stepper: Support stepper phase adjustments when homing

Add support for enhancing the precision of endstop switches by also
inspecting the phase of the stepper motor when the endstop triggers.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2016-07-26 22:06:14 -04:00
parent 170389ef14
commit 654546e338
6 changed files with 81 additions and 2 deletions

View File

@ -11,7 +11,7 @@
# available pin and board names.)
# Pin names may be preceded by an '!' to indicate that a reverse
# polarity should be used (eg, trigger on low instead of high). Input
# pins may be prceded by an '^' to indicate that a hardware pull-up
# pins may be preceded by a '^' to indicate that a hardware pull-up
# resistor should be enabled for the pin.
@ -38,6 +38,26 @@ homing_retract_dist: 5.0
# Distance to backoff (in mm) before homing a second time during homing
homing_positive_dir: False
# If true, homes in a positive direction (away from zero)
homing_stepper_phases: 0
# One may optionally set this to the number of phases of the stepper
# motor driver (which is the number of micro-steps multiplied by
# four). When set, the phase of the stepper driver will be used
# during homing to improve the accuracy of the endstop switch.
homing_endstop_accuracy: 0.200
# Sets the expected accuracy (in mm) of the endstop. This represents
# the maximum error distance the endstop may trigger (eg, if an
# endstop may occasionally trigger 100um early or up to 100um late
# then set this to 0.200 for 200um). This setting is used with
# homing_stepper_phases and is only useful if that parameter is also
# configured.
#homing_endstop_phase: 0
# This specifies the phase of the stepper motor driver to expect
# when hitting the endstop. This setting is only meaningful if
# homing_stepper_phases is also set. Only set this value if one is
# sure the stepper motor driver is reset every time the mcu is
# reset. If this is not set, but homing_stepper_phases is set, then
# the stepper phase will be detected on the first home and that
# phase will be used on all subsequent homes.
position_min: -0.25
# Minimum valid distance (in mm) the user may command the stepper to
# move to (not currently enforced)

View File

@ -12,6 +12,8 @@ max_velocity: 500
max_accel: 3000
endstop_pin: ^PB6
homing_speed: 50.0
homing_stepper_phases: 32
homing_endstop_accuracy: .200
position_min: -0.25
position_endstop: 0.0
position_max: 200
@ -25,6 +27,8 @@ max_velocity: 500
max_accel: 3000
endstop_pin: ^PB5
homing_speed: 50.0
homing_stepper_phases: 32
homing_endstop_accuracy: .200
position_min: -0.25
position_endstop: 0.0
position_max: 250
@ -39,6 +43,8 @@ max_accel: 30
endstop_pin: ^PB4
homing_speed: 4.0
homing_retract_dist: 2.0
homing_stepper_phases: 32
homing_endstop_accuracy: .050
position_min: 0.1
position_endstop: 0.7
position_max: 200

View File

@ -33,6 +33,8 @@ class CartKinematics:
accel_factor = min([self.steppers[i].max_accel / abs(axes_d[i])
for i in StepList if axes_d[i]])
return velocity_factor * move_d, accel_factor * move_d
def get_homed_position(self):
return [s.get_homed_position() for s in self.steppers]
def home(self, toolhead, axes):
# Each axis is homed independently and in order
homing_state = homing.Homing(toolhead, axes)

View File

@ -40,6 +40,8 @@ class MCU_stepper:
max_error, self._step_cmd.msgid, self._oid)
def get_oid(self):
return self._oid
def get_invert_dir(self):
return self._invert_dir
def note_stepper_stop(self):
self._sdir = -1
self._last_move_clock = -2**29
@ -88,6 +90,7 @@ class MCU_endstop:
, self._oid)
self._query_cmd = mcu.lookup_command("end_stop_query oid=%c")
self._homing = False
self._last_position = 0
self._next_query_clock = 0
mcu_freq = self._mcu.get_mcu_freq()
self._retry_query_ticks = mcu_freq * self.RETRY_QUERY
@ -104,6 +107,7 @@ class MCU_endstop:
self._stepper.note_stepper_stop()
def _handle_end_stop_state(self, params):
logging.debug("end_stop_state %s" % (params,))
self._last_position = params['pos']
self._homing = params['homing'] != 0
def is_homing(self):
if not self._homing:
@ -116,6 +120,10 @@ class MCU_endstop:
msg = self._query_cmd.encode(self._oid)
self._mcu.send(msg, cq=self._cmd_queue)
return self._homing
def get_last_position(self):
if self._stepper.get_invert_dir():
return -self._last_position
return self._last_position
def get_print_clock(self, print_time):
return self._mcu.get_print_clock(print_time)

View File

@ -21,6 +21,23 @@ class PrinterStepper:
self.homing_positive_dir = config.getboolean(
'homing_positive_dir', False)
self.homing_retract_dist = config.getfloat('homing_retract_dist', 5.)
self.homing_stepper_phases = config.getint('homing_stepper_phases')
self.homing_endstop_phase = config.getint('homing_endstop_phase')
endstop_accuracy = config.getfloat('homing_endstop_accuracy')
self.homing_endstop_accuracy = None
if self.homing_stepper_phases:
if endstop_accuracy is None:
self.homing_endstop_accuracy = self.homing_stepper_phases//2 - 1
elif self.homing_endstop_phase is not None:
self.homing_endstop_accuracy = int(math.ceil(
endstop_accuracy * self.inv_step_dist / 2.))
else:
self.homing_endstop_accuracy = int(math.ceil(
endstop_accuracy * self.inv_step_dist))
if self.homing_endstop_accuracy >= self.homing_stepper_phases/2:
logging.info("Endstop for %s is not accurate enough for stepper"
" phase adjustment" % (self.config.section,))
self.homing_stepper_phases = None
self.position_min = config.getfloat('position_min', 0.)
self.position_endstop = config.getfloat('position_endstop')
self.position_max = config.getfloat('position_max')
@ -68,3 +85,21 @@ class PrinterStepper:
move_clock = int(self.mcu_endstop.get_print_clock(move_time))
self.mcu_endstop.home(move_clock, int(self.clock_ticks / hz))
return self.mcu_endstop
def get_homed_position(self):
if not self.homing_stepper_phases:
return self.position_endstop
pos = self.mcu_endstop.get_last_position()
pos %= self.homing_stepper_phases
if self.homing_endstop_phase is None:
logging.info("Setting %s endstop phase to %d" % (
self.config.section, pos))
self.homing_endstop_phase = pos
return self.position_endstop
delta = (pos - self.homing_endstop_phase) % self.homing_stepper_phases
if delta >= self.homing_stepper_phases - self.homing_endstop_accuracy:
delta -= self.homing_stepper_phases
elif delta > self.homing_endstop_accuracy:
logging.error("Endstop %s incorrect phase (got %d vs %d)" % (
self.config.section, pos, self.homing_endstop_phase))
return self.position_endstop
return self.position_endstop + delta * self.step_dist

View File

@ -254,7 +254,15 @@ class ToolHead:
move = Move(self, newpos, move_d, axes_d, speed, self.max_xy_accel)
self.move_queue.add_move(move)
def home(self, axes):
return self.kin.home(self, axes)
homing = self.kin.home(self, axes)
def axes_update(axes):
pos = self.get_position()
homepos = self.kin.get_homed_position()
for axis in axes:
pos[axis] = homepos[axis]
self.set_position(pos)
homing.plan_axes_update(axes_update)
return homing
def dwell(self, delay):
self.get_last_move_time()
self.update_move_time(delay)