extruder: Move extruder specific lookahead into extruder class

Instead of calculating min/max_corner_v in the toolhead class,
calculate it in the extruder class.  This keeps the extruder specific
code together.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2017-01-27 22:06:54 -05:00
parent 19ed67331d
commit 1bb7a22115
2 changed files with 93 additions and 48 deletions

View File

@ -6,6 +6,8 @@
import math, logging import math, logging
import stepper, heater, homing import stepper, heater, homing
EXTRUDE_DIFF_IGNORE = 1.02
class PrinterExtruder: class PrinterExtruder:
def __init__(self, printer, config): def __init__(self, printer, config):
self.config = config self.config = config
@ -35,6 +37,7 @@ class PrinterExtruder:
self.stepper.motor_enable(move_time, 0) self.stepper.motor_enable(move_time, 0)
self.need_motor_enable = True self.need_motor_enable = True
def check_move(self, move): def check_move(self, move):
move.extrude_r = move.axes_d[3] / move.move_d
if not self.heater.can_extrude: if not self.heater.can_extrude:
raise homing.EndstopMoveError( raise homing.EndstopMoveError(
move.end_pos, "Extrude below minimum temp") move.end_pos, "Extrude below minimum temp")
@ -48,6 +51,39 @@ class PrinterExtruder:
logging.debug("%s vs %s" % (move.extrude_r, self.max_extrude_ratio)) logging.debug("%s vs %s" % (move.extrude_r, self.max_extrude_ratio))
raise homing.EndstopMoveError( raise homing.EndstopMoveError(
move.end_pos, "Move exceeds maximum extrusion cross section") move.end_pos, "Move exceeds maximum extrusion cross section")
def calc_junction(self, prev_move, move):
if move.axes_d[3] or prev_move.axes_d[3]:
if (not move.axes_d[3] or not prev_move.axes_d[3]
or move.extrude_r > prev_move.extrude_r * EXTRUDE_DIFF_IGNORE
or prev_move.extrude_r > move.extrude_r * EXTRUDE_DIFF_IGNORE):
# Extrude ratio between moves is too different
return 0.
move.extrude_r = prev_move.extrude_r
return move.max_cruise_v2
def lookahead(self, move_info, orig_flush_count, lazy):
if not self.pressure_advance:
return orig_flush_count
min_corner_v2 = max_corner_v2 = 0.
flush_count = len(move_info)
for i in range(flush_count-1, -1, -1):
move, start_v2, cruise_v2, end_v2 = move_info[i]
reachable_start_v2 = end_v2 + move.delta_v2
# Calculate min/max_corner_v2 - the speed the head will
# slow to due to junction cornering and the maximum speed
# the head will reach immediately afterwards.
move.extruder_min_corner_v2 = min_corner_v2
move.extruder_max_corner_v2 = max_corner_v2
if reachable_start_v2 > start_v2:
min_corner_v2 = start_v2
if (start_v2 + move.delta_v2 > end_v2
or end_v2 >= move_info[i+1][2]):
if lazy and max_corner_v2:
flush_count = i
lazy = False
max_corner_v2 = cruise_v2
if lazy:
return 0
return min(flush_count, orig_flush_count)
def move(self, move_time, move): def move(self, move_time, move):
if self.need_motor_enable: if self.need_motor_enable:
self.stepper.motor_enable(move_time, 1) self.stepper.motor_enable(move_time, 1)
@ -83,12 +119,14 @@ class PrinterExtruder:
prev_pressure_d += extra_accel_d prev_pressure_d += extra_accel_d
# Update decel and retract parameters when decelerating # Update decel and retract parameters when decelerating
if decel_t: if decel_t:
if move.min_corner_v: if move.extruder_min_corner_v2:
npd = move.max_corner_v*move_extrude_r*self.pressure_advance min_corner_v = math.sqrt(move.extruder_min_corner_v2)
max_corner_v = math.sqrt(move.extruder_max_corner_v2)
