Design And Analysis Of A Quadruped Robot With Variable Stiffness Flexible Joints

As the closest form of biological movement,leg walking robot has a variety of motion patterns and excellent ground adaptability,which has been a hot topic for researchers.With the advent of a series of high-performance quadruped robot designed by Boston Dynamics,higher motion frequency and speed have brought hope for the practical application of legged robots.However,in the working process parts wear seriously,high energy consumption,poor battery life is the key problems to be solved.Based on the study of bionics,this paper designs and analysis of a quadruped robot with variable stiffness flexible Joints,and obtains innovative work and results as follows:This paper studies the influence of different stiffness coefficients on the performance of legged single leg motion,and clarifies the practical significance of leg stiffness adjustment.A flexible joint(apVSJ)with both active and passive variable stiffness characteristics is designed based on the cam mechanism.The static stiffness test and dynamic throw test of apVSJ prototype are designed to verify the performance of apVSJ variable stiffuess.For the kinematical characteristics of quadruped robot,through the flexible one leg dynamic model with two degrees of freedom and the rebound motion of a single leg free fall,it is verified that the"three stage"passive variable stiffness can reduce the ground impact and shake after flight.Established the joint drive system power flow model include DC servo motor,harmonic reducer and the series elastic component,the jumping motion based on the SLIP model and horizontal walking motion are analyzed.Comparing the influence of different stiffness coefficients on the energy saving effect,the active variable stiffness strategy of quadruped robot is obtained.The SLIP control model of the ground phase of the leg based on the apVSJ joint is established.and the parameters self-tuning motion control method of flexible quadruped robot is designed.The prototype and control system design of quadruped robot is completed and the effect of the designed flexible joint on the stiffness of the leg and the effectiveness of the control algorithm are verified by the experiment...