{
  "schema_version": "assembly-1.0",
  "designir_kind": "coordinate_free_semantic_assembly",
  "model_id": "lcd25_harmonic_reducer",
  "family": "harmonic_reducer_module",
  "units": "mm",
  "design_intent": "A compact coaxial harmonic reducer whose geometry, assembly and motion are regenerated from functional interfaces rather than stored placements.",
  "parameters": {
    "nominal_size": {
      "kind": "length",
      "value": 25.0,
      "unit": "mm",
      "editable": true,
      "bounds": [20.0, 40.0],
      "status": "inferred",
      "description": "Nominal transmission size controlling the scalable component family."
    },
    "reduction_ratio": {
      "kind": "ratio",
      "value": 100.0,
      "editable": true,
      "bounds": [50.0, 160.0],
      "status": "inferred",
      "description": "Input rotations per output rotation."
    },
    "outer_envelope_diameter": {
      "kind": "length",
      "value": 110.0,
      "unit": "mm",
      "editable": true,
      "bounds": [90.0, 140.0],
      "status": "specified",
      "description": "Maximum housing envelope."
    },
    "axial_envelope": {
      "kind": "length",
      "value": 32.0,
      "unit": "mm",
      "editable": true,
      "bounds": [25.0, 50.0],
      "status": "specified",
      "description": "Maximum reducer axial package length."
    },
    "output_bore_diameter": {
      "kind": "length",
      "value": 14.0,
      "unit": "mm",
      "editable": true,
      "bounds": [8.0, 25.0],
      "status": "estimated",
      "description": "Central output interface bore."
    },
    "housing_wall": {
      "kind": "length",
      "value": 3.0,
      "unit": "mm",
      "editable": true,
      "bounds": [2.0, 6.0],
      "status": "estimated",
      "description": "Minimum structural housing wall."
    },
    "output_bolt_count": {
      "kind": "count",
      "value": 4,
      "editable": true,
      "bounds": [3, 8],
      "status": "inferred",
      "description": "Output flange fastener pattern count."
    },
    "housing_bolt_count": {
      "kind": "count",
      "value": 10,
      "editable": true,
      "bounds": [6, 16],
      "status": "inferred",
      "description": "Housing closure fastener count."
    },
    "output_torque_limit": {
      "kind": "torque",
      "value": 25.0,
      "unit": "N*m",
      "editable": true,
      "bounds": [5.0, 60.0],
      "status": "estimated",
      "description": "Initial simulation effort limit."
    },
    "output_speed_limit": {
      "kind": "speed",
      "value": 2.5,
      "unit": "rad/s",
      "editable": true,
      "bounds": [0.5, 5.0],
      "status": "estimated",
      "description": "Initial simulation output speed limit."
    }
  },
  "expressions": {
    "flexspline_tooth_count": "2 * round(reduction_ratio / 2)",
    "circular_spline_tooth_count": "flexspline_tooth_count + 2",
    "bearing_nominal_diameter": "0.72 * outer_envelope_diameter",
    "output_flange_diameter": "0.48 * outer_envelope_diameter",
    "housing_fastener_pitch_diameter": "0.82 * outer_envelope_diameter"
  },
  "modules": [
    {
      "id": "structure_module",
      "purpose": "Carry external loads and provide all mounting seats.",
      "members": ["housing", "rear_cover", "front_cover"],
      "replaceable_as_unit": true
    },
    {
      "id": "harmonic_stage",
      "purpose": "Generate the harmonic reduction between input and output.",
      "members": ["circular_spline", "flexspline", "wave_generator"],
      "replaceable_as_unit": true
    },
    {
      "id": "output_support_module",
      "purpose": "Support and locate the rotating output.",
      "members": ["output_bearing", "output_flange"],
      "replaceable_as_unit": true
    },
    {
      "id": "retention_module",
      "purpose": "Close and fasten structural interfaces.",
      "members": ["housing_fasteners", "output_fasteners"],
      "replaceable_as_unit": false
    }
  ],
  "components": [
    {
      "id": "housing",
      "role": "fixed_structure",
      "archetype": "coaxial_reducer_housing",
      "lifecycle": "required",
      "generation": {
        "strategy": "semantic_feature_program",
        "family": "annular_housing_with_mounting_flange",
        "parameter_bindings": {
          "outer_diameter": "outer_envelope_diameter",
          "axial_length": "axial_envelope",
          "minimum_wall": "housing_wall"
