Containing Behavioral Cascades from Manipulated Claims in LLM-Powered Multi-Robot Systems
Authors: Waleed Bin Khalid, Byung-Cheol Min
Organizations: SMART Lab, Department of Computer Science, Luddy School of Informatics, Computing, and Engineering, Indiana University Bloomington, Bloomington, IN, USA
Large language model (LLM)-powered multi-robot systems are vulnerable to semantic manipulation: an accepted false world-state claim can trigger a fleet-wide behavioral cascade, causing unnecessary replanning, increased path costs, congestion, or apparent mission infeasibility. Conditioning on a successful manipulation, we propose an active verification framework that contains its downstream effects before they propagate across the fleet. A dedicated verification module generates a structured Verify-Adapt-Hold plan: selected robots inspect consequential regions, a limited subset provisionally adapts when necessary, and the remaining robots retain their trusted plans. We evaluate the framework in a multi-robot transportation environment using injected false obstacle claims across different impacts and team sizes. Evaluation measures cascade containment, Sum-of-Costs, makespan, and coverage ratio. Results show that treating post-compromise verification as a team-level planning problem, rather than a binary trust decision, effectively limits the cascading physical consequences of semantic manipulation.
Figures & tables
Fig. 1 : (a) Under Naive Replan, all robots treat the false obstacle claim X as blocked and replan, propagating route changes even to robots whose paths do not intersect X . (b) Under Verify–Adapt–Hold, a selected robot verifies the claim from a stand-off, threatened robots provisionally adapt around unresolved claimed cells, and unaffected robots retain their trusted trajectories until physical evidence resolves the claim.
Fig. 2 : Overview of the proposed framework: A malicious input leads the compromised operator O to accept fake obstacles X and propose them as an occupancy set, which is never written to the trusted map. The verification module V , reasons over available physical evidence to produce a Verify–Adapt–Hold assignment (with Rest reserved for the close step). The initial call assigns every robot a verify, adapt or hold role and later calls reassign only the robots that triggered an event. A space-time A∗ planner executes the assignment.
Parameter
Configuration
Team size
N∈{3,6,9,12}
Warehouse layout
Fixed across all experiments
Grid Size
48 by 28
Pickup locations
∣P∣=3
Drop-off locations
∣D∣=N , with one unique drop-off per robot
Resources per pickup
N/3
TABLE I : Experimental setup.
Fig. 3 : Warehouse simulation environment at time tH for N=12 . S0 , S1 , and S2 denote the pickup stations, with four robots assigned to each station. Robots labeled with a letter have already collected their assigned resource. Red cells marked with × represent the claimed obstacle set X . Each robot’s drop-off location is indicated by the same color as the robot.
Fig. 4 : Sum of costs and Makespan variations across different scenarios and team sizes.
Fig. 5 : SOC at mission completion TM and verification completion TV under Mixed-impact claims.
Scenario
Naive
Verify-Min
Verify-All
Rule Based VAH
Ours
Low
87%
100%
100%
100%
100%
High
72%
100%
100%
100%
100%
Mixed
62%
100%
100%
100%
98%
Kill
—
100%
100%
100%
100%
TABLE II : Coverage results for N=12 at max(TM,TV) .
Scenario
N
Verify-Min
Verify-All
Rule Based VAH
Ours
Low
3
−3.89
−5.14
−4.06
1.00
6
−1.31
−5.32
−1.89
1.00
9
−1.36
−17.18
−2.22
0.98
12
−1.16
−6.56
−2.37
0.96
High
3
−5.49
−8.90
−5.47
−0.65
6
−1.25
−2.41
−1.51
0.81
TABLE III : Cascade containment ratio (CCR) results.