Structural Design Of Quadruped Robot With Parallel Torso With Motion Control

In recent years,scholars at home and abroad have designed different torso structures for use in quadruped robots by studying the role of the torso in the process of animal movement.However,the existing torso structures have problems such as poor flexibility and complex control.In this paper,a quadruped robot with a six-degree-of-freedom parallel torso is designed,the kinematic characteristics of the parallel torso are studied,and the robot’s center of mass is adjusted to fall on the diagonal of the supporting foot by using the parallel torso deflection motion to improve the stability of the robot’s diagonal gait movement,it is verified by simulation that adding parallel torso motion can improve the stability of the robot’s diagonal gait motion.First,Through the analysis of the cheetah’s bone structure and the investigation of the current quadruped robot’s leg and torso structure,combined with the principle of bionics to optimize the design of its leg structure and torso structure,a quadruped with a parallel torso is designed.robot model.Then,study the motion characteristics of the parallel torso,analyze the degrees of freedom of its mechanism,establish a mathematical model to solve the kinematics,and use the three-dimensional search method to solve the motion space on the basis of inverse kinematics.relationship,analyze the motion stability of quadruped robots under the diagonal gait,combine the movement rules of the torso under the animal’s diagonal gait,use the parallel trunk swing to change the center of mass of the robot so that it falls on the diagonal line of the supporting foot,and through the supporting phase The terminal position completes the torso trajectory planning.Finally,establish the mathematical model of the quadruped robot with a parallel trunk,solve the kinematics of the whole machine under the trunk movement,use the Hopf oscillator to generate the CPG signal,and simulate the animal’s diagonal gait movement law to generate the corresponding CPG signal to control the legs On this basis,the CPG signal is used to drive the trajectory of the foot end,and the trajectory planning is completed for the front and rear legs.The control of the whole machine includes leg control and trunk control.The leg control adopts the closed loop of the foot position PD based on Cartesian space.Control,trunk control adopts position PID control on the basis of parallel trunk kinematics,and performs gravity compensation on the robot according to the motion state of the legs under the diagonal gait.The simulation environment adopts the joint simulation of MATLAB and ADAMS.The simulation is divided into parallel torso motion simulation and quadruped robot diagonal gait motion simulation with parallel torso.Parallel torso motion simulation verifies that the torso track tracking effect is good through single-degree-of-freedom and multi-degree-of-freedom combined motion.The quadruped robot’s diagonal gait motion simulation with parallel torso is divided into two groups of comparative experiments,namely whether to add parallel torso motion and gait cycle.Taking the gait cycle T=0.5s as an example,compared with the fixed torso mode,the lateral displacement of the robot body in the moving torso mode is reduced by 89%,the body deflection angle pitch and roll are reduced by 60% and 63% respectively,and The peak value of the force at the foot end of the leg decreases,and the change trend of the force at the foot end is relatively flat,which verifies that the addition of parallel trunk motion can improve the motion stability of the quadruped robot in a diagonal gait.