Research On Kinetics Analysis And Simulation Of German Shepherd Dog's Gait

At present, most walking device of ground vehicles are wheeled and tracked, and the two devices have bad obstacle climbing capability and shortcomings of consuming large quantities of power, so they can not suit the walking on soft and irregular ground. About 50% of the land on earth is not suitable for wheeled or tracked wheel, thus people focus on the biology to extract bionic prototype. In nature, through billions of years'evolution, animals'structure,morphological characters and function continuously adapted to the environment ,and their flexible locomotion machine and astute locomotion patterns have become an inexhaustible bionic source for developing robots. Scientists kept to learn from the animals, and researched on the locomotion modes of all kinds of animals, such as human bipedal walking,four-legged animals'running,jumping and earthworms'crawling way and ect. Researchers also revealed constantly the mechanism of organisms'movement and combine their superior structure with other disciplines to obtain some bionic machinery which better perform than those in the natural world. The bionic machinery has quite a wide prospect in application.The research shows that quadruped have better carrying capacity and stability than bipedal, and also has the more simple configuration than hexapod and eight-legged animal. Through these researches, prophase work has been done for design of leg-mechanism and drive system.As the development of gait analysis methods, biomechanics of motion has been a hot topic. By gait analysis of the organism, temporal-spatial, kinematics, kinetics and electromyography parameters have been utilized to assess the normal degree of limb,joint,muscle and ligamenta. Simultaneously, analysis on pathogeny and diagnosis of illness can help to decide how to carry out healing therapy; comparison of the parameters at pre and post surgical, and the effect of the healing therapy can also be assessed.Gait analysis of German Shepherd dogs has a wide application value in the breed evaluation of German Shepherd dogs,national defense,medicine,industrial design and engineering and so on. measuring the gait parameters of German Shepherd dog , analyzing the kinematics and dynamics characteristics of canine, and establishing canine Kinetic model are used to provide proofs for judging the stability of canine'walking in a qualitative and quantitative way and they also provide theoretical proofs for quadrupedal robots'bionic design and stability. This paper selected German Shepherd dog as the trial object, and VICON MX 3D motion capture system was utilized to capture the motion and to obtain the kinematic data and we fitted the kinematic functionθ(t) and v(t) based on these data, the degree of fitting is 95.42%,97.21%,98.63%,97.21% and 99.36%。Using the force plate with 3D motion capture system to capture the kinetic data of German Shepherd dog, and to measure the peak vertical and horizontal ground reaction force of the forelimb and hind limb. Based on these kinematic and kinetic data, this paper have analyzed the locomotion mechanism and done researches on effects of the forelimb and hind limb in the locomotive process and obtained that in the walking process of German Shepherd dog forelimb support more of the weight with the top supporting force up to 63.64%±0.81%of the total weight, while hind limb 37.86%±0.96% of the total weight. Comparison on the peak horizontal ground reaction force of the forelimb and hind limb as well as comparison on the time of the forelimb and hind limb spent in braking and propulsion during the stance phase, this paper indicates that braking impulses were significantly greater in the forelimb, whereas propulsion impulses were significantly greater in the hind limb. This paper analyzed the braking and propulsion mechanism.Adopting the method of system dynamics—Kane method to analyze the kinetic of hind limb of German Shepherd dog, and the movement of hind limb was simplified as a four-hinged-rigid-body-system horizontal movement. According to Kane method, this paper established dynamic calculation model , and got the calculation equations of the hind limb. Adopting simulation software—Adams, this paper established the dynamic simulation model of hind limb, and preliminary tests are passed which offered a model foundation for the optimization of simulation design.