klipper-dgus/klippy/extruder.py

# Code for handling printer nozzle extruders
#
# Copyright (C) 2016  Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import logging
import stepper, heater

class PrinterExtruder:
    def __init__(self, printer, config):
        self.heater = heater.PrinterHeater(printer, config)
        self.stepper = stepper.PrinterStepper(printer, config)
        self.pressure_advance = config.getfloat('pressure_advance', 0.)
        self.stepper_pos = 0
        self.extrude_pos = 0.
    def build_config(self):
        self.heater.build_config()
        self.stepper.set_max_jerk(9999999.9)
        self.stepper.build_config()
    def motor_off(self, move_time):
        self.stepper.motor_enable(move_time, 0)
    def check_move(self, move):
        if (not move.do_calc_junction
            and not move.axes_d[0] and not move.axes_d[1]
            and not move.axes_d[2]):
            # Extrude only move - limit accel and velocity
            move.limit_speed(self.stepper.max_velocity, self.stepper.max_accel)
    def move(self, move_time, move):
        move_d = move.move_d
        inv_accel = 1. / move.accel

        start_v, cruise_v, end_v = move.start_v, move.cruise_v, move.end_v
        accel_t, cruise_t, decel_t = move.accel_t, move.cruise_t, move.decel_t
        accel_d = move.accel_r * move_d
        cruise_d = move.cruise_r * move_d
        decel_d = move.decel_r * move_d

        retract_t = retract_d = retract_v = 0.
        decel_v = cruise_v

        # Update for pressure advance
        if (move.axes_d[3] >= 0. and (move.axes_d[0] or move.axes_d[1])
            and self.pressure_advance):
            # Increase accel_d and start_v when accelerating
            extra_accel_d = (cruise_v - start_v) * self.pressure_advance
            accel_d += extra_accel_d
            if accel_t:
                start_v += extra_accel_d / accel_t
            # Update decel and retract parameters when decelerating
            if decel_t:
                extra_decel_d = (cruise_v - end_v) * self.pressure_advance
                extra_decel_v = extra_decel_d / decel_t
                decel_v -= extra_decel_v
                end_v -= extra_decel_v
                if decel_v <= 0.:
                    # The entire decel phase is replaced with retraction
                    retract_t = decel_t
                    retract_d = -(end_v + decel_v) * 0.5 * decel_t
                    retract_v = -decel_v
                    decel_t = decel_d = 0.
                elif end_v < 0.:
                    # Split decel phase into decel and retraction
                    retract_t = -end_v * inv_accel
                    retract_d = -end_v * 0.5 * retract_t
                    decel_t -= retract_t
                    decel_d = decel_v * 0.5 * decel_t
                else:
                    # There is still only a decel phase (no retraction)
                    decel_d -= extra_decel_d

        # Determine regular steps
        extrude_r = move.axes_d[3] / move_d
        forward_d = accel_d + cruise_d + decel_d
        self.extrude_pos += forward_d * extrude_r
        new_step_pos = int(self.extrude_pos*self.stepper.inv_step_dist + 0.5)
        steps = new_step_pos - self.stepper_pos
        if steps:
            self.stepper_pos = new_step_pos
            sdir = 0
            if steps < 0:
                sdir = 1
                steps = -steps
            mcu_time, so = self.stepper.prep_move(move_time, sdir)

            step_dist = forward_d / steps
            inv_step_dist = 1. / step_dist
            step_offset = 0.5

            # Acceleration steps
            #t = sqrt(2*pos/accel + (start_v/accel)**2) - start_v/accel
            accel_time_offset = start_v * inv_accel
            accel_sqrt_offset = accel_time_offset**2
            accel_multiplier = 2.0 * step_dist * inv_accel
            accel_steps = accel_d * inv_step_dist
            step_offset = so.step_sqrt(
                mcu_time - accel_time_offset, accel_steps, step_offset
                , accel_sqrt_offset, accel_multiplier)
            mcu_time += accel_t
            # Cruising steps
            #t = pos/cruise_v
            cruise_multiplier = step_dist / cruise_v
            cruise_steps = cruise_d * inv_step_dist
            step_offset = so.step_factor(
                mcu_time, cruise_steps, step_offset, cruise_multiplier)
            mcu_time += cruise_t
            # Deceleration steps
            #t = cruise_v/accel - sqrt((cruise_v/accel)**2 - 2*pos/accel)
            decel_time_offset = decel_v * inv_accel
            decel_sqrt_offset = decel_time_offset**2
            decel_steps = decel_d * inv_step_dist
            so.step_sqrt(
                mcu_time + decel_time_offset, decel_steps, step_offset
                , decel_sqrt_offset, -accel_multiplier)

        # Determine retract steps
        self.extrude_pos -= retract_d * extrude_r
        new_step_pos = int(self.extrude_pos*self.stepper.inv_step_dist + 0.5)
        steps = self.stepper_pos - new_step_pos
        if steps:
            self.stepper_pos = new_step_pos
            mcu_time, so = self.stepper.prep_move(
                move_time+accel_t+cruise_t+decel_t, 1)

            step_dist = retract_d / steps

            # Acceleration steps
            #t = sqrt(2*pos/accel + (start_v/accel)**2) - start_v/accel
            accel_time_offset = retract_v * inv_accel
            accel_sqrt_offset = accel_time_offset**2
            accel_multiplier = 2.0 * step_dist * inv_accel
            so.step_sqrt(mcu_time - accel_time_offset, steps, 0.5
                         , accel_sqrt_offset, accel_multiplier)