Coaxial Range Measurement Current Trends for Mobile Robotic Applications

The useful environmental interaction of a mobile robot is completely dependent on the reliable extraction of information from its immediate surroundings A review of some of the most commonly used coaxial active sensing methods in robotics is presented A coaxial sensor results if the transmitter and receiver are geometri cally arranged in a coaxial manner Certain advantages of such con gurations are discussed First optical sensors in which a controlled light signal is transmitted are re viewed with respect to their applicability to mobile robotics research A detailed overview of the literature describing light detection and ranging LIDAR systems for range measurement in robotics is given In any LIDAR design the physics of re ec tion of light from various surfaces must be addressed Specular and or di use re ection results which greatly a ects a sensor s ability to measure range The issues of the type of re ection dynamic range of the received signal strength and cross talk are addressed in relation to three popular LIDAR measurement techniques time of ight and frequency amplitude modulated continuous wave methods A review of mobile robot research using sound navigation and ranging SONAR is presented where processing algorithms are demonstrated for the correct interpreta tion of ultrasonic data recorded in indoor environments Once again to understand the data provided by ultrasonic sensors a model of the re ection mechanism is re quired Ultrasonic wave re ection is generally dominated by specular re ections Methods for the interpretation of SONAR data for correct target classi cation and hence range estimation are given based on the acoustic re ection mechanism This requires SONAR scans of particular objects from multiple view points Recent research has focussed on the use of arrays of SONARS to eliminate the necessity for multiple view point scanning for the classi cation of targets Methods will be presented which adopt multiple SONAR transducers to allow target identi cation and range estimation from a single view point Where possible actual sensor data is presented to highlight the review keywords Range sensing LIDAR SONAR