        }
      },
      "interfaces": [
        {
          "id": "main_axis",
          "type": "axis",
          "construction": "primary_axis"
        },
        {
          "id": "front_closure_seat",
          "type": "plane",
          "construction": "front_axial_face"
        },
        {
          "id": "rear_closure_seat",
          "type": "plane",
          "construction": "rear_axial_face"
        },
        {
          "id": "circular_spline_seat",
          "type": "cylinder",
          "construction": "inner_cylindrical_surface",
          "qualifiers": ["largest_internal_transmission_seat"]
        },
        {
          "id": "output_bearing_seat",
          "type": "bearing_seat",
          "construction": "inner_cylindrical_surface",
          "qualifiers": ["frontmost_bearing_seat"]
        },
        {
          "id": "closure_pattern",
          "type": "hole_pattern",
          "construction": "pitch_circle_pattern",
          "parameter_refs": ["housing_bolt_count"]
        }
      ],
      "material_class": "aluminum_alloy",
      "tags": ["fixed", "structural", "thermal_path"]
    },
    {
      "id": "circular_spline",
      "role": "fixed_tooth_member",
      "archetype": "internal_spline_ring",
      "lifecycle": "replaceable",
      "generation": {
        "strategy": "standard_library",
        "family": "harmonic_circular_spline",
        "parameter_bindings": {
          "nominal_size": "nominal_size",
          "tooth_count": "circular_spline_tooth_count"
        }
      },
      "interfaces": [
        {
          "id": "tooth_axis",
          "type": "axis",
          "construction": "primary_axis"
        },
        {
          "id": "housing_fit",
          "type": "cylinder",
          "construction": "outer_cylindrical_surface"
        },
        {
          "id": "anti_rotation",
          "type": "torque_interface",
          "construction": "generated_feature"
        }
      ],
      "material_class": "hardened_steel",
      "tags": ["fixed", "transmission"]
    },
    {
      "id": "flexspline",
      "role": "compliant_tooth_member",
      "archetype": "cup_flexspline",
      "lifecycle": "replaceable",
      "generation": {
        "strategy": "standard_library",
        "family": "harmonic_flexspline",
        "parameter_bindings": {
          "nominal_size": "nominal_size",
          "tooth_count": "flexspline_tooth_count",
          "output_bore": "output_bore_diameter"
        }
      },
      "interfaces": [
        {
          "id": "tooth_axis",
          "type": "axis",
          "construction": "primary_axis"
        },
        {
          "id": "wave_generator_seat",
          "type": "bearing_seat",
          "construction": "inner_cylindrical_surface"
        },
        {
          "id": "output_face",
          "type": "plane",
          "construction": "front_axial_face"
        },
        {
          "id": "output_torque_interface",
          "type": "torque_interface",
          "construction": "generated_feature"
        }
      ],
      "material_class": "spring_steel",
      "tags": ["rotating", "compliant", "transmission"]
    },
    {
      "id": "wave_generator",
      "role": "input_deformation_member",
      "archetype": "elliptical_wave_generator",
      "lifecycle": "replaceable",
      "generation": {
        "strategy": "subassembly_template",
        "family": "elliptical_cam_with_flexible_bearing",
        "parameter_bindings": {
          "nominal_size": "nominal_size"
        }
      },
      "interfaces": [
        {
          "id": "rotation_axis",
          "type": "axis",
          "construction": "primary_axis"
        },
        {
          "id": "input_torque_interface",
          "type": "torque_interface",
          "construction": "inner_cylindrical_surface"
        },
        {
          "id": "flexspline_contact",
          "type": "contact_envelope",
          "construction": "outer_cylindrical_surface",
          "qualifiers": ["elliptical_compliant_contact"]
        }
      ],
      "material_class": "bearing_steel",
      "tags": ["rotating", "input", "transmission"]
    },
    {
      "id": "output_bearing",
      "role": "combined_load_support",
      "archetype": "cross_roller_bearing",
      "lifecycle": "replaceable",
      "generation": {
        "strategy": "standard_library",
        "family": "cross_roller_bearing",
