klipper-dgus/klippy/chelper/kin_extruder.c

// Extruder stepper pulse time generation
//
// Copyright (C) 2018-2019  Kevin O'Connor <kevin@koconnor.net>
//
// 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
#include "itersolve.h" // struct stepper_kinematics
#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)
{
    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 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;
}