334 lines
16 KiB
Python
334 lines
16 KiB
Python
# Delta calibration support
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#
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# Copyright (C) 2017-2018 Kevin O'Connor <kevin@koconnor.net>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import math, logging, collections
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import probe, mathutil
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######################################################################
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# Delta "stable position" coordinates
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######################################################################
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# A "stable position" is a 3-tuple containing the number of steps
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# taken since hitting the endstop on each delta tower. Delta
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# calibration uses this coordinate system because it allows a position
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# to be described independent of the software parameters.
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# Storage helper for delta parameters
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DeltaParams = collections.namedtuple('DeltaParams', [
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'radius', 'angles', 'arms', 'endstops', 'stepdists',
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'towers', 'abs_endstops'])
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# Generate delta_params from delta configuration parameters
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def build_delta_params(params):
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radius = params['radius']
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angles = [params['angle_'+a] for a in 'abc']
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arms = [params['arm_'+a] for a in 'abc']
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endstops = [params['endstop_'+a] for a in 'abc']
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stepdists = [params['stepdist_'+a] for a in 'abc']
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# Calculate the XY cartesian coordinates of the delta towers
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radian_angles = [math.radians(a) for a in angles]
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towers = [(math.cos(a) * radius, math.sin(a) * radius)
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for a in radian_angles]
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# Calculate the absolute Z height of each tower endstop
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radius2 = radius**2
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abs_endstops = [e + math.sqrt(a**2 - radius2)
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for e, a in zip(endstops, arms)]
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return DeltaParams(radius, angles, arms, endstops, stepdists,
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towers, abs_endstops)
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# Return cartesian coordinates for the given stable_positions when the
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# given delta_params are used.
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def get_position_from_stable(stable_position, delta_params):
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dp = delta_params
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sphere_coords = [
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(t[0], t[1], es - sp * sd)
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for sd, t, es, sp in zip(
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dp.stepdists, dp.towers, dp.abs_endstops, stable_position) ]
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return mathutil.trilateration(sphere_coords, [a**2 for a in dp.arms])
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# Return a stable position from the nominal delta tower positions
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def get_stable_position(stepper_position, delta_params):
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dp = delta_params
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return [int((ep - sp) / sd + .5)
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for sd, ep, sp in zip(
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dp.stepdists, dp.abs_endstops, stepper_position)]
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# Return a stable position from a cartesian coordinate
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def calc_stable_position(coord, delta_params):
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dp = delta_params
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steppos = [
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math.sqrt(a**2 - (t[0]-coord[0])**2 - (t[1]-coord[1])**2) + coord[2]
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for t, a in zip(dp.towers, dp.arms) ]
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return [(ep - sp) / sd
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for sd, ep, sp in zip(dp.stepdists, dp.abs_endstops, steppos)]
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# Load a stable position from a config entry
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def load_config_stable(config, option):
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spos = config.get(option)
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try:
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sa, sb, sc = map(float, spos.split(','))
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except:
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msg = "Unable to parse stable position '%s'" % (spos,)
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logging.exception(msg)
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raise config.error(msg)
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return sa, sb, sc
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######################################################################
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# Delta calibration object
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######################################################################
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# The angles and distances of the calibration object found in
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# docs/prints/calibrate_size.stl
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MeasureAngles = [210., 270., 330., 30., 90., 150.]
