307 lines
13 KiB
Python
307 lines
13 KiB
Python
# Code for coordinating events on the printer toolhead
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#
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# Copyright (C) 2016 Kevin O'Connor <kevin@koconnor.net>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import math, logging, time
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import cartesian, delta
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EXTRUDE_DIFF_IGNORE = 1.02
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# Common suffixes: _d is distance (in mm), _v is velocity (in
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# mm/second), _v2 is velocity squared (mm^2/s^2), _t is time (in
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# seconds), _r is ratio (scalar between 0.0 and 1.0)
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# Class to track each move request
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class Move:
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def __init__(self, toolhead, start_pos, end_pos, speed):
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self.toolhead = toolhead
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self.start_pos = tuple(start_pos)
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self.end_pos = tuple(end_pos)
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self.accel = toolhead.max_accel
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self.do_calc_junction = self.is_kinematic_move = True
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self.axes_d = axes_d = [end_pos[i] - start_pos[i] for i in (0, 1, 2, 3)]
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if axes_d[2]:
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# Move with Z
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move_d = math.sqrt(sum([d*d for d in axes_d[:3]]))
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self.do_calc_junction = False
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else:
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move_d = math.sqrt(axes_d[0]**2 + axes_d[1]**2)
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if not move_d:
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# Extrude only move
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move_d = abs(axes_d[3])
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if not move_d:
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# No move
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self.move_d = 0.
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return
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self.do_calc_junction = self.is_kinematic_move = False
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self.move_d = move_d
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self.extrude_r = axes_d[3] / move_d
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# Junction speeds are tracked in velocity squared. The
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# delta_v2 is the maximum amount of this squared-velocity that
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# can change in this move.
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self.max_start_v2 = 0.
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self.max_cruise_v2 = speed**2
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self.delta_v2 = 2.0 * move_d * self.accel
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def limit_speed(self, speed, accel):
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self.max_cruise_v2 = min(self.max_cruise_v2, speed**2)
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if accel < self.accel:
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self.accel = accel
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self.delta_v2 = 2.0 * self.move_d * self.accel
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self.do_calc_junction = False
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def calc_junction(self, prev_move):
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if not self.do_calc_junction or not prev_move.do_calc_junction:
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return
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if (self.extrude_r > prev_move.extrude_r * EXTRUDE_DIFF_IGNORE
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or prev_move.extrude_r > self.extrude_r * EXTRUDE_DIFF_IGNORE):
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# Extrude ratio between moves is too different
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return
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self.extrude_r = prev_move.extrude_r
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# Find max velocity using approximated centripetal velocity as
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# described at:
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# https://onehossshay.wordpress.com/2011/09/24/improving_grbl_cornering_algorithm/
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junction_cos_theta = -((self.axes_d[0] * prev_move.axes_d[0]
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+ self.axes_d[1] * prev_move.axes_d[1])
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/ (self.move_d * prev_move.move_d))
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if junction_cos_theta > 0.999999:
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return
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junction_cos_theta = max(junction_cos_theta, -0.999999)
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sin_theta_d2 = math.sqrt(0.5*(1.0-junction_cos_theta))
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R = self.toolhead.junction_deviation * sin_theta_d2 / (1. - sin_theta_d2)
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self.max_start_v2 = min(
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R * self.accel, self.max_cruise_v2, prev_move.max_cruise_v2
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, prev_move.max_start_v2 + prev_move.delta_v2)
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def process(self, start_v2, cruise_v2, end_v2, min_corner_v2, max_corner_v2):
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# Determine accel, cruise, and decel portions of the move distance
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inv_delta_v2 = 1. / self.delta_v2
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self.accel_r = accel_r = (cruise_v2 - start_v2) * inv_delta_v2
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self.decel_r = decel_r = (cruise_v2 - end_v2) * inv_delta_v2
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self.cruise_r = cruise_r = 1. - accel_r - decel_r
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# Determine move velocities
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self.start_v = start_v = math.sqrt(start_v2)
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self.cruise_v = cruise_v = math.sqrt(cruise_v2)
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self.end_v = end_v = math.sqrt(end_v2)
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self.min_corner_v = math.sqrt(min_corner_v2)
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self.max_corner_v = math.sqrt(max_corner_v2)
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# Determine time spent in each portion of move (time is the
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# distance divided by average velocity)
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accel_t = accel_r * self.move_d / ((start_v + cruise_v) * 0.5)
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cruise_t = cruise_r * self.move_d / cruise_v
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decel_t = decel_r * self.move_d / ((end_v + cruise_v) * 0.5)
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self.accel_t, self.cruise_t, self.decel_t = accel_t, cruise_t, decel_t
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# Generate step times for the move
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next_move_time = self.toolhead.get_next_move_time()
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if self.is_kinematic_move:
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self.toolhead.kin.move(next_move_time, self)
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if self.axes_d[3]:
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self.toolhead.extruder.move(next_move_time, self)
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self.toolhead.update_move_time(accel_t + cruise_t + decel_t)
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# Class to track a list of pending move requests and to facilitate
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# "look-ahead" across moves to reduce acceleration between moves.
