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delta: Move "stable position" logic to delta_calibrate.py 

Move the "stable position" logic from the delta.py kinematics code to
the delta_calibrate.py calibration code.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2018-09-03 13:34:27 -04:00 committed by KevinOConnor
parent d48e8ea162
commit ed0882dc10
2 changed files with 82 additions and 44 deletions
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84
klippy/extras/delta_calibrate.py
View File

@ -3,9 +3,64 @@
# Copyright (C) 2017-2018 Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import math, logging
import math, logging, collections
import probe, mathutil
######################################################################
# Delta "stable position" coordinates
######################################################################
# A "stable position" is a 3-tuple containing the number of steps
# taken since hitting the endstop on each delta tower. Delta
# calibration uses this coordinate system because it allows a position
# to be described independent of the software parameters.
# Storage helper for delta parameters
DeltaParams = collections.namedtuple('DeltaParams', [
'radius', 'angles', 'arms', 'endstops', 'stepdists',
'towers', 'abs_endstops'])
# Generate delta_params from delta configuration parameters
def build_delta_params(params):
radius = params['radius']
angles = [params['angle_'+a] for a in 'abc']
arms = [params['arm_'+a] for a in 'abc']
endstops = [params['endstop_'+a] for a in 'abc']
stepdists = [params['stepdist_'+a] for a in 'abc']
# Calculate the XY cartesian coordinates of the delta towers
radian_angles = [math.radians(a) for a in angles]
towers = [(math.cos(a) * radius, math.sin(a) * radius)
for a in radian_angles]
# Calculate the absolute Z height of each tower endstop
radius2 = radius**2
abs_endstops = [e + math.sqrt(a**2 - radius2)
for e, a in zip(endstops, arms)]
return DeltaParams(radius, angles, arms, endstops, stepdists,
towers, abs_endstops)
# Return cartesian coordinates for the given stable_positions when the
# given delta_params are used.
def get_position_from_stable(stable_position, delta_params):
dp = delta_params
sphere_coords = [
(t[0], t[1], es - sp * sd)
for sd, t, es, sp in zip(
dp.stepdists, dp.towers, dp.abs_endstops, stable_position) ]
return mathutil.trilateration(sphere_coords, [a**2 for a in dp.arms])
# Return a stable position from the nominal delta tower positions
def get_stable_position(stepper_position, delta_params):
dp = delta_params
return [int((ep - sp) / sd + .5)
for sd, ep, sp in zip(
dp.stepdists, dp.abs_endstops, stepper_position)]
######################################################################
# Delta Calibrate class
######################################################################
class DeltaCalibrate:
def __init__(self, config):
self.printer = config.get_printer()
@ -32,27 +87,34 @@ class DeltaCalibrate:
self.probe_helper.start_probe()
def get_probed_position(self):
kin = self.printer.lookup_object('toolhead').get_kinematics()
return kin.get_stable_position()
return [s.get_commanded_position() for s in kin.get_steppers()]
def finalize(self, offsets, positions):
z_offset = offsets[2]
kin = self.printer.lookup_object('toolhead').get_kinematics()
logging.info("Calculating delta_calibrate with: %s", positions)
params = kin.get_calibrate_params()
logging.info("Initial delta_calibrate parameters: %s", params)
adj_params = ('endstop_a', 'endstop_b', 'endstop_c', 'radius',
'angle_a', 'angle_b')
orig_delta_params = build_delta_params(params)
stable_positions = [get_stable_position(p, orig_delta_params)
for p in positions]
logging.info("Calculating delta_calibrate with: %s\n"
"Initial delta_calibrate parameters: %s",
stable_positions, params)
adj_params = ('radius', 'angle_a', 'angle_b',
'endstop_a', 'endstop_b', 'endstop_c')
def delta_errorfunc(params):
delta_params = build_delta_params(params)
total_error = 0.
for x, y, z in kin.get_positions_from_stable(positions, params):
for stable_pos in stable_positions:
x, y, z = get_position_from_stable(stable_pos, delta_params)
total_error += (z - z_offset)**2
return total_error
new_params = mathutil.coordinate_descent(
adj_params, params, delta_errorfunc)
logging.info("Calculated delta_calibrate parameters: %s", new_params)
old_positions = kin.get_positions_from_stable(positions, params)
new_positions = kin.get_positions_from_stable(positions, new_params)
for oldpos, newpos in zip(old_positions, new_positions):
logging.info("orig: %s new: %s", oldpos, newpos)
new_delta_params = build_delta_params(new_params)
for spos in stable_positions:
logging.info("orig: %s new: %s",
get_position_from_stable(spos, orig_delta_params),
get_position_from_stable(spos, new_delta_params))
self.gcode.respond_info(
"stepper_a: position_endstop: %.6f angle: %.6f\n"
"stepper_b: position_endstop: %.6f angle: %.6f\n"

