Analysis And Simulation Of Kinematic Characteristics Of Goat's Multi-mode Gait

Footed robots are currently one of the hotspots of robotics research.Relying on strong ground adaptability,footed robots have a wide range of applications in transportation,rescue,service,and entertainment.Most of the footed robots are quadruped robots,because it has the best overall performance.The quadruped robot has stronger stability,better carrying capacity,and wider application scenarios than bipedal robots.At the same time,they have simpler structure and more convenient control than hexapod and octopod robots.Quadruped animals such as horse,dog,and goat have excellent movement capabilities and can quickly pass through rugged and complex terrain.Therefore,quadruped robots often use quadrupeds as bionic objects to simulate the body structure and walking gait of quadrupeds.The research on the gait of quadruped animals can provide design ideas and basis for quadruped robots and promote the development of robots.Goats have a strong ability to adapt to complex terrain.Relying on their unique body structure and gait,goats can quickly and steadily pass mountains,fields and snow,easily climb extremely steep slopes,and even climb branches and keep it steady.The analysis of the goat's gait is helpful to the optimal design of the quadruped robot.The current research on goat gait mainly focuses on the flat ground and slope,but little research on unconventional roads.In this paper,the kinematics analysis of the multimode gait of goats on ordinary and unusual roads is carried out,trying to analyze the gait adjustment mechanism on different roads,fitting the trajectory of the foot,and finally simulate the movement of the goat's quadruped model.Three types of unusual pavements were designed as test sites,namely snowfield,rugged pavement stacked with bricks,and trenches of different widths.Paste markers on the joints of the fore and hind limbs of the goat,record the motion video with a highfrequency camera,and process the video with professional data analysis software to obtain kinematic data such as speed,stance time,swing time,stride length,and joint angle.Comparing the kinematics data of goats on snowfield,rugged pavement and trenches with those of flat roads,it is found that goats adopt different gait adjustment modes.The forelimbs of goats mainly provide braking force,while the hindlimbs mainly provide impetus.Therefore,on snowfield that are prone to skidding,the goat's gait is mainly adjusted for the forelimbs,while rugged pavement and trenches require greater driving force,and the goats mainly adjust the hindlimbs.The trajectory of the goat's hoof is an important part of the gait,and there are obvious differences on different pavement.High-order polynomial fitting is performed on the trajectory of the hoof in the Origin software,and the fitting number is determined by combining the fitting parameters and the fitting image to obtain the fitting equation,which provides a basis for the gait design of the bionic quadruped robot.In order to verify the feasibility and rationality of the goat-like quadruped robot,a goat-like quadruped model was designed in Solid Works according to the goat's body structure parameters,and the forward and inverse kinematics analysis of the model was carried out.Import the model into ADAMS to set the physical parameters,and then import it into simulink of MATLAB to design the control system.Based on the walking gait of the goat,the walking gait of the quadruped model was designed,including the gait timing and the bionic hoof trajectory,and the sinusoidal hoof trajectory was designed for comparative analysis.In simulink,the walking gait simulation of the goatlike quadruped model is completed and the simulation results are output.The results show that the quadruped model is more stable when walking with the bionic hoof trajectory than the sinusoidal hoof trajectory.