Analysis On Passive Buffer Of A Hydraulically Actuated Quadruped Robot

Moving flexible and having strong adaptive ability to complex terrain,quadruped robot has huge potential in exploration,detection,rescue and relief work,military war.when walking,the feet of quadruped robot impact the ground ceaselessly.It is susceptible to damage the robot and it's control systerm.So it is very important to design the biffer device.For isolating the impact from the ground,according to sequence from hydraulic drive cylinder to single-ledded mechanism and to the whole robot,a buffer solution was made and verified in thid article.This dissertation mainly includes the following aspects:(1)This section gives a detailed overview of the present state of passive buffer in walking robot and analyzes the cause of hydraulic impact.For current buffer defect,the buffer solution of integrating the micro accumulator to hydraulic drive cylinder is made by imitating the buffer feature of tetrapods.(2)A mathematical model of the accumulator is made.The key parameter effecting the buffer performance of the accumulator is made.The model of hydraulic drive cylinder is set in AMESim environment.In the working condition of both stationary and work,a weight free fall impact simulation experiment with hydraulic actuator in the condition of integrating accumulator and no accumulator is made.And the simulation results show the feasibility of this solution.(3)The single leg model of quadruped robot is established.By seriesing spring at one end of the drive cylinder,free fall and standing jumping-up simulation of single-legged mechanism are made successively to verify the buffer solution of seriesing spring to the hydraulic drive cylinder effective and feasible to single leg mechanism.(4)In this section,the whole model of the quadruped robot is established.Followed by the gait selection and the foot motion trajectory planning,according to the inverse kinematics of robot obtained a set of piston motion trajectory of hydrocylinder of each joint,so as to drive the quadruped robot movement in the ADAMS environment.The walking impact simulation with the hydraulic drive cylinder seriesing spring and the walking impact simulation without seriesing spring to the hydraulic drive cylinder are made successively.By comparing the acceleration curve and joint force curve from the two simulation experiment,the buffer solution of seriesing spring to the hydraulic drive cylinder was proved effective and feasible.The author would like to thank Development of practical technology for four-legged bionic robot for field environment project(2015AA042201).this project is supported by the State 863 projects.