Cosplay/nhf/touhou/houjuu_nue/joints.py

1084 lines
38 KiB
Python

import math
from dataclasses import dataclass, field
from typing import Optional, Tuple
import cadquery as Cq
from nhf import Material, Role
from nhf.build import Model, target, assembly
from nhf.parts.springs import TorsionSpring
from nhf.parts.fasteners import FlatHeadBolt, HexNut, ThreaddedKnob
from nhf.parts.joints import TorsionJoint, HirthJoint
from nhf.parts.box import Hole, MountingBox, box_with_centre_holes
from nhf.touhou.houjuu_nue.electronics import Flexor, LinearActuator
import nhf.utils
TOL = 1e-6
# Parts used
# uxcell 2 Pcs Star Knobs Grips M12 x 30mm Male Thread Steel Zinc Stud Replacement PP
HS_JOINT_KNOB = ThreaddedKnob(
mass=77.3,
diam_thread=12.0,
height_thread=30.0,
diam_knob=50.0,
diam_neck=25.0,
height_neck=12.5,
height_knob=15.0,
)
# Tom's world 8Pcs M12-1.75 Hex Nut Assortment Set Stainless Steel 304(18-8)
# Metric Hexagon Nut for Bolts, Bright Finish, Full Thread (M12)
HS_JOINT_HEX_NUT = HexNut(
mass=14.9,
diam_thread=12.0,
pitch=1.75,
thickness=9.7,
width=18.9,
)
SHOULDER_AXIS_BOLT = FlatHeadBolt(
# FIXME: measure
mass=0.0,
diam_head=10.0,
height_head=3.0,
diam_thread=6.0,
height_thread=20.0,
)
# Hoypeyfiy 10 Pieces Torsion Spring Woodworking DIY 90 Degrees Torsional
# Springs Repair Maintenance Spring
SHOULDER_TORSION_SPRING = TorsionSpring(
mass=2.2,
# inner diameter = 9
radius=9/2 + 1.2,
thickness=1.3,
height=7.5,
)
# KALIONE 10 Pieces Torsion Spring, Stainless Steel Small Torsion Springs, Tiny
# Torsional Spring, 90° Deflection Compression Spring Kit for Repair Tools
# Woodworking DIY, 50mm
ELBOW_TORSION_SPRING = TorsionSpring(
mass=1.7,
radius=9 / 2,
thickness=1.3,
height=6.5,
tail_length=45.0,
right_handed=False,
)
@dataclass
class RootJoint(Model):
"""
The Houjuu-Scarlett Mechanism
"""
knob: ThreaddedKnob = HS_JOINT_KNOB
hex_nut: HexNut = HS_JOINT_HEX_NUT
hirth_joint: HirthJoint = field(default_factory=lambda: HirthJoint(
radius=25.0,
radius_inner=15.0,
tooth_height=7.0,
base_height=5.0,
n_tooth=24,
))
parent_width: float = 85
parent_thickness: float = 10
parent_corner_fillet: float = 5
parent_corner_cbore_diam: float = 12
parent_corner_cbore_depth: float = 2
parent_corner_inset: float = 12
parent_mount_thickness: float = 25.4 / 16
child_corner_dx: float = 17.0
child_corner_dz: float = 24.0
axis_diam: float = 12.0
axis_cbore_diam: float = 20
axis_cbore_depth: float = 3
corner_hole_diam: float = 6.0
child_height: float = 60.0
child_width: float = 50.0
child_mount_thickness: float = 25.4 / 4
def corner_pos(self) -> list[tuple[int, int]]:
"""
Generates a set of points corresponding to the connectorss
"""
dx = self.parent_width / 2 - self.parent_corner_inset
return [
(dx, dx),
(dx, -dx),
(-dx, -dx),
(-dx, dx),
]
@property
def total_height(self) -> float:
return self.parent_thickness + self.hirth_joint.total_height
@target(name="parent")
def parent(self):
"""
Parent part of the Houjuu-Scarlett joint, which is composed of a Hirth
coupling, a cylindrical base, and a mounting base.