npd = max_corner_v*move_extrude_r*self.pressure_advance
extra_decel_d = prev_pressure_d - npd extra_decel_d = prev_pressure_d - npd
if move.end_v > move.min_corner_v: if move.end_v > min_corner_v:
extra_decel_d *= ((move.cruise_v - move.end_v) extra_decel_d *= ((move.cruise_v - move.end_v)
/ (move.cruise_v - move.min_corner_v)) / (move.cruise_v - min_corner_v))
else: else:
npd = move.end_v * move_extrude_r * self.pressure_advance npd = move.end_v * move_extrude_r * self.pressure_advance
extra_decel_d = prev_pressure_d - npd extra_decel_d = prev_pressure_d - npd
@ -163,3 +201,17 @@ class PrinterExtruder:
, accel_sqrt_offset, accel_multiplier) , accel_sqrt_offset, accel_multiplier)
self.extrude_pos = start_pos + accel_d + cruise_d + decel_d - retract_d self.extrude_pos = start_pos + accel_d + cruise_d + decel_d - retract_d
# Dummy extruder class used when a printer has no extruder at all
class DummyExtruder:
def set_max_jerk(self, max_xy_halt_velocity, max_velocity, max_accel):
pass
def motor_off(self, move_time):
pass
def check_move(self, move):
raise homing.EndstopMoveError(
move.end_pos, "Extrude when no extruder present")
def calc_junction(self, prev_move, move):
return move.max_cruise_v2
def lookahead(self, moves, flush_count, lazy):
return flush_count

View File

@ -4,9 +4,7 @@
# #
# This file may be distributed under the terms of the GNU GPLv3 license. # This file may be distributed under the terms of the GNU GPLv3 license.
import math, logging, time import math, logging, time
import cartesian, delta import cartesian, delta, extruder
EXTRUDE_DIFF_IGNORE = 1.02
# Common suffixes: _d is distance (in mm), _v is velocity (in # Common suffixes: _d is distance (in mm), _v is velocity (in
# mm/second), _v2 is velocity squared (mm^2/s^2), _t is time (in # mm/second), _v2 is velocity squared (mm^2/s^2), _t is time (in
@ -36,7 +34,6 @@ class Move:
return return
self.do_calc_junction = self.is_kinematic_move = False self.do_calc_junction = self.is_kinematic_move = False
self.move_d = move_d self.move_d = move_d
self.extrude_r = axes_d[3] / move_d
# Junction speeds are tracked in velocity squared. The # Junction speeds are tracked in velocity squared. The
# delta_v2 is the maximum amount of this squared-velocity that # delta_v2 is the maximum amount of this squared-velocity that
# can change in this move. # can change in this move.
@ -52,11 +49,8 @@ class Move:
def calc_junction(self, prev_move): def calc_junction(self, prev_move):
if not self.do_calc_junction or not prev_move.do_calc_junction: if not self.do_calc_junction or not prev_move.do_calc_junction:
return return
if (self.extrude_r > prev_move.extrude_r * EXTRUDE_DIFF_IGNORE # Allow extruder to calculate its maximum junction
or prev_move.extrude_r > self.extrude_r * EXTRUDE_DIFF_IGNORE): extruder_v2 = self.toolhead.extruder.calc_junction(prev_move, self)
# Extrude ratio between moves is too different
return
self.extrude_r = prev_move.extrude_r
# Find max velocity using approximated centripetal velocity as # Find max velocity using approximated centripetal velocity as
# described at: # described at:
# https://onehossshay.wordpress.com/2011/09/24/improving_grbl_cornering_algorithm/ # https://onehossshay.wordpress.com/2011/09/24/improving_grbl_cornering_algorithm/
@ -70,8 +64,8 @@ class Move:
R = self.toolhead.junction_deviation * sin_theta_d2 / (1. - sin_theta_d2) R = self.toolhead.junction_deviation * sin_theta_d2 / (1. - sin_theta_d2)
self.max_start_v2 = min( self.max_start_v2 = min(
