klipper-dgus/klippy/extras/delta_calibrate.py

319 lines
15 KiB
Python

# Delta calibration support
#
# 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, 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 a cartesian coordinate
def calc_stable_position(coord, delta_params):
dp = delta_params
steppos = [
math.sqrt(a**2 - (t[0]-coord[0])**2 - (t[1]-coord[1])**2) + coord[2]
for t, a in zip(dp.towers, dp.arms) ]
return [(ep - sp) / sd
for sd, ep, sp in zip(dp.stepdists, dp.abs_endstops, steppos)]
# Load a stable position from a config entry
def load_config_stable(config, option):
spos = config.get(option)
try:
sa, sb, sc = map(float, spos.split(','))
except:
msg = "Unable to parse stable position '%s'" % (spos,)
logging.exception(msg)
raise config.error(msg)
return sa, sb, sc
######################################################################
# Delta calibration object
######################################################################
# The angles and distances of the calibration object found in
# docs/prints/calibrate_size.stl
MeasureAngles = [210., 270., 330., 30., 90., 150.]
MeasureOuterRadius = 65
MeasureRidgeRadius = 5. - .5
# How much to prefer a distance measurement over a height measurement
MEASURE_WEIGHT = 0.5
# Convert distance measurements made on the calibration object to
# 3-tuples of (actual_distance, stable_position1, stable_position2)
def measurements_to_distances(measured_params, delta_params):
# Extract params
mp = measured_params
dp = delta_params
scale = mp['SCALE'][0]
cpw = mp['CENTER_PILLAR_WIDTHS']
center_widths = [cpw[0], cpw[2], cpw[1], cpw[0], cpw[2], cpw[1]]
center_dists = [od - cw
for od, cw in zip(mp['CENTER_DISTS'], center_widths)]
outer_dists = [
od - opw
for od, opw in zip(mp['OUTER_DISTS'], mp['OUTER_PILLAR_WIDTHS']) ]
# Convert angles in degrees to an XY multiplier
obj_angles = map(math.radians, MeasureAngles)
xy_angles = zip(map(math.cos, obj_angles), map(math.sin, obj_angles))
# Calculate stable positions for center measurements
inner_ridge = MeasureRidgeRadius * scale
inner_pos = [(ax * inner_ridge, ay * inner_ridge, 0.)
for ax, ay in xy_angles]
outer_ridge = (MeasureOuterRadius + MeasureRidgeRadius) * scale
outer_pos = [(ax * outer_ridge, ay * outer_ridge, 0.)
for ax, ay in xy_angles]
center_positions = [
(cd, calc_stable_position(ip, dp), calc_stable_position(op, dp))
for cd, ip, op in zip(center_dists, inner_pos, outer_pos)]
# Calculate positions of outer measurements
outer_center = MeasureOuterRadius * scale
start_pos = [(ax * outer_center, ay * outer_center) for ax, ay in xy_angles]
shifted_angles = xy_angles[2:] + xy_angles[:2]
first_pos = [(ax * inner_ridge + spx, ay * inner_ridge + spy, 0.)
for (ax, ay), (spx, spy) in zip(shifted_angles, start_pos)]
second_pos = [(ax * outer_ridge + spx, ay * outer_ridge + spy, 0.)
for (ax, ay), (spx, spy) in zip(shifted_angles, start_pos)]
outer_positions = [
(od, calc_stable_position(fp, dp), calc_stable_position(sp, dp))
for od, fp, sp in zip(outer_dists, first_pos, second_pos)]
return center_positions + outer_positions
######################################################################
# Delta Calibrate class
######################################################################
class DeltaCalibrate:
def __init__(self, config):
self.printer = config.get_printer()
if config.getsection('printer').get('kinematics') != 'delta':
raise config.error("Delta calibrate is only for delta printers")
# Calculate default probing points
radius = config.getfloat('radius', above=0.)
points = [(0., 0.)]
