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delta: Convert delta kinematics to use iterative solver

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Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor
2018-06-08 21:30:38 -04:00
parent 2511471b0d
commit ca0d0135dc
5 changed files with 60 additions and 188 deletions
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146
klippy/chelper/kin_delta.c
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@@ -1,133 +1,39 @@
// Delta kinematics stepper pulse time generation
//
// Copyright (C) 2016-2018 Kevin O'Connor <kevin@koconnor.net>
// Copyright (C) 2018 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include <math.h> // sqrt
#include <stddef.h> // offsetof
#include <stdlib.h> // malloc
#include <string.h> // memset
#include "compiler.h" // __visible
#include "pyhelper.h" // errorf
#include "stepcompress.h" // queue_append
#include "itersolve.h" // struct stepper_kinematics
// Schedule steps using delta kinematics
static int32_t
_stepcompress_push_delta(
struct stepcompress *sc, int sdir
, double print_time, double move_sd, double start_sv, double accel
, double height, double startxy_sd, double arm_sd, double movez_r)
struct delta_stepper {
struct stepper_kinematics sk;
double arm2, tower_x, tower_y;
};
static double
delta_stepper_calc_position(struct stepper_kinematics *sk, struct move *m
, double move_time)
{
// Calculate number of steps to take
double movexy_r = movez_r ? sqrt(1. - movez_r*movez_r) : 1.;
double arm_sd2 = arm_sd * arm_sd;
double endxy_sd = startxy_sd - movexy_r*move_sd;
double end_height = safe_sqrt(arm_sd2 - endxy_sd*endxy_sd);
int count = (end_height + movez_r*move_sd - height) * (sdir ? 1. : -1.) + .5;
if (count <= 0 || count > 10000000) {
if (count) {
errorf("push_delta invalid count %d %d %f %f %f %f %f %f %f %f"
, stepcompress_get_oid(sc), count, print_time, move_sd
, start_sv, accel, height, startxy_sd, arm_sd, movez_r);
return ERROR_RET;
}
return 0;
}
int ret = set_next_step_dir(sc, sdir);
if (ret)
return ret;
int res = sdir ? count : -count;
// Calculate each step time
height += (sdir ? .5 : -.5);
if (!accel) {
// Move at constant velocity (zero acceleration)
struct queue_append qa = queue_append_start(sc, print_time, .5);
double inv_cruise_sv = stepcompress_get_mcu_freq(sc) / start_sv;
if (!movez_r) {
// Optimized case for common XY only moves (no Z movement)
while (count--) {
double v = safe_sqrt(arm_sd2 - height*height);
double pos = startxy_sd + (sdir ? -v : v);
int ret = queue_append(&qa, pos * inv_cruise_sv);
if (ret)
return ret;
height += (sdir ? 1. : -1.);
}
} else if (!movexy_r) {
// Optimized case for Z only moves
double pos = ((sdir ? height-end_height : end_height-height)
* inv_cruise_sv);
while (count--) {
int ret = queue_append(&qa, pos);
if (ret)
return ret;
pos += inv_cruise_sv;
}
} else {
// General case (handles XY+Z moves)
double start_pos = movexy_r*startxy_sd, zoffset = movez_r*startxy_sd;
while (count--) {
double relheight = movexy_r*height - zoffset;
double v = safe_sqrt(arm_sd2 - relheight*relheight);
double pos = start_pos + movez_r*height + (sdir ? -v : v);
int ret = queue_append(&qa, pos * inv_cruise_sv);
if (ret)
return ret;
height += (sdir ? 1. : -1.);
}
}
queue_append_finish(qa);
} else {
// Move with constant acceleration
double start_pos = movexy_r*startxy_sd, zoffset = movez_r*startxy_sd;
double mcu_freq = stepcompress_get_mcu_freq(sc);
double inv_accel = 1. / accel;
start_pos += 0.5 * start_sv*start_sv * inv_accel;
struct queue_append qa = queue_append_start(
sc, print_time, 0.5 - start_sv * inv_accel * mcu_freq);
double accel_multiplier = 2. * inv_accel * mcu_freq * mcu_freq;
while (count--) {
double relheight = movexy_r*height - zoffset;
double v = safe_sqrt(arm_sd2 - relheight*relheight);
double pos = start_pos + movez_r*height + (sdir ? -v : v);
v = safe_sqrt(pos * accel_multiplier);
int ret = queue_append(&qa, accel_multiplier >= 0. ? v : -v);
if (ret)
return ret;
height += (sdir ? 1. : -1.);
}
queue_append_finish(qa);
}
return res;
struct delta_stepper *ds = container_of(sk, struct delta_stepper, sk);
struct coord c = move_get_coord(m, move_time);
double dx = ds->tower_x - c.x, dy = ds->tower_y - c.y;
return sqrt(ds->arm2 - dx*dx - dy*dy) + c.z;
}
int32_t __visible
stepcompress_push_delta(
struct stepcompress *sc, double print_time, double move_sd
, double start_sv, double accel
, double height, double startxy_sd, double arm_sd, double movez_r)
struct stepper_kinematics * __visible
delta_stepper_alloc(double arm2, double tower_x, double tower_y)
{
double reversexy_sd = startxy_sd + arm_sd*movez_r;
if (reversexy_sd <= 0.)
// All steps are in down direction
return _stepcompress_push_delta(
sc, 0, print_time, move_sd, start_sv, accel
, height, startxy_sd, arm_sd, movez_r);
double movexy_r = movez_r ? sqrt(1. - movez_r*movez_r) : 1.;
if (reversexy_sd >= move_sd * movexy_r)
// All steps are in up direction
return _stepcompress_push_delta(
sc, 1, print_time, move_sd, start_sv, accel
, height, startxy_sd, arm_sd, movez_r);
// Steps in both up and down direction
int res1 = _stepcompress_push_delta(
sc, 1, print_time, reversexy_sd / movexy_r, start_sv, accel
, height, startxy_sd, arm_sd, movez_r);
if (res1 == ERROR_RET)
return res1;
int res2 = _stepcompress_push_delta(
sc, 0, print_time, move_sd, start_sv, accel
, height + res1, startxy_sd, arm_sd, movez_r);
if (res2 == ERROR_RET)
return res2;
return res1 + res2;
struct delta_stepper *ds = malloc(sizeof(*ds));
memset(ds, 0, sizeof(*ds));
ds->arm2 = arm2;
ds->tower_x = tower_x;
ds->tower_y = tower_y;
ds->sk.calc_position = delta_stepper_calc_position;
return &ds->sk;
}