"""
hirth = self.hirth_joint.generate()
conn = self.corner_pos()
result = (
Cq.Workplane('XY')
.box(
self.parent_width,
self.parent_width,
self.parent_thickness,
centered=(True, True, False))
.translate((0, 0, -self.parent_thickness))
.edges("|Z")
.fillet(self.parent_corner_fillet)
.faces(">Z")
.workplane()
.pushPoints(conn)
.cboreHole(
diameter=self.corner_hole_diam,
cboreDiameter=self.parent_corner_cbore_diam,
cboreDepth=self.parent_corner_cbore_depth)
)
# Creates a plane parallel to the holes but shifted to the base
plane = result.faces(">Z").workplane(offset=-self.parent_thickness)
for i, (px, py) in enumerate(conn):
plane.moveTo(px, py).tagPoint(f"h{i}")
result = (
result
.faces(">Z")
.workplane()
.union(hirth, tol=0.1)
.clean()
)
result = (
result.faces("<Z")
.workplane()
.hole(diameter=self.axis_diam)
.cut(self.hex_nut.generate().translate((0, 0, -self.parent_thickness)))
)
result.faces("<Z").tag("base")
return result
@target(name="child")
def child(self) -> Cq.Workplane:
hirth = self.hirth_joint.generate(is_mated=True)
dy = self.child_corner_dx
dx = self.child_corner_dz
conn = [
(-dx, -dy),
(dx, -dy),
(dx, dy),
(-dx, dy),
]
result = (
Cq.Workplane('XY')
.box(
self.child_height,
self.child_width,
self.hirth_joint.base_height,
centered=(True, True, False))
#.translate((0, 0, -self.base_joint.base_height))
#.edges("|Z")
#.fillet(self.hs_joint_corner_fillet)
.faces(">Z")
.workplane()
.pushPoints(conn)
.hole(self.corner_hole_diam)
)
# Creates a plane parallel to the holes but shifted to the base
plane = result.faces(">Z").workplane(offset=-self.hirth_joint.base_height)
for i, (px, py) in enumerate(conn):
plane.moveTo(px, py).tagPlane(f"conn{i}")
result = (
result
.faces(">Z")
.workplane()
.union(hirth, tol=0.1)
.clean()
)
result = (
result.faces("<Z")
.workplane()
.hole(self.axis_diam)
)
return result
def assembly(self,
offset: int = 0,
fastener_pos: float = 0) -> Cq.Assembly:
"""
Specify knob position to determine the position of the knob from fully
inserted (0) or fully uninserted (1)
"""
knob_h = self.hex_nut.thickness
result = (
Cq.Assembly()
.addS(self.parent(), name="parent",
material=Material.PLASTIC_PLA,
role=Role.PARENT)
.constrain("parent", "Fixed")
.addS(self.child(), name="child",
material=Material.PLASTIC_PLA,
role=Role.CHILD)
.addS(self.hex_nut.assembly(), name="hex_nut")
.addS(self.knob.assembly(), name="knob",
loc=Cq.Location((0, 0, knob_h * fastener_pos)))
.constrain("knob/thread", "Fixed")
.constrain("hex_nut?bot", "parent?base", "Plane", param=0)
.constrain("hex_nut?dirX", "parent@faces@>X", "Axis", param=0)
)
self.hirth_joint.add_constraints(
result,
"parent",
"child",
offset=offset
)
return result.solve()
@dataclass
class ShoulderJoint(Model):
bolt: FlatHeadBolt = SHOULDER_AXIS_BOLT
height: float = 70.0
torsion_joint: TorsionJoint = field(default_factory=lambda: TorsionJoint(
radius_track=18,
radius_rider=18,
groove_depth=4.8,
groove_radius_outer=16,
groove_radius_inner=13,
track_disk_height=5.0,
rider_disk_height=5.0,
radius_axle=3.0,
spring=SHOULDER_TORSION_SPRING,
rider_slot_begin=0,
rider_n_slots=1,
rider_slot_span=0,
))
# On the parent side, drill vertical holes
parent_conn_hole_diam: float = 6.0
# Position of the holes relative
parent_conn_hole_pos: list[Tuple[float, float]] = field(default_factory=lambda: [
(15, 8),
(15, -8),
])
