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.box import MountingBox 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, LINEAR_ACTUATOR_21, ) import nhf.geometry 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=5.60, base_height=4.0, 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 parent_substrate_thickness: float = 25.4 / 16 parent_substrate_cull_corners: Tuple[bool, bool, bool, bool] = (False, False, True, False) parent_substrate_cull_edges: Tuple[bool, bool, bool, bool] = (False, False, True, False) 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 __post_init__(self): assert self.child_extra_thickness > 0.0 assert self.parent_thickness >= self.hex_nut.thickness # twice the buffer allocated for substratum assert self.parent_width >= 4 * self.parent_corner_inset 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 child_extra_thickness(self) -> float: """ Extra thickness allocated to child for padding """ return self.knob.height_thread - self.hirth_joint.joint_height - self.child_mount_thickness - self.parent_thickness @property def base_to_surface_thickness(self) -> float: return self.hirth_joint.joint_height + self.child_extra_thickness @property def substrate_inset(self) -> float: return self.parent_corner_inset * 2 def bridge_pair_horizontal(self, centre_dx: float) -> MountingBox: hole_dx = centre_dx / 2 - self.parent_width / 2 + self.parent_corner_inset hole_dy = self.parent_width / 2 - self.parent_corner_inset holes = [ Hole(x=hole_dx, y=hole_dy), Hole(x=-hole_dx, y=hole_dy), Hole(x=-hole_dx, y=-hole_dy), Hole(x=hole_dx, y=-hole_dy), ] return MountingBox( length=centre_dx - self.parent_width + self.substrate_inset * 2, width=self.parent_width, thickness=self.parent_substrate_thickness, hole_diam=self.corner_hole_diam, holes=holes, centred=(True, True), generate_reverse_tags=True, ) def bridge_pair_vertical(self, centre_dy: float) -> MountingBox: hole_dy = centre_dy / 2 - self.parent_width / 2 + self.parent_corner_inset holes = [ Hole(x=0, y=hole_dy), Hole(x=0, y=-hole_dy), ] return MountingBox( length=self.substrate_inset, width=centre_dy - self.parent_width + self.substrate_inset * 2, thickness=self.parent_substrate_thickness, hole_diam=self.corner_hole_diam, holes=holes, centred=(True, True), generate_reverse_tags=True, ) @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( length=self.parent_width, width=self.parent_width, height=self.parent_thickness, centered=(True, True, False)) .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) ) sso = self.parent_width / 2 - self.substrate_inset loc_corner = Cq.Location((sso, sso, 0)) loc_edge= Cq.Location((sso, -sso, 0)) cut_corner = Cq.Solid.makeBox( length=self.parent_width, width=self.parent_width, height=self.parent_substrate_thickness, ) cut_edge = Cq.Solid.makeBox( length=self.parent_width, width=self.parent_width - self.substrate_inset * 2, height=self.parent_substrate_thickness, ) step = 90 for i, flag in enumerate(self.parent_substrate_cull_corners): if not flag: continue loc = Cq.Location((0,0,0),(0,0,1), i * step) * loc_corner result = result.cut(cut_corner.located(loc)) for i, flag in enumerate(self.parent_substrate_cull_edges): if not flag: continue loc = Cq.Location((0,0,0),(0,0,1), i * step) * loc_edge result = result.cut(cut_edge.located(loc)) result = result.translate((0, 0, -self.parent_thickness)) # 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(" 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( length=self.child_height, width=self.child_width, height=self.child_extra_thickness + self.hirth_joint.base_height, centered=(True, True, False)) .translate((0, 0, -self.child_extra_thickness)) #.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.copyWorkplane(Cq.Workplane('XY', origin=(0, 0, -self.child_extra_thickness))) for i, (px, py) in enumerate(conn): plane.moveTo(px, py).tagPlane(f"conn{i}", direction="-Z") result = ( result .faces(">Z") .workplane() .union(hirth, tol=0.1) .clean() ) result = ( result.faces(" 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) ) if not ignore_fasteners: ( result .addS(self.hex_nut.assembly(), name="hex_nut") .addS(self.knob.assembly(), name="knob", loc=Cq.Location((0, 0, knob_h * fastener_pos - self.parent_thickness))) .