251 lines
11 KiB
Python
251 lines
11 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
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# Common suffixes: _d is distance (in mm), _v is velocity (in
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# mm/second), _t is time (in seconds), _r is ratio (scalar between
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# 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, pos, move_d, axes_d, speed, accel):
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self.toolhead = toolhead
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self.pos = tuple(pos)
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self.move_d = move_d
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self.axes_d = axes_d
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self.accel = accel
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self.junction_max = speed**2
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self.junction_delta = 2.0 * move_d * accel
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self.junction_start_max = 0.
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def calc_junction(self, prev_move):
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# Find max start junction velocity using approximated
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# centripetal velocity as described at:
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# https://onehossshay.wordpress.com/2011/09/24/improving_grbl_cornering_algorithm/
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if not prev_move.move_d:
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return
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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.junction_start_max = min(
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R * self.accel, self.junction_max, prev_move.junction_max)
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def process(self, junction_start, junction_end):
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# Determine accel, cruise, and decel portions of the move
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junction_cruise = self.junction_max
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inv_junction_delta = 1. / self.junction_delta
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accel_r = (junction_cruise-junction_start) * inv_junction_delta
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decel_r = (junction_cruise-junction_end) * inv_junction_delta
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cruise_r = 1. - accel_r - decel_r
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if cruise_r < 0.:
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accel_r += 0.5 * cruise_r
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decel_r = 1.0 - accel_r
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cruise_r = 0.
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junction_cruise = junction_start + accel_r*self.junction_delta
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self.accel_r, self.cruise_r, self.decel_r = accel_r, cruise_r, decel_r
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# Determine move velocities
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start_v = math.sqrt(junction_start)
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cruise_v = math.sqrt(junction_cruise)
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end_v = math.sqrt(junction_end)
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self.start_v, self.cruise_v, self.end_v = start_v, cruise_v, end_v
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# Determine time spent in each portion of move
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accel_t = 2.0 * self.move_d * accel_r / (start_v + cruise_v)
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cruise_t = self.move_d * cruise_r / cruise_v
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decel_t = 2.0 * self.move_d * decel_r / (end_v + cruise_v)
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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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self.toolhead.kin.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, dummy_move):
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self.dummy_move = dummy_move
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self.queue = []
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self.prev_junction_max = 0.
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self.junction_flush = 0.
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def prev_move(self):
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if self.queue:
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return self.queue[-1]
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return self.dummy_move
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def flush(self, lazy=False):
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next_junction_max = 0.
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can_flush = not lazy
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flush_count = len(self.queue)
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junction_end = [None] * flush_count
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for i in range(len(self.queue)-1, -1, -1):
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move = self.queue[i]
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junction_end[i] = next_junction_max
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if not can_flush:
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flush_count -= 1
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next_junction_max = next_junction_max + move.junction_delta
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if next_junction_max >= move.junction_start_max:
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next_junction_max = move.junction_start_max
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can_flush = True
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prev_junction_max = self.prev_junction_max
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for i in range(flush_count):
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move = self.queue[i]
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next_junction_max = min(prev_junction_max + move.junction_delta
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, junction_end[i])
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move.process(prev_junction_max, next_junction_max)
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prev_junction_max = next_junction_max
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del self.queue[:flush_count]
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self.prev_junction_max = prev_junction_max
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self.junction_flush = 0.
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if self.queue:
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self.junction_flush = self.queue[-1].junction_max
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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 = move.junction_max
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return
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self.junction_flush -= move.junction_delta
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if self.junction_flush <= 0.:
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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.kin = cartesian.CartKinematics(printer, config)
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self.max_xy_speed, self.max_xy_accel = self.kin.get_max_xy_speed()
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self.junction_deviation = config.getfloat('junction_deviation', 0.02)
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dummy_move = Move(self, [0.]*4, 0., [0.]*4, 0., 0.)
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self.move_queue = MoveQueue(dummy_move)
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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.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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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.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_busy(self, eventtime):
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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, eventtime + 0.100)
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return False
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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 buffer_time > self.buffer_time_high
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def flush_handler(self, eventtime):
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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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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_with_z(self, newpos, axes_d, speed):
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self.move_queue.flush()
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move_d = math.sqrt(sum([d*d for d in axes_d[:3]]))
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# Limit velocity and accel to max for each stepper
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kin_speed, kin_accel = self.kin.get_max_speed(axes_d, move_d)
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speed = min(speed, self.max_xy_speed, kin_speed)
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accel = min(self.max_xy_accel, kin_accel)
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# Generate and execute move
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move = Move(self, newpos, move_d, axes_d, speed, accel)
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move.process(0., 0.)
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def _move_only_e(self, newpos, axes_d, speed):
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self.move_queue.flush()
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kin_speed, kin_accel = self.kin.get_max_e_speed()
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speed = min(speed, self.max_xy_speed, kin_speed)
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accel = min(self.max_xy_accel, kin_accel)
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move = Move(self, newpos, abs(axes_d[3]), axes_d, speed, accel)
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move.process(0., 0.)
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def move(self, newpos, speed, sloppy=False):
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axes_d = [newpos[i] - self.commanded_pos[i]
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for i in (0, 1, 2, 3)]
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self.commanded_pos[:] = newpos
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if axes_d[2]:
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self._move_with_z(newpos, axes_d, speed)
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return
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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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if axes_d[3]:
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self._move_only_e(newpos, axes_d, speed)
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return
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# Common xy move - create move and queue it
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speed = min(speed, self.max_xy_speed)
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move = Move(self, newpos, move_d, axes_d, speed, self.max_xy_accel)
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move.calc_junction(self.move_queue.prev_move())
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self.move_queue.add_move(move)
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def home(self, axis):
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return self.kin.home(self, axis)
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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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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.dwell(STALL_TIME)
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logging.debug('; Max time of %f' % (last_move_time,))
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