| Jumping robots have the strong ability to overcome obstacles and can move farther on alien surfaces with low gravitational acceleration,thus they can be used in military reconnaissance,environmental detection and space exploration.Many creatures in nature have the ability of jumping,and these unique jumping styles can provide inspiration for the research of new jumping robots.In this dissertation,primates of callitrichidae was selected to explore the mechanism of their trunk-to-trunk leaping.First,bone biomechanical analysis was performed.Femur models of callitrichidae lower limb was established by three dimensional reconstruction method,and its mechanical properties were analyzed by ANSYS,and the stress values of the cranial and caudal sampling areas were extracted.The mechanical characteristics of the femur of callitrichidae and other animals were compraed,and simplified models were established to further study the relationship between bone curvature and the direction of external loads.The simulation results show that the higher stress region of the femur is located in the middle 1/4 of the distal diaphysis,and the stress value of the cranial and caudal sampling area is low when the external force angle is about 90?.When the stress angle is100±5?,the stress value of curved structure is lower than that of straight structure,this indicates that bone curvature is related to the external loads of different motion modes.Secondly,kinematics and dynamics models of callitrichidae lower limbs were analyzed.The forward kinematics equations of lower limbs were derived based on D-H method,and the inverse kinematics was solved.The lower limb workspace was drawn by Monte Carlo method.The lower limb dynamics model was established based on Lagrange equation,and the functional relationship between the joint driving torque and the joint angle was obtained.The results show that the total displacement of the lower limb is2595mm,the maximum kinetic energy can reach 4×10~4N·mm during the takeoff,and the angle of the knee joint decreases to 26.87?during the takeoff and increases to 114.57?during the landing.Then,the effects of callitrichidae tails on their aerial posture were studied.According to different tail swing characteristics,ADAMS was used to simulate the yaw,roll and pitch posture of callitrichidae in the air.In order to improve the pitch posture of callitrichidae,different parameters were used in jumping experiments.To further control the body posture of callitrichidae,tail-body dynamics model was established and pitch angle feedback control was carried out.The simulation results show that the angular momentum between the tail and the body is conserved during the flight stage,and the tail swing can increase the pitch angle of the body.When the swing angle is 120?,the impact on the body pitch posture is the best.In the MATLAB/Simulink environment,the pitch angle of the robot dynamics model reaches the desired value at 0.5s by PID control.Finally,the jumping experiment of the bionic robot was carried out to verify the correctness of the theory and simulation.The experimental system consists of a catapult platform and a bionic robot.The ejection platform can simulate the jumping action of callitrichidae lower limbs to eject the robot.The robot prototype is tail-body two-link structure,using steering gear to control the swing of the tail.The slow motion in the flight stage shows that the tail swing can obviously increase the pitch angle of the robot.In this paper,callitrichidae were selected as biomimetic objects to study the mechanical properties of their bones and limb changes,and quantify the influence of tail on their body posture.The results show that tail plays an important role in adjusting the pitch posture of callitrichidae,and this biological characteristic can improve the posture stability of the jumping robot. |
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