Research On Obstacle-assisted Motion Of Snake-like Robot

As a new type of mobile robot,snake-like robot has been a research hotspot in the field of robotics because of its multi-gait motion ability and strong environmental adaptability.Among all kinds of motion forms of snake-like robot,winding motion is the most efficient,and the snake-like robot of this motion form can also assist itself by contacting with obstacles.But at present,there are few studies on obstacle-assisted motion of snake-like robot,and the algorithm of collision dynamics is relatively simple.Therefore,it is necessary to conduct in-depth research on obstacle-assisted motion snake-like robot.Firstly,a large number of references are consulted,representative snake-like robots at home and abroad are listed,and the development process of snake-like robots is introduced.On this basis,we focuse on snake-like robot with obstacle-assisted motion,and introduce the research status from two aspects of physical production and collision algorithm.Secondly,the design concept and manufacturing process of the prototype used in this paper are introduced,according to the actual configuration of the prototype,the dynamic equations considering the separated passive wheel and small eccentricity factor are established by Newton-Euler method,and the rationality of the dynamic model is verified by the first Lagrange equation.Proportional control based on line-of-sight guidance law is used to control the snake-like robot to move in the expected straight line,and the actual model is simulated with the existing simplified model.By comparison,the influence of actual factors on the motion of the robot is obtained.Thirdly,the Minkowsiki difference combine with GJK(Gilbert-Johnson-Keerthi)search algorithm in the real-time collision algorithm is introduced to detect the collision location.Due to the long computation time of the existing obstacle assisted motion algorithm,it is difficult to realize.Therefore,after detecting the collision point,the instantaneous impact model and the continuous contact force model are used to establish the collision dynamics equation of the snake-like robot.The simulation obtained the change curves of the position of the centroid and the joint Angle of the snake-like robot after the collision under the two modeling methods.It is proved that both of the two calculation methods can achieve high calculation efficiency,but the snake-like robot's centroid position calculated by the instantaneous impact model have a jump point,while the continuous contact force model don't have this problem,so the continuous contact force model is more consistent with the actual situation.In addition,the continuous contact force model can calculate the collision force without rigid assumption.From the perspective of improving the environmental adaptability of the snake-like robot,this modeling method is more suitable for obstacle assisted motion.The effectiveness of the method is verified by simulation calculation.In order to make the effect of obstacle assisted motion more obvious,the relationship among propulsion force,collision position and swing Angle is derived.After reasonable simplification,the occurrence condition of maximum propulsion is obtained.Finally,the influence of parameters on the collision effect of snake-like robot is further studied.By experiments,we have confirmed the snake-like robot's adaptive steering and obstacle assisted motion functions.The collision force of robot obstacle assisted motion is measured experimentally based on the RFP pressure sensor system.