klipper/klippy/kinematics/rotary_delta.py

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# Code for handling the kinematics of rotary delta robots
#
# Copyright (C) 2019 Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import math, logging
import stepper, mathutil, chelper, homing
class RotaryDeltaKinematics:
def __init__(self, toolhead, config):
# Setup tower rails
stepper_configs = [config.getsection('stepper_' + a) for a in 'abc']
rail_a = stepper.PrinterRail(
stepper_configs[0], need_position_minmax=False,
units_in_radians=True)
a_endstop = rail_a.get_homing_info().position_endstop
rail_b = stepper.PrinterRail(
stepper_configs[1], need_position_minmax=False,
default_position_endstop=a_endstop, units_in_radians=True)
rail_c = stepper.PrinterRail(
stepper_configs[2], need_position_minmax=False,
default_position_endstop=a_endstop, units_in_radians=True)
self.rails = [rail_a, rail_b, rail_c]
config.get_printer().register_event_handler("stepper_enable:motor_off",
self._motor_off)
# Setup stepper max halt velocity
max_velocity, max_accel = toolhead.get_max_velocity()
self.max_z_velocity = config.getfloat('max_z_velocity', max_velocity,
above=0., maxval=max_velocity)
for rail in self.rails:
rail.set_max_jerk(9999999.9, 9999999.9)
# Read config
shoulder_radius = config.getfloat('shoulder_radius', above=0.)
shoulder_height = config.getfloat('shoulder_height', above=0.)
a_upper_arm = stepper_configs[0].getfloat('upper_arm_length', above=0.)
upper_arms = [
sconfig.getfloat('upper_arm_length', a_upper_arm, above=0.)
for sconfig in stepper_configs]
a_lower_arm = stepper_configs[0].getfloat('lower_arm_length', above=0.)
lower_arms = [
sconfig.getfloat('lower_arm_length', a_lower_arm, above=0.)
for sconfig in stepper_configs]
angles = [sconfig.getfloat('angle', angle)
for sconfig, angle in zip(stepper_configs, [30., 150., 270.])]
# Setup rotary delta calibration helper
endstops = [rail.get_homing_info().position_endstop
for rail in self.rails]
stepdists = [rail.get_steppers()[0].get_step_dist()
for rail in self.rails]
self.calibration = RotaryDeltaCalibration(
shoulder_radius, shoulder_height, angles, upper_arms, lower_arms,
endstops, stepdists)
# Setup iterative solver
for r, a, ua, la in zip(self.rails, angles, upper_arms, lower_arms):
r.setup_itersolve('rotary_delta_stepper_alloc',
shoulder_radius, shoulder_height,
math.radians(a), ua, la)
for s in self.get_steppers():
s.set_trapq(toolhead.get_trapq())
toolhead.register_step_generator(s.generate_steps)
# Setup boundary checks
self.need_home = True
self.limit_xy2 = -1.
eangles = [r.calc_position_from_coord([0., 0., ep])
for r, ep in zip(self.rails, endstops)]
self.home_position = tuple(
self.calibration.actuator_to_cartesian(eangles))
self.max_z = min(endstops)
self.min_z = config.getfloat('minimum_z_position', 0, maxval=self.max_z)
min_ua = min([shoulder_radius + ua for ua in upper_arms])
min_la = min([la - shoulder_radius for la in lower_arms])
self.max_xy2 = min(min_ua, min_la)**2
arm_z = [self.calibration.elbow_coord(i, ea)[2]
for i, ea in enumerate(eangles)]
self.limit_z = min([az - la for az, la in zip(arm_z, lower_arms)])
logging.info(
"Delta max build height %.2fmm (radius tapered above %.2fmm)"
% (self.max_z, self.limit_z))
self.set_position([0., 0., 0.], ())
def get_steppers(self):
return [s for rail in self.rails for s in rail.get_steppers()]
def calc_tag_position(self):
spos = [rail.get_tag_position() for rail in self.rails]
return self.calibration.actuator_to_cartesian(spos)
def set_position(self, newpos, homing_axes):
for rail in self.rails:
rail.set_position(newpos)
self.limit_xy2 = -1.
if tuple(homing_axes) == (0, 1, 2):
self.need_home = False
def home(self, homing_state):
# All axes are homed simultaneously
homing_state.set_axes([0, 1, 2])
forcepos = list(self.home_position)
#min_angles = [-.5 * math.pi] * 3
#forcepos[2] = self.calibration.actuator_to_cartesian(min_angles)[2]
forcepos[2] = -1.
homing_state.home_rails(self.rails, forcepos, self.home_position)
def _motor_off(self, print_time):
self.limit_xy2 = -1.
self.need_home = True
def check_move(self, move):
end_pos = move.end_pos
end_xy2 = end_pos[0]**2 + end_pos[1]**2
if end_xy2 <= self.limit_xy2 and not move.axes_d[2]:
# Normal XY move
return
if self.need_home:
raise move.move_error("Must home first")
end_z = end_pos[2]
limit_xy2 = self.max_xy2
if end_z > self.limit_z:
limit_xy2 = min(limit_xy2, (self.max_z - end_z)**2)
if end_xy2 > limit_xy2 or end_z > self.max_z or end_z < self.min_z:
# Move out of range - verify not a homing move
if (end_pos[:2] != self.home_position[:2]
or end_z < self.min_z or end_z > self.home_position[2]):
raise move.move_error()
limit_xy2 = -1.
if move.axes_d[2]:
move.limit_speed(self.max_z_velocity, move.accel)
limit_xy2 = -1.
