Jerry
80 lines
3.0 KiB
Markdown
80 lines
3.0 KiB
Markdown
# Coordinate-free semantic assembly
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This directory defines the LCD25 reducer as a reusable mechanical design rather
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than a list of STEP filenames and placement matrices.
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## Authority
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`lcd25-harmonic-reducer.assembly-designir.json` is the editable assembly
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authority. It contains:
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- product parameters and expressions;
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- replaceable component archetypes;
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- semantic interfaces constructed from generated geometry;
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- mating and support relations;
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- rigid groups, joints and harmonic transmission behavior;
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- edit operations and interfaces that must remain stable.
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It intentionally contains no XYZ position, rotation, transform matrix, source
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STEP path, or occurrence coordinate. A backend generates each component,
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discovers its declared interfaces and solves the constraint graph. Numeric
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placements are compiler output and may be cached separately, but never become
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design authority.
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## Generality
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The contract is not specific to LCD25. Component identities describe functional
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roles such as `fixed_tooth_member`, `combined_load_support`, and
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`external_output_interface`. Each role selects a replaceable generation family.
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The same contract can express harmonic, planetary, cycloidal, belt, chain and
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screw transmissions by changing archetypes, relations and the transmission
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block.
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## Structural modification
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`variants/add-output-shaft.patch.json` demonstrates a structural edit. It adds:
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- editable shaft diameter and length;
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- a generated stepped-shaft component;
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- coaxial, shoulder-mate, insert and torque-lock relations;
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- output rigid-group membership;
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- a new public shaft-end interface.
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No coordinate is supplied. The assembly solver must position the shaft from its
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relations to the output flange.
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## Validation
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Validate the base model:
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```bash
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python3 models/lcd25-reducer/semantic-assembly/validate_assembly_design.py \
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models/lcd25-reducer/semantic-assembly/lcd25-harmonic-reducer.assembly-designir.json \
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--schema designir-pipeline/contracts/assembly-designir-1.0.schema.json
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```
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Apply and validate the shaft variant:
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```bash
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python3 models/lcd25-reducer/semantic-assembly/validate_assembly_design.py \
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models/lcd25-reducer/semantic-assembly/lcd25-harmonic-reducer.assembly-designir.json \
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--schema designir-pipeline/contracts/assembly-designir-1.0.schema.json \
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--patch models/lcd25-reducer/semantic-assembly/variants/add-output-shaft.patch.json \
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--resolved-output models/lcd25-reducer/semantic-assembly/generated/lcd25-with-output-shaft.assembly-designir.json
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```
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## Compiler boundary
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The next compiler stage must:
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1. generate or select geometry for each component archetype;
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2. resolve every semantic interface against generated topology;
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3. solve relations from a scrambled initial state;
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4. emit STEP occurrence placements only as derived output;
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5. compile joints and transmissions to URDF/MJCF;
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6. reject underconstrained, overconstrained or interfering assemblies.
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The current validator proves schema integrity, coordinate independence,
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reference integrity and graph connectivity. It does not yet solve B-Rep
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constraints or generate the final reducer STEP.
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