parent_lip_length: float = 25.0
parent_lip_width: float = 30.0
parent_lip_thickness: float = 5.0
parent_lip_ext: float = 40.0
parent_lip_guard_height: float = 8.0
# Generates a child guard which covers up the internals. The lip length is
# relative to the +X surface of the guard.
child_guard_ext: float = 30.0
child_guard_width: float = 25.0
# guard length measured from axle
child_lip_length: float = 40.0
child_lip_width: float = 20.0
child_conn_hole_diam: float = 6.0
# Measured from centre of axle
child_conn_hole_pos: list[float] = field(default_factory=lambda: [15, 25])
child_core_thickness: float = 3.0
# Rotates the torsion joint to avoid collisions or for some other purpose
axis_rotate_bot: float = 225.0
axis_rotate_top: float = -225.0
directrix_id: int = 0
angle_neutral: float = 10.0
angle_max_deflection: float = 80.0
def __post_init__(self):
assert self.parent_lip_length * 2 < self.height
@property
def radius(self):
return self.torsion_joint.radius
def parent_arm_loc(self) -> Cq.Location:
"""
2d location of the arm surface on the parent side, relative to axle
"""
return Cq.Location.rot2d(self.angle_neutral) * Cq.Location.from2d(self.parent_lip_ext, 0, 0)
def parent(self, top: bool = False) -> Cq.Assembly:
joint = self.torsion_joint
# Thickness of the lip connecting this joint to the wing root
assert self.parent_lip_width <= joint.radius_track * 2
assert self.parent_lip_ext > joint.radius_track
lip_guard = (
Cq.Solid.makeBox(
self.parent_lip_ext,
self.parent_lip_width,
self.parent_lip_guard_height)
.located(Cq.Location((0, -self.parent_lip_width/2 , 0)))
.cut(Cq.Solid.makeCylinder(joint.radius_track, self.parent_lip_guard_height))
)
lip = MountingBox(
length=self.parent_lip_length,
width=self.parent_lip_width,
thickness=self.parent_lip_thickness,
holes=[
Hole(x=self.height / 2 - x, y=y)
for x, y in self.parent_conn_hole_pos
],
hole_diam=self.parent_conn_hole_diam,
generate_side_tags=False,
)
# Flip so the lip's holes point to -X
loc_axis = Cq.Location((0,0,0), (0, 1, 0), -90)
# so they point to +X
loc_dir = Cq.Location((0,0,0), (0, 0, 1), 180)
loc_pos = Cq.Location((self.parent_lip_ext - self.parent_lip_thickness, 0, 0))
rot = -self.axis_rotate_top if top else self.axis_rotate_bot
result = (
Cq.Assembly()
.add(joint.track(), name="track",
loc=Cq.Location((0, 0, 0), (0, 0, 1), rot))
.add(lip_guard, name="lip_guard")
.add(lip.generate(), name="lip", loc=loc_pos * loc_dir * loc_axis)
)
return result
@target(name="parent-bot")
def parent_bot(self) -> Cq.Assembly:
return self.parent(top=False)
@target(name="parent-top")
def parent_top(self) -> Cq.Assembly:
return self.parent(top=True)
@property
def child_height(self) -> float:
"""
Calculates the y distance between two joint surfaces on the child side
of the shoulder joint.
"""
joint = self.torsion_joint
return self.height - 2 * joint.total_height + 2 * joint.rider_disk_height
@target(name="child")
def child(self) -> Cq.Assembly:
"""
Creates the top/bottom shoulder child joint
"""
joint = self.torsion_joint
assert all(r < self.child_lip_length for r in self.child_conn_hole_pos)
# Half of the height of the bridging cylinder
dh = self.height / 2 - joint.total_height
core_start_angle = 30
core_end_angle1 = 90
core_end_angle2 = 180
radius_core_inner = joint.radius_rider - self.child_core_thickness
core_profile1 = (
Cq.Sketch()
.arc((0, 0), joint.radius_rider, core_start_angle, core_end_angle1-core_start_angle)
.segment((0, 0))
.close()
.assemble()
.circle(radius_core_inner, mode='s')
)
core_profile2 = (
Cq.Sketch()
.arc((0, 0), joint.radius_rider, -core_start_angle, -(core_end_angle2-core_start_angle))
.segment((0, 0))
.close()
.assemble()
.circle(radius_core_inner, mode='s')
)
core_guard = (
Cq.Workplane('XY')
.box(
length=self.child_guard_ext,
width=self.child_guard_width,
height=self.height,
centered=(False, True, True),
)
.copyWorkplane(Cq.Workplane('XY'))
.cylinder(
radius=self.radius,
height=self.height,
combine='cut',
centered=True,
)
.copyWorkplane(Cq.Workplane('XY'))
.box(
length=self.child_guard_ext,
width=self.child_lip_width,
height=self.height - self.torsion_joint.total_height * 2,
combine='cut',
centered=(False, True, True),
)
)
core = (
Cq.Workplane('XY')
.placeSketch(core_profile1)
.toPending()
.extrude(dh * 2)
.copyWorkplane(Cq.Workplane('XY'))
.placeSketch(core_profile2)
