Mechanism Design And Bipedal Simulation Of A Hydraulically Actuated Biped Robot

The biped robotics, which involves mechanical manufacturing, bionics, artificial intelligence and so on, has been paid great attention and can reflect the high-tech strength of a nation. And with the achievement of hydraulically actuated Petman and Atlas of Boston Dynamics in USA, many research institutions start to do research on hydraulically actuated robot due to the fast dynamic ability and high power-to-mass ratio of hydraulic systems. However, the research work on biped robot actuated by hydraulic system is relatively few in China. In this thesis, the focus is paid to the mechanism design and bipedal simulation of a hydraulically actuated biped robot. The main contents are as follows:1. The bionic freedom distribution and the dimensional model of a biped robot are firstly analyzed based on human’s joints and muscles. Then, two different parallelly-connected linearly-driven mechanisms with two degrees of freedom (DOFs) of each are designed for the joints of ankle and hip, while the joint of knee is designed based on a linearly-driven linkage mechanism with one DOF. Finally, the overall design is accomplished for the mechanical structure of the biped robot driven by hydraulic system.2. The sagittal and lateral kinematical models are established based on the biped robot and the solutions of the forward and inverse kinematical equations are obtained. The local model of each joint is established based on the D-H method and the kinematical equations of parallel hydraulic drivers strongly coupled with each other are also solved.3. The gait of the previously designed biped robot is planned based on the largest stability margin by the ZMP method. For the present robot, the parameters of the sagittal and lateral trajectories are optimally chosen from the largest stability margin and the optimal gait of biped robot is then planned based on the optimal parameters.4. The virtual prototype of biped robot is established and simulated based on the ADAMS platform. It is shown that the virtual prototype can walk stably, which verifies the present bionic mechanism design, kinematical model and planned gait. Moreover, several important simulation results, such as the dynamic loads of drivers, are also given, which may be instructive on the selection of the hydraulic system.