Bridging Perspectives in Navigation · IROS 2026

Corridors, Not Detours

Bounding Language Preferences by
Local Opportunity and Embodiment

Pranay MeshramKarthik Dantu

University at Buffalo

University at BuffaloDrones Lab

The same request can produce different safe routes.
Local opportunity bounds the response. Robot consequences determine which response is feasible.

Proposed two-stage framework connecting language, terrain and robot context to local attention and global route selection
Local cross-attention grounds region representations; global attention scores bounded routes. The current evaluation begins from typed intents.

The idea

Transfer the requested value.
Ground the route in the map and the robot.

Outdoor operators describe preferences such as avoid severe slopes or preserve energy. Yet an instruction alone does not determine a useful route: a suitable alternative may not exist near the start–goal query, and different robots experience the same terrain differently.

We present ongoing work on corridor-feasible language alignment. A semantic region graph exposes bounded alternatives, separating transferable mission values from environment- and embodiment-dependent route consequences. Preferences without meaningful local opportunity are reported as unsupported rather than inducing arbitrary detours.

Robot-specific Jackal and Spot cost models are trained using simulated traversal data. Initial held-out results support corridor-bounded adaptation from typed physical intents. Free-form language grounding and physical robot validation remain future work.

01 / Corridor contract

Bound the alternatives before selecting the route

A method-independent corridor is fixed using robot, distance, and objective-specific lower-bound routes. Candidate routes must satisfy the active robot’s mobility constraints and traversal-cost budget.

Fix the corridor, measure available local opportunity, and select a bounded response
The corridor example retains the selected route inside the opportunity-bounded corridor and the 1.25× path-length cap.
GROUND

Requested values

Relate the preference to terrain properties on a connected semantic-geometric graph.

EXPOSE

Feasible alternatives

Measure how much improvement is available relative to the neutral route.

SCORE

Robot consequences

Evaluate complete routes using the active robot’s energy, risk and mobility model.

ABSTAIN

Insufficient opportunity

Make a lack of meaningful local alternatives explicit.

The prototype uses the CLEAR semantic-geometric abstraction to bind preferences and robot consequences to connected, elevation-aware terrain regions.

02 / Grounded routes

Same local opportunity. Different grounded response.

Terrain intent

“Prefer forested terrain while remaining robot-feasible.”

Lower-bound routes and selected Spot and Jackal routes for a forest preference
Both robots increase forest exposure while remaining near their feasible length lower bounds. Illustrative held-out simulated terrain request.

Robot-conditioned risk

“Minimize traversal risk for the active robot.”

Spot and Jackal route responses to a robot-specific risk request on the same query
Spot and Jackal select different responses within their own feasible corridors on the same simulated query.

03 / Initial evidence

Response, opportunity and robot feasibility

Held-out simulation evaluates typed slope, roughness and traction intents with separate wheeled and legged robot cost models.

94.6%

Directional response

95% CI: 93.4–95.8%
2,519 actionable atomic cases

0.146

Mean CBIR

95% CI: 0.133–0.160
2,505 referenced cases

All routes

Within simulated budget

Every selected route satisfies the simulated robot-cost budget.

8 unseen terrain maps90 endpoint-pair clusters1,882 compound casesJackal + Spot embodiments

What counts as a response?

The preference gain must reach both an absolute floor of 0.005 and 10% of the available local opportunity.

Responseᵢ = 𝟙[gainᵢ ≥ max(0.005, 0.10 × opportunityᵢ)]

How much improvement is recovered?

Corridor-Bounded Intent Regret (CBIR) compares the chosen route with an approximate objective-specific reference from the same feasible alternatives.

CBIR = (g(chosen) − g(reference)) / (g(neutral) − g(reference))

0 = reference · 1 = neutral · lower is better. CBIR applies when the reference improves on neutral routing.

04 / Validation agenda

The next tests

Generalization

Independent maps and sensor conditions, including cases with no meaningful alternative.

Embodiment

Paired Jackal–Spot trials on the same maps and instructions, measuring physical outcomes.

Alignment

Blinded human route comparisons, including disagreement and inter-rater reliability.

Matched controls

Comparisons with adaptive search and existing language-conditioned cost-map methods.