        "parameter_bindings": {
          "nominal_diameter": "bearing_nominal_diameter"
        }
      },
      "interfaces": [
        {
          "id": "bearing_axis",
          "type": "axis",
          "construction": "primary_axis"
        },
        {
          "id": "outer_ring_seat",
          "type": "bearing_seat",
          "construction": "outer_cylindrical_surface"
        },
        {
          "id": "inner_ring_seat",
          "type": "bearing_seat",
          "construction": "inner_cylindrical_surface"
        },
        {
          "id": "axial_reference",
          "type": "plane",
          "construction": "center_plane"
        }
      ],
      "material_class": "bearing_steel",
      "tags": ["support", "split_kinematic_membership"]
    },
    {
      "id": "output_flange",
      "role": "external_output_interface",
      "archetype": "bolted_output_flange",
      "lifecycle": "replaceable",
      "generation": {
        "strategy": "semantic_feature_program",
        "family": "annular_output_flange",
        "parameter_bindings": {
          "diameter": "output_flange_diameter",
          "bore_diameter": "output_bore_diameter",
          "bolt_count": "output_bolt_count"
        }
      },
      "interfaces": [
        {
          "id": "rotation_axis",
          "type": "axis",
          "construction": "primary_axis"
        },
        {
          "id": "flexspline_mate",
          "type": "plane",
          "construction": "rear_axial_face"
        },
        {
          "id": "bearing_fit",
          "type": "bearing_seat",
          "construction": "outer_cylindrical_surface"
        },
        {
          "id": "external_mount_face",
          "type": "plane",
          "construction": "front_axial_face"
        },
        {
          "id": "external_bolt_pattern",
          "type": "hole_pattern",
          "construction": "pitch_circle_pattern",
          "parameter_refs": ["output_bolt_count"]
        },
        {
          "id": "output_bore",
          "type": "shaft_seat",
          "construction": "inner_cylindrical_surface",
          "parameter_refs": ["output_bore_diameter"]
        }
      ],
      "material_class": "alloy_steel",
      "tags": ["rotating", "output", "public_interface"]
    },
    {
      "id": "front_cover",
      "role": "front_axial_retainer",
      "archetype": "annular_cover",
      "lifecycle": "required",
      "generation": {
        "strategy": "semantic_feature_program",
        "family": "bolted_annular_cover",
        "parameter_bindings": {
          "outer_diameter": "outer_envelope_diameter",
          "bolt_count": "housing_bolt_count"
        }
      },
      "interfaces": [
        {
          "id": "housing_mate",
          "type": "plane",
          "construction": "rear_axial_face"
        },
        {
          "id": "main_axis",
          "type": "axis",
          "construction": "primary_axis"
        },
        {
          "id": "fastener_pattern",
          "type": "hole_pattern",
          "construction": "pitch_circle_pattern",
          "parameter_refs": ["housing_bolt_count"]
        }
      ],
      "material_class": "aluminum_alloy",
      "tags": ["fixed", "structural"]
    },
    {
      "id": "rear_cover",
      "role": "rear_axial_retainer",
      "archetype": "annular_cover",
      "lifecycle": "required",
      "generation": {
        "strategy": "semantic_feature_program",
        "family": "bolted_annular_cover",
        "parameter_bindings": {
          "outer_diameter": "outer_envelope_diameter"
        }
      },
      "interfaces": [
        {
          "id": "housing_mate",
          "type": "plane",
          "construction": "front_axial_face"
        },
        {
          "id": "main_axis",
          "type": "axis",
          "construction": "primary_axis"
        }
      ],
      "material_class": "aluminum_alloy",
      "tags": ["fixed", "structural"]
    },
    {
      "id": "housing_fasteners",
      "role": "housing_closure_fasteners",
      "archetype": "socket_head_screw_pattern",
      "lifecycle": "generated_pattern",
      "quantity": "housing_bolt_count",
      "generation": {
        "strategy": "standard_library",
        "family": "metric_socket_head_screw",
        "parameter_bindings": {
          "nominal_thread": "M5",
          "count": "housing_bolt_count"
        }
