{"abstract":"Feedforward escapes the actuator command limit.","category":"Discrete control systems","checks":6,"contract":"Return clamp(feedback+feedforward,low,high) for low<=high; individual terms may exceed bounds.","evaluation_group":"model-3d723ab3d75041d7","failed_approach":"Clamping each contribution separately destroys cancellation.","family":"z-control_systems-sum-before-saturation","id":"FA-11981","implementations":{"attempt":{"sha256":"10e8a07cdefc7694928f00532a171a006b1e44a75b30d895ce60afbd5f0b347f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(feedback, feedforward, low, high):\n    return max(low,min(high,max(low,min(high,feedback))+max(low,min(high,feedforward))))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('upper overflow', solve(N, N, -N, N), N)\ncheck('cancel large terms', solve(3*N, -2*N, -N, N), N)\ncheck('lower overflow', solve(-N, -N, -N, N), -N)\ncheck('reverse cancel', solve(-3*N, 2*N, -N, N), -N)\ncheck('zero', solve(0, 0, -N, N), 0)\ncheck('within', solve(N, -N, -2*N, 2*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":"3ce1154f47c3165d67c537f2dfc9ddcd67daf5085d081aa1113dcded84678ec7","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(feedback, feedforward, low, high):\n    return max(low,min(high,feedback))+feedforward\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('upper overflow', solve(N, N, -N, N), N)\ncheck('cancel large terms', solve(3*N, -2*N, -N, N), N)\ncheck('lower overflow', solve(-N, -N, -N, N), -N)\ncheck('reverse cancel', solve(-3*N, 2*N, -N, N), -N)\ncheck('zero', solve(0, 0, -N, N), 0)\ncheck('within', solve(N, -N, -2*N, 2*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"},"fixed":{"sha256":"98815538b158ff98c2ba0684c7dc19dd327d7a4d6074aef8a435a035c2fd0f2e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(feedback, feedforward, low, high):\n    return max(low,min(high,feedback+feedforward))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('upper overflow', solve(N, N, -N, N), N)\ncheck('cancel large terms', solve(3*N, -2*N, -N, N), N)\ncheck('lower overflow', solve(-N, -N, -N, N), -N)\ncheck('reverse cancel', solve(-3*N, 2*N, -N, N), -N)\ncheck('zero', solve(0, 0, -N, N), 0)\ncheck('within', solve(N, -N, -2*N, 2*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":"Integer-valued controlled examples only; no physical plant, stability guarantee, timing jitter, or hardware behavior is modeled. 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-control_systems-sum-before-saturation","generated_at":"2026-09-29T14:38:52.780494+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"An offline discrete controller model isolates this state or arithmetic fault; it makes no physical plant or safety claim.","repair":"Sum all command contributions before applying the final clamp.","root_cause":"Feedback is clamped before feedforward is added.","sha256":"84171d314d4e906de2f3d353ddaa052d8e0dc6ceab0e32ff3caac931a9f817e3","title":"Feedforward escapes the actuator command limit · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":38.463,"exit_code":1,"observations":[{"actual":1,"check":"upper overflow","expected":1,"passed":true},{"actual":0,"check":"cancel large terms","expected":1,"passed":false},{"actual":-1,"check":"lower overflow","expected":-1,"passed":true},{"actual":0,"check":"reverse cancel","expected":-1,"passed":false},{"actual":0,"check":"zero","expected":0,"passed":true},{"actual":0,"check":"within","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"upper overflow\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"cancel large terms\", \"actual\": 0, \"expected\": 1, \"passed\": false}, {\"check\": \"lower overflow\", \"actual\": -1, \"expected\": -1, \"passed\": true}, {\"check\": \"reverse cancel\", \"actual\": 0, \"expected\": -1, \"passed\": false}, {\"check\": \"zero\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"within\", \"actual\": 0, \"expected\": 0, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":43.26,"exit_code":1,"observations":[{"actual":2,"check":"upper overflow","expected":1,"passed":false},{"actual":-1,"check":"cancel large terms","expected":1,"passed":false},{"actual":-2,"check":"lower overflow","expected":-1,"passed":false},{"actual":1,"check":"reverse cancel","expected":-1,"passed":false},{"actual":0,"check":"zero","expected":0,"passed":true},{"actual":0,"check":"within","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"upper overflow\", \"actual\": 2, \"expected\": 1, \"passed\": false}, {\"check\": \"cancel large terms\", \"actual\": -1, \"expected\": 1, \"passed\": false}, {\"check\": \"lower overflow\", \"actual\": -2, \"expected\": -1, \"passed\": false}, {\"check\": \"reverse cancel\", \"actual\": 1, \"expected\": -1, \"passed\": false}, {\"check\": \"zero\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"within\", \"actual\": 0, \"expected\": 0, \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":40.385,"exit_code":0,"observations":[{"actual":1,"check":"upper overflow","expected":1,"passed":true},{"actual":1,"check":"cancel large terms","expected":1,"passed":true},{"actual":-1,"check":"lower overflow","expected":-1,"passed":true},{"actual":-1,"check":"reverse cancel","expected":-1,"passed":true},{"actual":0,"check":"zero","expected":0,"passed":true},{"actual":0,"check":"within","expected":0,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"upper overflow\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"cancel large terms\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"lower overflow\", \"actual\": -1, \"expected\": -1, \"passed\": true}, {\"check\": \"reverse cancel\", \"actual\": -1, \"expected\": -1, \"passed\": true}, {\"check\": \"zero\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"within\", \"actual\": 0, \"expected\": 0, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}