The Study For A New Foot Structure Based On Mast-type Octahedral Tensegrity Structure

The foot,as the part of the human being that is in direct contact with the ground during walking,has evolved in nature to develop the ability to walk on complex ground adaptively and plays a vital role in the gait walking process.Similarly,the motion of the foot is closely related to shock absorption and weight-bearing stability,and for robots,the foot structure of the robot also plays a crucial role in robotic gait walking.In order to make the foot structure of a humanoid robot have similar walking function as human foot and improve the stability of robot gait walking,this paper proposes a new foot structure based on the mast-type octahedral tensegrity structure to improve the flexibility,stability and self-adaptability of the traditional foot structure.The main content of this paper contains the following parts: firstly,a mathematical model of the mast-type octahedral tensegrity structure is established.The mast-type octahedral structure is analyzed statically and inverse dynamically,and the equivalent structure of the mast-type octahedral tensegrity structure is obtained through the rigid replacement between the components,and the ADAMS simulation is used to verify that the equivalent structure can well simulate the basic motion characteristics of the human foot;In order to better limit the degrees of freedom of the equivalent structure and avoid the structural instability caused by too many degrees of freedom,the mechanism mapping model of the new foot structure is designed,and the effectiveness of the proposed design method of the new foot structure based on the mast-type octahedral tensegrity structure is verified through the spatial analysis of the mechanism mapping model.Secondly,the structural design of the new foot structure.The mechanical structure of the foot structure is designed according to the mechanism mapping model,and a locking structure based on the ratchet gear structure is added to the equivalent structure of the mast-type octahedral tensegrity structure to improve the stability of the foot structure.Finally,the physical prototype model was fabricated and tested for performance.Some parts of the prototype were manufactured by rapid prototyping technology,and the assembly and debugging of the mechanism were completed according to the designed prototype model.An experimental platform was built to experimentally verify the topographic adaptive motion functional characteristics of the new foot structure and the stability of the ratchet gear locking mechanism.The new foot structure takes the biological model of human foot as the bionic sample,combines the tensegrity structure with the mechanism science design,uses the locking structure,realizes the free switching between the rigid foot structure and the flexible foot structure,improves the stability of the traditional foot structure,better simulates the motion characteristics of human foot,and is used to solve the problem of adaptive terrain walking of the foot mechanism of the humanoid robot foot.