229 lines
11 KiB
Python
229 lines
11 KiB
Python
# Code for handling the kinematics of rotary delta robots
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#
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# Copyright (C) 2019-2021 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, mathutil, chelper
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class RotaryDeltaKinematics:
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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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units_in_radians=True)
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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, units_in_radians=True)
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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, units_in_radians=True)
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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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# Read config
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max_velocity, max_accel = toolhead.get_max_velocity()
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self.max_z_velocity = config.getfloat('max_z_velocity', max_velocity,
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above=0., maxval=max_velocity)
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shoulder_radius = config.getfloat('shoulder_radius', above=0.)
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shoulder_height = config.getfloat('shoulder_height', above=0.)
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a_upper_arm = stepper_configs[0].getfloat('upper_arm_length', above=0.)
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upper_arms = [
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sconfig.getfloat('upper_arm_length', a_upper_arm, above=0.)
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for sconfig in stepper_configs]
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a_lower_arm = stepper_configs[0].getfloat('lower_arm_length', above=0.)
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lower_arms = [
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sconfig.getfloat('lower_arm_length', a_lower_arm, above=0.)
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for sconfig in stepper_configs]
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angles = [sconfig.getfloat('angle', angle)
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for sconfig, angle in zip(stepper_configs, [30., 150., 270.])]
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# Setup rotary delta calibration helper
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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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self.calibration = RotaryDeltaCalibration(
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shoulder_radius, shoulder_height, angles, upper_arms, lower_arms,
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endstops, stepdists)
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# Setup iterative solver
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for r, a, ua, la in zip(self.rails, angles, upper_arms, lower_arms):
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r.setup_itersolve('rotary_delta_stepper_alloc',
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shoulder_radius, shoulder_height,
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math.radians(a), ua, la)
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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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eangles = [r.calc_position_from_coord([0., 0., ep])
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for r, ep in zip(self.rails, endstops)]
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self.home_position = tuple(
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self.calibration.actuator_to_cartesian(eangles))
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self.max_z = min(endstops)
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self.min_z = config.getfloat('minimum_z_position', 0, maxval=self.max_z)
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min_ua = min([shoulder_radius + ua for ua in upper_arms])
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min_la = min([la - shoulder_radius for la in lower_arms])
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self.max_xy2 = min(min_ua, min_la)**2
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arm_z = [self.calibration.elbow_coord(i, ea)[2]
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for i, ea in enumerate(eangles)]
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self.limit_z = min([az - la for az, la in zip(arm_z, lower_arms)])
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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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max_xy = math.sqrt(self.max_xy2)
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self.axes_min = toolhead.Coord(-max_xy, -max_xy, self.min_z, 0.)
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self.axes_max = toolhead.Coord(max_xy, max_xy, self.max_z, 0.)
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self.set_position([0., 0., 0.], ())
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def get_steppers(self):
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return [s for rail in self.rails for s in rail.get_steppers()]
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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.calibration.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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#min_angles = [-.5 * math.pi] * 3
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#forcepos[2] = self.calibration.actuator_to_cartesian(min_angles)[2]
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forcepos[2] = -1.
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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 move.move_error("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 move.move_error()
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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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self.limit_xy2 = limit_xy2
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def get_status(self, eventtime):
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return {
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'homed_axes': '' if self.need_home else 'xyz',
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'axis_minimum': self.axes_min,
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'axis_maximum': self.axes_max,
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}
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def get_calibration(self):
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return self.calibration
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# Rotary delta parameter calibration for DELTA_CALIBRATE tool
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class RotaryDeltaCalibration:
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def __init__(self, shoulder_radius, shoulder_height, angles,
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upper_arms, lower_arms, endstops, stepdists):
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self.shoulder_radius = shoulder_radius
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self.shoulder_height = shoulder_height
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self.angles = angles
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self.upper_arms = upper_arms
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self.lower_arms = lower_arms
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self.endstops = endstops
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self.stepdists = stepdists
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# Calculate the absolute angle of each endstop
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ffi_main, self.ffi_lib = chelper.get_ffi()
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self.sks = [ffi_main.gc(self.ffi_lib.rotary_delta_stepper_alloc(
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shoulder_radius, shoulder_height, math.radians(a), ua, la),
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self.ffi_lib.free)
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for a, ua, la in zip(angles, upper_arms, lower_arms)]
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self.abs_endstops = [
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self.ffi_lib.itersolve_calc_position_from_coord(sk, 0., 0., es)
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for sk, es in zip(self.sks, endstops)]
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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 = ('shoulder_height', 'endstop_a', 'endstop_b', 'endstop_c')
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if is_extended:
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adj_params += ('shoulder_radius', 'angle_a', 'angle_b')
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params = { 'shoulder_radius': self.shoulder_radius,
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'shoulder_height': self.shoulder_height }
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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['upper_arm_'+axis] = self.upper_arms[i]
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params['lower_arm_'+axis] = self.lower_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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shoulder_radius = params['shoulder_radius']
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shoulder_height = params['shoulder_height']
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angles = [params['angle_'+a] for a in 'abc']
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upper_arms = [params['upper_arm_'+a] for a in 'abc']
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lower_arms = [params['lower_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 RotaryDeltaCalibration(
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shoulder_radius, shoulder_height, angles, upper_arms, lower_arms,
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endstops, stepdists)
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def elbow_coord(self, elbow_id, spos):
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# Calculate elbow position in coordinate system at shoulder joint
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sj_elbow_x = self.upper_arms[elbow_id] * math.cos(spos)
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sj_elbow_y = self.upper_arms[elbow_id] * math.sin(spos)
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# Shift and rotate to main cartesian coordinate system
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angle = math.radians(self.angles[elbow_id])
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x = (sj_elbow_x + self.shoulder_radius) * math.cos(angle)
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y = (sj_elbow_x + self.shoulder_radius) * math.sin(angle)
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z = sj_elbow_y + self.shoulder_height
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return (x, y, z)
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def actuator_to_cartesian(self, spos):
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sphere_coords = [self.elbow_coord(i, sp) for i, sp in enumerate(spos)]
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lower_arm2 = [la**2 for la in self.lower_arms]
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return mathutil.trilateration(sphere_coords, lower_arm2)
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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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spos = [ea - sp * sd
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for ea, sp, sd in zip(self.abs_endstops, stable_position,
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self.stepdists)]
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return self.actuator_to_cartesian(spos)
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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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pos = [ self.ffi_lib.itersolve_calc_position_from_coord(
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sk, coord[0], coord[1], coord[2])
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for sk in self.sks ]
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return [(ep - sp) / sd
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for sd, ep, sp in zip(self.stepdists, self.abs_endstops, pos)]
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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', 'shoulder_radius', "%.6f"
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% (self.shoulder_radius,))
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configfile.set('printer', 'shoulder_height', "%.6f"
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% (self.shoulder_height,))
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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, '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\n"
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"stepper_b: position_endstop: %.6f angle: %.6f\n"
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"stepper_c: position_endstop: %.6f angle: %.6f\n"
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"shoulder_radius: %.6f shoulder_height: %.6f"
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% (self.endstops[0], self.angles[0],
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self.endstops[1], self.angles[1],
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self.endstops[2], self.angles[2],
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self.shoulder_radius, self.shoulder_height))
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def load_kinematics(toolhead, config):
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return RotaryDeltaKinematics(toolhead, config)
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