Mechanism Analysis And Simulation Research On Quadruped Of Hybrid Elastic Drive

The research subject comes from National Natural Science Foundation Project of china. In order to improve the mobility, flexibility, load capacity, complex terrain adaptability of quadruped walking robot, the research is developed in this dissertation involves studies on mechanical structure design, kinematic mathematic model, motion space, damping buffering capacity of walking leg and motion simulation based on virtual prototype technology.Firstly, based on the analysis of related technical research of various walking robots and walking legs at home and abroad, according to the features of quadruped Mammalian leg, a hybrid elastic drive walking leg with 3-DOF is proposed, it is composed of a serial mechanism and a 2-DOF parallel mechanism. A novel hybrid drive quadruped walking robot is designed and its drive system is studied, a new hybrid elastic drive scheme by adopting elastic actuator to provide power is proposed, in addition, the implementation plan of robot control system is put forward.Secondly, mathematical models of forward and inverse kinematics are established to obtain the kinematics characteristic equations, which means that it is able to calculate the velocity and acceleration of walking leg, and stiffness matrix of the toe is established. Meanwhile, the motion space distribution cloud of the toe is analyzed by the Graphic Method and Monte Carlo Method. The analysis results shows that motion space of walking leg is larger in the scope of walking forward direction than that of leg raise and side rotation, which is similar to the movement of quadruped Mammalian leg when it is walking, and can meet the request of quadruped robot motion space of leg, which provides the basis for mechanical structure design of walking leg. The establishment of stiffness matrix improves the kinematic characteristics and positioning accuracy of walking leg, which provides reference for the research of the impedance.Thirdly, for further basic research of quadruped robot, the concrete structure of walking leg is designed, the thigh adopts parallel drive mode to increase the vertical driving force and load capacity of walking leg; the shank adopts to serial drive mode to increase the motion space of foot. Then, this dissertation discusses the interference condition of Hooke jiont and Spherical hinge in the process of movement of walking leg, and their structures are designed, in addition, the Hooke jiont is optimized, which makes structural size smaller under the condition of Hooke joint no interference.Finally, a great number of simulation experiments on quadruped robotic walking leg are carried on, which are based on the virtual simulation model by using ADAMS and MATLAB, these simulations mainly include kinematic and anti-impact force experiment of walking leg. The simulation results shows that walking leg has a good kinematic characteristics and damping buffering capacity, impace force of the foot when using elastic damping elements far less than not using. The above experiments obtain some meaningful data and results. It proves that the structure of walking leg is reasonable and provides that potent reference for the development of quadruped robotic real prototype.