Determine the causal role of force input in compliance-output policies

Determine whether the force-history input causally contributes to the performance of the compliance-output policy and the ForceVLA-style and hybrid comparison policies in the whiteboard-wiping task.

Background

The paper evaluates policies that receive a history of estimated contact wrenches, but the force-channel ablation freezes this history at its first observed value rather than removing it entirely. Although performance decreases under the frozen-force condition, the authors report that the decreases are not statistically significant and are similar across the affected policies. Consequently, the experiment does not establish whether the force input is causally used by the policies, leaving this question unresolved.

References

The evidence is also narrow (one task, one platform) and the rollout budget is small enough that the force-channel ablation (Sec.~\ref{sec:results-m7}) is underpowered by more than an order of magnitude, leaving the causal role of the force input open.

— Compliance for Free: Learning Identifiable Impedance via Bilateral Teleoperation  (2609.19976 - Guda et al., 17 Sep 2026) in Section Limitations, with reference to Section 4.4 ("Is the force channel used?")