Modeling And Kinematic Analysis Of A Bionic Quadruped Wall Climbing Robot Based On Sharp Hooks

As an important branch of special robots,wall-climbing robots have important practical value in the fields of planetary exploration,military search and rescue,geological survey,and nuclear waste detection.The attachment technologies of wall-climbing robots mainly include magnetic adhesion,negative pressure adhesion and bionic material adhesion and so on.However,for some special environments,such as steep cliff detection,bridge safety detection,detection of inner walls of mines,it is difficult to adhere to these complex rough walls by means of traditional magnetic adsorption and negative pressure adsorption.The hooks of insect feet play an important role in the process of climbing walls was found by biomimetic researches.Therefore,we designed a bionic quadruped wall-climbing robot based on sharp hooks,which is attached to the wall by the mechanical lock between the sharp hook and the micro-protrusion to improve the reliability of grasping.In the design process of quadruped wall-climbing robot with bionic flexible gripper as attachment structure,the surface characteristics of rough wall were defined firstly,and a simplified model of rough wall micro-protrusion was established.According to the distance between the micro-protrusion,the interaction mechanism between the sharp hook and the wall micro-protrusion was studied.The effects of key parameters such as the end size of the sharp hook,the geometric characteristics of the wall micro-protrusion,the friction coefficient between the sharp hook and the wall and the contact angle of the sharp hook on the attachment performance were discussed.Then,based on the study of the tarsal chain of cockroach foot,the bionic flexible claw was designed.The stiffness matrix of the flexible claw was calculated by pseudo-rigid-body model,and the correctness of the model was verified by finite element analysis method.Through the parallel array combination of flexible claws,the bionic gripper was designed,the maximum grasping force of the gripper was calculated,and the quadruped wall climbing robot based on the gripper was designed.In order to improve the gripping stability of the wall-climbing robot,the parallel four-bar structure of the legs was designed to prevent the robot from receiving additional torque during the crawling process.At the same time,three rotating joints were designed on each leg of the robot to ensure that it can cross a certain range of obstacles and improve the robot's flexibility.Finally,the diagonal gait was used to plan the crawling trajectory of straight and turning for the robot,and the ADAMS software was used for simulation and analysis.The results show that the designed quadruped wall climbing robot has a crawling speed of 59 mm/s,a turning speed of 4°/s and the stability is strong on the rough wall.