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 = 4.0 # Position of the holes relative centre line parent_conn_hole_pos: list[Tuple[float, float]] = field(default_factory=lambda: [ (20, 8), (20, -8), ]) # Distance from centre of lips to the axis parent_lip_ext: float = 40.0 parent_lip_length: float = 25.0 parent_lip_width: float = 30.0 parent_lip_thickness: float = 5.0 # The parent side has arms which connect to the lips parent_arm_width: float = 25.0 parent_arm_height: float = 12.0 # 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 = 20.0 child_guard_width: float = 25.0 # guard length measured from axle child_lip_ext: float = 50.0 child_lip_width: float = 20.0 child_lip_height: float = 40.0 child_lip_thickness: float = 5.0 child_conn_hole_diam: float = 4.0 # Measured from centre of axle child_conn_hole_pos: list[float] = field(default_factory=lambda: [-15, -5, 5, 15]) child_core_thickness: float = 3.0 # Rotates the torsion joint to avoid collisions or for some other purpose axis_rotate_bot: float = 90 axis_rotate_top: float = 0 directrix_id: int = 0 angle_neutral: float = -15.0 angle_max_deflection: float = 65.0 spool_radius: float = 14.0 spool_groove_depth: float = 1.0 spool_base_height: float = 3.0 spool_height: float = 5.0 spool_groove_inset: float = 2.0 flip: bool = False actuator: LinearActuator = LINEAR_ACTUATOR_21 def __post_init__(self): assert self.parent_lip_length * 2 < self.height assert self.child_guard_ext > self.torsion_joint.radius_rider assert self.spool_groove_depth < self.spool_radius < self.torsion_joint.radius_rider - self.child_core_thickness assert self.spool_base_height > self.spool_groove_depth assert self.child_lip_height < self.height assert self.draft_length <= self.actuator.stroke_length @property def radius(self): return self.torsion_joint.radius @property def draft_length(self): """ Amount of wires that need to draft on the spool """ return (self.spool_radius - self.spool_groove_depth / 2) * math.radians(self.angle_max_deflection) @property def draft_height(self): """ Position of the middle of the spool measured from the middle """ return self.height / 2 - self.torsion_joint.total_height - self.spool_base_height / 2 def parent_lip_loc(self, left: bool=True) -> Cq.Location: """ 2d location of the arm surface on the parent side, relative to axle """ dy = self.parent_arm_width / 2 sign = 1 if left else -1 loc_dir = Cq.Location((0,sign * dy,0), (0, 0, 1), sign * 90) return Cq.Location.from2d(self.parent_lip_ext, 0, 0) * loc_dir def child_lip_loc(self) -> Cq.Location: """ 2d location to middle of lip """ return Cq.Location.from2d(self.child_lip_ext - self.child_guard_ext, 0, 180) @property def _max_contraction_angle(self) -> float: return 180 - self.angle_max_deflection + self.angle_neutral def _contraction_cut_geometry(self, parent: bool = False, mirror: bool=False) -> Cq.Solid: """ Generates a cylindrical sector which cuts away overlapping regions of the child and parent """ aspect = self.child_guard_width / self.parent_arm_width theta = math.radians(self._max_contraction_angle) #theta_p = math.atan(math.sin(theta) / (math.cos(theta) + aspect)) theta_p = math.atan2(math.sin(theta), math.cos(theta) + aspect) angle = math.degrees(theta_p) assert 0 <= angle <= 90 # outer radius of the cut, overestimated cut_radius = math.sqrt(self.child_guard_width ** 2 + self.parent_arm_width ** 2) span = 180 result = ( Cq.Solid.makeCylinder( height=self.height, radius=cut_radius, angleDegrees=span, ).cut(Cq.Solid.makeCylinder( height=self.height, radius=self.torsion_joint.radius, )) ) if parent: angle = - span - angle else: angle = self._max_contraction_angle - angle result = result.located(Cq.Location((0,0,-self.height/2), (0,0,1), angle)) if mirror: result = result.mirror('XZ') return result 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_arm_width <= joint.radius_track * 2 assert self.parent_lip_ext > joint.radius_track arm = ( Cq.Solid.makeBox( self.parent_lip_ext + self.parent_lip_width / 2, self.parent_arm_width, self.parent_arm_height) .located(Cq.Location((0, -self.parent_arm_width/2 , 0))) .cut(Cq.Solid.makeCylinder(joint.radius_track, self.parent_arm_height)) .cut(self._contraction_cut_geometry(parent=True, mirror=top)) ) lip_args = dict( length=self.parent_lip_length, width=self.parent_lip_width, thickness=self.parent_lip_thickness, hole_diam=self.parent_conn_hole_diam, generate_side_tags=False, ) lip1 = MountingBox( **lip_args, holes=[ Hole(x=self.height / 2 - x, y=-y) for x, y in self.parent_conn_hole_pos ], ) lip2 = MountingBox( **lip_args, holes=[ Hole(x=self.height / 2 - x, y=y) for x, y in self.parent_conn_hole_pos ], ) lip_dy = self.parent_arm_width / 2 - self.parent_lip_thickness # Flip so the lip's holes point to -X loc_axis = Cq.Location((0,0,0), (0, 1, 0), -90) loc_dir1 = Cq.Location((0,lip_dy,0), (0, 0, 1), -90) loc_dir2 = Cq.Location((0,-lip_dy,0), (0, 0, 1), 90) loc_pos = Cq.Location((self.parent_lip_ext, 0, 0)) rot = -self.axis_rotate_top if top else self.axis_rotate_bot lip_p_tag, lip_n_tag = "lip_right", "lip_left" if not top: lip_p_tag, lip_n_tag = lip_n_tag, lip_p_tag result = ( Cq.Assembly() .add(joint.track(), name="track", loc=Cq.Location((0, 0, 0), (0, 0, 1), rot)) .add(arm, name="arm") .add(lip1.generate(), name=lip_p_tag, loc=loc_pos * loc_dir1 * loc_axis) .add(lip2.generate(), name=lip_n_tag, loc=loc_pos * loc_dir2 * 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 def _spool(self) -> Cq.Workplane: """ Generates the spool piece which holds the line in tension """ t = self.spool_groove_depth bulk = Cq.Solid.makeCylinder( radius=self.spool_radius, height=self.spool_height, ).located(Cq.Location((0, 0, self.spool_base_height))) base = Cq.Solid.makeCylinder( radius=self.spool_radius - t, height=self.spool_base_height, ) hole_x = self.spool_radius - (t + self.spool_groove_inset) slot = Cq.Solid.makeBox( length=t + self.spool_groove_inset, width=t, height=self.spool_base_height, ).located(Cq.Location((hole_x, -t/2, 0))) hole = Cq.Solid.makeBox( length=t, width=t, height=self.spool_height + self.spool_base_height, ).located(Cq.Location((hole_x, -t/2, 0))) centre_hole = Cq.Solid.makeCylinder( radius=self.torsion_joint.radius_axle, height=self.spool_height + self.spool_base_height, ) return bulk.fuse(base).cut(slot, hole, centre_hole) @target(name="child") def child(self) -> Cq.Assembly: """ Creates the top/bottom shoulder child joint """ joint = self.torsion_joint # Half of the height of the bridging cylinder dh = self.height / 2 - joint.total_height core_start_angle = 30 radius_core_inner = joint.radius_rider - self.child_core_thickness core_profile1 = ( Cq.Sketch() .arc((0, 0), joint.radius_rider, core_start_angle, self.angle_max_deflection) .segment((0, 0)) .close() .assemble() .circle(radius_core_inner, mode='s') ) core_profile2 = ( Cq.Sketch() .arc((0, 0), joint.radius_rider, -core_start_angle, -(90 - self.angle_neutral)) .segment((0, 0)) .close() .assemble() .circle(radius_core_inner, mode='s') ) lip_extension = ( Cq.Solid.makeBox( length=self.child_lip_ext - self.child_guard_ext, width=self.child_lip_width, height=self.child_lip_height, ).cut(Cq.Solid.makeBox( length=self.child_lip_ext - self.child_guard_ext, width=self.child_lip_width - self.child_lip_thickness * 2, height=self.child_lip_height, ).located(Cq.Location((0, self.child_lip_thickness, 0)))) .located(Cq.Location(( self.child_guard_ext, -self.child_lip_width / 2, -self.child_lip_height / 2, ))) ) 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')) #.box( # length=self.child_lip_ext, # width=self.child_guard_width, # height=self.child_lip_height, # combine=True, # 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_lip_ext, width=self.child_lip_width - 2 * self.child_lip_thickness, height=self.height - self.torsion_joint.total_height * 2, combine='cut', centered=(False, True, True), ) .union(lip_extension) .cut(self._contraction_cut_geometry(parent=False)) ) 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 sign = 1 if