.toPending()
.extrude(dh * 2)
.translate(Cq.Vector(0, 0, -dh))
.union(core_guard)
)
assert self.child_lip_width / 2 <= joint.radius_rider
lip_thickness = joint.rider_disk_height
lip = box_with_centre_holes(
length=self.child_lip_length,
width=self.child_lip_width,
height=lip_thickness,
hole_loc=self.child_conn_hole_pos,
hole_diam=self.child_conn_hole_diam,
)
theta = self.torsion_joint.spring.angle_neutral - self.torsion_joint.rider_slot_span
loc_rotate = Cq.Location((0, 0, 0), (1, 0, 0), 180)
loc_axis_rotate_bot = Cq.Location((0, 0, 0), (0, 0, 1), self.axis_rotate_bot + self.angle_neutral)
loc_axis_rotate_top = Cq.Location((0, 0, 0), (0, 0, 1), self.axis_rotate_top + self.angle_neutral)
result = (
Cq.Assembly()
.add(core, name="core", loc=Cq.Location())
.add(joint.rider(rider_slot_begin=-90, reverse_directrix_label=True), name="rider_top",
loc=loc_axis_rotate_top * Cq.Location((0, 0, dh), (0, 0, 1), -90) * Cq.Location((0, 0, 0), (0, 0, 1), theta))
.add(joint.rider(rider_slot_begin=180), name="rider_bot",
loc=loc_axis_rotate_bot * Cq.Location((0, 0, -dh), (0, 0, 1), -90) * loc_rotate)
.add(lip, name="lip_top",
loc=Cq.Location((self.child_guard_ext, 0, dh)))
.add(lip, name="lip_bot",
loc=Cq.Location((self.child_guard_ext, 0, -dh)) * loc_rotate)
)
return result
@assembly()
def assembly(self, fastener_pos: float = 0.0, deflection: float = 0) -> Cq.Assembly:
assert deflection <= self.angle_max_deflection
directrix = self.directrix_id
mat = Material.RESIN_TRANSPERENT
mat_spring = Material.STEEL_SPRING
bolt_z = self.height / 2 + self.bolt.height_thread * (fastener_pos - 1)
result = (
Cq.Assembly()
.addS(self.child(), name="child",
role=Role.CHILD, material=mat)
.constrain("child/core", "Fixed")
.addS(self.torsion_joint.spring.assembly(deflection=-deflection), name="spring_top",
role=Role.DAMPING, material=mat_spring)
.addS(self.parent_top(),
name="parent_top",
role=Role.PARENT, material=mat)
.addS(self.torsion_joint.spring.assembly(deflection=deflection), name="spring_bot",
role=Role.DAMPING, material=mat_spring)
.addS(self.parent_bot(),
name="parent_bot",
role=Role.PARENT, material=mat)
# Fasteners
.addS(self.bolt.assembly(), name="bolt_top",
loc=Cq.Location((0, 0, bolt_z)))
.constrain("bolt_top?root", 'Fixed')
.addS(self.bolt.assembly(), name="bolt_bot",
loc=Cq.Location((0, 0, -bolt_z), (1,0,0), 180))
.constrain("bolt_bot?root", 'Fixed')
)
TorsionJoint.add_constraints(
result,
rider="child/rider_top",
track="parent_top/track",
spring="spring_top",
directrix=directrix)
TorsionJoint.add_constraints(
result,
rider="child/rider_bot",
track="parent_bot/track",
spring="spring_bot",
directrix=directrix)
return result.solve()
@dataclass
class Beam:
"""
A I-shaped spine with two feet
"""
foot_length: float = 40.0
foot_width: float = 20.0
foot_height: float = 5.0
spine_thickness: float = 4.0
spine_length: float = 10.0
total_height: float = 50.0
hole_diam: float = 6.0
# distance between the centres of the two holes
hole_dist: float = 24.0
def __post_init__(self):
assert self.spine_height > 0
assert self.hole_diam + self.hole_dist < self.foot_length
assert self.hole_dist - self.hole_diam >= self.spine_length
@property
def spine_height(self):
return self.total_height - self.foot_height * 2
def foot(self) -> Cq.Workplane:
"""
just one foot
"""
dx = self.hole_dist / 2
result = (
Cq.Workplane('XZ')
.box(self.foot_length, self.foot_width, self.foot_height,
centered=(True, True, False))
.faces(">Y")
.workplane()
.pushPoints([(dx, 0), (-dx, 0)])
.hole(self.hole_diam)
)
plane = result.faces(">Y").workplane()
plane.moveTo(dx, 0).tagPlane("conn1")
plane.moveTo(-dx, 0).tagPlane("conn0")
return result
def generate(self, flip: bool = False) -> Cq.Assembly:
beam = (
Cq.Workplane('XZ')
.box(self.spine_length, self.spine_thickness, self.spine_height)
)
h = self.spine_height / 2 + self.foot_height
tag_p, tag_n = "top", "bot"
if flip:
tag_p, tag_n = tag_n, tag_p
result = (
Cq.Assembly()
.add(beam, name="beam")
.add(self.foot(), name=tag_p,
loc=Cq.Location((0, h, 0)))
.add(self.foot(), name=tag_n,
loc=Cq.Location((0, -h, 0), (1, 0, 0), 180))
)
return result
@dataclass
class DiskJoint(Model):
"""
Sandwiched disk joint for the wrist and elbow
We embed a spring inside the joint, with one leg in the disk and one leg in
the housing. This provides torsion resistance.