scatter = [.95, .90, .85, .70, .75, .80]
for i in range(6):
r = math.radians(90. + 60. * i)
dist = radius * scatter[i]
points.append((math.cos(r) * dist, math.sin(r) * dist))
self.probe_helper = probe.ProbePointsHelper(
config, self.probe_finalize, default_points=points)
self.probe_helper.minimum_points(3)
# Restore probe stable positions
self.last_probe_positions = []
for i in range(999):
height = config.getfloat("height%d" % (i,), None)
if height is None:
break
height_pos = load_config_stable(config, "height%d_pos" % (i,))
self.last_probe_positions.append((height, height_pos))
# Restore distance measurements
self.delta_analyze_entry = {'SCALE': (1.,)}
self.last_distances = []
for i in range(999):
dist = config.getfloat("distance%d" % (i,), None)
if dist is None:
break
distance_pos1 = load_config_stable(config, "distance%d_pos1" % (i,))
distance_pos2 = load_config_stable(config, "distance%d_pos2" % (i,))
self.last_distances.append((dist, distance_pos1, distance_pos2))
# Register gcode commands
self.gcode = self.printer.lookup_object('gcode')
self.gcode.register_command('DELTA_CALIBRATE', self.cmd_DELTA_CALIBRATE,
desc=self.cmd_DELTA_CALIBRATE_help)
self.gcode.register_command('DELTA_ANALYZE', self.cmd_DELTA_ANALYZE,
desc=self.cmd_DELTA_ANALYZE_help)
def save_state(self, probe_positions, distances, params):
# Save main delta parameters
configfile = self.printer.lookup_object('configfile')
configfile.set('printer', 'delta_radius', "%.6f" % (params['radius']))
for axis in 'abc':
configfile.set('stepper_'+axis, 'angle',
"%.6f" % (params['angle_'+axis],))
configfile.set('stepper_'+axis, 'arm_length',
"%.6f" % (params['arm_'+axis],))
configfile.set('stepper_'+axis, 'position_endstop',
"%.6f" % (params['endstop_'+axis],))
# Save probe stable positions
section = 'delta_calibrate'
configfile.remove_section(section)
for i, (z_offset, spos) in enumerate(probe_positions):
configfile.set(section, "height%d" % (i,), z_offset)
configfile.set(section, "height%d_pos" % (i,),
"%.3f,%.3f,%.3f" % tuple(spos))
# Save distance measurements
for i, (dist, spos1, spos2) in enumerate(distances):
configfile.set(section, "distance%d" % (i,), dist)
configfile.set(section, "distance%d_pos1" % (i,),
"%.3f,%.3f,%.3f" % tuple(spos1))
configfile.set(section, "distance%d_pos2" % (i,),
"%.3f,%.3f,%.3f" % tuple(spos2))
def probe_finalize(self, offsets, positions):
# Convert positions into (z_offset, stable_position) pairs
z_offset = offsets[2]
kin = self.printer.lookup_object('toolhead').get_kinematics()
delta_params = build_delta_params(kin.get_calibrate_params())
probe_positions = [(z_offset, calc_stable_position(p, delta_params))
for p in positions]
# Perform analysis
self.calculate_params(probe_positions, self.last_distances)
def calculate_params(self, probe_positions, distances):
# Setup for coordinate descent analysis
kin = self.printer.lookup_object('toolhead').get_kinematics()
params = kin.get_calibrate_params()
orig_delta_params = build_delta_params(params)
logging.info("Calculating delta_calibrate with:\n%s\n%s\n"
"Initial delta_calibrate parameters: %s",
probe_positions, distances, params)
adj_params = ('radius', 'angle_a', 'angle_b',
'endstop_a', 'endstop_b', 'endstop_c')
z_weight = 1.
if distances:
adj_params += ('arm_a', 'arm_b', 'arm_c')
z_weight = len(distances) / (MEASURE_WEIGHT * len(probe_positions))
# Perform coordinate descent
def delta_errorfunc(params):
# Build new delta_params for params under test
delta_params = build_delta_params(params)
# Calculate z height errors
total_error = 0.