self.limit_xy2 = limit_xy2
def get_status(self, eventtime):
max_xy = math.sqrt(self.max_xy2)
axes_min = [-max_xy, -max_xy, self.min_z, 0.]
axes_max = [max_xy, max_xy, self.max_z, 0.]
return {
'homed_axes': '' if self.need_home else 'XYZ',
'axis_minimum': homing.Coord(*axes_min),
'axis_maximum': homing.Coord(*axes_max)
}
def get_calibration(self):
return self.calibration
# Rotary delta parameter calibration for DELTA_CALIBRATE tool
class RotaryDeltaCalibration:
def __init__(self, shoulder_radius, shoulder_height, angles,
upper_arms, lower_arms, endstops, stepdists):
self.shoulder_radius = shoulder_radius
self.shoulder_height = shoulder_height
self.angles = angles
self.upper_arms = upper_arms
self.lower_arms = lower_arms
self.endstops = endstops
self.stepdists = stepdists
# Calculate the absolute angle of each endstop
ffi_main, self.ffi_lib = chelper.get_ffi()
self.sks = [ffi_main.gc(self.ffi_lib.rotary_delta_stepper_alloc(
shoulder_radius, shoulder_height, math.radians(a), ua, la),
self.ffi_lib.free)
for a, ua, la in zip(angles, upper_arms, lower_arms)]
self.abs_endstops = [
self.ffi_lib.itersolve_calc_position_from_coord(sk, 0., 0., es)
for sk, es in zip(self.sks, endstops)]
def coordinate_descent_params(self, is_extended):
# Determine adjustment parameters (for use with coordinate_descent)
adj_params = ('shoulder_height', 'endstop_a', 'endstop_b', 'endstop_c')
if is_extended:
adj_params += ('shoulder_radius', 'angle_a', 'angle_b')
params = { 'shoulder_radius': self.shoulder_radius,
'shoulder_height': self.shoulder_height }
for i, axis in enumerate('abc'):
params['angle_'+axis] = self.angles[i]
params['upper_arm_'+axis] = self.upper_arms[i]
params['lower_arm_'+axis] = self.lower_arms[i]
params['endstop_'+axis] = self.endstops[i]
params['stepdist_'+axis] = self.stepdists[i]
return adj_params, params
def new_calibration(self, params):
# Create a new calibration object from coordinate_descent params
shoulder_radius = params['shoulder_radius']
shoulder_height = params['shoulder_height']
angles = [params['angle_'+a] for a in 'abc']
upper_arms = [params['upper_arm_'+a] for a in 'abc']
lower_arms = [params['lower_arm_'+a] for a in 'abc']
endstops = [params['endstop_'+a] for a in 'abc']
stepdists = [params['stepdist_'+a] for a in 'abc']
return RotaryDeltaCalibration(
shoulder_radius, shoulder_height, angles, upper_arms, lower_arms,
endstops, stepdists)
def elbow_coord(self, elbow_id, spos):
# Calculate elbow position in coordinate system at shoulder joint
sj_elbow_x = self.upper_arms[elbow_id] * math.cos(spos)
sj_elbow_y = self.upper_arms[elbow_id] * math.sin(spos)
# Shift and rotate to main cartesian coordinate system
angle = math.radians(self.angles[elbow_id])
x = (sj_elbow_x + self.shoulder_radius) * math.cos(angle)
y = (sj_elbow_x + self.shoulder_radius) * math.sin(angle)
z = sj_elbow_y + self.shoulder_height
return (x, y, z)
def actuator_to_cartesian(self, spos):
sphere_coords = [self.elbow_coord(i, sp) for i, sp in enumerate(spos)]
lower_arm2 = [la**2 for la in self.lower_arms]
return mathutil.trilateration(sphere_coords, lower_arm2)
def get_position_from_stable(self, stable_position):
# Return cartesian coordinates for the given stable_position
spos = [ea - sp * sd
for ea, sp, sd in zip(self.abs_endstops, stable_position,
self.stepdists)]
return self.actuator_to_cartesian(spos)
def calc_stable_position(self, coord):
# Return a stable_position from a cartesian coordinate
pos = [ self.ffi_lib.itersolve_calc_position_from_coord(
sk, coord[0], coord[1], coord[2])
for sk in self.sks ]
return [(ep - sp) / sd
for sd, ep, sp in zip(self.stepdists, self.abs_endstops, pos)]
def save_state(self, configfile):
# Save the current parameters (for use with SAVE_CONFIG)
configfile.set('printer', 'shoulder_radius', "%.6f"
% (self.shoulder_radius,))
configfile.set('printer', 'shoulder_height', "%.6f"
% (self.shoulder_height,))
for i, axis in enumerate('abc'):
configfile.set('stepper_'+axis, 'angle', "%.6f" % (self.angles[i],))
configfile.set('stepper_'+axis, 'position_endstop',
"%.6f" % (self.endstops[i],))
gcode = configfile.get_printer().lookup_object("gcode")
gcode.respond_info(
"stepper_a: position_endstop: %.6f angle: %.6f\n"
"stepper_b: position_endstop: %.6f angle: %.6f\n"
"stepper_c: position_endstop: %.6f angle: %.6f\n"
"shoulder_radius: %.6f shoulder_height: %.6f"
% (self.endstops[0], self.angles[0],
self.endstops[1], self.angles[1],
self.endstops[2], self.angles[2],
self.shoulder_radius, self.shoulder_height))
def load_kinematics(toolhead, config):
return RotaryDeltaKinematics(toolhead, config)