"""
spring: TorsionSpring = ELBOW_TORSION_SPRING
radius_housing: float = 22.0
radius_disk: float = 20.0
radius_axle: float = 3.0
housing_thickness: float = 4.0
disk_thickness: float = 7.0
# Amount by which the wall carves in
wall_inset: float = 2.0
# Height of the spring hole; if you make it too short the spring can't enter
spring_tail_hole_height: float = 2.0
# Spring angle at 0 degrees of movement
spring_angle_at_0: float = 90.0
spring_slot_offset: float = 5.0
# Angular span of movement
movement_angle: float = 120.0
# Angular span of tongue on disk
tongue_span: float = 30.0
tongue_length: float = 10.0
generate_inner_wall: bool = False
def __post_init__(self):
super().__init__(name="disk-joint")
assert self.radius_housing > self.radius_disk > self.radius_axle
assert self.spring.height < self.housing_thickness + self.disk_thickness
assert self.housing_upper_carve_offset > 0
assert self.spring_tail_hole_height > self.spring.thickness
@property
def neutral_movement_angle(self) -> Optional[float]:
a = self.spring.angle_neutral - self.spring_angle_at_0
if 0 <= a and a <= self.movement_angle:
return a
return None
@property
def total_thickness(self) -> float:
return self.housing_thickness * 2 + self.disk_thickness
@property
def disk_bot_thickness(self) -> float:
"""
Pads the bottom of the disk up to spring height
"""
return max(0, self.disk_thickness + self.spring.thickness - self.spring.height)
@property
def opening_span(self) -> float:
return self.movement_angle + self.tongue_span
@property
def housing_upper_carve_offset(self) -> float:
"""
Distance between the spring track and the outside of the upper housing
"""
return self.spring_tail_hole_height + (self.disk_thickness - self.disk_bot_thickness) - self.spring.height
@property
def housing_upper_dz(self) -> float:
"""
Distance between the default upper housing location and the median line
"""
return self.total_thickness / 2 - self.housing_thickness
def _disk_cut(self) -> Cq.Workplane:
return (
Cq.Solid.makeBox(
length=self.spring.tail_length,
width=self.spring.thickness,
height=self.spring.height-self.disk_bot_thickness,
)
.located(Cq.Location((0, self.spring.radius_inner, self.disk_bot_thickness)))
.rotate((0, 0, 0), (0, 0, 1), self.spring_slot_offset)
)
@target(name="disk")
def disk(self) -> Cq.Workplane:
radius_tongue = self.radius_disk + self.tongue_length
tongue = (
Cq.Solid.makeCylinder(
height=self.disk_thickness,
radius=radius_tongue,
angleDegrees=self.tongue_span,
).cut(Cq.Solid.makeCylinder(
height=self.disk_thickness,
radius=self.radius_disk,
))
)
result = (
Cq.Workplane('XY')
.cylinder(
height=self.disk_thickness,
radius=self.radius_disk,
centered=(True, True, False)
)
.union(tongue, tol=TOL)
.copyWorkplane(Cq.Workplane('XY'))
.cylinder(
height=self.disk_thickness,
radius=self.spring.radius,
centered=(True, True, False),
combine='cut',
)
.cut(self._disk_cut())
)
plane = result.copyWorkplane(Cq.Workplane('XY'))
theta = math.radians(self.spring_slot_offset)
plane.tagPlane("dir", direction=(math.cos(theta), math.sin(theta), 0))
plane.workplane(offset=self.disk_thickness).tagPlane("mate_top")
plane.workplane(offset=self.disk_bot_thickness).tagPlane("mate_spring")
result.copyWorkplane(Cq.Workplane('YX')).tagPlane("mate_bot")
return result
def wall(self) -> Cq.Compound:
height = self.disk_thickness + self.wall_inset
wall = Cq.Solid.makeCylinder(
radius=self.radius_housing,
height=height,
angleDegrees=360 - self.opening_span,
).cut(Cq.Solid.makeCylinder(
radius=self.radius_disk,
height=height,
)).rotate((0, 0, 0), (0, 0, 1), self.opening_span)
return wall
@target(name="housing-lower")
def housing_lower(self) -> Cq.Workplane:
result = (
Cq.Workplane('XY')
.cylinder(
