Study On Slope Gait Planning Of Six-legged Robot Based On CPG With Feedback Model

Bionic six-legged robot mirrors animal's rhythm movement pattern and reflection mechanism,its CPG(Central Pattern Generator)can generate stable periodic signal.To achieve the rhythm movement of the bionic robot in the regular terrain,the feedback CPG model according to animal movement mechanism is designed,the output of the CPG is changeable in order to adapt to the external environment,which is suitable for six-legged robot gait planning in irregular terrain.First,with "Hex Ant" six-legged robot as the research object,based on robotics and parallel mechanism,the D-H coordinate system is established;In the swing phase,the relationship between each joint angle of swinging leg and foot position is analyzed;In the support phase,the relationship between the body posture and each joint angle of support legs is analyzed;Based on Matlab,kinematics analysis of six-legged robot is verified.Then,the slope movement of six-legged robot is analyzed,and the maximum slope angle of the six-legged robot that could stand still through force analysis is acquired,the qualitative relation between the stability and body pitching angle is obtained by the slope walking stability analysis,and slope movement gait based on CPG with middle reflex is planed;Six-legged robot--transition movement from ground to slope is analyzed,the condition under which six-legged robot transition movement do not slip is acquired,and the transition movement gait based on CPG with the bottom reflex is planed.Next,according to the mechanism of biological reflex,three layers of reflection mechanism based on CPG are designed;Based on the basis of the Hopf model,the feedback Hopf model by introduceing the feedback items is built;According to the principle of single variable,the influence of convergence coefficient to output characteristics of Hopf model with feedback are analyzed;The three joint signal generator model of single leg is designed,the influence of different convergence coefficient combination to the output characteristics of coupling Hopf model is analysised,and three joint angle function of single leg is defined;Based on single leg gait generator model,six-legged robot gait generator model is designed,and the symmetric network and loop network topology structure are established,through the analysis of the output curve of tripod gait simulation under two kind of topology network structure,the symmetrical topology network structure to realize coupling between six-legged robot legs is selected.Finally,six-legged robot simulation platform is construct,the tripod gait based on Hopf and feedback Hopf model are designed;Respectively for six-legged robot on 12°and 16° slope downhill movement,simulation experiment are done with two kinds of gait generation model;The transition gait based on the bottom reflex of Hopf model is Design,and movement on the ground to the transition of 12° slope are simulated;The six-legged robot experiment platform is Perfect,the simulation content are done again by physical model;According to the simulation and physical experement analysis,the feasibility of the slope gait generator with feedback Hopf model and the transition gait based on bottom reflex of Hopf model are verified.