42
klippy/kinematics/delta.py
View File

@ -12,8 +12,7 @@ SLOW_RATIO = 3.
class DeltaKinematics:
def __init__(self, toolhead, config):
# Setup tower rails
stepper_configs = [config.getsection('stepper_' + n)
for n in ['a', 'b', 'c']]
stepper_configs = [config.getsection('stepper_' + a) for a in 'abc']
rail_a = stepper.PrinterRail(
stepper_configs[0], need_position_minmax = False)
a_endstop = rail_a.get_homing_info().position_endstop
@ -31,9 +30,9 @@ class DeltaKinematics:
sconfig.getfloat('arm_length', arm_length_a, above=radius)
for sconfig in stepper_configs]
self.arm2 = [arm**2 for arm in arm_lengths]
self.endstops = [(rail.get_homing_info().position_endstop
+ math.sqrt(arm2 - radius**2))
for rail, arm2 in zip(self.rails, self.arm2)]
self.abs_endstops = [(rail.get_homing_info().position_endstop
+ math.sqrt(arm2 - radius**2))
for rail, arm2 in zip(self.rails, self.arm2)]
# Setup boundary checks
self.need_motor_enable = self.need_home = True
self.limit_xy2 = -1.
@ -41,7 +40,7 @@ class DeltaKinematics:
for rail in self.rails])
self.min_z = config.getfloat('minimum_z_position', 0, maxval=self.max_z)
self.limit_z = min([ep - arm
for ep, arm in zip(self.endstops, arm_lengths)])
for ep, arm in zip(self.abs_endstops, arm_lengths)])
logging.info(
"Delta max build height %.2fmm (radius tapered above %.2fmm)" % (
self.max_z, self.limit_z))
@ -115,7 +114,7 @@ class DeltaKinematics:
homing_speed/2.0, second_home=True)
# Set final homed position
spos = [ep + rail.get_homed_offset()
for ep, rail in zip(self.endstops, self.rails)]
for ep, rail in zip(self.abs_endstops, self.rails)]
homing_state.set_homed_position(self._actuator_to_cartesian(spos))
def motor_off(self, print_time):
self.limit_xy2 = -1.
@ -160,38 +159,15 @@ class DeltaKinematics:
self._check_motor_enable(print_time)
for rail in self.rails:
rail.step_itersolve(move.cmove)
# Helper functions for DELTA_CALIBRATE script
def get_stable_position(self):
steppers = [rail.get_steppers()[0] for rail in self.rails]
return [int((ep - s.get_commanded_position()) / s.get_step_dist() + .5)
for ep, s in zip(self.endstops, steppers)]
# Helper function for DELTA_CALIBRATE script
def get_calibrate_params(self):
out = { 'radius': self.radius }
for i, axis in enumerate('abc'):
rail = self.rails[i]
out['endstop_'+axis] = rail.get_homing_info().position_endstop
out['stepdist_'+axis] = rail.get_steppers()[0].get_step_dist()
out['angle_'+axis] = self.angles[i]
out['arm_'+axis] = self.arm_lengths[i]
return out
def get_positions_from_stable(self, stable_positions, params):
angle_names = ['angle_a', 'angle_b', 'angle_c']
angles = [math.radians(params[an]) for an in angle_names]
radius = params['radius']
radius2 = radius**2
towers = [(math.cos(a) * radius, math.sin(a) * radius) for a in angles]
arm2 = [params[an]**2 for an in ['arm_a', 'arm_b', 'arm_c']]
stepdist_names = ['stepdist_a', 'stepdist_b', 'stepdist_c']
stepdists = [params[sn] for sn in stepdist_names]
endstop_names = ['endstop_a', 'endstop_b', 'endstop_c']
endstops = [params[en] + math.sqrt(a2 - radius2)
for en, a2 in zip(endstop_names, arm2)]
out = []
for spos in stable_positions:
sphere_coords = [
(t[0], t[1], es - sp * sd)
for t, es, sd, sp in zip(towers, endstops, stepdists, spos) ]
out.append(mathutil.trilateration(sphere_coords, arm2))
out['endstop_'+axis] = rail.get_homing_info().position_endstop
out['stepdist_'+axis] = rail.get_steppers()[0].get_step_dist()
return out
def load_kinematics(toolhead, config):