Research On Control Method Of Six-Legged Robots On Rough Terrain Based On Free Gait

Heavy six-legged robots have the characteristic of high bearing capacity and high stability performance,which are always applied for transporting goods in rough terrain.Therefore,the research on walking control of large six-legged robot on rough road is the focus of global research at present.Regular walking style for six-legged robots is swing three legs at the same time,but this kind of gait have poor stability performance because of the little supporting position when they walk in the rough terrain,which will result in an incalculable consequences.Ensuring the stability requirement and speed requirement for six-legged robots has become an important research direction.This paper plans gait sequences which can adapt to the topographic change for six-legged robots by use of graph search.Combining the feedback information of force sensors,the condition of every foot can be converted automatically to comfort to the terrain,which can realize the function of walking on the rough slope for six-legged robots.Firstly,in order to adapt to different slopes,planning the gait transition process which can adapt to the change of terrain slope,the robot can generate free and continuous sequence to fit for the terrain.Establish evaluation function to select optimal supporting state to satisfy kinematic constraints and stability restraint.Judge the current stability margin by the use of SSM method and predict the stability margin of next step.Adjust the relative position among the body and six feet of the robot to satisfy the requirement of minimum stability margin.Then analysis the gait transition and value of stability margin when the robot climb different slopes by the use of the free gait.Secondly,combined with the feedback information of the plantar force sensor,the gait can be adjusted automatically,so that the robot can generate free gait conforming to the terrain.Establish gait control method for six legged robots to climb slopes,cross obstacles and cross gully.Planning smooth and flexible groove trajectory to cross the obstacles and gullys.Verifying gait feedback control method for six-legged robot in the situation with different terrain including uneven road surface,convex hull and slope terrain in simulation.Finally,establish a complex terrain to verify the effectiveness of the free gait control method.At last,in order to verify the effectiveness and practicability of the free gait control method for the six legged robot walking on the rough terrain,a prototype verification experiment was carried out.The algorithm is compiled into a C++ project for the six legged robot prototype motion control,then the experimental environment including convex hull,uneven road surface and slope is built.The prototype experiments are carried out in the environment.The experimental results verify the validity and practicability of the free gait control method,which offers reference for the six-legged robots to walk on the rough terrain.