Hiding the acoustic signature of a mobile robot

A mobile robot can be a rather significant source of noise: noisy fans cool onboard computers, motors are spinning, rubber wheels are squeaking against the floor, and mechanical parts are grinding against each other. Despite these noise problems, robots are often suggested as ideal security and surveillance tools, since they can reliably patrol an area, and remove people from harms way. While the arguments for using a robot are persuasive, the use of a noisy robot for these tasks is questionable. Certainly, they might allow a human to be separated from immediate harm, but given the ease with which people and/or machines can detect changes in the ambient noise, a noisy robot might not be very effective at performing its duties. One solution is to make very small, very quiet robots. But such small robots do not usually do very much either, as their sensing and computational power is minimal. An alternative solution is to use a larger robot, but make the robot aware of its own acoustic signature. Combined with knowledge about sound sources and sound flow through the environment, an acoustically aware robot may hide its own acoustic signature in the ambient noise to reduce the risk of being detected.