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class MoveQueue:
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def __init__(self):
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self.queue = []
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self.junction_flush = 0.
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def reset(self):
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del self.queue[:]
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def flush(self, lazy=False):
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flush_count = len(self.queue)
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move_info = [None] * flush_count
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# Traverse queue from last to first move and determine maximum
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# junction speed assuming the robot comes to a complete stop
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# after the last move.
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next_end_v2 = min_corner_v2 = max_corner_v2 = 0.
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for i in range(flush_count-1, -1, -1):
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move = self.queue[i]
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reachable_start_v2 = next_end_v2 + move.delta_v2
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start_v2 = min(move.max_start_v2, reachable_start_v2)
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cruise_v2 = min((start_v2 + reachable_start_v2) * .5
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, move.max_cruise_v2)
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move_info[i] = (start_v2, cruise_v2, next_end_v2
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, min_corner_v2, max_corner_v2)
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# Calculate min/max_corner_v2 - the speed the head will
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# slow to due to junction cornering and the maximum speed
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# the head will reach immediately afterwards.
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if reachable_start_v2 > start_v2:
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min_corner_v2 = start_v2
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if (start_v2 + move.delta_v2 > next_end_v2
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or next_end_v2 >= move_info[i+1][1]):
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if lazy and max_corner_v2:
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flush_count = i
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lazy = False
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max_corner_v2 = cruise_v2
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next_end_v2 = start_v2
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if lazy:
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flush_count = 0
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# Generate step times for all moves ready to be flushed
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for i in range(flush_count):
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self.queue[i].process(*move_info[i])
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# Remove processed moves from the queue
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del self.queue[:flush_count]
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if self.queue:
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self.junction_flush = 2. * self.queue[-1].max_cruise_v2
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def add_move(self, move):
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self.queue.append(move)
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if len(self.queue) == 1:
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self.junction_flush = 2. * move.max_cruise_v2
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return
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move.calc_junction(self.queue[-2])
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self.junction_flush -= move.delta_v2
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if self.junction_flush <= 0.:
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# There are enough queued moves to return to zero velocity
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# from the first move's maximum possible velocity, so at
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# least one move can be flushed.
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self.flush(lazy=True)
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STALL_TIME = 0.100
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# Main code to track events (and their timing) on the printer toolhead
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class ToolHead:
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def __init__(self, printer, config):
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self.printer = printer
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self.reactor = printer.reactor
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self.extruder = printer.objects.get('extruder')
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kintypes = {'cartesian': cartesian.CartKinematics,
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'delta': delta.DeltaKinematics}
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self.kin = config.getchoice('kinematics', kintypes)(printer, config)
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self.max_speed = config.getfloat('max_velocity')
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self.max_accel = config.getfloat('max_accel')
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self.junction_deviation = config.getfloat('junction_deviation', 0.02)
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self.move_queue = MoveQueue()
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self.commanded_pos = [0., 0., 0., 0.]
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# Print time tracking
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self.buffer_time_high = config.getfloat('buffer_time_high', 5.000)
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self.buffer_time_low = config.getfloat('buffer_time_low', 0.150)
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self.move_flush_time = config.getfloat('move_flush_time', 0.050)
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self.motor_off_delay = config.getfloat('motor_off_time', 60.000)
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self.print_time = 0.
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self.need_check_stall = -1.
