{"abstract":"A mounted sensor offset is added in the world frame.","category":"Robotics frame conventions","checks":6,"contract":"Given parent world translation a and quarter-turn heading qa, and child translation b in parent coordinates with heading qb, return child world translation. qb does not affect its own origin.","contract_signature":"a, qa, b, qb","evaluation_group":"model-0928053791b17de9","failed_approach":"Rotating the offset by its own child heading uses the wrong parent frame.","family":"z-robotics_frames-extrinsic-chain","id":"FA-12111","implementations":{"attempt":{"sha256":"03213818cb505acf8248b03730089142814ee30d62c3cf93128179d8835a2f97","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\ndef rot(v, q):\n    x,y = v\n    return [(x,y),(-y,x),(-x,-y),(y,-x)][q%4]\n\nN = 1\nobservations = []\ndef solve(a, qa, b, qb):\n    r=rot(b,qb)\n    return [a[i]+r[i] for i in range(2)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('rotated mount', solve([N,N],1,[N,0],0), [N,2*N])\ncheck('child orientation irrelevant', solve([N,N],0,[N,0],1), [2*N,N])\ncheck('half turn parent', solve([N,N],2,[N,2*N],1), [0,-N])\ncheck('zero mount', solve([N,N],1,[0,0],3), [N,N])\ncheck('world origin', solve([0,0],-1,[N,2*N],2), [2*N,-N])\ncheck('identity chain', solve([N,-N],0,[2*N,N],0), [3*N,0])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"40bec626cf309d699cc515d93242ed0083278643c2241872794443ee898a40c2","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\ndef rot(v, q):\n    x,y = v\n    return [(x,y),(-y,x),(-x,-y),(y,-x)][q%4]\n\nN = 1\nobservations = []\ndef solve(a, qa, b, qb):\n    return [a[i]+b[i] for i in range(2)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('rotated mount', solve([N,N],1,[N,0],0), [N,2*N])\ncheck('child orientation irrelevant', solve([N,N],0,[N,0],1), [2*N,N])\ncheck('half turn parent', solve([N,N],2,[N,2*N],1), [0,-N])\ncheck('zero mount', solve([N,N],1,[0,0],3), [N,N])\ncheck('world origin', solve([0,0],-1,[N,2*N],2), [2*N,-N])\ncheck('identity chain', solve([N,-N],0,[2*N,N],0), [3*N,0])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Small exact offline frame model; not a robot middleware implementation or continuous pose estimator. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"z-robotics_frames-extrinsic-chain","generated_at":"2026-09-29T14:38:53.947009+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Robot adapters must preserve the declared frame, reference point, and representation conventions across interfaces.","root_cause":"Child extrinsic translation is added directly to the parent world translation.","sha256":"caf8c80e175ca28616f48d846489c46b2c802dcb223996bce12f404246c05d7a","title":"A mounted sensor offset is added in the world frame · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":39.465,"exit_code":1,"observations":[{"actual":[2,1],"check":"rotated mount","expected":[1,2],"passed":false},{"actual":[1,2],"check":"child orientation irrelevant","expected":[2,1],"passed":false},{"actual":[-1,2],"check":"half turn parent","expected":[0,-1],"passed":false},{"actual":[1,1],"check":"zero mount","expected":[1,1],"passed":true},{"actual":[-1,-2],"check":"world origin","expected":[2,-1],"passed":false},{"actual":[3,0],"check":"identity chain","expected":[3,0],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"rotated mount\", \"actual\": [2, 1], \"expected\": [1, 2], \"passed\": false}, {\"check\": \"child orientation irrelevant\", \"actual\": [1, 2], \"expected\": [2, 1], \"passed\": false}, {\"check\": \"half turn parent\", \"actual\": [-1, 2], \"expected\": [0, -1], \"passed\": false}, {\"check\": \"zero mount\", \"actual\": [1, 1], \"expected\": [1, 1], \"passed\": true}, {\"check\": \"world origin\", \"actual\": [-1, -2], \"expected\": [2, -1], \"passed\": false}, {\"check\": \"identity chain\", \"actual\": [3, 0], \"expected\": [3, 0], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.852,"exit_code":1,"observations":[{"actual":[2,1],"check":"rotated mount","expected":[1,2],"passed":false},{"actual":[2,1],"check":"child orientation irrelevant","expected":[2,1],"passed":true},{"actual":[2,3],"check":"half turn parent","expected":[0,-1],"passed":false},{"actual":[1,1],"check":"zero mount","expected":[1,1],"passed":true},{"actual":[1,2],"check":"world origin","expected":[2,-1],"passed":false},{"actual":[3,0],"check":"identity chain","expected":[3,0],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"rotated mount\", \"actual\": [2, 1], \"expected\": [1, 2], \"passed\": false}, {\"check\": \"child orientation irrelevant\", \"actual\": [2, 1], \"expected\": [2, 1], \"passed\": true}, {\"check\": \"half turn parent\", \"actual\": [2, 3], \"expected\": [0, -1], \"passed\": false}, {\"check\": \"zero mount\", \"actual\": [1, 1], \"expected\": [1, 1], \"passed\": true}, {\"check\": \"world origin\", \"actual\": [1, 2], \"expected\": [2, -1], \"passed\": false}, {\"check\": \"identity chain\", \"actual\": [3, 0], \"expected\": [3, 0], \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}