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delta: Support different arm lengths for each tower 

Change the config file so that the delta arm length is specified
per-tower.  This makes it possible to support advanced calibration.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2017-10-29 14:14:12 -04:00
parent efb4a5daa1
commit bc5d900e61
2 changed files with 30 additions and 26 deletions
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8
config/example-delta.cfg
View File

@ -17,6 +17,11 @@ enable_pin: !ar38
step_distance: .01 step_distance: .01
endstop_pin: ^ar2 endstop_pin: ^ar2
position_endstop: 297.05 position_endstop: 297.05
arm_length: 333.0
# Length (in mm) of the diagonal rod that connects this tower to the
# print head. This parameter must be provided for stepper_a; for
# stepper_b and stepper_c this parameter defaults to the value
# specified for stepper_a.
#angle: #angle:
# This option specifies the angle (in degrees) that the tower is # This option specifies the angle (in degrees) that the tower is
# at. The default is 210 for stepper_a, 330 for stepper_b, and 90 # at. The default is 210 for stepper_a, 330 for stepper_b, and 90
@ -91,9 +96,6 @@ max_z_velocity: 150
# maximum speed of up/down moves (which require a higher step rate # maximum speed of up/down moves (which require a higher step rate
# than other moves on a delta printer). The default is to use # than other moves on a delta printer). The default is to use
# max_velocity for max_z_velocity. # max_velocity for max_z_velocity.
delta_arm_length: 333.0
# Length (in mm) of the diagonal rods that connect the linear axes
# to the print head. This parameter must be provided.
delta_radius: 174.75 delta_radius: 174.75
# Radius (in mm) of the horizontal circle formed by the three linear # Radius (in mm) of the horizontal circle formed by the three linear
# axis towers. This parameter may also be calculated as: # axis towers. This parameter may also be calculated as:

