Research On Motion Control Of Hexapod Robot In Rough Terrain

As a novel type of robot,the hexapod robot possesses a multi-degree-of-freedom limb structure and discrete foothold points,exhibiting remarkable mobility and adaptability.However,the motion control of hexapod robots in complex and rugged terrains remains a significant challenge due to the unpredictable external disturbances in these environments,which may cause the robot to become unstable and unable to move accurately.Therefore,this study focuses on the motion control of hexapod robots in rugged terrain,and the specific research content is summarized as follows:Firstly,In order to meet the motion requirements of hexapod robots and based on the bionic prototype of ants,a three-degree-of-freedom mechanical leg and a closed,compact,lightweight box-shaped body structure were designed based on the principle of low inertia.Ansys Work Bench software was used to perform stress and strain analysis on the leg force components to verify the rationality and reliability of the structure.Secondly,this article conducted a kinematic and dynamic analysis of the hexapod robot system,with the aim of establishing a complete mathematical model to describe its motion characteristics.In the kinematic part,the D-H model of the leg system was created,and the kinematic solution of the robot was obtained by using a combination of geometric and algebraic methods.The Jacobian matrix of the foot and the workspace of the foot were also solved.In the dynamic part,the dynamic model of the leg was first established,and then using the Lagrange’s equation,the driving torque values of each joint of the leg were obtained.Thirdly,this paper uses the output signal of the central pattern generator(CPG)for phase delay to generate the control signal of each leg,and then uses the control signal to complete the motion control of the three-legged,four-legged and five-legged gait of the hexapod robot.This signal is used as the driving signal of the foot end trajectory to complete the trajectory planning of the foot end of the robot’s swing phase based on the Bezier curve.And the gait simulation of the hexapod robot is carried out through the Gazebo software,and the effect of the robot completing three gait movements under the control of the CPG signal is verified.Finally,a hexapod robot motion control strategy based on virtual model control was adopted to improve the robot’s motion stability in rugged terrain.The method mainly includes a swing phase virtual model,a support phase virtual model,and a state machine that smoothly switches between the swing and support phases of the leg.The Gazebo software was used to simulate and verify the effectiveness of this method.The virtual prototype successfully completed uphill and rugged terrain experiments,preliminarily verifying the effectiveness of the control strategy.To further validate the effectiveness and reliability of the method,the control strategy was applied to physical prototypes for climbing and crossing rugged terrain experiments.Experimental results show that the control strategy can make the robot have better motion stability in complex terrain.