Study On Walking Mechanism And Stability Of The Eight-legged Robot

With the development of the robot technology, walking bionic robot is gradually becoming the hotspot. This is due to that its advantage of mobility, good stability, fast walking speed in unstructured terrain. This research is originated from "Research on the Multi-legged Bionic Crab-liked Robot's Walking Method of the Complex Topography", which is funded by National Natural Science Foundation of China. Through the analysis of the crab body structure, the research aims to design and product a eight-legged bionic robot, imitate the crab movement mechanism and find the appropriate gait planning method, which will make eight-legged robot walk more stably and efficiently.Firstly, This thesis presents the multi-legged robot development at home and abroad briefly and the key technologies and the development trend of multi-legged robot. Based on the achievement of the former, the overall structure are proposed and designed, including modular joint based on elastic rotation drive and the arc-type bionic leg-end structure. This thesis also presents the hierarchical control architecture scheme and hardware circuit design of the eight-legged robot briefly. Base on the structure design, though the analysis of the institutional characteristics of the whole eight-legged robot and single leg, both of them are simplified. According to the simplified body model, the kinematics model of the single leg is established with the D-H method, and the whole robot kinematic model is analyzed briefly. Meanwhile, the author carries out the dynamics analysis of the eight-legged robot, including dynamics analysis of the single elastic rotated joints, the single leg and the overall dynamics analysis. Kinematics and dynamics analysis lays a complete theoretical foundation for the study on the eight-legged robot movement mechanism.Moreover, based on mechanism characteristics analysis and kinematics analysis of the eight-legged robot, the author presents the robot static stability description method which is realized by using normalized energy stability margin criterion, and general statically-stable margin mathematical calculation model of the robot are established. And the stability with different walk way was compared on the horizontal and inclined plane respectively.Then, with the result of research on stability, the studies on the robot walking gait are presented. The author puts forward the continuous likeness rolling gait, which are compared with traditional double four-footed gait on performance, proving the superior properties of the continuous likeness rolling gait. Base on the study of the horizontal walking gait, the author also analyses the longitudinal walking gait and obstacle-navigation gait, getting the following guide gait thoughts be applied to the longitudinal walking gait planning of the eight-legged robot.At last, a number of experiments on the key technologies of the eight-legged robot studies are carried out, including vibration performance testing of the elastic rotation drive joints, which is based on "ADAMS" and "Pro/E" virtual simulation; continuous likeness rolling gait's walking performance testing and longitudinal guiding gait's walking performance testing; both of which are based on "dSPACE" and prototype. Through the experimental analysis, the author proves the good vibration characteristics of the elastic rotation drive joints, and excellent walking performance of the continuous likeness rolling gait.