V-VLAPS: Value-Guided Planning for Vision-Language-Action Models
Summary
Value Vision-Language-Action Planning and Search (V-VLAPS) is a framework that augments Monte Carlo Tree Search (MCTS) with a lightweight, learnable value function to address the brittleness of Vision-Language-Action (VLA) models under distribution shift. Existing MCTS formulations for VLA models rely solely on the VLA prior, lacking a grounded estimate of future return, which necessitates extensive simulation for correction. V-VLAPS trains a simple multi-layer perceptron (MLP) on the latent representations of a fixed VLA backbone (Octo) to provide an explicit success signal. Evaluated on the LIBERO robotic manipulation suite, V-VLAPS improves success rates by over 5 percentage points and reduces the average number of MCTS simulations by 5–15% compared to baselines. The learned value head also demonstrated generalization to unseen tasks within the same suite.
Key takeaway
For Machine Learning Engineers deploying Vision-Language-Action (VLA) models for robotic manipulation, V-VLAPS offers a method to significantly improve robustness and efficiency. If your VLA models exhibit brittle behavior or require extensive simulations for planning, consider integrating a lightweight value head into your MCTS-augmented VLA pipelines to bias action selection towards high-return states and reduce computational overhead.
Key insights
V-VLAPS enhances VLA-guided MCTS with a learned value function for robust robotic manipulation.
Principles
- VLA models benefit from planning to overcome out-of-distribution brittleness.
- Value functions improve MCTS by guiding action selection toward high-value regions.
- Lightweight MLPs can effectively estimate state value from VLA latent representations.
Method
Collect VLA rollouts to compute Monte Carlo value targets. Train a 3-layer MLP value head on VLA latent representations to predict these targets. Integrate the learned value into MCTS node selection using a PUCT-style score.
In practice
- Augment existing VLA-MCTS pipelines with a small, learnable value head.
- Use sparse terminal rewards for Monte Carlo value target generation.
- Apply class balancing to training data to prevent value head collapse on imbalanced outcomes.
Topics
- Vision-Language-Action Models
- Monte Carlo Tree Search
- Robotic Manipulation
- Value Functions
- Reinforcement Learning
- Octo Model
Best for: Research Scientist, AI Scientist, Machine Learning Engineer, Robotics Engineer
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Editorial summary, takeaway, and curation by AIssential. Original article published by cs.AI updates on arXiv.org.