Research On Energy-saving Underactuated Bionic Biped Robot

The biped walking machine mainly includes fully passive biped walkers and underactuated biped walkers respectively.These two types both have the characteristics of natural walking gait and high walking efficiency.At present,the fully passive biped robot and underactuated bipedal robot developed by researchers have been improved in the stability of walking.But there still has distance with human beings in terms of walking efficiency and natural gait pattern.They are also the develop directions of biped walkers based on the principle of passive walking mechanism.Human body is the best subject that give new inspirations for the research of biped walkers.Due to the delicate and complex musculoskeletal system,the walking of human beings is more efficient and have natural gait pattern.The objective of this thesis is to develop new human musculoskeletal system inspired passive dynamic walkers,which has higher performance in walking efficiency and natural gait pattern.The results obtained in the work are of significance for the robotic field.In the study,based on the deep understanding of human musculoskeletal system,the bionic design of key components of passive biped walkers was conducted.Two different biped walkers were developed including fully passive walker and underactuated walker.These two walkers both have good performance in energy saving and natural gait pattern.The main work and conclusions are as following:(1)The analysis of the musculoskeletal structure of the lower limbs and its bionic design.The specific functional structure of human lower extremity joint(hip joint,knee joint,ankle joint,metatarsophalangeal joint,etc.)were analyzed,and its influence rules on human lower limb motion were studied.Its function display mode and biomechanical characteristics are discussed.Based on this,the design of the key components of the bionic knee joint,the bionic foot and other walking machines were conducted.(2)On the basis of bionic design of key components,a new passive bionic walking machine with bionic subtalar joint(sagittal plane joint axis inclination 45 degree)and metatarsophalangeal joint(toes)was developed.At the same time,a multibody model of the passive walker was constructed and simulated in Adams to verify the feasibility of its walking.Based on single factor test and multi-factor test,the walking performance of the biped robot was tested,the primary and secondary factors and the best match in the research area were obtained.The experimental results showed that the fully passive bionic biped robot achieve high walking efficiency under the optimal mechanical structure,it also achieve stable walking at the same time.Finally,the control system was designed,and a fully passive bionic walking machine with knee joints was developed based on the completely passive bionic walking machine without knee joints.(3)After the manufacture of the fully passive bipedal bionic robot,the design of the angular bisector(design of straight tooth wheel angular bisection mechanism and designs of bevel gear angle bisection mechanism)and the underactuated bipedal bionic robot(the design of an underactuated bipedal bionic robot with a knee joint and the design of an underactuated bipedal bionic robot without the knee joint)were carried out.Finally,it was demonstrated that the lateral swinging mechanism should be added to the underactuated bionic robot without knee joint.The final design scheme for the underactuated bionic biped robot was determined.(4)On the basis of the passive bionic biped robot without knee joints,a drive mechanism and a connecting rod angular bisector were added to the hip joint,and a mechanism that assists the side swing motion was also developed to the underactuated bionic biped robot.Then the physical prototype of the underactuated bipedal bionic robot was manufactured.Finally,the design of the control system was realized with Arduino,and the walking measurement was completed for the underactuated bionic biped robot.The results showed that the underactuated bionic robot developed in this work can show the compound natural walking gait with lateral swinging and walking,meanwhile achieving stable and energy-saving walking.