48
klippy/delta.py
View File

@ -13,17 +13,22 @@ SLOW_RATIO = 3.
class DeltaKinematics: class DeltaKinematics:
def __init__(self, toolhead, printer, config): def __init__(self, toolhead, printer, config):
self.steppers = [stepper.PrinterHomingStepper( stepper_configs = [config.getsection('stepper_' + n)
printer, config.getsection('stepper_' + n)) for n in ['a', 'b', 'c']]
for n in ['a', 'b', 'c']] self.steppers = [stepper.PrinterHomingStepper(printer, sconfig)
for sconfig in stepper_configs]
self.need_motor_enable = self.need_home = True self.need_motor_enable = self.need_home = True
radius = config.getfloat('delta_radius', above=0.) radius = config.getfloat('delta_radius', above=0.)
arm_length = config.getfloat('delta_arm_length', above=radius) arm_length_a = stepper_configs[0].getfloat('arm_length', above=radius)
self.arm_length2 = arm_length**2 arm_lengths = [sconfig.getfloat('arm_length', arm_length_a, above=radius)
for sconfig in stepper_configs]
self.arm2 = [arm**2 for arm in arm_lengths]
self.endstops = [s.position_endstop + math.sqrt(arm2 - radius**2)
for s, arm2 in zip(self.steppers, self.arm2)]
self.limit_xy2 = -1. self.limit_xy2 = -1.
tower_height_at_zeros = math.sqrt(self.arm_length2 - radius**2)
self.max_z = min([s.position_endstop for s in self.steppers]) self.max_z = min([s.position_endstop for s in self.steppers])
self.limit_z = self.max_z - (arm_length - tower_height_at_zeros) self.limit_z = min([ep - arm
for ep, arm in zip(self.endstops, arm_lengths)])
logging.info( logging.info(
"Delta max build height %.2fmm (radius tapered above %.2fmm)" % ( "Delta max build height %.2fmm (radius tapered above %.2fmm)" % (
self.max_z, self.limit_z)) self.max_z, self.limit_z))
@ -36,22 +41,22 @@ class DeltaKinematics:
for s in self.steppers: for s in self.steppers:
s.set_max_jerk(max_halt_velocity, self.max_accel) s.set_max_jerk(max_halt_velocity, self.max_accel)
# Determine tower locations in cartesian space # Determine tower locations in cartesian space
angles = [config.getsection('stepper_a').getfloat('angle', 210.), angles = [sconfig.getfloat('angle', angle)
config.getsection('stepper_b').getfloat('angle', 330.), for sconfig, angle in zip(stepper_configs, [210., 330., 90.])]
config.getsection('stepper_c').getfloat('angle', 90.)]
self.towers = [(math.cos(math.radians(angle)) * radius, self.towers = [(math.cos(math.radians(angle)) * radius,
math.sin(math.radians(angle)) * radius) math.sin(math.radians(angle)) * radius)
for angle in angles] for angle in angles]
# Find the point where an XY move could result in excessive # Find the point where an XY move could result in excessive
# tower movement # tower movement
half_min_step_dist = min([s.step_dist for s in self.steppers]) * .5 half_min_step_dist = min([s.step_dist for s in self.steppers]) * .5
min_arm_length = min(arm_lengths)
def ratio_to_dist(ratio): def ratio_to_dist(ratio):
return (ratio * math.sqrt(self.arm_length2 / (ratio**2 + 1.) return (ratio * math.sqrt(min_arm_length**2 / (ratio**2 + 1.)
- half_min_step_dist**2) - half_min_step_dist**2)
+ half_min_step_dist) + half_min_step_dist)
self.slow_xy2 = (ratio_to_dist(SLOW_RATIO) - radius)**2 self.slow_xy2 = (ratio_to_dist(SLOW_RATIO) - radius)**2
self.very_slow_xy2 = (ratio_to_dist(2. * SLOW_RATIO) - radius)**2 self.very_slow_xy2 = (ratio_to_dist(2. * SLOW_RATIO) - radius)**2
self.max_xy2 = min(radius, arm_length - radius, self.max_xy2 = min(radius, min_arm_length - radius,
ratio_to_dist(4. * SLOW_RATIO) - radius)**2 ratio_to_dist(4. * SLOW_RATIO) - radius)**2
logging.info( logging.info(
"Delta max build radius %.2fmm (moves slowed past %.2fmm and %.2fmm)" "Delta max build radius %.2fmm (moves slowed past %.2fmm and %.2fmm)"
@ -61,8 +66,7 @@ class DeltaKinematics:
def get_steppers(self): def get_steppers(self):
return list(self.steppers) return list(self.steppers)
def _cartesian_to_actuator(self, coord): def _cartesian_to_actuator(self, coord):
return [math.sqrt(self.arm_length2 return [math.sqrt(self.arm2[i] - (self.towers[i][0] - coord[0])**2
- (self.towers[i][0] - coord[0])**2
- (self.towers[i][1] - coord[1])**2) + coord[2] - (self.towers[i][1] - coord[1])**2) + coord[2]
for i in StepList] for i in StepList]
def _actuator_to_cartesian(self, pos): def _actuator_to_cartesian(self, pos):
@ -82,9 +86,9 @@ class DeltaKinematics:
ez = matrix_cross(ex, ey) ez = matrix_cross(ex, ey)
j = matrix_dot(ey, s31) j = matrix_dot(ey, s31)
x = d**2 / (2. * d) x = (self.arm2[0] - self.arm2[1] + d**2) / (2. * d)
y = (j**2 + (x-i)**2 - x**2) / (2. * j) y = (self.arm2[0] - self.arm2[2] - x**2 + (x-i)**2 + j**2) / (2. * j)
z = -math.sqrt(self.arm_length2 - x**2 - y**2) z = -math.sqrt(self.arm2[0] - x**2 - y**2)
ex_x = matrix_mul(ex, x) ex_x = matrix_mul(ex, x)
ey_y = matrix_mul(ey, y) ey_y = matrix_mul(ey, y)
@ -105,7 +109,7 @@ class DeltaKinematics:
homing_speed = s.get_homing_speed() homing_speed = s.get_homing_speed()
homepos = [0., 0., self.max_z, None] homepos = [0., 0., self.max_z, None]
coord = list(homepos) coord = list(homepos)
coord[2] = -1.5 * math.sqrt(self.arm_length2-self.max_xy2) coord[2] = -1.5 * math.sqrt(max(self.arm2)-self.max_xy2)
homing_state.home(coord, homepos, endstops, homing_speed) homing_state.home(coord, homepos, endstops, homing_speed)
# Retract # Retract
coord[2] = homepos[2] - s.homing_retract_dist coord[2] = homepos[2] - s.homing_retract_dist
@ -115,10 +119,8 @@ class DeltaKinematics:
homing_state.home(coord, homepos, endstops, homing_state.home(coord, homepos, endstops,
homing_speed/2.0, second_home=True) homing_speed/2.0, second_home=True)
# Set final homed position # Set final homed position
spos = self._cartesian_to_actuator(homepos) spos = [ep + s.get_homed_offset()
spos = [spos[i] + self.steppers[i].position_endstop - self.max_z for ep, s in zip(self.endstops, self.steppers)]
+ self.steppers[i].get_homed_offset()
for i in StepList]
homing_state.set_homed_position(self._actuator_to_cartesian(spos)) homing_state.set_homed_position(self._actuator_to_cartesian(spos))
def motor_off(self, print_time): def motor_off(self, print_time):
self.limit_xy2 = -1. self.limit_xy2 = -1.
@ -192,7 +194,7 @@ class DeltaKinematics:
towery_d = self.towers[i][1] - origy towery_d = self.towers[i][1] - origy
vt_startxy_d = (towerx_d*axes_d[0] + towery_d*axes_d[1])*inv_movexy_d vt_startxy_d = (towerx_d*axes_d[0] + towery_d*axes_d[1])*inv_movexy_d
tangentxy_d2 = towerx_d**2 + towery_d**2 - vt_startxy_d**2 tangentxy_d2 = towerx_d**2 + towery_d**2 - vt_startxy_d**2
vt_arm_d = math.sqrt(self.arm_length2 - tangentxy_d2) vt_arm_d = math.sqrt(self.arm2[i] - tangentxy_d2)
vt_startz = origz vt_startz = origz
# Generate steps # Generate steps