feat: Bent elbow joint

nhf/touhou/houjuu_nue/joints.py

@@ -313,6 +313,9 @@ class Beam:
 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 = field(default_factory=lambda: TorsionSpring(
         radius=9 / 2,
@@ -328,14 +331,15 @@ class DiskJoint(Model):
 
     housing_thickness: float = 4.0
     disk_thickness: float = 7.0
-    # Gap between disk and the housing
+
-    #disk_thickness_gap: float = 0.1
+    # 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 = 60.0
+    spring_angle_at_0: float = 90.0
-    spring_slot_offset: float = 15.0
+    spring_slot_offset: float = 5.0
-
-    wall_inset: float = 2.0
 
     # Angular span of movement
     movement_angle: float = 120.0
@@ -348,10 +352,11 @@ class DiskJoint(Model):
 
     def __post_init__(self):
         super().__init__(name="disk-joint")
-        assert self.housing_thickness > self.wall_inset
+        assert self.radius_housing > self.radius_disk > self.radius_axle
-        assert self.radius_housing > self.radius_disk
+        assert self.spring.height < self.housing_thickness + self.disk_thickness
-        assert self.radius_disk > self.radius_axle
+
         assert self.housing_upper_carve_offset > 0
+        assert self.spring_tail_hole_height > self.spring.thickness
 
     @property
     def neutral_movement_angle(self) -> Optional[float]:
@@ -363,6 +368,12 @@ class DiskJoint(Model):
     @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:
@@ -373,7 +384,7 @@ class DiskJoint(Model):
         """
         Distance between the spring track and the outside of the upper housing
         """
-        return self.housing_thickness + self.disk_thickness - self.spring.height
+        return self.spring_tail_hole_height + (self.disk_thickness - self.disk_bot_thickness) - self.spring.height
 
     @property
     def housing_upper_dz(self) -> float:
@@ -387,9 +398,9 @@ class DiskJoint(Model):
             Cq.Solid.makeBox(
                 length=self.spring.tail_length,
                 width=self.spring.thickness,
-                height=self.disk_thickness,
+                height=self.spring.height-self.disk_bot_thickness,
             )
-            .located(Cq.Location((0, self.spring.radius_inner, 0)))
+            .located(Cq.Location((0, self.spring.radius_inner, self.disk_bot_thickness)))
             .rotate((0, 0, 0), (0, 0, 1), self.spring_slot_offset)
         )
 
@@ -427,6 +438,7 @@ class DiskJoint(Model):
         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
@@ -474,11 +486,11 @@ class DiskJoint(Model):
         carve = (
             Cq.Solid.makeCylinder(
                 radius=self.spring.radius,
-                height=self.housing_thickness
+                height=self.spring_tail_hole_height,
             ).fuse(Cq.Solid.makeBox(
                 length=self.spring.tail_length,
                 width=self.spring.thickness,
-                height=self.housing_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 = (
@@ -515,6 +527,7 @@ class DiskJoint(Model):
         result = (
             result
             .union(wall, tol=TOL)
+            #.cut(carve)
             .cut(carve.located(Cq.Location((0, 0, -self.housing_upper_carve_offset))))
         )
         return result.clean()
@@ -541,7 +554,7 @@ class DiskJoint(Model):
             .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_bot", f"{spring_name}?bot", "Plane", 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)
@@ -608,13 +621,26 @@ class ElbowJoint(Model):
 
     material: Material = Material.RESIN_TRANSPERENT
 
-    angle_neutral: float = 0.0
+    angle_neutral: float = 30.0
 
     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
 
+    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) -> 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
+        """
+        return Cq.Location.rot2d(self.angle_neutral) * Cq.Location.from2d(self.child_arm_radius, 0, 180)
+
     def lip(self) -> Cq.Workplane:
         holes = [
             h
@@ -649,8 +675,9 @@ class ElbowJoint(Model):
             Cq.Location((0, 0, 0), (0, 1, 0), 90)
         )
         loc_disk = flip_x * flip_z * Cq.Location((-self.child_arm_radius, 0, -dz), (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 * Cq.Location((0, self.disk_joint.spring.radius_inner, 0)) * loc_disk)
+            loc_lip.inverse * loc_cut_rel * loc_disk)
         result = (
             Cq.Assembly()
             .add(self.lip().cut(disk_cut), name="lip", loc=loc_lip)

nhf/touhou/houjuu_nue/wing.py

@@ -53,6 +53,7 @@ class WingProfile(Model):
             movement_angle=55,
         ),
         hole_diam=6.0,
+        angle_neutral=15.0,
     ))
     # Distance between the two spacers on the elbow, halved
     elbow_h2: float = 5.0
@@ -70,6 +71,7 @@ class WingProfile(Model):
         child_arm_radius=23.0,
         parent_arm_radius=30.0,
         hole_diam=4.0,
+        angle_neutral=30.0,
     ))
     # Distance between the two spacers on the elbow, halved
     wrist_h2: float = 5.0
@@ -86,6 +88,8 @@ class WingProfile(Model):
     elbow_height: float
     wrist_bot_loc: Cq.Location
     wrist_height: float
+    elbow_rotate: float = -5
+    wrist_rotate: float = 30.0
 
     flip: bool = False
 
@@ -94,6 +98,8 @@ class WingProfile(Model):
 
         self.elbow_top_loc = self.elbow_bot_loc * Cq.Location.from2d(0, self.elbow_height)
         self.wrist_top_loc = self.wrist_bot_loc * Cq.Location.from2d(0, self.wrist_height)
+        self.elbow_axle_loc = self.elbow_bot_loc * Cq.Location.from2d(0, self.elbow_height / 2)
+        self.wrist_axle_loc = self.wrist_bot_loc * Cq.Location.from2d(0, self.wrist_height / 2)
 
         self.shoulder_joint.angle_neutral = -self.shoulder_angle_neutral - self.shoulder_angle_bias
 
