mirror of https://github.com/Desuuuu/klipper.git
231 lines
11 KiB
Python
231 lines
11 KiB
Python
# Code for handling the kinematics of linear delta robots
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#
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# Copyright (C) 2016-2019 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
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import stepper, homing, mathutil
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# Slow moves once the ratio of tower to XY movement exceeds SLOW_RATIO
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SLOW_RATIO = 3.
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class DeltaKinematics:
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def __init__(self, toolhead, config):
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# Setup tower rails
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stepper_configs = [config.getsection('stepper_' + a) for a in 'abc']
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rail_a = stepper.PrinterRail(
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stepper_configs[0], need_position_minmax = False)
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a_endstop = rail_a.get_homing_info().position_endstop
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rail_b = stepper.PrinterRail(
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stepper_configs[1], need_position_minmax = False,
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default_position_endstop=a_endstop)
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rail_c = stepper.PrinterRail(
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stepper_configs[2], need_position_minmax = False,
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default_position_endstop=a_endstop)
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self.rails = [rail_a, rail_b, rail_c]
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config.get_printer().register_event_handler("stepper_enable:motor_off",
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self._motor_off)
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# Setup stepper max halt velocity
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self.max_velocity, self.max_accel = toolhead.get_max_velocity()
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self.max_z_velocity = config.getfloat(
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'max_z_velocity', self.max_velocity,
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above=0., maxval=self.max_velocity)
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max_halt_velocity = toolhead.get_max_axis_halt() * SLOW_RATIO
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max_halt_accel = self.max_accel * SLOW_RATIO
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for rail in self.rails:
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rail.set_max_jerk(max_halt_velocity, max_halt_accel)
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# Read radius and arm lengths
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self.radius = radius = config.getfloat('delta_radius', above=0.)
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arm_length_a = stepper_configs[0].getfloat('arm_length', above=radius)
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self.arm_lengths = arm_lengths = [
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sconfig.getfloat('arm_length', arm_length_a, above=radius)
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for sconfig in stepper_configs]
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self.arm2 = [arm**2 for arm in arm_lengths]
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self.abs_endstops = [(rail.get_homing_info().position_endstop
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+ math.sqrt(arm2 - radius**2))
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for rail, arm2 in zip(self.rails, self.arm2)]
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# Determine tower locations in cartesian space
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self.angles = [sconfig.getfloat('angle', angle)
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for sconfig, angle in zip(stepper_configs,
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[210., 330., 90.])]
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self.towers = [(math.cos(math.radians(angle)) * radius,
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math.sin(math.radians(angle)) * radius)
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for angle in self.angles]
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for r, a, t in zip(self.rails, self.arm2, self.towers):
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r.setup_itersolve('delta_stepper_alloc', a, t[0], t[1])
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for s in self.get_steppers():
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s.set_trapq(toolhead.get_trapq())
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toolhead.register_step_generator(s.generate_steps)
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# Setup boundary checks
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self.need_home = True
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self.limit_xy2 = -1.
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self.home_position = tuple(
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self._actuator_to_cartesian(self.abs_endstops))
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self.max_z = min([rail.get_homing_info().position_endstop
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for rail in self.rails])
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self.min_z = config.getfloat('minimum_z_position', 0, maxval=self.max_z)
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self.limit_z = min([ep - arm
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for ep, arm in zip(self.abs_endstops, arm_lengths)])
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logging.info(
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"Delta max build height %.2fmm (radius tapered above %.2fmm)" % (
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self.max_z, self.limit_z))
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# Find the point where an XY move could result in excessive
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# tower movement
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half_min_step_dist = min([r.get_steppers()[0].get_step_dist()
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for r in self.rails]) * .5
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min_arm_length = min(arm_lengths)
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def ratio_to_dist(ratio):
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return (ratio * math.sqrt(min_arm_length**2 / (ratio**2 + 1.)
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- half_min_step_dist**2)
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+ half_min_step_dist)
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self.slow_xy2 = (ratio_to_dist(SLOW_RATIO) - radius)**2
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self.very_slow_xy2 = (ratio_to_dist(2. * SLOW_RATIO) - radius)**2
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self.max_xy2 = min(radius, min_arm_length - radius,
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ratio_to_dist(4. * SLOW_RATIO) - radius)**2
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logging.info("Delta max build radius %.2fmm (moves slowed past %.2fmm"
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" and %.2fmm)" % (
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math.sqrt(self.max_xy2), math.sqrt(self.slow_xy2),
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math.sqrt(self.very_slow_xy2)))
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self.set_position([0., 0., 0.], ())
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def get_steppers(self, flags=""):
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return [s for rail in self.rails for s in rail.get_steppers()]
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def _actuator_to_cartesian(self, spos):
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sphere_coords = [(t[0], t[1], sp) for t, sp in zip(self.towers, spos)]
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return mathutil.trilateration(sphere_coords, self.arm2)
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def calc_tag_position(self):
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spos = [rail.get_tag_position() for rail in self.rails]
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return self._actuator_to_cartesian(spos)
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def set_position(self, newpos, homing_axes):
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for rail in self.rails:
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rail.set_position(newpos)
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self.limit_xy2 = -1.
