Any robot aiming to achieve autonomous navigation in unknown environment must effectively and reliably perceive environmental information

and ultrasonic wave sensor plays a wide role in detecting obstacles distance information.Design and implementation principle of the sonar ring sensor system of travels II is introduced

and the precision of sonar is test.On the basis of these

a simple mobile robot obstacle avoidance strategy is proposed

and two basic static and dynamic obstacle avoidance experiments are used.The experiments verify the correctness and effectiveness of obstacle avoidance strategy.