Hardware Circuit Design And Modeling Of Non-crosstalk Ultrasonic Ranging Systems

Recently, ultrasonic ranging sensors have been widely used in mobile robot obstacle avoidance systems. Compared with other sensors such as laser, infrared, radio wave and image, ultrasonic sensors have advantages of low cost and strong adaptability. However, there are some problems in the application of ultrasonic sensors to robots, in which the well-known one is the ultrasonic crosstalk phenomenon caused by multiple ultrasonic ranging sensors working together. The crosstalk decreases the measurement accuracy of distance, and prevents the ultrasonic sensors from being applied in mobile robots. Different methods have been proposed by researchers in order to solve ultrasonic crosstalk, in which the better one is the hardware circuit based correlation method, but the current circuits still need to be improved.Based on the deep analysis of classic circuits and lots of experiments, a set of ultrasonic ranging hardware system which integrates ultrasonic transmitting and receiving is designed, and the functions of every component and main chips are described. The designed hardware system has characters such as far detecting distance and short blind area, small distortion and high accuracy, large dynamic range and stable echo, low cost and easy to spread. The Auto-Regressive Moving Average (ARMA) model and Prony parameter estimation method are used to set up the transfer function of the ultrasonic range system, and the correctness of the transfer function is verified through experiments. The mathematic model of the designed circuits can facilitate the choice of pulse coding and modulation mode for the non-crosstalk ultrasonic ranging system, so the cumbersome hardware verification can be avoided, which meets the need of theoretic study and simulation work.