Research On Trotting Gait Control Of A Quadruped Robot

Mobile robots have been one of the research hotspots for nearly a century.Compared with wheeled and tracked robots,legged robots are more adaptable to various rugged terrain because only discrete landing sites are needed to achieve stable motion.Among them,quadruped robots have better stability than biped robots and are easier to control than hexapod or more legged robots,which makes quadruped robots have tremendous research and application value.However,quadruped robot is a multi-input,multi-output and time-varying complex system,It is difficult to achieve fast and stable motion on rugged road surface.Control algorithm is the main restriction factor.In order to solve the above problems,this paper designs a bionic quadruped robot based on the bionic dog,and studies the control strategy and method of the stable movement of the quadruped robot diagonal trot on the uneven road.Firstly,based on the analysis of biological dog's physiological structure,the adult Labrador dogs are captured to study the motion law of each joint.Guided by this,combined with the design principle of quadruped robot,the overall structure of quadruped robot is designed,and carry out forward kinematics and foot workspace analysis for single leg.Secondly,Several common gaits of quadruped robots are analyzed and gait planning is carried out.Aiming at the motion control of quadruped robot on rough terrain,two control strategies based on event and gait adjustment are proposed.Next,the principle of VMC method is briefly introduced and applied to motion control of quadruped robot.Aiming at the limitations of traditional VMC method and decomposed VMC method,a control method combining traditional VMC and decomposed VMC is studied.The traditional VMC method is used in biped support phase to ensure accurate and stable control,and the simple decomposed VMC method is used in tripod and quadruped support phase.For the control of swing phase,VMC control method is also used to avoid the complex solution process of inverse kinematics.Combining with the gait and control strategy of the previous planning,the controller of the quadruped robot for diagonal trotting is established,and the simulation analysis of MATLAB-Adams is carried out to verify the feasibility of the proposed method.Finally,a quadruped robot test platform is built,and single leg motion and quadruped robot trotting diagonally on flat,inclined and convex terrain experiment are carried out.The experimental results show that the control strategy based on event and gait adjustment and the combination of traditional VMC and decomposed VMC can achieve the stable motion of quadruped robot on uneven road.The research results in this paper solve the problem of stability of quadruped robot in fast motion on rough road to a certain extent.It is of great significance to improve the motion performance of quadruped robot on rough road.