Robots use their movements to send hidden messages remotely
Remotely Detectable Keyed Communication through Motion
Robotics
Summary
Robots usually communicate through things like sounds or wireless signals, but this paper explores how robots can send messages just by the way they move. The authors developed a method that changes a robot's movements slightly to carry short messages without affecting how the robot normally behaves. These messages can be detected from a distance using cameras or motion sensors, without needing extra equipment or direct communication links. They tested this with simulated and real robots and showed that multiple robots could share simple messages through movement at a steady pace.
roboticsmotion capturecommunication protocolsremote sensingrobot policysignal encodingwireless communicationpayloadmulti-robot systems
Authors
Benjamin Chang, Michael Amir, Manon Flageat, Amanda Prorok
Abstract
Messages from electronic devices are conventionally received as text, audio, or radio signals. But robots move with rich, articulate motion in the real world, opening up the possibility of transmitting messages through motion itself. In this paper, we consider the problem of motion-based communication, where we seek to modify a robot's movements so as to transmit messages detectable from remote sensing (e.g., video or motion capture), without degrading policy performance. We introduce a method for messaging through motion capable of encoding arbitrary message content over short payloads - such as an agent's current intent - as noise in any pre-trained policy's actions. This brings a new kind of robustness to robot communication: this 'physical' channel complements standard wireless communications channels but does not depend on them, requiring no extra hardware nor the establishment of a direct link to the robot. We systematically characterize the space of encoding schemes and derive design heuristics, then validate them across simulated environments and real-robot deployment; on real robots running at 50 Hz, four robots jointly recover an 8-bit message at an aggregate 0.67 bits/s.