R * self.accel, self.max_cruise_v2, prev_move.max_cruise_v2 R * self.accel, self.max_cruise_v2, prev_move.max_cruise_v2
, prev_move.max_start_v2 + prev_move.delta_v2) , extruder_v2, prev_move.max_start_v2 + prev_move.delta_v2)
def process(self, start_v2, cruise_v2, end_v2, min_corner_v2, max_corner_v2): def set_junction(self, start_v2, cruise_v2, end_v2):
# Determine accel, cruise, and decel portions of the move distance # Determine accel, cruise, and decel portions of the move distance
inv_delta_v2 = 1. / self.delta_v2 inv_delta_v2 = 1. / self.delta_v2
self.accel_r = accel_r = (cruise_v2 - start_v2) * inv_delta_v2 self.accel_r = accel_r = (cruise_v2 - start_v2) * inv_delta_v2
@ -81,66 +75,64 @@ class Move:
self.start_v = start_v = math.sqrt(start_v2) self.start_v = start_v = math.sqrt(start_v2)
self.cruise_v = cruise_v = math.sqrt(cruise_v2) self.cruise_v = cruise_v = math.sqrt(cruise_v2)
self.end_v = end_v = math.sqrt(end_v2) self.end_v = end_v = math.sqrt(end_v2)
self.min_corner_v = math.sqrt(min_corner_v2)
self.max_corner_v = math.sqrt(max_corner_v2)
# Determine time spent in each portion of move (time is the # Determine time spent in each portion of move (time is the
# distance divided by average velocity) # distance divided by average velocity)
accel_t = accel_r * self.move_d / ((start_v + cruise_v) * 0.5) self.accel_t = accel_r * self.move_d / ((start_v + cruise_v) * 0.5)
cruise_t = cruise_r * self.move_d / cruise_v self.cruise_t = cruise_r * self.move_d / cruise_v
decel_t = decel_r * self.move_d / ((end_v + cruise_v) * 0.5) self.decel_t = decel_r * self.move_d / ((end_v + cruise_v) * 0.5)
self.accel_t, self.cruise_t, self.decel_t = accel_t, cruise_t, decel_t def move(self):
# Generate step times for the move # Generate step times for the move
next_move_time = self.toolhead.get_next_move_time() next_move_time = self.toolhead.get_next_move_time()
if self.is_kinematic_move: if self.is_kinematic_move:
self.toolhead.kin.move(next_move_time, self) self.toolhead.kin.move(next_move_time, self)
if self.axes_d[3]: if self.axes_d[3]:
self.toolhead.extruder.move(next_move_time, self) self.toolhead.extruder.move(next_move_time, self)
self.toolhead.update_move_time(accel_t + cruise_t + decel_t) self.toolhead.update_move_time(
self.accel_t + self.cruise_t + self.decel_t)
# Class to track a list of pending move requests and to facilitate # Class to track a list of pending move requests and to facilitate
# "look-ahead" across moves to reduce acceleration between moves. # "look-ahead" across moves to reduce acceleration between moves.
class MoveQueue: class MoveQueue:
def __init__(self): def __init__(self, extruder_lookahead):
self.extruder_lookahead = extruder_lookahead
self.queue = [] self.queue = []
self.junction_flush = 0. self.junction_flush = 0.
def reset(self): def reset(self):
del self.queue[:] del self.queue[:]
def flush(self, lazy=False): def flush(self, lazy=False):
flush_count = len(self.queue) update_flush_count = lazy
queue = self.queue
flush_count = len(queue)
move_info = [None] * flush_count move_info = [None] * flush_count
# Traverse queue from last to first move and determine maximum # Traverse queue from last to first move and determine maximum
# junction speed assuming the robot comes to a complete stop # junction speed assuming the robot comes to a complete stop
# after the last move. # after the last move.
next_end_v2 = min_corner_v2 = max_corner_v2 = 0. next_end_v2 = 0.