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MeasureOuterRadius = 65
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MeasureRidgeRadius = 5. - .5
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# How much to prefer a distance measurement over a height measurement
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MEASURE_WEIGHT = 0.5
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# Convert distance measurements made on the calibration object to
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# 3-tuples of (actual_distance, stable_position1, stable_position2)
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def measurements_to_distances(measured_params, delta_params):
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# Extract params
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mp = measured_params
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dp = delta_params
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scale = mp['SCALE'][0]
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cpw = mp['CENTER_PILLAR_WIDTHS']
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center_widths = [cpw[0], cpw[2], cpw[1], cpw[0], cpw[2], cpw[1]]
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center_dists = [od - cw
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for od, cw in zip(mp['CENTER_DISTS'], center_widths)]
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outer_dists = [
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od - opw
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for od, opw in zip(mp['OUTER_DISTS'], mp['OUTER_PILLAR_WIDTHS']) ]
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# Convert angles in degrees to an XY multiplier
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obj_angles = map(math.radians, MeasureAngles)
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xy_angles = zip(map(math.cos, obj_angles), map(math.sin, obj_angles))
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# Calculate stable positions for center measurements
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inner_ridge = MeasureRidgeRadius * scale
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inner_pos = [(ax * inner_ridge, ay * inner_ridge, 0.)
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for ax, ay in xy_angles]
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outer_ridge = (MeasureOuterRadius + MeasureRidgeRadius) * scale
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outer_pos = [(ax * outer_ridge, ay * outer_ridge, 0.)
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for ax, ay in xy_angles]
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center_positions = [
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(cd, calc_stable_position(ip, dp), calc_stable_position(op, dp))
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for cd, ip, op in zip(center_dists, inner_pos, outer_pos)]
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# Calculate positions of outer measurements
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outer_center = MeasureOuterRadius * scale
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start_pos = [(ax * outer_center, ay * outer_center) for ax, ay in xy_angles]
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shifted_angles = xy_angles[2:] + xy_angles[:2]
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first_pos = [(ax * inner_ridge + spx, ay * inner_ridge + spy, 0.)
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for (ax, ay), (spx, spy) in zip(shifted_angles, start_pos)]
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second_pos = [(ax * outer_ridge + spx, ay * outer_ridge + spy, 0.)
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for (ax, ay), (spx, spy) in zip(shifted_angles, start_pos)]
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outer_positions = [
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(od, calc_stable_position(fp, dp), calc_stable_position(sp, dp))
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for od, fp, sp in zip(outer_dists, first_pos, second_pos)]
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return center_positions + outer_positions
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######################################################################
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# Delta Calibrate class
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######################################################################
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class DeltaCalibrate:
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def __init__(self, config):
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self.printer = config.get_printer()
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if config.getsection('printer').get('kinematics') != 'delta':
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raise config.error("Delta calibrate is only for delta printers")
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# Calculate default probing points
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radius = config.getfloat('radius', above=0.)
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points = [(0., 0.)]
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scatter = [.95, .90, .85, .70, .75, .80]
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for i in range(6):
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r = math.radians(90. + 60. * i)
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dist = radius * scatter[i]
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points.append((math.cos(r) * dist, math.sin(r) * dist))
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self.probe_helper = probe.ProbePointsHelper(
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config, self, default_points=points)
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# Restore probe stable positions
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self.last_probe_positions = []
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for i in range(999):
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height = config.getfloat("height%d" % (i,), None)
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if height is None:
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break
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height_pos = load_config_stable(config, "height%d_pos" % (i,))
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self.last_probe_positions.append((height, height_pos))
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# Restore distance measurements
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self.delta_analyze_entry = {'SCALE': (1.,)}
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self.last_distances = []
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for i in range(999):