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if tuple(homing_axes) == (0, 1, 2):
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self.need_home = False
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def home(self, homing_state):
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# All axes are homed simultaneously
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homing_state.set_axes([0, 1, 2])
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forcepos = list(self.home_position)
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forcepos[2] = -1.5 * math.sqrt(max(self.arm2)-self.max_xy2)
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homing_state.home_rails(self.rails, forcepos, self.home_position)
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def _motor_off(self, print_time):
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self.limit_xy2 = -1.
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self.need_home = True
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def check_move(self, move):
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end_pos = move.end_pos
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end_xy2 = end_pos[0]**2 + end_pos[1]**2
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if end_xy2 <= self.limit_xy2 and not move.axes_d[2]:
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# Normal XY move
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return
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if self.need_home:
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raise homing.EndstopMoveError(end_pos, "Must home first")
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end_z = end_pos[2]
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limit_xy2 = self.max_xy2
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if end_z > self.limit_z:
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limit_xy2 = min(limit_xy2, (self.max_z - end_z)**2)
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if end_xy2 > limit_xy2 or end_z > self.max_z or end_z < self.min_z:
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# Move out of range - verify not a homing move
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if (end_pos[:2] != self.home_position[:2]
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or end_z < self.min_z or end_z > self.home_position[2]):
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raise homing.EndstopMoveError(end_pos)
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limit_xy2 = -1.
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if move.axes_d[2]:
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move.limit_speed(self.max_z_velocity, move.accel)
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limit_xy2 = -1.
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# Limit the speed/accel of this move if is is at the extreme
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# end of the build envelope
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extreme_xy2 = max(end_xy2, move.start_pos[0]**2 + move.start_pos[1]**2)
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if extreme_xy2 > self.slow_xy2:
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r = 0.5
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if extreme_xy2 > self.very_slow_xy2:
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r = 0.25
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max_velocity = self.max_velocity
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if move.axes_d[2]:
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max_velocity = self.max_z_velocity
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move.limit_speed(max_velocity * r, self.max_accel * r)
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limit_xy2 = -1.
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self.limit_xy2 = min(limit_xy2, self.slow_xy2)
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def get_status(self, eventtime):
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return {'homed_axes': '' if self.need_home else 'xyz'}
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def get_calibration(self):
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endstops = [rail.get_homing_info().position_endstop
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for rail in self.rails]
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stepdists = [rail.get_steppers()[0].get_step_dist()
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for rail in self.rails]
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return DeltaCalibration(self.radius, self.angles, self.arm_lengths,
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endstops, stepdists)
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# Delta parameter calibration for DELTA_CALIBRATE tool
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class DeltaCalibration:
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def __init__(self, radius, angles, arms, endstops, stepdists):
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self.radius = radius
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self.angles = angles
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self.arms = arms
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self.endstops = endstops
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self.stepdists = stepdists
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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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self.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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self.abs_endstops = [e + math.sqrt(a**2 - radius2)
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for e, a in zip(endstops, arms)]
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def coordinate_descent_params(self, is_extended):
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# Determine adjustment parameters (for use with coordinate_descent)
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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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if is_extended:
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adj_params += ('arm_a', 'arm_b', 'arm_c')
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params = { 'radius': self.radius }
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for i, axis in enumerate('abc'):
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params['angle_'+axis] = self.angles[i]
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params['arm_'+axis] = self.arms[i]
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params['endstop_'+axis] = self.endstops[i]
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params['stepdist_'+axis] = self.stepdists[i]
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return adj_params, params
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def new_calibration(self, params):
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# Create a new calibration object from coordinate_descent 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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return DeltaCalibration(radius, angles, arms, endstops, stepdists)
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def get_position_from_stable(self, stable_position):
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# Return cartesian coordinates for the given stable_position
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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(self.stepdists, self.towers,
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self.abs_endstops, stable_position) ]
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return mathutil.trilateration(sphere_coords, [a**2 for a in self.arms])
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def calc_stable_position(self, coord):
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# Return a stable_position from a cartesian coordinate
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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(self.towers, self.arms) ]
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return [(ep - sp) / sd
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for sd, ep, sp in zip(self.stepdists,
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self.abs_endstops, steppos)]
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def save_state(self, configfile):
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# Save the current parameters (for use with SAVE_CONFIG)
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configfile.set('printer', 'delta_radius', "%.6f" % (self.radius,))
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for i, axis in enumerate('abc'):
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configfile.set('stepper_'+axis, 'angle', "%.6f" % (self.angles[i],))
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configfile.set('stepper_'+axis, 'arm_length',
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"%.6f" % (self.arms[i],))
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configfile.set('stepper_'+axis, 'position_endstop',
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"%.6f" % (self.endstops[i],))
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gcode = configfile.get_printer().lookup_object("gcode")
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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"
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% (self.endstops[0], self.angles[0], self.arms[0],
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self.endstops[1], self.angles[1], self.arms[1],
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self.endstops[2], self.angles[2], self.arms[2],
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self.radius))
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def load_kinematics(toolhead, config):
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return DeltaKinematics(toolhead, config)
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