Research On Intelligent Wheelchair Obstacle Detection System

China is gradually entering an aging society,and for most elderly people and people with physical disabilities,wheelchairs have become an indispensable mobility tool.In order to improve the quality of life of the elderly and disabled people,the research on the intelligence of wheelchairs is constantly deepening,and environmental perception is one of the important research contents.It is the basis for realizing intelligent functions such as active obstacle avoidance and path planning,which can eliminate potential safety hazards.Most of the existing environmental perception systems applied to wheelchairs have problems such as poor economy and high hardware requirements.This paper starts from the safety and economy aspects of intelligent wheelchairs,and designs an obstacle detection system based on ultrasonic ranging technology.This paper first discusses the characteristics of several environmental perception technologies,such as visual detection,lidar detection,infrared ranging,and ultrasonic ranging,and chooses ultrasonic ranging technology with strong environmental adaptability and high economy as the main obstacle detection technology in this paper.It introduces the research status of intelligent wheelchair,the basic concepts and ranging principle of ultrasonic wave,and analyzes the sources and solutions of ultrasonic ranging errors,and completes the design of the overall scheme of intelligent wheelchair obstacle detection system based on the structural characteristics and performance requirements of intelligent wheelchair,which includes human-computer interaction module,obstacle detection module,communication module,wheelchair drive module,power module and mechanical structure.This paper designs the main controller and ultrasonic sensor of the intelligent wheelchair obstacle detection system based on STM32F103CBT6 chip,and introduces them in detail from both hardware circuit and software algorithm aspects.The main work of the hardware circuit part is: to complete the schematic design and PCB board design of MCU minimum system circuit,power circuit,communication circuit,human-computer interaction module circuit,ultrasonic transceiver circuit and other modules;the main work of the software algorithm part is: to realize the accurate measurement of obstacle distance by ultrasonic sensor through Hilbert envelope extraction,filtering,echo start point search,temperature compensation and other algorithms,to realize the data transmission between multiple ultrasonic sensors,main controller and motor driver through CAN bus,to complete the obstacle warning work through the voice module and display,and to design a motion control algorithm based on multi-sensor fusion,which improves the safety of wheelchair.Finally,an experimental platform is built to test the intelligent wheelchair obstacle detection system.The accuracy experiment and ranging angle experiment of ultrasonic sensor are completed,which can stably measure the distance of planar obstacles in the range of 0.26-2.5 m and the relative error does not exceed 1%,the detection angle is not less than 45.8 degrees within 0.9 m range,and the detection angle is 15.4 degrees at 2.50 m.The function test of obstacle detection system is completed,and the experimental results show that the intelligent wheelchair obstacle detection system can realize obstacle detection and warning in six directions such as front,and its fusion motion control algorithm can complete wheelchair braking before collision,which improves the safety of wheelchair.