diff options
Diffstat (limited to 'klippy/extras/delta_calibrate.py')
| -rw-r--r-- | klippy/extras/delta_calibrate.py | 84 |
1 files changed, 73 insertions, 11 deletions
diff --git a/klippy/extras/delta_calibrate.py b/klippy/extras/delta_calibrate.py index 99b59490..b065da74 100644 --- a/klippy/extras/delta_calibrate.py +++ b/klippy/extras/delta_calibrate.py @@ -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" |