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extruder: Initial support for "smoothed pressure advance"

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Support averaging the extruder position over a time range to "smooth
out" the velocity changes that occur during pressure advance.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor
2019-11-05 16:21:06 -05:00
parent da06e185fb
commit 6d0c55b6c1
7 changed files with 108 additions and 175 deletions
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6
klippy/chelper/__init__.py
View File

@@ -91,10 +91,8 @@ defs_kin_winch = """
defs_kin_extruder = """
struct stepper_kinematics *extruder_stepper_alloc(void);
void extruder_add_move(struct trapq *tq, double print_time
, double accel_t, double cruise_t, double decel_t, double start_e_pos
, double start_v, double cruise_v, double accel
, double extra_accel_v, double extra_decel_v);
void extruder_set_pressure(struct stepper_kinematics *sk
, double pressure_advance, double half_smooth_time);
"""
defs_serialqueue = """

103
klippy/chelper/kin_extruder.c
View File

@@ -4,6 +4,7 @@
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include <stddef.h> // offsetof
#include <stdlib.h> // malloc
#include <string.h> // memset
#include "compiler.h" // __visible
@@ -11,70 +12,58 @@
#include "pyhelper.h" // errorf
#include "trapq.h" // move_get_distance
struct extruder_stepper {
struct stepper_kinematics sk;
double pressure_advance_factor, half_smooth_time, inv_smooth_time;
};
static double
extruder_calc_position(struct stepper_kinematics *sk, struct move *m
, double move_time)
{
return m->start_pos.x + move_get_distance(m, move_time);
struct extruder_stepper *es = container_of(sk, struct extruder_stepper, sk);
double hst = es->half_smooth_time;
if (!hst)
// Pressure advance not enabled
return m->start_pos.x + move_get_distance(m, move_time);
// Calculate average position over smooth_time
double area = trapq_integrate(m, 'x', move_time - hst, move_time + hst);
double base_pos = area * es->inv_smooth_time;
// Calculate position 'half_smooth_time' in the past
double start_time = move_time - hst;
struct move *sm = trapq_find_move(m, &start_time);
double start_dist = move_get_distance(sm, start_time);
double pa_start_pos = sm->start_pos.y + (sm->axes_r.y ? start_dist : 0.);
// Calculate position 'half_smooth_time' in the future
double end_time = move_time + hst;
struct move *em = trapq_find_move(m, &end_time);
double end_dist = move_get_distance(em, end_time);
double pa_end_pos = em->start_pos.y + (em->axes_r.y ? end_dist : 0.);
// Calculate position with pressure advance
return base_pos + (pa_end_pos - pa_start_pos) * es->pressure_advance_factor;
}
void __visible
extruder_set_pressure(struct stepper_kinematics *sk
, double pressure_advance, double half_smooth_time)
{
struct extruder_stepper *es = container_of(sk, struct extruder_stepper, sk);
if (! half_smooth_time) {
es->pressure_advance_factor = es->half_smooth_time = 0.;
return;
}
es->sk.scan_past = es->sk.scan_future = half_smooth_time;
es->half_smooth_time = half_smooth_time;
es->inv_smooth_time = .5 / half_smooth_time;
es->pressure_advance_factor = pressure_advance * es->inv_smooth_time;
}
struct stepper_kinematics * __visible
extruder_stepper_alloc(void)
{
struct stepper_kinematics *sk = malloc(sizeof(*sk));
memset(sk, 0, sizeof(*sk));
sk->calc_position_cb = extruder_calc_position;
sk->active_flags = AF_X;
return sk;
}
// Populate a 'struct move' with an extruder velocity trapezoid
void __visible
extruder_add_move(struct trapq *tq, double print_time
, double accel_t, double cruise_t, double decel_t
, double start_e_pos
, double start_v, double cruise_v, double accel
, double extra_accel_v, double extra_decel_v)
{
struct coord start_pos, axes_r;
start_pos.x = start_e_pos;
axes_r.x = 1.;
start_pos.y = start_pos.z = axes_r.y = axes_r.z = 0.;
if (accel_t) {
struct move *m = move_alloc();
m->print_time = print_time;
m->move_t = accel_t;
m->start_v = start_v + extra_accel_v;
m->half_accel = .5 * accel;
m->start_pos = start_pos;
m->axes_r = axes_r;
trapq_add_move(tq, m);
print_time += accel_t;
start_pos.x += move_get_distance(m, accel_t);
}
if (cruise_t) {
struct move *m = move_alloc();
m->print_time = print_time;
m->move_t = cruise_t;
m->start_v = cruise_v;
m->half_accel = 0.;
m->start_pos = start_pos;
m->axes_r = axes_r;
trapq_add_move(tq, m);
print_time += cruise_t;
start_pos.x += move_get_distance(m, cruise_t);
}
if (decel_t) {
struct move *m = move_alloc();
m->print_time = print_time;
m->move_t = decel_t;
m->start_v = cruise_v + extra_decel_v;
m->half_accel = -.5 * accel;
m->start_pos = start_pos;
m->axes_r = axes_r;
trapq_add_move(tq, m);
}
struct extruder_stepper *es = malloc(sizeof(*es));
memset(es, 0, sizeof(*es));
es->sk.calc_position_cb = extruder_calc_position;
es->sk.active_flags = AF_X;
return &es->sk;
}