Design Of An Electric-Driven Qurdurped Robot Single Leg And Research On Trajectory Planning

With the development of robotics,legged robots increasingly become one of the hottest research topics.Legged robots have discrete landing points,strong terrain adaptability,and have plenty of animals to study and imitate in nature,making them have prosperous applications in indoor working,emergency relief,field exploration,etc.Electric-driven system has less noise,with much higher stability and much stronger capacity but simple structure when it is compared against its hydraulic,biped and hexapodal equivalents,which makes it draw more attention.In this paper,a single-legged system of electric-driven quadruped robot is designed,and the trajectory planning of quadruped robot is carried out.Finally,quadruped joint simulation and single-leg experiments are finished.Firstly,this paper concludes the Ground Reaction Force model and designs a simple composite cycloidal trajectory as design basis.The generalized formula of joint moment is proposed,and the joint moment is discussed for different leg postures.Aiming to reduce joint moment and rotating speed,serial double-four-linkage mechanism is used.Finally,the dynamics and kinematics model of the single-leg system are given and verified.Secondly,the mechanical and electric system of this single-leg are designed.The maximum forces on joints and leg linkages are calculated according to external force.Based on it,leg linkages are optimized and checked,joint motors and speed reducers are selected and checked,electric parts are selected and designed.Then,the paper analyzed structures of this single-leg system and explains how it works.Thirdly,based on the linear second-order inverted pendulum model,the paper proposes the trajectory planning of Double-Support-Phase with changeable height of center of mass,introduces the complete planning including starting-up phase,intermediate phase and braking phase.Problems remaining in current linear second-order inverted pendulum,high velocity fluctuation and discontinuity of acceleration,are solved.Fourthly,based on the Adams-MATLAB joint simulation platform the proposed quadruped trajectory planning is verified,then the influence of the two variables is discussed,the maximum speed of the quadruped robot with designed single-leg is obtained.Finally,a single-leg experimental platform is set up,swinging and rising experiments are carried out,the feasibility of the designed single-leg system is verified.