@@ -439,13 +445,12 @@ class WingProfile(Model):
             ("shoulder_top", Cq.Location.from2d(0, h + shoulder_h, 270)),
         ]
         h = self.elbow_height / 2
+        loc_elbow = Cq.Location.rot2d(self.elbow_rotate) * self.elbow_joint.parent_arm_loc()
         tags_elbow = [
-            ("elbow_bot", self.elbow_bot_loc * Cq.Location.from2d(
+            ("elbow_bot", self.elbow_axle_loc * loc_elbow *\
-                -self.elbow_joint.parent_arm_radius,
+             Cq.Location.from2d(0, -self.elbow_h2)),
-                h - self.elbow_h2)),
+            ("elbow_top", self.elbow_axle_loc * loc_elbow *\
-            ("elbow_top", self.elbow_bot_loc * Cq.Location.from2d(
+             Cq.Location.from2d(0, self.elbow_h2)),
-                -self.elbow_joint.parent_arm_radius,
-                h + self.elbow_h2)),
         ]
         profile = self.profile_s1()
         tags = tags_shoulder + tags_elbow
@@ -507,24 +512,20 @@ class WingProfile(Model):
         return profile
     def surface_s2(self, front: bool = True) -> Cq.Workplane:
         h = self.elbow_height / 2
+        loc_elbow = Cq.Location.rot2d(self.elbow_rotate) * self.elbow_joint.child_arm_loc()
         tags_elbow = [
-            ("elbow_bot", self.elbow_bot_loc * Cq.Location.from2d(
+            ("elbow_bot", self.elbow_axle_loc * loc_elbow *\
-                self.elbow_joint.child_arm_radius,
+             Cq.Location.from2d(0, self.elbow_h2)),
-                h - self.elbow_h2,
+            ("elbow_top", self.elbow_axle_loc * loc_elbow *\
-                180)),
+             Cq.Location.from2d(0, -self.elbow_h2)),
-            ("elbow_top", self.elbow_bot_loc * Cq.Location.from2d(
-                self.elbow_joint.child_arm_radius,
-                h + self.elbow_h2,
-                180)),
         ]
         h = self.wrist_height / 2
+        loc_wrist = Cq.Location.rot2d(self.wrist_rotate) * self.wrist_joint.parent_arm_loc().flip_y()
         tags_wrist = [
-            ("wrist_bot", self.wrist_bot_loc * Cq.Location.from2d(
+            ("wrist_bot", self.wrist_axle_loc * loc_wrist *\
-                -self.wrist_joint.parent_arm_radius,
+             Cq.Location.from2d(0, -self.wrist_h2)),
-                h - self.wrist_h2)),
+            ("wrist_top", self.wrist_axle_loc * loc_wrist *\
-            ("wrist_top", self.wrist_bot_loc * Cq.Location.from2d(
+             Cq.Location.from2d(0, self.wrist_h2)),
-                -self.wrist_joint.parent_arm_radius,
-                h + self.wrist_h2)),
         ]
         profile = self.profile_s2()
         tags = tags_elbow + tags_wrist
@@ -564,7 +565,7 @@ class WingProfile(Model):
                 o.generate(),
                 point_tag=t,
                 flipped=is_top == is_parent,
-                #rotate=True,
+                #rotate=not is_parent,
             )
         return result.solve()
 
@@ -579,15 +580,12 @@ class WingProfile(Model):
     def surface_s3(self,
                    front: bool = True) -> Cq.Workplane:
         h = self.wrist_height / 2
+        loc_wrist = Cq.Location.rot2d(self.wrist_rotate) * self.wrist_joint.child_arm_loc().flip_y()
         tags = [
-            ("wrist_bot", self.wrist_bot_loc * Cq.Location.from2d(
+            ("wrist_bot", self.wrist_axle_loc * loc_wrist *\
-                self.wrist_joint.child_arm_radius,
+             Cq.Location.from2d(0, self.wrist_h2)),
-                h - self.wrist_h2,
+            ("wrist_top", self.wrist_axle_loc * loc_wrist *\
-                180)),
+             Cq.Location.from2d(0, -self.wrist_h2)),
-            ("wrist_top", self.wrist_bot_loc * Cq.Location.from2d(
-                self.wrist_joint.child_arm_radius,
-                h + self.wrist_h2,
-                180)),
         ]
         profile = self.profile_s3()
         return extrude_with_markers(profile, self.panel_thickness, tags, reverse=front)

nhf/utils.py

@@ -82,6 +82,15 @@ def with_angle_2d(self: Cq.Location, angle: float) -> Tuple[float, float]:
     return Cq.Location.from2d(x, y, angle)
 Cq.Location.with_angle_2d = with_angle_2d
 
+def flip_x(self: Cq.Location) -> Cq.Location:
+    (x, y), a = self.to2d()
+    return Cq.Location.from2d(-x, y, 90 - a)
+Cq.Location.flip_x = flip_x
+def flip_y(self: Cq.Location) -> Cq.Location:
+    (x, y), a = self.to2d()
+    return Cq.Location.from2d(x, -y, -a)
+Cq.Location.flip_y = flip_y
+
 ### Tags
 
 def tagPoint(self, tag: str):