Research Of A Multi-functional Electronic Travel Aid Based On Ultrasonic Sensors

According to the latest data from the World Health Organization, there are a large number of visually impaired people in the world. As we know that vision is the most important human sense, so it is inconvenientfor the visually impaired to move around. Currently, white canes are the most popular tools for assisting visual impaired individuals, but there are many restrictions when using them. To further improve the quality of the blind’s life, the travel aids have been in a hot research. This paper presents an electronic travel aid, with the function of obstacle avoidance and indoor localization.In this thesis, the system consists of two parts: obstacle avoidance and indoor localization. In the first part, we use the ultrasonic sensors around the waist and on the top of shoes to detect the obstacles both in the air and on the ground. Whether to use the ultrasonic sensors on the shoes depends on the pressure sensors under feet. The collected obstacle data are transmitted to the user by means of sensory substitution, which means to give the feedback through the vibration of the micro vibration motors. In order to achieve the indoor positioning, we use the posture sensors and human kinematics to realize the relative localization, in combination with the observation data collected by sonar around the waist, using the extended kalman filter to realize the data fusion.The indoor location information is transmitted to the user via bone conduction earphones. When the bone conduction earphones are playing the information, the ears are open. So it is safety for the visually impaired.Finally, we managed to prove our system’s validity and practicality by some experiments according to the function of the electronic travel aid. Including distance test of single ultrasonic sensor, the test of threshold detection and vibration feedback about the ultrasonic sensors on the shoes, the test of indoor localization and voice broadcast and so on. Due to the system is inexpensive, easy to use, compact, and wearable, it is expected to achieve commercialization in the future.