acceleration constant for each axis individually. 

For now, keep behaviour identical, like still use STEPS_PER_M_X.
This is about to change soon.
This commit is contained in:
Markus Hitter 2014-07-09 23:19:07 +02:00
parent 2ad7517e27
commit 294f0eda26
2 changed files with 16 additions and 8 deletions
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21
dda.c
View File

@ -12,6 +12,7 @@
#endif
#include "dda_maths.h"
#include "preprocessor_math.h"
#include "dda_lookahead.h"
#include "timer.h"
#include "serial.h"
@ -70,6 +71,16 @@ static const axes_uint32_t PROGMEM maximum_feedrate_P = {
MAXIMUM_FEEDRATE_E
};
/// \var c0_P
/// \brief Initialization constant for the ramping algorithm. Timer cycles for
/// first step interval.
static const axes_uint32_t PROGMEM c0_P = {
((uint32_t)((double)F_CPU / SQRT((double)(STEPS_PER_M_X * ACCELERATION / 2000.)))) << 8,
((uint32_t)((double)F_CPU / SQRT((double)(STEPS_PER_M_Y * ACCELERATION / 2000.)))) << 8,
((uint32_t)((double)F_CPU / SQRT((double)(STEPS_PER_M_Z * ACCELERATION / 2000.)))) << 8,
((uint32_t)((double)F_CPU / SQRT((double)(STEPS_PER_M_E * ACCELERATION / 2000.)))) << 8
};
/*! Set the direction of the 'n' axis
*/
static void set_direction(DDA *dda, enum axis_e n, int dir) {
@ -383,14 +394,14 @@ void dda_create(DDA *dda, TARGET *target) {
dda_join_moves(prev_dda, dda);
dda->n = dda->start_steps;
if (dda->n == 0)
dda->c = C0;
dda->c = pgm_read_dword(&c0_P[X]);
else
dda->c = ((C0 >> 8) * int_inv_sqrt(dda->n)) >> 5;
dda->c = ((pgm_read_dword(&c0_P[X]) >> 8) * int_inv_sqrt(dda->n)) >> 5;
if (dda->c < dda->c_min)
dda->c = dda->c_min;
#else
dda->n = 0;
dda->c = C0;
dda->c = pgm_read_dword(&c0_P[X]);
#endif
#elif defined ACCELERATION_TEMPORAL
@ -853,11 +864,11 @@ void dda_clock() {
}
if (recalc_speed) {
if (dda->n == 0)
move_c = C0;
move_c = pgm_read_dword(&c0_P[X]);
else
// Explicit formula: c0 * (sqrt(n + 1) - sqrt(n)),
// approximation here: c0 * (1 / (2 * sqrt(n))).
move_c = ((C0 >> 8) * int_inv_sqrt(dda->n)) >> 5;
move_c = ((pgm_read_dword(&c0_P[X]) >> 8) * int_inv_sqrt(dda->n)) >> 5;
// TODO: most likely this whole check is obsolete. It was left as a
// safety margin, only. Rampup steps calculation should be accurate

3
dda_maths.h
View File

@ -56,7 +56,4 @@ uint32_t acc_ramp_len(uint32_t feedrate, uint32_t steps_per_m);
// For X axis only, should become obsolete:
#define ACCELERATE_RAMP_LEN(speed) (((speed)*(speed)) / (uint32_t)((7200000.0f * ACCELERATION) / (float)STEPS_PER_M_X))
// Initialization constant for the ramping algorithm. Timer cycles for first step interval.
#define C0 (((uint32_t)((double)F_CPU / sqrt((double)(STEPS_PER_M_X * ACCELERATION / 2000.)))) << 8)
#endif /* _DDA_MATHS_H */