self.flip else -1 holes = [Hole(x=sign * x) for x in self.child_conn_hole_pos] lip_obj = MountingBox( length=self.child_lip_height, width=self.child_lip_width, thickness=self.child_lip_thickness, holes=holes, hole_diam=self.child_conn_hole_diam, centred=(True, True), generate_side_tags=False, generate_reverse_tags=False, ) 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) spool_dz = self.height / 2 - self.torsion_joint.total_height spool_angle = 180 + self.angle_neutral loc_spool_flip = Cq.Location((0,0,0),(0,1,0),180) if self.flip else Cq.Location() 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_obj.generate(), name="lip", loc=Cq.Location((self.child_lip_ext - self.child_lip_thickness,0,0), (0,1,0), 90)) .add(self._spool(), name="spool", loc=loc_spool_flip * Cq.Location((0, 0, -spool_dz), (0, 0, 1), spool_angle)) ) return result @assembly() def assembly( self, fastener_pos: float = 0.0, deflection: float = 0.0, ignore_fasteners: bool = False, ) -> 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) ) if not ignore_fasteners: ( result # 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 = 8.0 # 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 # leave some gap for cushion movement_gap: float = 5.0 # Angular span of tongue on disk tongue_span: float = 25.0 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: rl = Cq.Location((0, 0, 0), (0, 0, 1), self.spring_slot_offset) r = ( Cq.Solid.makeBox( length=self.spring.tail_length, width=self.spring.thickness, height=self.disk_thickness - self.disk_bot_thickness, ) .moved(rl * Cq.Location((0, self.spring.radius_inner, self.disk_bot_thickness))) #.rotate((0, 0, 0), (0, 0, 1), self.spring_slot_offset) ) return ( Cq.Workplane() .union(r) .val() ) @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 - self.movement_gap*2, ).cut(Cq.Solid.makeCylinder( radius=self.radius_disk, height=height, )).rotate((0, 0, 0), (0, 0, 1), self.opening_span+self.movement_gap) 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").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.spring.angle_neutral - self.spring_angle_at_0) 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: [12, 24]) 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 # If set to true, the joint is flipped upside down. flip: bool = False angle_neutral: float = 30.0 actuator: Optional[LinearActuator] = None flexor: Optional[Flexor] = None # Rotates the entire flexor flexor_offset_angle: float = 0 # Rotates the surface of the mount relative to radially inwards flexor_mount_angle_parent: float = 0 flexor_mount_angle_child: float = -90 flexor_pos_smaller: bool = True flexor_child_arm_radius: Optional[float] = None flexor_line_length: float = 0.0 flexor_line_slack: float = 0.0 flexor_parent_angle_fix: Optional[float] = 180.0 flexor_child_angle_fix: Optional[float] = None 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 if self.actuator: self.flexor = Flexor( actuator=self.actuator, motion_span=self.motion_span, pos_smaller=self.flexor_pos_smaller, arm_radius=self.flexor_child_arm_radius, line_length=self.flexor_line_length, line_slack=self.flexor_line_slack, ) def hole_loc_tags(self): """ An iterator which iterates through positions of the hole and tags """ for i, x in enumerate(self.hole_pos): yield x, f"conn_top{i}" yield -x, f"conn_bot{i}" @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, 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 """ result = Cq.Location.rot2d(self.angle_neutral + angle) * Cq.Location.from2d(self.child_arm_radius, 0, 180) return result.flip_y() if self.