An Under-actuated Crawling Robot Inspired By Hexapod Insect

In large-scale disaster sites,such as earthquakes,landslides,and hurricanes,the required number of professional rescuers typically cannot meet the site demand.This is mainly due to the difficulty for rescuers to access sites,where sites are full of collapsed structures.Therefore,the development of disaster rescue robots bears a great significance.Rescue robots have the key characteristics of small size,flexible,and capable of accessing complex working environments.As such,they are highly suitable in security and disaster investigating missions.However,existing rescue robots use complex control and actuation systems to achieve specific motion,which make them heavy and expensive.Therefore,simplifying the robot design such as reducing the overall weight is an ongoing challenge.This paper proposed a novel crawling robot named “HIbot” with key characteristics of low cost,lightweight and simple control.In this research,ants and other hexapods are selected as bionic objects.Through observation and analysis,the correlation between their body structure and movement is characterized.We introduced the body structure of hexapods and the design philosophy of mechanical intelligence into the design of the robot.This has led to the development of a crawling robot with an under-actuated movable lumbar joint,where it has good environmental adaptability in complex ground conditions.Secondly,the legged-wheels are introduced into the design of the crawling robot.Legged-wheels can move quickly and climb over large obstacles.We optimized the traditional multi-spoke legged-wheels,and analyzed the influence of the phase difference between adjacent legged-wheels on the smoothness and climbing ability of the robot through kinematics and simulation analysis.In addition,we also analyze the motion characteristics of the crawling robot under different gaits.After comprehensively comparing the motion characteristics of various structures and gaits,the final configuration of the HIbot robot with the four-spoke wheg III under the crawling gait is produced.The phase difference between adjacent legged-wheels is 30 degrees.Finally,for future practical rescue applications,we have proposed two solutions for gait switching and steering,which can further improve the movement performance of the robot in complex environments.This paper systematically introduces the design and manufacture process of the HIbot.A series of experiments have demonstrated that the HIbot can crawl in various outdoor environments such as gravel,grassland,etc.It can cross obstacles that are as high as 2.8 times of the radius of the legged-wheel.The robot has strong climbing ability and environmental adaptability.In addition,it has the characteristics of simple structure,simple control,lightweight and low cost.It has broad application prospects in disaster relief,battlefield investigation and other fields.