[
    {
        "id": "osp-16926",
        "type": "article-journal",
        "title": "The Robot Is Not Its Description: GaugeBench for Representation Robustness in Morphology-Aware Policies",
        "author": [
            {
                "family": "Malladi",
                "given": "Rahath"
            },
            {
                "family": "Sangwan",
                "given": "Arshia"
            },
            {
                "family": "Gupta",
                "given": "Rajesh K."
            },
            {
                "family": "Rahman",
                "given": "Tauhidur"
            }
        ],
        "URL": "https://omanscience.com/ar/articles/the-robot-is-not-its-description-gaugebench-for-representation-robustness-in-morphology-aware-policies",
        "language": "en",
        "issued": {
            "date-parts": [
                [
                    2026
                ]
            ]
        },
        "abstract": "A robot description does more than specify a physical mechanism: it also encodes arbitrary conventions, such as joint-axis direction, joint-angle zero, and the order and names of links and joints. Morphology-aware policies consume interfaces built from these descriptions, yet cross-embodiment evaluation typically changes the robot while keeping those conventions fixed. This leaves a simple question unanswered: does behavior survive when the robot stays fixed but its description changes? GaugeBench isolates this case by rewriting a fixed mechanism under physically equivalent conventions, verifying that its physics and policy interface are preserved, and then evaluating the same policy weights. The result is stark: three MetaMorph policies score 4030.6 on 80 familiar robots, but only 51.6 when those same robots are equivalently re-described, while 98 genuinely held-out robots score 1489.6. A new description can therefore be more damaging than a new robot. Tracing the failure reveals that axis reversal alone reproduces the collapse, joint-angle zero changes are nearly harmless, and reordering lies between them; moreover, changing joint-state and torque coordinates alone is sufficient to cause the failure, while changing description-derived features alone is not. The same phenomenon appears in ModuMorph and an unrelated PyBullet framework. Yet it is not irreversible: exact two-description transport restores the original controller, and training across equivalent axis conventions raises retained return under axis reversal from 3.6% to 80.6%. Together, these results separate mechanism robustness from representation robustness and show that cross-embodiment evaluation should test both."
    }
]