Active Compliance Control Based On Trot Gait For Quadruped Robot

Legged robots can apply to unstructured environments easily.Compared with wheeled and tracked robots,only independent support points are needed.They can reach any position by optimizing the foothold and the trajectory.In addition,it can also move smoothly and flexibly by decoupling the movement of the trunk and foot even under heavy load and rough terrain.All of them,quadruped robots have increasingly become a hot topic in domestic and foreign researches due to their good load capacity and motion stability.During the movement of the quadruped robot,contacting with the ground in a compliance way is also a very important indicator,at present,the research of robots is much based on position control that was called rigidly contact,however,this often leads to a greater impact which is extremely unfavorable for the stable movement of the quadruped robot.The passive compliant control method can reduce the impact by adding flexible components,but it also increases the uncontrollability of the system.There introduce active compliance that can achieve the same result with the passive compliant control method.It doesn't include flexible components.So,It can not only ensure the controllability,but also can make robot contact with the ground softly.Therefore,the active compliance control method has gradually become a hotspot in the field of quadruped robots.In this paper,we first design and optimize the leg structure parameters in terms of the foot motion space,and design the torso platform from the perspective of improving the carrying capacity of the quadruped robot So that we can get the overall structure of the quadruped robot.The D-H coordinate system is established according to the designed quadruped robot structure,and the forward kinematics and inverse kinematics equations are derived.The foot trajectory of the single-legged robot is planned,and the dynamic process of compliant contact based on position is analyzed under the impedance control.Analyzing the decoupling motion control method,to improve the rapidity of motion and reduce a large number of kinematics calculation angles,and to realize the rapid plane continuous jumping for the single-legged robots.The impedance control of the four-legged robot based on trot gait is analyzed,and the trajectory planning of the swing phase and the support phase is performed respectively,and then the foot following effect and the stability of the movement under the impedance control are analyzed.The virtual simulation experiment adopts Adams and Simulink co-simulation method.In Adams,the virtual models of single-leg and quadruped robots are established respectively,and the contact parameters are defined.In Simulink,a control system block diagram is built according to the control algorithm,and the interface both of them is realized by input and output variables so that it can conduct virtual simulation experiments to verify the effectiveness of the various algorithm.