Automated measurements in the anechoic chamber with a mobile robot
It is common for the frequency response of a loudspeaker to be characterized at a single point directly in front of the speaker. A loudspeaker’s frequency response depends on the spatial position of the microphone, and being able to obtain the frequency response at more than one location may be desirable. Acoustic measurements in three dimensions are not easy to do accurately and require an automated system in order to be precise and consistent. Previous attempts have used robotic arm manipulators or linear tracks for moving a microphone around a room. Modern robotics offers a cost effective way of obtaining measurements accurately and robust enough to be expanded to other rooms or spaces at a later time. The robot presented here costs less then $500 and uses all open source hardware and software. Most of the data in this project was gathered using ROS (robot operating system) and OpenCV, which are open source software libraries. The technical references are for a similar project, of which one could be found, and references for the kinematic model of a three-wheel drive robot. It is possible to make a robot that costs less than $500 that is capable of characterizing loudspeakers in three dimensions. Although the robot was designed for a particular room, for it to function in other rooms will only require new software.