Advanced acoustic sensing system on a mobile robot: design, construction and measurements

In this paper, we describe the construction and characterization of a low-cost ultrasonic sensing system for obstacle avoidance on a mobile robot. In some locations and in certain conditions where electronic components are not readily available and not affordable, it is more advantageous to design an obstacle sensing system with a single sensor (e.g., HC-SR04) to reduce the construction cost. We decided to use only one sensor, mounted on a servo on the front of a mobile robot that scans and detects obstacles within the interval from 15° to 165° according to our design, to allow the estimation of the distance of currently detected obstacles with the help of a fuzzy rules set. The embedded fuzzy algorithm will select what obstacles should be avoided to perform collision-free navigation. A microcontroller with an Arduino boot loader was used to perform calculations and control the sensor (HC-SR04) and actuator (SG90 mini gear). The robot has two independent wheels, driven by geared PM dc motors, via the H driver L928N. The ultrasonic sensing system accuracy can be improved by considering ambient temperature in sound speed computation.