Introducing the pirouette FPV frame for GFPV

Signed-off-by: Arnaud Morin <arnaud.gfpv@mailops.fr>

arm.py

@@ -0,0 +1,153 @@
+# @author Arnaud Morin <arnaud.gfpv@mailops.fr>
+# SPDX-License-Identifier: Apache-2.0
+#
+
+import cadquery as cq
+
+from frame_params import (CF_DENSITY, PLATE_GAP, SPAR_H, TENON_L,
+                          THICKNESS, TBONE_D)
+
+# The arm spans the plate gap, so its height IS PLATE_GAP -- the body
+# reaches the plates' inner faces at +-HALF_H and every tenon stands one
+# THICKNESS proud of that, landing flush with the far face.
+HALF_H = PLATE_GAP / 2.0
+# and the lower motor base's top face, which hangs SPAR_H below the upper
+# one, i.e. below the top plate
+BASE_Z = HALF_H - SPAR_H
+
+
+def _custom_filets(wp):
+    """Every vertical edge of the flat pattern (parallel to Y) -- one per
+    corner, found automatically instead of being listed by hand."""
+    picked = []
+    for e in wp.edges().vals():
+        vs = e.Vertices()
+        if len(vs) != 2:
+            continue
+        a, b = vs[0].toTuple(), vs[1].toTuple()
+        if abs(a[0] - b[0]) > 1e-6 or abs(a[2] - b[2]) > 1e-6:
+            continue
+        picked.append(e)
+    return wp.newObject(picked)
+
+
+def arm():
+    part = cq.Workplane("XZ").polyline([
+        (0.0, HALF_H),
+        # first tenon, the one that fit in top plate
+        (3.8, HALF_H),
+        (3.8, HALF_H + THICKNESS),
+        (3.8 + TENON_L, HALF_H + THICKNESS),
+        (3.8 + TENON_L, HALF_H),
+        # End of top plate
+        (12, HALF_H),
+        (12, HALF_H + THICKNESS),
+        # Arm to motor base
+        (20.0, HALF_H + THICKNESS),
+        # Begining of motor base
+        (20.0, HALF_H),
+        (25.0, HALF_H),
+        # Tenon into motor base
+        (25, HALF_H + THICKNESS),
+        (25 + TENON_L, HALF_H + THICKNESS),
+        # Under the motor base
+        (25 + TENON_L, HALF_H),
+        (32, HALF_H),
+        # Come back to bottom plate
+        (32, BASE_Z),
+        # Tenon under the motor base, symmetrical to the one above
+        (25 + TENON_L, BASE_Z),
+        (25 + TENON_L, BASE_Z - THICKNESS),
+        (25, BASE_Z - THICKNESS),
+        (25, BASE_Z),
+        (20, BASE_Z),
+        # Diag
+        (13, -(HALF_H + THICKNESS)),
+        (12, -(HALF_H + THICKNESS)),
+        (12, -HALF_H),
+        # Tenon in bottom plate
+        (3.8 + TENON_L, -HALF_H),
+        (3.8 + TENON_L, -(HALF_H + THICKNESS)),
+        (3.8, -(HALF_H + THICKNESS)),
+        (3.8, -HALF_H),
+        (1.5, -HALF_H)
+    ])
+    part = (
+        part.lineTo(2, -7)
+        .threePointArc(
+            (5, 0.0),
+            (0.0, 6)
+        )
+    )
+    # Extrude. Both = True do the extrusion along the Y axis each face,
+    # so no need to translate later :)
+    part = part.close().extrude(THICKNESS / 2.0, both=True)
+
+    # Hole
+    cut = (
+        cq.Workplane('XZ')
+        .polyline([
+            (7, 4),
+            (17, 4),
+            (12.5, -5),
+            (6.5, -5),
+        ])
+        .threePointArc(
+            (7.5, 0.0),
+            (6, 4),
+        )
+        .close()
+        .extrude(THICKNESS / 2.0, both=True)
+    )
+
+    # smooth every sharp corner, no bare angles left
+    cut = _custom_filets(cut).fillet(1.0)
+    part = part.cut(cut)
+
+    # T-Bones on tenons (x, z)
+    tbones = [
+        # root tenon into top plate, shifted 1 mm right
+        (3.8 - TBONE_D / 2 + 0.05, HALF_H),
+        (3.8 + TENON_L + TBONE_D / 2 - 0.05, HALF_H),
+        # tenon into motor base
+        (25 - TBONE_D / 2 + 0.05, HALF_H),
+        (25 + TENON_L + TBONE_D / 2 - 0.05, HALF_H),
+        # tenon under the motor base
+        (25 - TBONE_D / 2 + 0.05, BASE_Z),
+        (25 + TENON_L + TBONE_D / 2 - 0.05, BASE_Z),
+        # root tenon into bottom plate, shifted 1 mm right
+        (3.8 - TBONE_D / 2 + 0.05, -HALF_H),
+        (3.8 + TENON_L + TBONE_D / 2 - 0.05, -HALF_H),
+        # 3 more sharp inside corners that need relief, away from any tenon:
+        # where the flat top steps up into the raised motor-base flange...
+        (12 - TBONE_D / 2 + 0.05, HALF_H),
+        # ... its mirror on the bottom edge ...
+        (12 - TBONE_D / 2 + 0.05, -HALF_H),
+        # ... and the sharp corner where the diagonal brace meets the tip block
+        (20 + TBONE_D / 2 - 0.05, HALF_H),
+    ]
+
+    # Cut the T-Bones
+    cut = cq.Workplane("XZ")
+    for x, z in tbones:
+        cut = cut.moveTo(x, z).circle(TBONE_D / 2.0)
+    part = part.cut(cut.extrude(THICKNESS / 2.0, both=True))
+
+    return part
+
+
+result = arm()
+
+assert result.solids().size() == 1, "arm is not one solid"
+
+if "show_object" not in globals():           # running outside CQ-editor
+    def show_object(*args, **kwargs):
+        pass
+
+show_object(result)
+
+if __name__ == "__main__":
+    vol = result.val().Volume()
+    m = vol * CF_DENSITY
+    print(f"arm  mass {m:.2f} g each, {4*m:.2f} g for four")
+