      },
      "interfaces": [
        {
          "id": "fastener_axes",
          "type": "hole_pattern",
          "construction": "pitch_circle_pattern",
          "parameter_refs": ["housing_bolt_count"]
        },
        {
          "id": "head_seats",
          "type": "fastener_seat",
          "construction": "generated_feature"
        }
      ],
      "material_class": "steel",
      "tags": ["fixed", "fastener_pattern"]
    },
    {
      "id": "output_fasteners",
      "role": "output_interface_fasteners",
      "archetype": "countersunk_screw_pattern",
      "lifecycle": "generated_pattern",
      "quantity": "output_bolt_count",
      "generation": {
        "strategy": "standard_library",
        "family": "metric_countersunk_screw",
        "parameter_bindings": {
          "nominal_thread": "M2_5",
          "count": "output_bolt_count"
        }
      },
      "interfaces": [
        {
          "id": "fastener_axes",
          "type": "hole_pattern",
          "construction": "pitch_circle_pattern",
          "parameter_refs": ["output_bolt_count"]
        },
        {
          "id": "head_seats",
          "type": "fastener_seat",
          "construction": "generated_feature"
        }
      ],
      "material_class": "steel",
      "tags": ["rotating", "fastener_pattern"]
    }
  ],
  "relations": [
    {
      "id": "circular_spline_centering",
      "type": "coaxial",
      "a": "housing.main_axis",
      "b": "circular_spline.tooth_axis",
      "intent": "Center the fixed tooth member in the housing.",
      "mobility": "fixed"
    },
    {
      "id": "circular_spline_fixing",
      "type": "torque_lock",
      "a": "housing.circular_spline_seat",
      "b": "circular_spline.anti_rotation",
      "intent": "Prevent rotation of the circular spline relative to the housing.",
      "mobility": "fixed"
    },
    {
      "id": "flexspline_centering",
      "type": "coaxial",
      "a": "circular_spline.tooth_axis",
      "b": "flexspline.tooth_axis",
      "intent": "Keep both spline members on the reducer axis.",
      "mobility": "allow_rotation"
    },
    {
      "id": "wave_generator_centering",
      "type": "coaxial",
      "a": "flexspline.tooth_axis",
      "b": "wave_generator.rotation_axis",
      "intent": "Place the wave generator on the transmission axis.",
      "mobility": "allow_rotation"
    },
    {
      "id": "wave_generator_contact",
      "type": "bearing_support",
      "a": "flexspline.wave_generator_seat",
      "b": "wave_generator.flexspline_contact",
      "intent": "Transfer the elliptical deformation while allowing relative rotation.",
      "mobility": "allow_rotation",
      "confidence": 0.82,
      "evidence": ["harmonic_stage_topology", "nested_flexible_bearing"]
    },
    {
      "id": "output_bearing_housing_fit",
      "type": "bearing_support",
      "a": "housing.output_bearing_seat",
      "b": "output_bearing.outer_ring_seat",
      "intent": "Fix and support the bearing outer ring in the housing.",
      "mobility": "fixed"
    },
    {
      "id": "output_bearing_flange_fit",
      "type": "bearing_support",
      "a": "output_flange.bearing_fit",
      "b": "output_bearing.inner_ring_seat",
      "intent": "Support output flange rotation through the bearing inner ring.",
      "mobility": "allow_rotation"
    },
    {
      "id": "flexspline_output_face",
      "type": "face_mate",
      "a": "flexspline.output_face",
      "b": "output_flange.flexspline_mate",
      "intent": "Locate the flexspline axially against the output flange.",
      "value": 0.0,
      "tolerance": 0.01,
      "mobility": "fixed"
    },
    {
      "id": "flexspline_output_torque",
      "type": "torque_lock",
      "a": "flexspline.output_torque_interface",
      "b": "output_flange.external_bolt_pattern",
      "intent": "Transmit flexspline torque to the output flange.",
      "mobility": "fixed"
    },
    {
      "id": "front_cover_centering",
      "type": "coaxial",
      "a": "housing.main_axis",
      "b": "front_cover.main_axis",
      "intent": "Center the front closure.",
      "mobility": "fixed"
    },
    {
      "id": "front_cover_seating",
      "type": "face_mate",
      "a": "housing.front_closure_seat",
      "b": "front_cover.housing_mate",
      "intent": "Close the front housing interface.",
      "value": 0.0,
      "tolerance": 0.02,
