Study On The Mechanism Of Head And Bounding Dynamic Stability Of Spinal Quadruped Robot

At present,there are many mature cases of quadruped robots with rigid trunk,while spinal quadruped robot only exists in the laboratory environment.In theory,the spine joint can improve the speed and efficiency of energy utilization of quadruped robot.However,the spine joint makes the motion stability of quadruped robot more complex.If the spine motion is not properly controlled,it is easy to destabilize the movement of quadruped robot.By observing the high-speed movement of animals such as belgian malinois,it is found that the spine movement is often accompanied by the head movement.Inspired by this,this paper mainly studies the mechanism of the head in the bounding movement of the spinal quadruped robot,as well as the dynamic stability of the bounding gait of the spinal quadruped robot,explores the role of the head movement in the movement stability.Taking the belgian malinois as the bionic object,through the analysis of the body structure and movement characteristics of the dog,the simplified model of the spinal quadruped robot with a head is established,the periodic bounding gait with the head and spine movement is designed,and the dynamic equations of the simplified model in each stage of the bounding gait are derived.Because of the limitation of the simplified model,the whole body model of the spinal quadruped robot is designed.The mapping relationship between virtual elastic legs and joint legs is established at the same time.Through theoretical analysis,the mechanism of the head is summarized: the adjustment of the position of the center of mass,the adjustment of the pitching movement of the trunk.Through the mass center trace diagram of the head and spine movement,it is concluded that the head moves the whole mass center forward,and the head up and down swing can raise and lower the center of gravity,and the relationship between the head movement and the trunk pitching movement is obtained.Through simulation,it is proved that the unstable bounding can be adjusted to the stable bounding movement through the reasonable head movement.The influence of head motion on bounding parameters is analyzed by comparison.The dynamic stability of the spinal quadruped robot is analyzed,and the dynamic stability margin is obtained by optimization: ZMP stability margin and periodic symmetric bounding stability margin.The evaluation method of bounding stability is established.Particle swarm optimization algorithm is used to optimize the head motion parameters.The objective function of the optimization process is established according to the dynamic stability margin.And the joint simulation environment is established,complete the process of optimization iteration through simulation.Through the analysis of simulation results,the effectiveness of the method is verified.A prototype of spinal quadruped robot with a head is designed and manufactured,and the experimental environment is built.Through the analysis of the motion process snapshot and the experimental data of the prototype,shown that the adjustment of the head motion to the spinal quadruped robot can indeed improve the bounding stability.