Develop Of Mechenical Prototype And Reserch On Kinetic Characteristic Of Quasi-Passive Dynamic Walking Robot

The design of passive dynamic walking requires us to fully use of the natural dynamics of passive walkers, so the gait is natural and the energy consumption is low during walking. The pure-passive walking robots can walk on the slope stably only relying on gravity, while the quasi-passive walkers can walk on level ground naturally and stably under certain controls.Current research on passive biped robot mainly focuses on control strategies for walking stability and structure optimization, but less on gait character analysis. In order to get a better understanding of the quasi-passive biped robot walking gait characters, the paper developed a mechanical prototype of quasi-passive biped robot, and designed a series elastic actuator that can adjust the stiffness of the spring, and resolved the collision problem of the knee which can lead to instability of walking. On this basis, the paper made an intensive study of the control system of the quasi-passive biped robot and put forward the position control law of the DC motor. The motor target output angle algorithm was also put forward at the same time to solve the problem which can not calculate the extension of the spring correctly. At the end the paper used ADAMS to create a simulation of the prototype that was built in Pro/E and analyzed the gait characteristics of quasi-passive biped robot walking on level ground, and proved the correctness of the structural parameters and control strategies by walking experiment.First, the paper built a dynamic model of passive biped walking robot, and optimized the structural parameters of the model, and made a full analysis of how the different structural parameters can influence the stability of the passive walking robot. On the basis of optimization results, the paper built a simulation model with knee joint and upper body in ADAMS, and fully discussed the gait characters of this model.Secondly, the paper gave a detailed analysis of the characteristics of the flexible drive, and indicated that the stiffness and equilibrium position of the elastic actuator can influence the gait characteristics of passive walkers, and designed a new serials elastic actuator that can adjust the stiffness. Based on this, the paper then established the mechanical prototype of quasi-passive biped robot with upper body and knees.Then, the paper put forward the torque input model of the swing leg of quasi-passive biped robot and calculated out of the control parameters of this torque input model. Proposed a position control strategy of the quasi-passive biped walking robot, and proposed the implementation method according to the drive DC motor actuator's property. In order to solve the problem which can not calculate the extension of the spring correctly, the paper put forward the target output angle algorithm.Finally, the paper used ADAMS to create a simulation of the prototype that was built in Pro/E and analyzed the gait characteristics of quasi-passive biped robot walking on level ground. Made a further analysis of the gait characteristics of quasi-passive biped robot by real experiment, and proved the influence of the structural parameters, the stiffness of elastic actuator and the control strategies on walking gait characteristics.