radius=self.radius_housing,
height=self.housing_thickness,
centered=(True, True, False),
)
.cut(Cq.Solid.makeCylinder(
radius=self.radius_axle,
height=self.housing_thickness,
))
)
result.faces(">Z").tag("mate")
result.faces(">Z").workplane().tagPlane("dirX", direction="+X")
result = result.cut(
self
.wall()
.located(Cq.Location((0, 0, self.housing_thickness - self.wall_inset)))
#.rotate((0, 0, 0), (1, 0, 0), 180)
#.located(Cq.Location((0, 0, self.disk_thickness + self.housing_thickness)))
)
return result
@target(name="housing-upper")
def housing_upper(self) -> Cq.Workplane:
carve_angle = -(self.spring_angle_at_0 - self.spring_slot_offset)
carve = (
Cq.Solid.makeCylinder(
radius=self.spring.radius,
height=self.spring_tail_hole_height,
).fuse(Cq.Solid.makeBox(
length=self.spring.tail_length,
width=self.spring.thickness,
height=self.spring_tail_hole_height,
).located(Cq.Location((0, -self.spring.radius, 0))))
).rotate((0, 0, 0), (0, 0, 1), carve_angle)
result = (
Cq.Workplane('XY')
.cylinder(
radius=self.radius_housing,
height=self.housing_thickness,
centered=(True, True, False),
)
)
theta = math.radians(carve_angle)
result.faces("<Z").tag("mate")
p_xy = result.copyWorkplane(Cq.Workplane('XY'))
p_xy.tagPlane("dirX", direction="+X")
p_xy.tagPlane("dir", direction=(math.cos(theta), math.sin(theta), 0))
result = result.faces(">Z").hole(self.radius_axle * 2)
# tube which holds the spring interior
if self.generate_inner_wall:
tube = (
Cq.Solid.makeCylinder(
radius=self.radius_spring_internal,
height=self.disk_thickness + self.housing_thickness,
).cut(Cq.Solid.makeCylinder(
radius=self.radius_axle,
height=self.disk_thickness + self.housing_thickness,
))
)
result = result.union(tube)
wall = (
self.wall()
.located(Cq.Location((0, 0, -self.disk_thickness-self.wall_inset)))
)
result = (
result
.union(wall, tol=TOL)
#.cut(carve)
.cut(carve.located(Cq.Location((0, 0, -self.housing_upper_carve_offset))))
)
return result.clean()
def add_constraints(self,
assembly: Cq.Assembly,
housing_lower: str,
housing_upper: str,
disk: str,
angle: float = 0.0,
) -> Cq.Assembly:
assert 0 <= angle <= self.movement_angle
deflection = angle - self.neutral_movement_angle
spring_name = disk.replace("/", "__Z") + "_spring"
(
assembly
.addS(
self.spring.assembly(deflection=-deflection),
name=spring_name,
role=Role.DAMPING,
material=Material.STEEL_SPRING)
.constrain(f"{disk}?mate_bot", f"{housing_lower}?mate", "Plane")
.constrain(f"{disk}?mate_top", f"{housing_upper}?mate", "Plane")
.constrain(f"{housing_lower}?dirX", f"{housing_upper}?dirX", "Axis", param=0)
.constrain(f"{housing_upper}?dir", f"{spring_name}?dir_top", "Axis", param=0)
.constrain(f"{spring_name}?dir_bot", f"{disk}?dir", "Axis", param=0)
.constrain(f"{disk}?mate_spring", f"{spring_name}?bot", "Plane")
#.constrain(f"{housing_lower}?dirX", f"{housing_upper}?dir", "Axis", param=0)
#.constrain(f"{housing_lower}?dirX", f"{disk}?dir", "Axis", param=angle)
#.constrain(f"{housing_lower}?dirY", f"{disk}?dir", "Axis", param=angle - 90)
)
return (
assembly
)
def assembly(self, angle: Optional[float] = 0) -> Cq.Assembly:
if angle is None:
angle = self.neutral_movement_angle
if angle is None:
angle = 0
else:
assert 0 <= angle <= self.movement_angle
result = (
Cq.Assembly()
.addS(self.disk(), name="disk", role=Role.CHILD)
.addS(self.housing_lower(), name="housing_lower", role=Role.PARENT)
.addS(self.housing_upper(), name="housing_upper", role=Role.CASING)
.constrain("housing_lower", "Fixed")
)
result = self.add_constraints(
result,
housing_lower="housing_lower",
housing_upper="housing_upper",
disk="disk",
angle=angle,
)
return result.solve()
@dataclass(kw_only=True)
class ElbowJoint(Model):
"""
Creates the elbow and wrist joints.
