Study On The Single Leg Of A Four-legged Robot Walking On A Slope In Imitation Of A Goat

In recent years,with the development of intelligent agricultural machinery and equipment,agricultural robots have achieved rapid development.At present,mobile agricultural robots mainly have crawler,wheel and foot.Foot robots have good obstacle-obstacle and flexible motion performance compared to other walking robots.At present,quadrupeds are more commonly used in agriculture,but the complex agricultural environment requires higher requirements for its stable walking ability.Therefore,the research on quadrupeds that can walk in rugged terrain is of great significance for promoting the development of intelligent agricultural machinery equipment in China.The goat's body is small,and after thousands of years of evolution,it has been able to walk freely on uneven ground,providing a bionic blueprint for the study of agricultural quadruped robots.1.Experiment and analysis of goat slope walking.The goat slope walking test system was built,and the image sequence of goat movement was obtained and processed.The motion parameters such as speed,acceleration,joint angle,walking gait and foot trajectory were obtained and analyzed.2.The mathematical model of the irregular bionic morphology at the bottom of the goat's hoof.The goat hoof three-dimensional scanning system was built to obtain the point cloud data of the goat hoof surface,and the point cloud,point,polygon,precise surface processing and deviation analysis were performed on the point cloud data.According to the characteristics of the goat's hoof,the point cloud data at the bottom of the goat's hoof is segmented,the segmented point cloud data is processed by non-uniform filtering and the three-dimensional coordinate values are derived,and then the three-dimensional coordinate values of the point cloud data are imported into the Matlab software.The polynomial fitting is performed,and the residual squared(SSE),mean square error(RMSE)and coefficient of determination(R~2)of the fitting result are analyzed to obtain the mathematical model of the irregular surface of the goat's hoof.Finally,the other three goat bottoms are selected.The three-dimensional coordinate values of the point cloud data are imported into the mathematical model and the correctness of the mathematical model is verified.3.Research on the design and mathematical model of imitation goat quadruped robot.Based on the analysis of the quadruped robot topology and the goat body mechanism,the goat-like quadruped robot is designed.Then,the four-legged robot is designed with the DH representation to analyze the kinematics of the single leg and the whole machine.The velocity and acceleration equations of angle change;finally,the kinetic analysis is carried out by Lagrange equation method to obtain the dynamic equation.4.Imitation goat quadruped robot gait movement planning.In the walk gait planning,the zero-impact foot-foot trajectory planning method based on high-order polynomial is used to plan the swing phase and the support phase respectively,then the Matlab software is used to calculate and draw the foot-end trajectory,and finally the four-legged robot is on the walk.The step-up diagram of the leg-lifting step when walking in gait.In the Trot gait planning,the modified compound cycloid trajectory planning method is used to divide the acceleration into three stages in the walking direction and the lifting leg of the quadruped robot in the order of lifting legs,stepping and landing,respectively.The acceleration is 0,the acceleration of the leg raising and landing stages is taken as a sine function.The variation of the acceleration of the single-leg foot end trajectory with time,the curve of speed with time and the displacement of the four-footed robot in the Trot gait can be obtained by Matlab software.According to the curve of time,the step-up sequence of the leg-lifting step of the quadruped robot in the Trot gait is finally obtained.5.Construction and testing of a goat-like four-legged robot test platform.On the basis of introducing the hardware of the test platform,the mechanical one-leg test platform and the whole machine test platform were built respectively,and the upper computer software was developed based on the OtoStudio software platform.Finally,the joint motion control experiment was performed on the mechanical single leg,based on the walk gait planning.The whole machine carries out the step-up test of the lifting leg,and after testing,it can achieve the desired effect.