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dist = config.getfloat("distance%d" % (i,), None)
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if dist is None:
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break
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distance_pos1 = load_config_stable(config, "distance%d_pos1" % (i,))
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distance_pos2 = load_config_stable(config, "distance%d_pos2" % (i,))
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self.last_distances.append((dist, distance_pos1, distance_pos2))
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# Register gcode commands
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self.gcode = self.printer.lookup_object('gcode')
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self.gcode.register_command('DELTA_CALIBRATE', self.cmd_DELTA_CALIBRATE,
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desc=self.cmd_DELTA_CALIBRATE_help)
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self.gcode.register_command('DELTA_ANALYZE', self.cmd_DELTA_ANALYZE,
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desc=self.cmd_DELTA_ANALYZE_help)
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def save_state(self, probe_positions, distances, params):
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# Save main delta parameters
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configfile = self.printer.lookup_object('configfile')
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configfile.set('printer', 'delta_radius', "%.6f" % (params['radius']))
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for axis in 'abc':
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configfile.set('stepper_'+axis, 'angle',
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"%.6f" % (params['angle_'+axis],))
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configfile.set('stepper_'+axis, 'arm_length',
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"%.6f" % (params['arm_'+axis],))
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configfile.set('stepper_'+axis, 'position_endstop',
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"%.6f" % (params['endstop_'+axis],))
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# Save probe stable positions
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section = 'delta_calibrate'
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configfile.remove_section(section)
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for i, (z_offset, spos) in enumerate(probe_positions):
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configfile.set(section, "height%d" % (i,), z_offset)
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configfile.set(section, "height%d_pos" % (i,),
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"%d,%d,%d" % tuple(spos))
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# Save distance measurements
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for i, (dist, spos1, spos2) in enumerate(distances):
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configfile.set(section, "distance%d" % (i,), dist)
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configfile.set(section, "distance%d_pos1" % (i,),
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"%.3f,%.3f,%.3f" % tuple(spos1))
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configfile.set(section, "distance%d_pos2" % (i,),
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"%.3f,%.3f,%.3f" % tuple(spos2))
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def get_probed_position(self):
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kin = self.printer.lookup_object('toolhead').get_kinematics()
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return [s.get_commanded_position() for s in kin.get_steppers()]
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def finalize(self, offsets, positions):
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# Convert positions into (z_offset, stable_position) pairs
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z_offset = offsets[2]
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kin = self.printer.lookup_object('toolhead').get_kinematics()
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delta_params = build_delta_params(kin.get_calibrate_params())
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probe_positions = [(z_offset, get_stable_position(p, delta_params))
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for p in positions]
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# Perform analysis
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self.calculate_params(probe_positions, self.last_distances)
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def calculate_params(self, probe_positions, distances):
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# Setup for coordinate descent analysis
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kin = self.printer.lookup_object('toolhead').get_kinematics()
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params = kin.get_calibrate_params()
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orig_delta_params = build_delta_params(params)
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logging.info("Calculating delta_calibrate with:\n%s\n%s\n"
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"Initial delta_calibrate parameters: %s",
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probe_positions, distances, params)
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adj_params = ('radius', 'angle_a', 'angle_b',
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'endstop_a', 'endstop_b', 'endstop_c')
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z_weight = 1.
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if distances:
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adj_params += ('arm_a', 'arm_b', 'arm_c')
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z_weight = len(distances) / (MEASURE_WEIGHT * len(probe_positions))
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# Perform coordinate descent
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call_count = [0]
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def delta_errorfunc(params):
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call_count[0] += 1
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if not call_count[0] % 1000:
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self.gcode.respond_info("Working on calibration...")
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self.printer.get_reactor().pause(0.)
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# Build new delta_params for params under test
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delta_params = build_delta_params(params)
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# Calculate z height errors
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total_error = 0.
