Research On Coordination Control Of Quadruped Parallel Torso Robot

Now,quadruped robot industry is very mature,and many different types of quadruped robots have been designed and manufactured at home and abroad.However,most of the fuselages of the existing quadruped robots are integrated,and their fuselages cannot move actively except through their legs.In vertebrates with a torso,the function of the torso is irreplaceable in their movement.Therefore,in the future research of robots,it must be a trend for robot body to join moving trunk.Based on the shortcomings of the stationary quadruped robot,this paper proposes the research of the quadruped parallel quadruped robot,which greatly improves the flexibility of the robot.In addition to the structural design,this paper also carries out the mathematical modeling of the quadruped parallel torso robot,and obtains its forward and inverse kinematics solutions.Firstly,the Hopf harmonic oscillator is used to simulate and generate the Central Mode Generator(CPG)signal.Based on the CPG signal,the quadruped parallel torso robot is controlled.By observing the movement rules of quadruped mammals,the CPG rhythm of four legs of the robot was firstly simulated,and then the movement rhythm of spine and trunk was generated from the rhythm of four legs.In this paper,the inverse kinematics of the quadruped parallel torso robot was used to generate the foot trajectory and the torso trajectory of the robot combined with CPG signals.At the same time,various gaits of quadruped mammals were simulated,and the rhythms of various gaits of the robot were simulated.Secondly,based on the forward and inverse kinematics solution of the quadruped parallel torso robot,this paper adopts the closed-loop PD control to control the legs of the quadruped parallel torso robot and track the position of the feet of the control robot in real time.Different control strategies are adopted for the diagonal gait and running gait of the robot,and torque control is used to make the quadruped parallel torso robot reach the desired position.For the parallel body of the robot,closed-loop position control is also adopted in this paper,so that the parallel torso can reduce the error in the process of movement.In addition,for robot fuselage control,this paper mainly includes fuselage height control,fuselage pitch angle control and fuselage gravity compensation.These controls can be superimposed on the robot to achieve the expected control effect of quadruped parallel torso robot.Finally,this paper uses Adams and Simulink to co-simulate the four-legged parallel torso robot,and analyzes the force of the connecting rod of the robot’s body with different gaits.Under different gait conditions,the characteristics of the robot,such as joint torque,body pitch Angle and body velocity,were analyzed.In the same control strategy and method,the characteristics of the quadruped parallel torso robot under the condition of the torso moving and not moving were compared.In the simulation,the running speed of the fixed torso robot is 0.7-0.9m/s,the trot speed of the fixed spine and torso robot is 0.5-0.8m/s,and the running speed of the moving torso robot is 0.9-1.1m/s.According to the simulation results,it can be seen that the motion speed of quadruped robot can be increased after the parallel body is added,which shows the advantage of the parallel body.