VLA action choice stops trusting the top score alone: FRS-Grounding adds neighborhood consistency for 86.4% simulated success
The highest-scoring action from a vision-language-action (VLA) model is not always the most reliable one to execute. FRS-Grounding keeps the finite candidate set after VLA inference, fuses normalized candidate scores with distance to a safe-action set into a fuzzy action set, and builds a pairwise relation from pose differences and collision-free states before fuzzy rough lower and upper approximations separate strongly supported candidates from boundary cases. Across 1500 randomized simulations the full pipeline reached 86.4% success and a 2.1% safety-violation rate, versus 74.8% and 8.2% for the pointwise hard-constraint baseline VLA-HC; under positional noise with σ = 10 mm it retained about 78% success against about 28% for VLA-HC.