This consists of a disk joint, where each side of the joint has mounting
holes for connection to the exoskeleton. Each side 2 mounting feet on the
top and bottom, and each foot has 2 holes.
On the parent side, additional bolts are needed to clamp the two sides of
the housing together.
"""
disk_joint: DiskJoint = field(default_factory=lambda: DiskJoint(
movement_angle=60,
))
# Distance between the child/parent arm to the centre
child_arm_radius: float = 40.0
parent_arm_radius: float = 40.0
lip_thickness: float = 5.0
lip_length: float = 60.0
hole_pos: list[float] = field(default_factory=lambda: [15, 25])
parent_arm_width: float = 10.0
# Angle of the beginning of the parent arm
parent_arm_angle: float = 180.0
# Size of the mounting holes
hole_diam: float = 4.0
material: Material = Material.RESIN_TRANSPERENT
angle_neutral: float = 30.0
actuator: LinearActuator
flexor: Flexor = None
# Rotates the entire flexor
flexor_offset_angle: float = 0
# Rotates the surface of the mount
flexor_mount_rot: float = 90.0
def __post_init__(self):
assert self.child_arm_radius > self.disk_joint.radius_housing
assert self.parent_arm_radius > self.disk_joint.radius_housing
self.disk_joint.tongue_length = self.child_arm_radius - self.disk_joint.radius_disk - self.lip_thickness / 2
self.flexor = Flexor(
actuator=self.actuator,
motion_span=self.motion_span
)
@property
def total_thickness(self):
return self.disk_joint.total_thickness
@property
def motion_span(self) -> float:
return self.disk_joint.movement_angle
def parent_arm_loc(self) -> Cq.Location:
"""
2d Location of the centre of the arm surface on the parent side, assuming
axle is at position 0, and parent direction is -X
"""
return Cq.Location.from2d(-self.parent_arm_radius, 0, 0)
def child_arm_loc(self, flip: bool = False, angle: float = 0.0) -> Cq.Location:
"""
2d Location of the centre of the arm surface on the child side, assuming
axle is at position 0, and parent direction is -X
Set `flip=True` to indicate that the joint is supposed to be installed upside down
"""
result = Cq.Location.rot2d(self.angle_neutral + angle) * Cq.Location.from2d(self.child_arm_radius, 0, 180)
return result.flip_y() if flip else result
def actuator_mount(self) -> Cq.Workplane:
holes = [
Hole(x=0, y=0, tag="mount"),
]
mbox = MountingBox(
length=self.disk_joint.total_thickness,
width=self.disk_joint.total_thickness,
thickness=self.lip_thickness,
holes=holes,
hole_diam=self.hole_diam,
centred=(True, True),
generate_side_tags=False,
)
return mbox.generate()
def actuator_mount_loc(self, child: bool) -> Cq.Location:
# Orientes the hole surface so it faces +X
loc_thickness = Cq.Location((-self.lip_thickness, 0, 0), (0, 1, 0), 90)
# Moves the hole so the axle of the mount is perpendicular to it
loc_mount = Cq.Location.from2d(self.flexor.mount_height, 0) * Cq.Location.rot2d(180)
loc_mount_orient = Cq.Location.rot2d(self.flexor_mount_rot * (-1 if child else 1))
# Moves the hole to be some distance apart from 0
loc_span = Cq.Location.from2d(self.flexor.mount_loc_r, 0)
r = (-self.flexor.mount_loc_angle if child else 0) + 180
loc_rot = Cq.Location.rot2d(r + self.flexor_offset_angle)
return loc_rot * loc_span * loc_mount_orient * loc_mount * loc_thickness
def lip(self) -> Cq.Workplane:
holes = [
h
for i, x in enumerate(self.hole_pos)
for h in [
Hole(x=x, tag=f"conn_top{i}"),
Hole(x=-x, tag=f"conn_bot{i}")
]
]
mbox = MountingBox(
length=self.lip_length,
width=self.disk_joint.total_thickness,
thickness=self.lip_thickness,
holes=holes,
hole_diam=self.hole_diam,
centred=(True, True),
generate_side_tags=False,