      "mobility": "fixed"
    },
    {
      "id": "rear_cover_centering",
      "type": "coaxial",
      "a": "housing.main_axis",
      "b": "rear_cover.main_axis",
      "intent": "Center the rear closure.",
      "mobility": "fixed"
    },
    {
      "id": "rear_cover_seating",
      "type": "face_mate",
      "a": "housing.rear_closure_seat",
      "b": "rear_cover.housing_mate",
      "intent": "Close the rear housing interface.",
      "value": 0.0,
      "tolerance": 0.02,
      "mobility": "fixed"
    },
    {
      "id": "housing_fastener_alignment",
      "type": "fasten_pattern",
      "a": "housing.closure_pattern",
      "b": "housing_fasteners.fastener_axes",
      "intent": "Instantiate and align the housing closure screws.",
      "mobility": "fixed"
    },
    {
      "id": "output_fastener_alignment",
      "type": "fasten_pattern",
      "a": "output_flange.external_bolt_pattern",
      "b": "output_fasteners.fastener_axes",
      "intent": "Instantiate and align output flange screws.",
      "mobility": "fixed"
    }
  ],
  "kinematics": {
    "anchor_component": "housing",
    "rigid_groups": [
      {
        "id": "fixed_group",
        "members": ["housing", "circular_spline", "front_cover", "rear_cover", "housing_fasteners"]
      },
      {
        "id": "output_group",
        "members": ["flexspline", "output_flange", "output_fasteners"]
      },
      {
        "id": "input_group",
        "members": ["wave_generator"]
      }
    ],
    "joints": [
      {
        "id": "input_joint",
        "type": "continuous",
        "parent_group": "fixed_group",
        "child_group": "input_group",
        "axis_ref": "wave_generator.rotation_axis",
        "station_ref": "flexspline.wave_generator_seat",
        "dynamics": {
          "damping": 0.002,
          "friction": 0.003,
          "parameter_status": "estimated"
        }
      },
      {
        "id": "output_joint",
        "type": "continuous",
        "parent_group": "fixed_group",
        "child_group": "output_group",
        "axis_ref": "output_flange.rotation_axis",
        "station_ref": "output_bearing.axial_reference",
        "dynamics": {
          "damping": 0.08,
          "friction": 0.12,
          "effort_limit": "output_torque_limit",
          "velocity_limit": "output_speed_limit",
          "parameter_status": "estimated"
        }
      }
    ],
    "transmissions": [
      {
        "id": "harmonic_stage_transmission",
        "type": "harmonic",
        "input_joint": "input_joint",
        "output_joint": "output_joint",
        "ratio_expression": "output_angle = -input_angle / reduction_ratio",
        "fixed_member": "circular_spline",
        "compliance_model": "reduced_order_torsional_compliance"
      }
    ]
  },
  "edit_interface": {
    "editable_parameters": [
      "nominal_size",
      "reduction_ratio",
      "outer_envelope_diameter",
      "axial_envelope",
      "output_bore_diameter",
      "housing_wall",
      "output_bolt_count",
      "housing_bolt_count",
      "output_torque_limit",
      "output_speed_limit"
    ],
    "structural_operations": [
      "add_component",
      "remove_component",
      "replace_component",
      "change_relation",
      "change_transmission",
      "add_module"
    ],
    "preserved_interfaces": [
      "housing.main_axis",
      "housing.front_closure_seat",
      "output_flange.external_mount_face",
      "output_flange.external_bolt_pattern",
      "output_flange.output_bore"
    ]
  },
  "validation_contract": {
    "coordinate_free_source": true,
    "required_checks": [
      "schema_valid",
      "reference_integrity",
      "constraint_graph_connected",
      "assembly_solvable_from_scrambled_state",
      "no_overconstraint",
      "interface_compatibility",
      "clearance",
      "interference",
      "joint_mobility",
      "parameter_perturbation",
      "preserved_interface",
      "urdf_load",
      "mjcf_load"
    ],
    "acceptance_rules": [
      "No component placement may be authored as a coordinate or transform.",
      "The solver must recover a unique assembly from semantic interfaces and relations.",
      "Changing an editable parameter must rebuild affected components and re-solve all relations.",
      "Structural edits must preserve declared public interfaces unless the patch explicitly changes the contract."
    ]
  }
}