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delta: Rework delta math to avoid using inv_movexy_r

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Taking the inverse of the XY move distance can lead to extremely large
values when the XY distance is very small.  This can lead to
saturation of the double precision variables and incorrect results.

Rework the delta kinematic math to avoid using this inverse.  Pass the
closestxy_d value directly to the C functions so that the C code can
calculate its intermediate constants.

After this change the move_z special case is no longer necessary as
the regular delta functions now work with movexy_r=0 and movez_r=1.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor
2016-12-04 19:30:35 -05:00
parent 5458f3cbd2
commit 9c932ad514
4 changed files with 83 additions and 126 deletions
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20
klippy/mcu.py
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@@ -86,21 +86,25 @@ class MCU_stepper:
self._stepqueue, steps, step_offset, clock, factor * self._mcu_freq)
self.commanded_position += count
return count
def step_delta_const(self, mcu_time, dist, step_dist, start_pos
, closest_height2, height, movez_r, inv_velocity):
def step_delta_const(self, mcu_time, dist, start_pos
, inv_velocity, step_dist
, height, closestxy_d, closest_height2, movez_r):
clock = mcu_time * self._mcu_freq
count = self.ffi_lib.stepcompress_push_delta_const(
self._stepqueue, clock, dist, step_dist, start_pos
, closest_height2, height, movez_r, inv_velocity * self._mcu_freq)
self._stepqueue, clock, dist, start_pos
, inv_velocity * self._mcu_freq, step_dist
, height, closestxy_d, closest_height2, movez_r)
self.commanded_position += count
return count
def step_delta_accel(self, mcu_time, dist, step_dist, start_pos
, closest_height2, height, movez_r, accel_multiplier):
def step_delta_accel(self, mcu_time, dist, start_pos
, accel_multiplier, step_dist
, height, closestxy_d, closest_height2, movez_r):
clock = mcu_time * self._mcu_freq
mcu_freq2 = self._mcu_freq**2
count = self.ffi_lib.stepcompress_push_delta_accel(
self._stepqueue, clock, dist, step_dist, start_pos
, closest_height2, height, movez_r, accel_multiplier * mcu_freq2)
self._stepqueue, clock, dist, start_pos
, accel_multiplier * mcu_freq2, step_dist
, height, closestxy_d, closest_height2, movez_r)
self.commanded_position += count
return count
def get_errors(self):