Research On Dynamic Gait Planning For A Hydraulic Quadruped Robot

With its high flexibility,high speed and strong adaptability to environment,the quadruped robot attracts the attention of scholars in various countries,and becomes a hot topic in the field of robot research.Quadruped robot research area involves various levels,and technology related with research also covers a number of areas.Gait planning is the foundation and the key of quadruped robot research field.How to design and control the motion of the quadruped robot realizing stable dynamic movement is a key and difficult point in research of quadruped robot,these all need the reasonable gait planning of the quadruped robot.In this paper,we simulate the motion of the robot using the quadruped robot platform developed by our laboratory.First,we establish kinematic model of the quadruped robot,make forward kinematics and inverse kinematics analysis using analytic geometry method.Because of redundant degree of freedom,we can't get the unique analytical solution of the inverse kinematics analysis.Thus we introduce an additional constraint by fixing the angle so as to get the unique solution to complete the inverse kinematics analysis.And then we research the working space of the foot end point overall.Then we study the pace gait of the quadruped robot.According to the motion characteristics of this gait,we design two different foot trajectories including swinging phase and support phase,and choice appropriate stride and leg lift height as gait parameters according to the foot working space.Finally,we set up the control algorithm and module,realizing the stable motion of the quadruped robot using pace gait.Besides,we study the bound gait of the quadruped robot.According to the motion characteristics of bound gait,we design a 4-different-state of motion stage in bound gait,and set up the different control strategies with different foot trajectory.Finally we implement these methods in the control module successfully.Based on the foresaid stages,we study the effect of gait parameters on the energy consumption of the robot system respectively,by changing the different gait parameters.We introduce the rate of energy consumption as the index,to explore and analyze the variation between different gait parameters and the rate of energy consumption,furthermore,we optimize the gait parameters based on the variation.Finally wemake a reasonable analysis about optimized gait parameter from two aspects of the foot working space and the tracking speed of the hydraulic cylinder.