Recearch On The Biological Mechanism Dynamics And Jumping Dexterity Of Domestic Cats

Researching the movement mechanism of animals and developing bionic robots are important methods for robot research.Jumping ability is an important athletic ability for many terrestrial animals,enabling them to adapt to various complex terrains.Cats are very good at jumping.In this paper,the principle of cat's motion dynamics during the jumping process is analyzed to explain the biodynamic mechanism of motion flexibility and design a robotic mechanism with cat-like jumping ability.(1)A skeletal structure model of a cat is established.By analyzing the anatomical configuration of the cat's skeletal mechanism,the characteristics of the its jumping movement were researched,its mechanism was simplified,and its functional sections were divided.The mass,centroid position and moment of inertia of each segment were estimated based on the geometric characteristics of each segment.(2)The kinematic model of the cat mechanism model was established.The D-H method was used to analyze the kinematic model.The movement model of the cat in three jumping processes was established,including the processes of taking off,flying,and landing.(3)The dynamic model of the cat mechanism model is established.The Lagrangian method was used to establish the dynamic model of the cat mechanism.The torque was calculated in MATLAB,and the simulation results were compared with Adams to verify the correctness of the dynamic model.(4)The morphological parameters(mass of each segment,position of centroid,and moment of inertia)of the mechanism model were optimized.Cats were used to make jumping experiments.The force on the ground during the cat's take-off and the center of mass trajectory and morphological changes of the catapult were recorded.The results obtained from the calculations made by the model were compared with those obtained from experiments,and clear errors were found.The Levenberg-Marquardt method is used for iterative optimization to obtain parameters that make the trajectory error smaller.The optimized parameters are used as accurate morphological data.(5)It is analyzed that the cat can make itself more flexible by adjusting the angle of the waist joint during the vacant stage.Based on the principle of conservation of momentum,the adjustment ability of cats in the jumping phase is analyzed.It has been proved that cats can use their waist movements to adjust the toe and hind toe position to a certain extent after taking off.Finally,according to the cat's bone structure and in order to improve the flexibility of the robot,a cat-like jumping robot with two rods at the waist was manufactured.