for i in range(flush_count-1, -1, -1): for i in range(flush_count-1, -1, -1):
move = self.queue[i] move = queue[i]
reachable_start_v2 = next_end_v2 + move.delta_v2 reachable_start_v2 = next_end_v2 + move.delta_v2
start_v2 = min(move.max_start_v2, reachable_start_v2) start_v2 = min(move.max_start_v2, reachable_start_v2)
cruise_v2 = min((start_v2 + reachable_start_v2) * .5 cruise_v2 = min((start_v2 + reachable_start_v2) * .5
, move.max_cruise_v2) , move.max_cruise_v2)
move_info[i] = (start_v2, cruise_v2, next_end_v2 move_info[i] = (move, start_v2, cruise_v2, next_end_v2)
, min_corner_v2, max_corner_v2) if update_flush_count and reachable_start_v2 > start_v2:
# Calculate min/max_corner_v2 - the speed the head will flush_count = i
# slow to due to junction cornering and the maximum speed update_flush_count = False
# the head will reach immediately afterwards.
if reachable_start_v2 > start_v2:
min_corner_v2 = start_v2
if (start_v2 + move.delta_v2 > next_end_v2
or next_end_v2 >= move_info[i+1][1]):
if lazy and max_corner_v2:
flush_count = i
lazy = False
max_corner_v2 = cruise_v2
next_end_v2 = start_v2 next_end_v2 = start_v2
if lazy: if update_flush_count:
flush_count = 0 flush_count = 0
# Traverse queue in forward direction propagating final values
for move, start_v2, cruise_v2, end_v2 in move_info[:flush_count]:
move.set_junction(start_v2, cruise_v2, end_v2)
# Allow extruder to do its lookahead
flush_count = self.extruder_lookahead(move_info, flush_count, lazy)
# Generate step times for all moves ready to be flushed # Generate step times for all moves ready to be flushed
for i in range(flush_count): for move in queue[:flush_count]:
self.queue[i].process(*move_info[i]) move.move()
# Remove processed moves from the queue # Remove processed moves from the queue
del self.queue[:flush_count] del queue[:flush_count]
if self.queue: if queue:
self.junction_flush = 2. * self.queue[-1].max_cruise_v2 self.junction_flush = 2. * queue[-1].max_cruise_v2
def add_move(self, move): def add_move(self, move):
self.queue.append(move) self.queue.append(move)
if len(self.queue) == 1: if len(self.queue) == 1:
@ -162,13 +154,15 @@ class ToolHead:
self.printer = printer self.printer = printer
self.reactor = printer.reactor self.reactor = printer.reactor
self.extruder = printer.objects.get('extruder') self.extruder = printer.objects.get('extruder')
if self.extruder is None:
self.extruder = extruder.DummyExtruder()
kintypes = {'cartesian': cartesian.CartKinematics, kintypes = {'cartesian': cartesian.CartKinematics,
'delta': delta.DeltaKinematics} 'delta': delta.DeltaKinematics}
self.kin = config.getchoice('kinematics', kintypes)(printer, config) self.kin = config.getchoice('kinematics', kintypes)(printer, config)
self.max_speed = config.getfloat('max_velocity') self.max_speed = config.getfloat('max_velocity')
self.max_accel = config.getfloat('max_accel') self.max_accel = config.getfloat('max_accel')
self.junction_deviation = config.getfloat('junction_deviation', 0.02) self.junction_deviation = config.getfloat('junction_deviation', 0.02)
self.move_queue = MoveQueue() self.move_queue = MoveQueue(self.extruder.lookahead)
self.commanded_pos = [0., 0., 0., 0.] self.commanded_pos = [0., 0., 0., 0.]
# Print time tracking # Print time tracking
self.buffer_time_high = config.getfloat('buffer_time_high', 5.000) self.buffer_time_high = config.getfloat('buffer_time_high', 5.000)
@ -183,8 +177,7 @@ class ToolHead:
def build_config(self): def build_config(self):
xy_halt = 0.005 * self.max_accel # XXX xy_halt = 0.005 * self.max_accel # XXX
self.kin.set_max_jerk(xy_halt, self.max_speed, self.max_accel) self.kin.set_max_jerk(xy_halt, self.max_speed, self.max_accel)
if self.extruder is not None: self.extruder.set_max_jerk(xy_halt, self.max_speed, self.max_accel)
self.extruder.set_max_jerk(xy_halt, self.max_speed, self.max_accel)
self.kin.build_config() self.kin.build_config()
# Print time tracking # Print time tracking
def update_move_time(self, movetime): def update_move_time(self, movetime):