Mechanism Research Of Quadruped Bounding With An Actuated Spinal Joint

The research subject comes from Basic Research Fund of Central Universities.In order toimprove the mobility and flexibility of quadruped, research the role of the spinal joint in thehigh-speed gait of quadruped, we have proposed a new quadruped robot model with a spinaljoint, and designed principle experimental setup of two-dimensional quadruped boundingrobot with spinal joint. We carry out the simulation and experimental study the impact of thespinal joint for bounding movement.Firstly, based on the analysis and summary of hopping robot and quadruped robot athome and abroad, we indicate the limitations of rigid trunk of the typical quadruped robot,therefore, we propose a quadruped robot model with a spinal joint. For the quadruped robotbounding gait to simplify the model, we come to two-dimensional mathematical model of therobot with a spinal joint eventually. On that basis, the spinal joint and joint-type legmechanism are designed respectively, in addition, the pneumatic control system and theimplementation plan of the overall control system is put forward.Secondly, by means of the establishment with quadruped hopping robot mathematicalmodel, and the analysis of the bounding gait, we come to the four movement states in acomplete bounding gait cycle of motion. In the case of specific assumptions, kinematics anddynamics analysis are made by the Lagrange equations for the four movement states. Eachmovement phase corresponds to an equation of motion. In addition, make analysis for eachmovement state accordingly. According to the characteristics of bounding locomotion,propose event-based changes in the conditions of the movement bounding gait.Thirdly, by the method of Poincaré mapping for quadruped robot with a spinal joint, toperform an analysis of the periodic bounding stability, sum up the four state of motion due toa mixed system, and build Poincaré mapping function for the system. By the method ofNewton-Euler iterative equations to find a fixed point for the mixed system. And thus toresearch the stability of the bounding movement.Finally, we create a spinal joint bounding quadruped robot virtual simulation model byADAMS software, and by comparison with the simulation of rigid body model, we come tothat spine mechanism helps increase stride length, resulting in increased horizontal speed.When touching the ground, the impact force of the toe suffered is reduced for spinal jointmovement, thus the energy is fully absorbed into the elastic energy storage components of theleg touches the ground, thereby reducing the energy loss during this process; In addition, the movement of spinal joints provide extra boost power for the legs, resulting a higher hoppingheights of robot body. The above experiments obtain some meaningful data and results. Itprovides potent reference for the development of quadruped robot with spinal joints.