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delta: Convert delta kinematics to use iterative solver 

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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5
klippy/chelper/__init__.py
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@ -62,9 +62,8 @@ defs_kin_cartesian = """
"""
defs_kin_delta = """
int32_t stepcompress_push_delta(struct stepcompress *sc
, double clock_offset, double move_sd, double start_sv, double accel
, double height, double startxy_sd, double arm_d, double movez_r);
struct stepper_kinematics *delta_stepper_alloc(double arm2
, double tower_x, double tower_y);
"""
defs_serialqueue = """

146
klippy/chelper/kin_delta.c
View File

@ -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;
}

70
klippy/delta.py
View File

@ -4,7 +4,7 @@
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import math, logging
import stepper, homing
import stepper, homing, chelper
StepList = (0, 1, 2)
@ -56,6 +56,14 @@ class DeltaKinematics:
self.towers = [(math.cos(math.radians(angle)) * radius,
math.sin(math.radians(angle)) * radius)
for angle in self.angles]
# Setup iterative solver
ffi_main, ffi_lib = chelper.get_ffi()
self.cmove = ffi_main.gc(ffi_lib.move_alloc(), ffi_lib.free)
self.move_fill = ffi_lib.move_fill
for s, a, t in zip(self.steppers, self.arm2, self.towers):
sk = ffi_main.gc(ffi_lib.delta_stepper_alloc(a, t[0], t[1]),
ffi_lib.free)
s.setup_itersolve(sk)
# Find the point where an XY move could result in excessive
# tower movement
half_min_step_dist = min([s.step_dist for s in self.steppers]) * .5
@ -154,58 +162,14 @@ class DeltaKinematics:
def move(self, print_time, move):
if self.need_motor_enable:
self._check_motor_enable(print_time)
axes_d = move.axes_d
move_d = move.move_d
movexy_r = 1.
movez_r = 0.
inv_movexy_d = 1. / move_d
if not axes_d[0] and not axes_d[1]:
# Z only move
movez_r = axes_d[2] * inv_movexy_d
movexy_r = inv_movexy_d = 0.
elif axes_d[2]:
# XY+Z move
movexy_d = math.sqrt(axes_d[0]**2 + axes_d[1]**2)
movexy_r = movexy_d * inv_movexy_d
movez_r = axes_d[2] * inv_movexy_d
inv_movexy_d = 1. / movexy_d
origx, origy, origz = move.start_pos[:3]
accel = move.accel
cruise_v = move.cruise_v
accel_d = move.accel_r * move_d
cruise_d = move.cruise_r * move_d
decel_d = move.decel_r * move_d
for i in StepList:
# Calculate a virtual tower along the line of movement at
# the point closest to this stepper's tower.
towerx_d = self.towers[i][0] - origx
towery_d = self.towers[i][1] - origy
vt_startxy_d = (towerx_d*axes_d[0] + towery_d*axes_d[1])*inv_movexy_d
tangentxy_d2 = towerx_d**2 + towery_d**2 - vt_startxy_d**2
vt_arm_d = math.sqrt(self.arm2[i] - tangentxy_d2)
vt_startz = origz
# Generate steps
step_delta = self.steppers[i].step_delta
move_time = print_time
if accel_d:
step_delta(move_time, accel_d, move.start_v, accel,
vt_startz, vt_startxy_d, vt_arm_d, movez_r)
vt_startz += accel_d * movez_r
vt_startxy_d -= accel_d * movexy_r
move_time += move.accel_t
if cruise_d:
step_delta(move_time, cruise_d, cruise_v, 0.,
vt_startz, vt_startxy_d, vt_arm_d, movez_r)
vt_startz += cruise_d * movez_r
vt_startxy_d -= cruise_d * movexy_r
move_time += move.cruise_t
if decel_d:
step_delta(move_time, decel_d, cruise_v, -accel,
vt_startz, vt_startxy_d, vt_arm_d, movez_r)
self.move_fill(
self.cmove, print_time,
move.accel_t, move.cruise_t, move.decel_t,
move.start_pos[0], move.start_pos[1], move.start_pos[2],
move.axes_d[0], move.axes_d[1], move.axes_d[2],
move.start_v, move.cruise_v, move.accel)
for stepper in self.steppers:
stepper.step_itersolve(self.cmove)
# Helper functions for DELTA_CALIBRATE script
def get_stable_position(self):
return [int((ep - s.mcu_stepper.get_commanded_position())