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 = False, # If set to true, use the local coordinate system unflip: bool = False, ) -> Cq.Location: # 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) mount_angle = self.flexor_mount_angle_child if child else self.flexor_mount_angle_parent loc_mount_orient = Cq.Location.rot2d(mount_angle) # Moves the hole to be some distance apart from 0 mount_r, mount_loc_angle, mount_parent_r = self.flexor.open_pos() loc_span = Cq.Location.from2d(mount_r if child else mount_parent_r, 0) if self.flexor_parent_angle_fix is not None: alpha = (-mount_loc_angle if child else 0) + self.flexor_parent_angle_fix - self.flexor_offset_angle elif self.flexor_child_angle_fix is not None: alpha = self.flexor_child_angle_fix + (0 if child else mount_loc_angle) else: raise ValueError("One of flexor_{parent,child}_angle_fix must be set") loc_rot = Cq.Location.rot2d(alpha) loc = loc_rot * loc_span * loc_mount_orient * loc_mount return loc.flip_y() if self.flip and not unflip else loc def lip(self) -> Cq.Workplane: sign = -1 if self.flip else 1 holes = [ h for i, x in enumerate(self.hole_pos) for h in [ Hole(x=sign * x, tag=f"conn_top{i}"), Hole(x=-sign * 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() def child_joint(self, generate_mount: bool=False, generate_tags=True) -> 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_rot_neutral = Cq.Location.rot2d(self.angle_neutral) loc_disk = flip_x * flip_z * Cq.Location((-self.child_arm_radius, 0, 0)) loc_cut_rel = Cq.Location((0, self.disk_joint.spring.radius_inner, -self.disk_joint.disk_bot_thickness)) loc_disk_orient = Cq.Location((0, 0, -dz), (0,0,1), angle) disk_cut = self.disk_joint._disk_cut().moved( #Cq.Location(0,0,0)) loc_lip.inverse * loc_disk * loc_disk_orient) #lip_extra = Cq.Solid.makeBox( # length=self.child_lip_extra_length, # width=self.total_thickness, # height=self.lip_thickness, #).located(Cq.Location(( # self.lip_length / 2, # -self.total_thickness / 2, # 0, #))) result = ( Cq.Assembly() .add(self.disk_joint.disk(), name="disk", loc=loc_rot_neutral * loc_disk_orient) .add(self.lip().cut(disk_cut), name="lip", loc=loc_rot_neutral * loc_disk.inverse * loc_lip) #.add(lip_extra, name="lip_extra", # loc=loc_rot_neutral * loc_disk.inverse * loc_lip) ) # Orientes the hole surface so it faces +X loc_thickness = Cq.Location((-self.lip_thickness, 0, 0), (0, 1, 0), 90) if self.flexor and generate_tags: loc_mount = self.actuator_mount_loc(child=True, unflip=True) result.add( Cq.Edge.makeLine((-1,0,0), (1,0,0)), name="act", loc=loc_mount) if generate_mount: # Orientes the hole surface so it faces +X loc_thickness = Cq.Location((-self.lip_thickness, 0, 0), (0, 1, 0), 90) result.add( self.actuator_mount(), name="act_mount", loc=loc_mount * loc_thickness, ) return result @target(name="child") def target_child(self) -> Cq.Assembly: return self.child_joint(generate_tags=False) @target(name="parent-lower") def parent_joint_lower(self) -> Cq.Workplane: return self.disk_joint.housing_lower() def parent_joint_upper(self, generate_mount: bool=False, generate_tags=True): 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, housing_dz), (0, 0, 1), -self.disk_joint.tongue_span / 2 + self.angle_neutral ) lip_dz = self.lip_thickness result = ( Cq.Assembly() # rotate so 0 degree is at +X .add(housing, name="housing", loc=housing_loc) .add(self.lip(), name="lip", loc= axial_offset.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") #.constrain("housing", "Fixed") #.constrain("connector", "Fixed") #.solve() ) if self.flexor and generate_tags: loc_mount = self.actuator_mount_loc(child=False, unflip=True) result.add( Cq.Edge.makeLine((-1,0,0), (1,0,0)), name="act", loc=loc_mount) if generate_mount: # Orientes the hole surface so it faces +X loc_thickness = Cq.Location((-self.lip_thickness, 0, 0), (0, 1, 0), 90) result.add( self.actuator_mount(), name="act_mount", loc=loc_mount * loc_thickness ) return result @target(name="parent-upper") def target_parent_upper(self) -> Cq.Assembly: return self.parent_joint_upper(generate_tags=False) @assembly() def assembly(self, angle: float = 0, generate_mount: bool = False, ignore_actuators: bool = False) -> Cq.Assembly: assert 0 <= angle <= self.motion_span result = ( Cq.Assembly() .addS(self.child_joint(generate_mount=generate_mount), 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(generate_mount=generate_mount), 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 not ignore_actuators and 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", 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()