toolhead: Support calculation of cornering minimum and maximum

Calculate the next "cornering" minimum and maximum for each move.  The
"cornering minimum" is the lowest speed the head will reach
immediately after this move (with no interleaving acceleration or
cruising).  The "cornering maximum" is the maximum speed the head will
reach after the cornering minimum (with no interleaving deceleration
or cruising).

These cornering calculations will be helpful in the extruder "pressure
advance" code.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2016-11-04 15:08:41 -04:00
parent 6285cc6f66
commit 9d7aa1e155
1 changed files with 25 additions and 21 deletions

View File

@ -70,10 +70,9 @@ class Move:
self.junction_start_max = min(
R * self.accel, self.junction_max, prev_move.junction_max
, prev_move.junction_start_max + prev_move.junction_delta)
def process(self, junction_start, junction_end):
def process(self, junction_start, junction_cruise, junction_end
, cornering_min, cornering_max):
# Determine accel, cruise, and decel portions of the move distance
junction_cruise = min((junction_start + junction_end
+ self.junction_delta) * .5, self.junction_max)
inv_junction_delta = 1. / self.junction_delta
accel_r = (junction_cruise-junction_start) * inv_junction_delta
decel_r = (junction_cruise-junction_end) * inv_junction_delta
@ -84,6 +83,8 @@ class Move:
cruise_v = math.sqrt(junction_cruise)
end_v = math.sqrt(junction_end)
self.start_v, self.cruise_v, self.end_v = start_v, cruise_v, end_v
self.corner_min = math.sqrt(cornering_min)
self.corner_max = math.sqrt(cornering_max)
# Determine time spent in each portion of move (time is the
# distance divided by average velocity)
accel_t = accel_r * self.move_d / ((start_v + cruise_v) * 0.5)
@ -102,42 +103,45 @@ class Move:
class MoveQueue:
def __init__(self):
self.queue = []
self.prev_junction_max = 0.
self.junction_flush = 0.
def reset(self):
del self.queue[:]
self.prev_junction_max = self.junction_flush = 0.
def flush(self, lazy=False):
flush_count = len(self.queue)
junction_end = [None] * flush_count
move_info = [None] * flush_count
# Traverse queue from last to first move and determine maximum
# junction speed assuming the robot comes to a complete stop
# after the last move.
next_junction_max = 0.
next_junction_end = cornering_min = cornering_max = 0.
for i in range(flush_count-1, -1, -1):
move = self.queue[i]
junction_end[i] = next_junction_max
next_junction_max = next_junction_max + move.junction_delta
if next_junction_max >= move.junction_start_max:
next_junction_max = move.junction_start_max
reachable_start = next_junction_end + move.junction_delta
junction_start = min(move.junction_start_max, reachable_start)
junction_cruise = min((junction_start + reachable_start) * .5
, move.junction_max)
move_info[i] = (junction_start, junction_cruise, next_junction_end
, cornering_min, cornering_max)
if reachable_start > junction_start:
cornering_min = junction_start
if junction_start + move.junction_delta > next_junction_end:
cornering_max = junction_cruise
if lazy:
flush_count = i
lazy = False
next_junction_end = junction_start
if lazy:
flush_count = 0
# Generate step times for all moves ready to be flushed
prev_junction_max = self.prev_junction_max
for i in range(flush_count):
move = self.queue[i]
move.process(prev_junction_max, junction_end[i])
prev_junction_max = junction_end[i]
self.prev_junction_max = prev_junction_max
self.queue[i].process(*move_info[i])
# Remove processed moves from the queue
del self.queue[:flush_count]
if self.queue:
self.junction_flush = self.queue[-1].junction_max
self.junction_flush = 2. * self.queue[-1].junction_max
def add_move(self, move):
self.queue.append(move)
if len(self.queue) == 1:
self.junction_flush = move.junction_max
self.junction_flush = 2. * move.junction_max
return
move.calc_junction(self.queue[-2])
self.junction_flush -= move.junction_delta