24
klippy/mcu.py
View File

@ -26,7 +26,8 @@ class MCU_stepper:
self._stepqueue = ffi_main.gc(self._ffi_lib.stepcompress_alloc(oid),
self._ffi_lib.stepcompress_free)
self._mcu.register_stepqueue(self._stepqueue)
self._stepcompress_push_const = self._stepcompress_push_delta = None
self._stepcompress_push_const = self._itersolve_gen_steps = None
self._stepper_kinematics = None
self.set_ignore_move(False)
def get_mcu(self):
return self._mcu
@ -40,6 +41,10 @@ class MCU_stepper:
def setup_step_distance(self, step_dist):
self._step_dist = step_dist
self._inv_step_dist = 1. / step_dist
def setup_itersolve(self, sk):
self._stepper_kinematics = sk
self._ffi_lib.itersolve_set_stepcompress(
sk, self._stepqueue, self._step_dist)
def build_config(self):
max_error = self._mcu.get_max_stepper_error()
min_stop_interval = max(0., self._min_stop_interval - max_error)
@ -67,6 +72,9 @@ class MCU_stepper:
def get_step_dist(self):
return self._step_dist
def set_position(self, pos):
if self._stepper_kinematics is not None:
self._ffi_lib.itersolve_set_commanded_pos(
self._stepper_kinematics, pos)
steppos = pos * self._inv_step_dist
self._mcu_position_offset += self._commanded_pos - steppos
self._commanded_pos = steppos
@ -82,10 +90,10 @@ class MCU_stepper:
is not self._ffi_lib.stepcompress_push_const)
if ignore_move:
self._stepcompress_push_const = (lambda *args: 0)
self._stepcompress_push_delta = (lambda *args: 0)
self._itersolve_gen_steps = (lambda *args: 0)
else:
self._stepcompress_push_const = self._ffi_lib.stepcompress_push_const
self._stepcompress_push_delta = self._ffi_lib.stepcompress_push_delta
self._itersolve_gen_steps = self._ffi_lib.itersolve_gen_steps
return was_ignore
def note_homing_start(self, homing_clock):
ret = self._ffi_lib.stepcompress_set_homing(
@ -127,14 +135,8 @@ class MCU_stepper:
if count == STEPCOMPRESS_ERROR_RET:
raise error("Internal error in stepcompress")
self._commanded_pos += count
def step_delta(self, print_time, dist, start_v, accel
, height_base, startxy_d, arm_d, movez_r):
inv_step_dist = self._inv_step_dist
height = self._commanded_pos - height_base * inv_step_dist
count = self._stepcompress_push_delta(
self._stepqueue, print_time, dist * inv_step_dist,
start_v * inv_step_dist, accel * inv_step_dist,
height, startxy_d * inv_step_dist, arm_d * inv_step_dist, movez_r)
def step_itersolve(self, cmove):
count = self._itersolve_gen_steps(self._stepper_kinematics, cmove)
if count == STEPCOMPRESS_ERROR_RET:
raise error("Internal error in stepcompress")
self._commanded_pos += count

3
klippy/stepper.py
View File

@ -49,7 +49,8 @@ class PrinterStepper:
self.mcu_stepper.setup_step_distance(self.step_dist)
self.step = self.mcu_stepper.step
self.step_const = self.mcu_stepper.step_const
self.step_delta = self.mcu_stepper.step_delta
self.step_itersolve = self.mcu_stepper.step_itersolve
self.setup_itersolve = self.mcu_stepper.setup_itersolve
self.enable = lookup_enable_pin(ppins, config.get('enable_pin', None))
# Register STEPPER_BUZZ command
stepper_buzz = printer.try_load_module(config, 'stepper_buzz')