generate_reverse_tags=True,
)
return mbox.generate()
@target(name="child")
def child_joint(self) -> Cq.Assembly:
angle = -self.disk_joint.tongue_span / 2
dz = self.disk_joint.disk_thickness / 2
# We need to ensure the disk is on the "other" side so
flip_x = Cq.Location((0, 0, 0), (1, 0, 0), 180)
flip_z = Cq.Location((0, 0, 0), (0, 0, 1), 180)
lip_dz = self.lip_thickness
loc_lip = (
Cq.Location((0, 0, 0), (0, 1, 0), 180) *
Cq.Location((-lip_dz, 0, 0), (1, 0, 0), 90) *
Cq.Location((0, 0, 0), (0, 1, 0), 90)
)
loc_disk = flip_x * flip_z * Cq.Location((-self.child_arm_radius, 0, 0), (0, 0, 1), angle)
loc_cut_rel = Cq.Location((0, self.disk_joint.spring.radius_inner, -self.disk_joint.disk_bot_thickness))
disk_cut = self.disk_joint._disk_cut().located(
loc_lip.inverse * loc_cut_rel * loc_disk)
result = (
Cq.Assembly()
.add(self.disk_joint.disk(), name="disk", loc=Cq.Location((0, 0, -dz)))
.add(self.lip().cut(disk_cut), name="lip", loc=loc_disk.inverse * loc_lip)
.add(self.actuator_mount(), name="act", loc=self.actuator_mount_loc(child=True))
)
return result
@target(name="parent-lower")
def parent_joint_lower(self) -> Cq.Workplane:
return self.disk_joint.housing_lower()
@target(name="parent-upper")
def parent_joint_upper(self):
axial_offset = Cq.Location((self.parent_arm_radius, 0, 0))
housing_dz = self.disk_joint.housing_upper_dz
conn_h = self.disk_joint.total_thickness
conn_w = self.parent_arm_width
connector = (
Cq.Solid.makeBox(
length=self.parent_arm_radius,
width=conn_w,
height=conn_h,
).located(Cq.Location((0, -conn_w/2, 0)))
#Cq.Solid.makeCylinder(
# height=conn_h,
# radius=self.parent_arm_radius - self.lip_thickness / 2,
# angleDegrees=self.parent_arm_span)
.cut(Cq.Solid.makeCylinder(
height=conn_h,
radius=self.disk_joint.radius_housing,
))
.located(Cq.Location((0, 0, -conn_h / 2)))
.rotate((0,0,0), (0,0,1), 180)
#.rotate((0,0,0), (0,0,1), 180-self.parent_arm_span / 2)
)
housing = self.disk_joint.housing_upper()
housing_loc = Cq.Location(
(0, 0, 0),
(0, 0, 1),
-self.disk_joint.tongue_span / 2 + self.angle_neutral
)
lip_dz = self.lip_thickness
loc_net_housing = axial_offset * housing_loc
result = (
Cq.Assembly()
.add(housing, name="housing", loc=Cq.Location((0, 0, housing_dz)))
.add(self.lip(), name="lip", loc=
loc_net_housing.inverse *
Cq.Location((0, 0, 0), (0, 1, 0), 180) *
Cq.Location((-lip_dz, 0, 0), (1, 0, 0), 90) *
Cq.Location((0, 0, 0), (0, 1, 0), 90))
.add(connector, name="connector",
loc=loc_net_housing.inverse * axial_offset)
.add(self.actuator_mount(),
name="act", loc=self.actuator_mount_loc(child=False))
#.constrain("housing", "Fixed")
#.constrain("connector", "Fixed")
#.solve()
)
return result
@assembly()
def assembly(self, angle: float = 0) -> Cq.Assembly:
result = (
Cq.Assembly()
.addS(self.child_joint(), name="child",
role=Role.CHILD, material=self.material)
.addS(self.parent_joint_lower(), name="parent_lower",
role=Role.CASING, material=self.material)
.addS(self.parent_joint_upper(), name="parent_upper",
role=Role.PARENT, material=self.material)
#.constrain("child/disk?mate_bot", "Fixed")
)
result = self.disk_joint.add_constraints(
result,
housing_lower="parent_lower",
housing_upper="parent_upper/housing",
disk="child/disk",
angle=angle,
)
if self.flexor:
target_length = self.flexor.target_length_at_angle(
angle=angle,
)
self.flexor.add_to(
result,
target_length=target_length,
tag_hole_back="parent_upper/act?mount",
tag_hole_front="child/act?mount",
tag_dir="parent_lower?mate",
)
return result.solve()
if __name__ == '__main__':
p = ShoulderJoint()
p.build_all()
p = DiskJoint()
p.build_all()