Structure Design And Kinematics Analysis Of A Lightweight Quadruped Robot

City inspection is an indispensable and important part of smart cities.The urban environment is complex,and the requirements for the travel efficiency and terrain adaptability of the inspection robot are relatively high.The driving wheeled-legged quadrupedal robots combine the speed advantage of wheeled robots in the structured environments with the excellent obstacle crossing performance of quadruped robots in the nonstructured environments.However,its driving wheel-leg has the disadvantages such as heavy structure,poor stability and complex control system etc.In order to solve these problems,a passive wheeled-legged quadrupedal robot is proposed in this paper,for which lightweight structure is designed and an all-terrain adaptive gait are planned.For the structured environments,wheeled skating gait can improve walking efficiency.For the non-structured environments,the stable obstacle crossing can be achieved by foot adaptive gait.The main contents and contributions can be summarized as follows:(1)A lightweight passive wheeled-legged quadrupedal robot is designed.The ratio of self-weight and load is designated to 2:1 through the lightweight structure design of the integrated hollow joint,leg structure and body structure.The corresponding kinematics analysis,workspace analysis,structural parameter design,statics analysis,model drawing,finite element analysis and structural optimization are completed;(2)The roller-skating gait for the structured environments and the foot adaptive gait for the non-structured environments are designed.On the one hand,the starting gait,the straight gait,the turning gait,the fast turning gait and the corresponding trajectory of passive wheels are designed for roller-skating gait.On the other hand,the adaptive control strategy and the corresponding trajectory of passive wheels are designed for foot adaptive gait;(3)A gait simulation model of the passive wheeled-legged quadrupedal robot is established to verify the effectiveness and correctness of kinematics analysis,the structure design,the gait planning,the trajectory planning of passive wheels and the control algorithm.The flat ground simulated structured environments is used to simulate and verify the rollerskating gait.The terrain of stairs simulated non-structured environments is used to simulate and verify the foot adaptive gait.The experimental results satisfy the design requirements.