for z_offset, stable_pos in probe_positions:
x, y, z = get_position_from_stable(stable_pos, delta_params)
total_error += (z - z_offset)**2
total_error *= z_weight
# Calculate distance errors
for dist, stable_pos1, stable_pos2 in distances:
x1, y1, z1 = get_position_from_stable(stable_pos1, delta_params)
x2, y2, z2 = get_position_from_stable(stable_pos2, delta_params)
d = math.sqrt((x1-x2)**2 + (y1-y2)**2 + (z1-z2)**2)
total_error += (d - dist)**2
return total_error
new_params = mathutil.background_coordinate_descent(
self.printer, adj_params, params, delta_errorfunc)
# Log and report results
logging.info("Calculated delta_calibrate parameters: %s", new_params)
new_delta_params = build_delta_params(new_params)
for z_offset, spos in probe_positions:
logging.info("height orig: %.6f new: %.6f goal: %.6f",
get_position_from_stable(spos, orig_delta_params)[2],
get_position_from_stable(spos, new_delta_params)[2],
z_offset)
for dist, spos1, spos2 in distances:
x1, y1, z1 = get_position_from_stable(spos1, orig_delta_params)
x2, y2, z2 = get_position_from_stable(spos2, orig_delta_params)
orig_dist = math.sqrt((x1-x2)**2 + (y1-y2)**2 + (z1-z2)**2)
x1, y1, z1 = get_position_from_stable(spos1, new_delta_params)
x2, y2, z2 = get_position_from_stable(spos2, new_delta_params)
new_dist = math.sqrt((x1-x2)**2 + (y1-y2)**2 + (z1-z2)**2)
logging.info("distance orig: %.6f new: %.6f goal: %.6f",
orig_dist, new_dist, dist)
self.gcode.respond_info(
"stepper_a: position_endstop: %.6f angle: %.6f arm: %.6f\n"
"stepper_b: position_endstop: %.6f angle: %.6f arm: %.6f\n"
"stepper_c: position_endstop: %.6f angle: %.6f arm: %.6f\n"
"delta_radius: %.6f\n"
"The SAVE_CONFIG command will update the printer config file\n"
"with these parameters and restart the printer." % (
new_params['endstop_a'], new_params['angle_a'],
new_params['arm_a'],
new_params['endstop_b'], new_params['angle_b'],
new_params['arm_b'],
new_params['endstop_c'], new_params['angle_c'],
new_params['arm_c'],
new_params['radius']))
# Store results for SAVE_CONFIG
self.save_state(probe_positions, distances, new_params)
cmd_DELTA_CALIBRATE_help = "Delta calibration script"
def cmd_DELTA_CALIBRATE(self, params):
self.probe_helper.start_probe(params)
def do_extended_calibration(self):
# Extract distance positions
if len(self.delta_analyze_entry) <= 1:
distances = self.last_distances
elif len(self.delta_analyze_entry) < 5:
raise self.gcode.error("Not all measurements provided")
else:
kin = self.printer.lookup_object('toolhead').get_kinematics()
delta_params = build_delta_params(kin.get_calibrate_params())
distances = measurements_to_distances(
self.delta_analyze_entry, delta_params)
if not self.last_probe_positions:
raise self.gcode.error(
"Must run basic calibration with DELTA_CALIBRATE first")
# Perform analysis
self.calculate_params(self.last_probe_positions, distances)
cmd_DELTA_ANALYZE_help = "Extended delta calibration tool"
def cmd_DELTA_ANALYZE(self, params):
# Parse distance measurements
args = {'CENTER_DISTS': 6, 'CENTER_PILLAR_WIDTHS': 3,
'OUTER_DISTS': 6, 'OUTER_PILLAR_WIDTHS': 6, 'SCALE': 1}
for name, count in args.items():
if name not in params:
continue
data = self.gcode.get_str(name, params)
try:
parts = map(float, data.split(','))
except:
raise self.gcode.error("Unable to parse parameter '%s'" % (
name,))
if len(parts) != count:
raise self.gcode.error("Parameter '%s' must have %d values" % (
name, count))
self.delta_analyze_entry[name] = parts
logging.info("DELTA_ANALYZE %s = %s", name, parts)
# Perform analysis if requested
if 'CALIBRATE' in params:
action = self.gcode.get_str('CALIBRATE', params)
actions = {'extended': 1}
if action not in actions:
raise self.gcode.error("Unknown calibrate action")
self.do_extended_calibration()
def load_config(config):
return DeltaCalibrate(config)