Design And Research On The Lower Limb Of Humanoid Robot With Rope-gear Hybrid Transmission

Under the progress of technology and the development of social economy,the field of robots has been studied by more scholars at home and abroad,which has been widely used in many fields.However,there are still many key problems to be solved in humanoid robots.Considering that the driving mode of the motor,and reducer of the traditional robot make the mass of each joint of the whole robot large,resulting in the greater motion rigidity of the robot.In this paper,from the perspective of bionics,flexible ropes are used to replace muscle and tendon tissues to drive joint movement.The rope transmission mode can make the terminal joint show better compliance,and can also absorb certain terminal impact to protect the mechanism from damage.However,rope transmission requires a certain length of power arm based on lever principle.Considering that the hip joint of the lower limb of the human body is too close to the waist,if rope transmission is used,the power arm of a certain length cannot be realized and the required joint torque cannot be reached;If the hip joint is driven by a traditional motor,it can achieve a larger torque and bring a smaller end joint mass.In conclusion,this paper focuses on the design and related research of the lower limb of humanoid robot using rope-gear hybrid transmission scheme.The main contents are as follows:Firstly,the mechanism of human lower limb movement is analyzed,and the relevant human walking data are fitted with curve function and designed with error function to evaluate the fitting degree.Then the design of hybrid transmission is introduced.The gear transmission scheme of hip joint and the rope transmission scheme of knee joint and ankle joint are proposed,and the transmission configuration and tension control of rope are introduced.Moreover,the overall three-dimensional modeling of the structure of the humanoid lower limb robot is carried out.Secondly,based on the process of alternating swinging of legs when walking,the humanoid lower limb structure is simplified to a four-bar mechanism,and its kinematics and dynamics are analyzed and simulated in MATLAB and ADAMS.Finally,the DC motor and reducer module used in hip joint are modeled mathematically and simulated in Simulink.PD control strategy simulation based on dynamic model is carried out on human-like lower limb structure and the results are analyzed.The PID control strategy is used to carry out the joint simulation of ADAMS and MATLAB on the imported three-dimensional model,and the results are compared and analyzed with the simulation results based on the dynamic model.A PID controller is obtained,which can effectively control the rotation torque and speed when the rope antagonizes the drive joint.