A low cost map building sensor system for mobile robot

A range finder sensor module which consists of low cost PSD (position sensitive detector) sensor array and high speed RISC MPU was developed. PSD sensor is cost effective and light weighting but its signal has many noises. Mobile robot has various sensors for mapping the external world. The ultrasonic sensor widely applied to the most mobile robot to detect the obstacle and environment owing to low cost, its easy to use. However, ultrasonic sensor has major problems: the uncertainty information of sensor, false readings caused by specular reflection, multi path effect, low angular resolution and sensitivity to changes in temperature and humidity. We propose H/W filter and S/W filter to effectively remove these noises. In this paper, we equipped the PSD sensor module on a mobile robot and compared ultrasonic sensor output with PSD sensor output. We proved this systempsilas validity through field test.