Study On Sound Source Localization For Mobile Robot Based On Tetrahedral Microphone Array

With the continuous development and improvement of digital signal processingtechnology and acoustic electric technology, and the progress on artificial intelligence levelof the humanoid robot, auditory system, as an important part of the human senses, hasbecome an important research direction of the robot. Hearing can work in very dark or darkenvironment, using the characteristics of sound diffraction can also locate the sound sourcetarget which is at the back of an obstacle, and has unique advantages compared with othersensory sensor. Hearing robot can be used in dangerous situations, disaster relief, military,medical and service industries. In this paper, for intelligent robot auditory targeting which isthe key problems to be solved, the following three aspects are mainly studied.1. Three dimensional space sound sources localization based on tetrahedral arrayBased on the study of microphone array, the tetrahedral array is proposed to locatesound source target. Establish precise geometric localization model, deduces the locationformulas, analyzes the impact on the positioning error of the approximate model and ofdelay estimation error, and provides a theoretical basis for the design of the actual robotauditory system by theoretical analysis and numerical calculation. Build a sound sourcelocalization experiment platform of mobile robot based on tetrahedral, and positioningperformance of three dimensional space sound source localization system based ontetrahedral array is verified by the experiments.2. Locate the sound source combining the movement of the mobile robotMost of the existing robot sound source positioning device can only locate azimuthand elevation, can not accurately positioning the distance. In response to this situation,combining the movement of the mobile robot is proposed to locate the sound source.Through the robot movement actively, robot in different locations collects sound sourceinformation for many times, finally realizes the target source of accurate positioning.Establish the sound source localization model of combining the movement of the mobilerobot, and analyzes the impact on the positioning error of the walk error of robot, of theelevation error and of azimuth error. Finally the effectiveness of the proposed method isverified by experiments.3. The microphone position calibration for tetrahedral arrayThe errors between the actual microphone array and assumption array model exist. It results in heavily degrading of performance of speech localization and enhancementalgorithms based on microphone. In this paper, a new active calibration approach forposition error of regular tetrahedron microphone array is proposed. A sound source whosedistance is known in the space is moved several times and measured several times, andcalculates microphone position using the data obtained through multiple measurements.This method is only necessary to measure the distance of the sound source, avoidingprecise location measurement of the sound source, using Levenberg-Marquardt method toprocess the repeatedly measured data, and obtains a good correction effect. Computersimulations verify its effectiveness.