| Since the robot was born, Technologies of robots have become more and more mature. Especially in recent decades, with the rapid development of the technologies of robots, robots are widely used in more and more engineering fields, and then the requirements for robots in the practical engineering are increasing. Compared with wheeled robot, legged robots are more flexible to adapt to various environments. Furthermore, among them quadruped robots possess the most excellent comprehensive characteristics, thus they have become a hot spot of the research of scientists all over the world.In this paper, high performance quadruped robots, which are droved by hydraulic, take the advantage of high dynamics, high load capacity, simple structure on leg but compact and so on. However, the rigid legs in the presented robot bring some big impact acceleration into the robot body when it walks normally. This situation may have interference on the control system, even destroying the control system, and making the robot hard to be controlled. At the same time, the huge impact will increase the clearance of legs and decrease the control accuracy of robots. In order to reduce the impact on the robot to protect the control system and ensure the control accuracy, spring buffer devices are designed to install on the legs of the robot.At the beginning of this paper, based on the summary of the present situation of development and research about quadruped robot at home and abroad, the schematic diagram of robot and single leg D-H coordinate system are established, and then the forward and inverse kinematics equations are deduced by coordinate transfer method. The correct solutions of the joint angles which are determined by foot trajectory are verified, and then the foot trajectory for quadruped robot under trot gait is planned. In order to ensure the robot starting from the standing condition correctly, the robot’s four legs in the right positions should be determined using half-stride first, and then followed by the normal trot gaits. Also, track of legs and joints of the robot are simulated by MATLAB from the standing condition. Using the Lagrange method, the dynamic model of this quadruped robot is established, and then the solution of kinematics issues and the dynamic equations of quadruped robots are deduced.Due to the fact that the structure of the robot is very complicated, there is no need to obtain completely accurate model of the robot when modeling. In this paper, the complexity level of the model is simplified appropriately and the structure of the robot is established by UG. Importing this model into ADAMS, the correctly virtual prototyping model can be obtained simulated by ADAMS. By analyzing the curve of the displacement, velocity and acceleration respectively, it indicates that the impact on the robot is very serious, so it is necessary to install the spring buffer device to isolate the impact. In comparison with the robot with rigid legs, it is proved that the spring buffer device take the remarkable effect of on the reducing of impact. To make full use of this spring buffer device, taking the spring damping coefficient as design variables for the parametric spring, optimization analysis of spring damping coefficient are performed by choosing appropriate optimization method of ADAMS. The acceleration impact has been further reduced and the issues of poor traction and stability have been solved. In that case, it can guarantee the stability of control system for this quadruped robot and provide good environment for the installation of the hydraulic station system loaded by the robot later. |
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