Research On A New Method Of Target Positioning For Mobile Robot Based On Multiple Ultrasonic Sensors

Mobile robot is an important branch of robot research,which has been widely used in industrial,logistic and military fields.Target positioning is one of the key technologies for mobile robots to achieve autonomous movement,which plays an important role in obstacle avoidance,navigation and target identification.Therefore,the research on target positioning for mobile robot is of great significance.As a common ranging and positioning technology,ultrasonic technology has the advantages of low cost,low power consumption and low computational complexity.However,there are still some problems to be solved in the practical application of ultrasonic positioning technology,among which the most prominent problem is the influence of environmental temperature on the positioning accuracy.At present,to overcome the influence of environmental temperature on the accuracy of ultrasonic positioning,many research works have been undertaken to improve the accuracy of ultrasonic positioning system,by introducing additional temperature sensors and ultrasonic velocity calibration process.These methods have achieved some results,but make the positioning system more complex,which is not conducive for the practical application of ultrasonic positioning technology in the field of mobile robot.Therefore,it is of great significance to seek a new ultrasonic positioning method without requiring additional environmental temperature information and ultrasonic velocity calibration process.In this dissertation,the research on a new method of target positioning for mobile robot based on multiple ultrasonic sensors is carried out.The main works and innovations of this dissertation are as follows:(1)A new ultrasonic target positioning method based on the ratios of time-of-flights is proposed.Three ultrasonic sensors are used to obtain the time-of-flights and the ratios of time-of-flights are used to implement positioning,so the influence of environmental temperature and ultrasonic velocity is avoided.(2)Based on the three ultrasonic sensors,the general sensor configuration and the simplified sensor configuration were constructed.Correspondingly,two positioning models of these two sensor configurations,the generalized positioning model and the simplified positioning model,were established.Further,the solutions of the two positioning models and the identification methods of multiple solutions were investigated in detail.(3)Combined with the mobile robot,an ultrasonic positioning system was developed.The feasibility and effectiveness of the proposed method are verified by practical ultrasonic positioning experiments.The experimental results show that the proposed method is effective,both the two established models can implement positioning successfully,and the positioning accuracy is satisfactory.Compared with the conventional ultrasonic positioning method with the default ultrasonic velocity,the positioning accuracy is greatly improved by the proposed method.Compared with the ultrasonic positioning method with additional temperature compensation,the results obtained by the proposed method are comparable.