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for z_offset, stable_pos in probe_positions:
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x, y, z = get_position_from_stable(stable_pos, delta_params)
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total_error += (z - z_offset)**2
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total_error *= z_weight
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# Calculate distance errors
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for dist, stable_pos1, stable_pos2 in distances:
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x1, y1, z1 = get_position_from_stable(stable_pos1, delta_params)
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x2, y2, z2 = get_position_from_stable(stable_pos2, delta_params)
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d = math.sqrt((x1-x2)**2 + (y1-y2)**2 + (z1-z2)**2)
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total_error += (d - dist)**2
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return total_error
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new_params = mathutil.coordinate_descent(
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adj_params, params, delta_errorfunc)
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# Log and report results
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logging.info("Calculated delta_calibrate parameters: %s", new_params)
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new_delta_params = build_delta_params(new_params)
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for z_offset, spos in probe_positions:
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logging.info("height orig: %.6f new: %.6f goal: %.6f",
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get_position_from_stable(spos, orig_delta_params)[2],
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get_position_from_stable(spos, new_delta_params)[2],
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z_offset)
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for dist, spos1, spos2 in distances:
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x1, y1, z1 = get_position_from_stable(spos1, orig_delta_params)
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x2, y2, z2 = get_position_from_stable(spos2, orig_delta_params)
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orig_dist = math.sqrt((x1-x2)**2 + (y1-y2)**2 + (z1-z2)**2)
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x1, y1, z1 = get_position_from_stable(spos1, new_delta_params)
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x2, y2, z2 = get_position_from_stable(spos2, new_delta_params)
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new_dist = math.sqrt((x1-x2)**2 + (y1-y2)**2 + (z1-z2)**2)
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logging.info("distance orig: %.6f new: %.6f goal: %.6f",
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orig_dist, new_dist, dist)
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self.gcode.respond_info(
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"stepper_a: position_endstop: %.6f angle: %.6f arm: %.6f\n"
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"stepper_b: position_endstop: %.6f angle: %.6f arm: %.6f\n"
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"stepper_c: position_endstop: %.6f angle: %.6f arm: %.6f\n"
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"delta_radius: %.6f\n"
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"The SAVE_CONFIG command will update the printer config file\n"
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"with these parameters and restart the printer." % (
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new_params['endstop_a'], new_params['angle_a'],
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new_params['arm_a'],
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new_params['endstop_b'], new_params['angle_b'],
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new_params['arm_b'],
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new_params['endstop_c'], new_params['angle_c'],
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new_params['arm_c'],
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new_params['radius']))
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# Store results for SAVE_CONFIG
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self.save_state(probe_positions, distances, new_params)
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cmd_DELTA_CALIBRATE_help = "Delta calibration script"
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def cmd_DELTA_CALIBRATE(self, params):
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self.gcode.run_script_from_command("G28")
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self.probe_helper.start_probe()
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def do_extended_calibration(self):
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# Extract distance positions
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if len(self.delta_analyze_entry) <= 1:
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distances = self.last_distances
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elif len(self.delta_analyze_entry) < 5:
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raise self.gcode.error("Not all measurements provided")
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else:
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kin = self.printer.lookup_object('toolhead').get_kinematics()
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delta_params = build_delta_params(kin.get_calibrate_params())
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distances = measurements_to_distances(
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self.delta_analyze_entry, delta_params)
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if not self.last_probe_positions:
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raise self.gcode.error(
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"Must run basic calibration with DELTA_CALIBRATE first")
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# Perform analysis
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self.calculate_params(self.last_probe_positions, distances)
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cmd_DELTA_ANALYZE_help = "Extended delta calibration tool"
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def cmd_DELTA_ANALYZE(self, params):
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# Parse distance measurements
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args = {'CENTER_DISTS': 6, 'CENTER_PILLAR_WIDTHS': 3,
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'OUTER_DISTS': 6, 'OUTER_PILLAR_WIDTHS': 6, 'SCALE': 1}
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for name, count in args.items():
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if name not in params:
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continue
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data = self.gcode.get_str(name, params)
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try:
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parts = map(float, data.split(','))
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except:
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raise self.gcode.error("Unable to parse parameter '%s'" % (
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name,))
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if len(parts) != count:
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raise self.gcode.error("Parameter '%s' must have %d values" % (
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name, count))
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self.delta_analyze_entry[name] = parts
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logging.info("DELTA_ANALYZE %s = %s", name, parts)
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# Perform analysis if requested
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if 'CALIBRATE' in params:
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action = self.gcode.get_str('CALIBRATE', params)
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actions = {'extended': 1}
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if action not in actions:
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raise self.gcode.error("Unknown calibrate action")
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self.do_extended_calibration()
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def load_config(config):
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return DeltaCalibrate(config)
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