Design Method For A Bionic Knee Joint Mechanism Based On Tensegrity Structure

The bionic knee joint robot imitates the flexibility and self-adaptive characteristics of biological movement to realize the stable walking in an unstructured environment.As the most complex structure of human body,it has the characteristics of flexibility,self-locking and semi-autonomous reset,which can interact with unstructured environment to ensure the stable walking of human body.In order to make the bionic knee joint mechanism similar to the human knee joint which has the walking function,this paper designed a bionic knee joint mechanism to realize the flexion and extension function of the knee joint robot,based on the bionic theory and the tensegrity structure theory,through the bionic mapping to organically integrate the shape structure of the human knee joint and the tensegrity structure.It is used to realize the function of knee joint robot buckling and straightening.(1)Multi-coupling biological mapping model of human knee joint.Based on the bionics theory and method,the motion mechanism and morphological structure of human knee joint are extracted and simplified,and the multi coupling biological mapping model of human knee joint is established;(2)Theoretical study on the overall structure of tension.According to the schematic diagram of bionic knee joint mechanism,through the theory and method of stretching the whole structure,the bionic mapping is used to establish the structure design similar to human knee joint;(3)Configuration analysis and stability judgment of bionic knee joint mechanism.Based on the positive definiteness of tangent stiffness matrix,the stability of bionic knee joint mechanism is judged;(4)Kinematic analysis of bionic knee joint mechanism.The mapping model of the mechanism is established,and the length variation of the spring element of the mechanism is solved by the inverse solution of the position.The size parameters of the bionic knee joint mechanism are determined according to the characteristic parameters of the human knee joint.Due to the structural characteristics,the kinematic analysis of the bionic knee joint mechanism is carried out to match the spring stiffness of the spring element of the mechanism,and the spring stiffness matching of the mechanism is carried out through the static balance to complete the kinematic analysis of the bionic knee joint mechanism;(5)Virtual prototype simulation and experimental verification.Through ADAMS simulation,it is verified that the bionic knee joint mechanism can realize the change movement similar to the human knee joint.The stiffness of spring element in the motion process of the mechanism is matched to the mechanism in ADAMS.Through the simulation output of spring element shape variable,the simulation results are compared with the theoretical calculation results to further verify the correctness of the theoretical method.Using 3D printing technology to make physical prototype,and complete the assembly and debugging.Through the experimental test platform,the flexion movement and extension movement test of the motion simulation mechanism,it is verified that the bionic knee joint mechanism has the flexion and extension movement state and performance similar to the human knee joint.Taking the human knee as the bionic model,combined with the tensegrity structure theory and the mechanism design method,the bionic knee mechanism configuration design is realized,which is used to solve the problem that the bionic robot knee joint can not self lock itself.