Mechanical Design And Analysis Of Lower Limbs Of Humanoid Robot

Humanoid robotics is a hot research field in recent years, it has human-like appearance, and has a flexible way of walking to adapt to the complex terrain and environment. It can help people to accomplish a variety of tasks and be able to replace human work in the dangerous environment, and its application prospect seems very broad. So the humanoid robot research has the very high academic value and practical significance. Among them, the hydraulic-drived humanoid robot is the forefront subject in this field, the output power density hydraulic drive and the ratio of output power and weight are big. It is more suitable robots that need work outside with heavy load. This article is based on engineering problems of hydraulic-drived humanoid robot, completing the structural design of lower limb and prototype of the humanoid robot, the robot kinematics and dynamics analysis and kinematics simulation analysis. The main research work is as follows:After studying the current development of humanoid robot all over the world, we understand the drive way and degree-of-freedom configuration of these robots. Then we analysis the movement of human lower limbs, and the function of its all joint. Then according to the design purpose and function of the robot, we choose the way of hydraulic drive. And then according to the actual robot movement, we design the robot's bionic structure of each joint of lower limb, making each joint can satisfy the requirement of the robot movement.Combining with the designed robot structure, we complete the positive and inverse kinematics analysis of the joints including connecting rod structure and parallel mechanism, so that we know the relationship between hydraulic cylinder output and joint Angle. And then analyze the influence of error of the hydraulic cylinder's synchronous motion and the processing and assembling in the ankle joint. The analysis above will guide the size design of the joint.Then we complete the robot kinematics modeling using the D-H method. Then we establish the whole robot kinematics equation of single leg support phase and get its inverse solution of six-DOF single leg. Finally we discuss the dynamic analysis model and the method of humanoid robot.Combining with the stability criterion, we complete the robot walking gait planning based on the inverted pendulum model, and finish walking simulation in ADAMS software, getting the relation curve between each joint and hydraulic cylinder, which lays a foundation for the robot prototype walking. On the basis of simulation, we make finite element analysis on the robots with a special key time and gesture, including static analysis and modal analysis, avoiding the vibration or damage in robot motion. Finally we complete parts processing and assembling of the robot prototype, inspect the range of movement of all joints and make experimental platform for the prototype.Through the above work, we establish a humanoid robot prototype te st platform meeting the design requirements, laying a foundation for further control and stability control research.