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self.print_time_stall = 0
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self.motor_off_time = self.reactor.NEVER
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self.flush_timer = self.reactor.register_timer(self._flush_handler)
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def build_config(self):
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xy_halt = 0.005 * self.max_accel # XXX
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self.kin.set_max_jerk(xy_halt, self.max_speed, self.max_accel)
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if self.extruder is not None:
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self.extruder.set_max_jerk(xy_halt, self.max_speed, self.max_accel)
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self.kin.build_config()
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# Print time tracking
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def update_move_time(self, movetime):
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self.print_time += movetime
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flush_to_time = self.print_time - self.move_flush_time
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self.printer.mcu.flush_moves(flush_to_time)
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def get_next_move_time(self):
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if not self.print_time:
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self.print_time = self.buffer_time_low + STALL_TIME
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curtime = time.time()
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self.printer.mcu.set_print_start_time(curtime)
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self.reactor.update_timer(self.flush_timer, self.reactor.NOW)
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return self.print_time
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def get_last_move_time(self):
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self.move_queue.flush()
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return self.get_next_move_time()
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def reset_motor_off_time(self, eventtime):
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self.motor_off_time = eventtime + self.motor_off_delay
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def reset_print_time(self):
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self.move_queue.flush()
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self.printer.mcu.flush_moves(self.print_time)
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self.print_time = 0.
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self.need_check_stall = -1.
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self.reset_motor_off_time(time.time())
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self.reactor.update_timer(self.flush_timer, self.motor_off_time)
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def _check_stall(self):
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if not self.print_time:
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# XXX - find better way to flush initial move_queue items
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if self.move_queue.queue:
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self.reactor.update_timer(self.flush_timer, time.time() + 0.100)
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return
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eventtime = time.time()
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while 1:
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buffer_time = self.printer.mcu.get_print_buffer_time(
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eventtime, self.print_time)
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stall_time = buffer_time - self.buffer_time_high
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if stall_time <= 0.:
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break
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eventtime = self.reactor.pause(eventtime + stall_time)
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if not self.print_time:
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return
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self.need_check_stall = self.print_time - stall_time + 0.100
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def _flush_handler(self, eventtime):
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try:
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if not self.print_time:
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self.move_queue.flush()
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if not self.print_time:
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if eventtime >= self.motor_off_time:
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self.motor_off()
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self.reset_print_time()
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self.motor_off_time = self.reactor.NEVER
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return self.motor_off_time
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print_time = self.print_time
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buffer_time = self.printer.mcu.get_print_buffer_time(
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eventtime, print_time)
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if buffer_time > self.buffer_time_low:
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return eventtime + buffer_time - self.buffer_time_low
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self.move_queue.flush()
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if print_time != self.print_time:
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self.print_time_stall += 1
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self.dwell(self.buffer_time_low + STALL_TIME)
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return self.reactor.NOW
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self.reset_print_time()
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return self.motor_off_time
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except:
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logging.exception("Exception in flush_handler")
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self.force_shutdown()
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def stats(self, eventtime):
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buffer_time = 0.
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if self.print_time:
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buffer_time = self.printer.mcu.get_print_buffer_time(
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eventtime, self.print_time)
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return "print_time=%.3f buffer_time=%.3f print_time_stall=%d" % (
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self.print_time, buffer_time, self.print_time_stall)
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# Movement commands
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def get_position(self):
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return list(self.commanded_pos)
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def set_position(self, newpos):
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self.move_queue.flush()
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self.commanded_pos[:] = newpos
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self.kin.set_position(newpos)
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def move(self, newpos, speed):
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speed = min(speed, self.max_speed)
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move = Move(self, self.commanded_pos, newpos, speed)
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if not move.move_d:
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return
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if move.is_kinematic_move:
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self.kin.check_move(move)
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if move.axes_d[3]:
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self.extruder.check_move(move)
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self.commanded_pos[:] = newpos
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self.move_queue.add_move(move)
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if self.print_time > self.need_check_stall:
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self._check_stall()
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def home(self, homing_state):
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self.kin.home(homing_state)
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def dwell(self, delay):
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self.get_last_move_time()
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self.update_move_time(delay)
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self._check_stall()
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def motor_off(self):
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self.dwell(STALL_TIME)
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last_move_time = self.get_last_move_time()
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self.kin.motor_off(last_move_time)
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self.extruder.motor_off(last_move_time)
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self.dwell(STALL_TIME)
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logging.debug('; Max time of %f' % (last_move_time,))
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def wait_moves(self):
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self.move_queue.flush()
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eventtime = time.time()
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while self.print_time:
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eventtime = self.reactor.pause(eventtime + 0.100)
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def query_endstops(self):
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last_move_time = self.get_last_move_time()
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return self.kin.query_endstops(last_move_time)
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def force_shutdown(self):
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self.printer.mcu.force_shutdown()
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self.move_queue.reset()
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self.reset_print_time()
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