| Based on bionics,combined with fluid transmission technology,software materials,structure design and so on,a bionic jellyfish robot with good flexibility and underwater sampling function is designed in this paper.It has certain engineering application value when it is applied to the field of underwater resources exploration and exploitation.The main contents and achievements of this paper are as follows:(1)The overall structure of sampling jellyfish is designed.The sea moon jellyfish is selected as the bionic object.Combined with the biological morphology and swimming characteristics of jellyfish,the body structure of the sampled jellyfish is designed.And establish a theoretical model of dynamics,It provides a theoretical basis for the design of swimming attitude.In addition,the theoretical model of underwater clamping operation is established to provide theoretical support for the rational design of sampling gripper.(2)The sampling jellyfish pushes forward through the contraction and relaxation of the umbrella cavity driven by the software driver.When designing the actuator,analyze the mechanical properties of the software material,The key parameters of the actuator are simulated and analyzed to determine the reasonable structure parameters of the actuator.The actuator mold is designed and manufactured,and the actuator is made by pouring method using silicone rubber material.An experimental platform is built for the bending performance of the actuator,and the relationship between air pressure and bending angle is measured.The experimental results are compared with the simulation results to verify the reliability of the simulation results.(3)An underwater sampling gripper is designed and manufactured,which is operated by three soft variable stiffness actuators.The actuator is composed of a driving part and a variable stiffness part.In the design of the variable stiffness part,combined with the design goal of the underwater gripper and the problems existing in the particle blocking technology,Taking inspiration from human fingers,based on bionics,the variable stiffness technology of mixed blockage of endoskeleton and particles is proposed.The large-scale variable stiffness ability of the actuator is realized.In the design of the driving part,the bearing capacity and reliability of the actuator are improved based on the filament winding method.When determining the filament winding parameters,the experimental platform is built,and the scientific and reasonable parameters are obtained from the four aspects of fiber diameter,coverage,material and position.Finally,the software variable stiffness actuator is manufactured by layer-by-layer processing method,and the prototype is assembled and completed.(4)In order to verify the performance of the sampling gripper,the theoretical model of the bending angle of the actuator is established,and the experimental platform is built to analyze the bending angle control,bending accuracy,bending stiffness adjustment and response speed of the actuator.The results show that the actuator has higher control precision,larger stiffness adjustment range and faster response speed,which is consistent with the results of the theoretical model.In addition,the underwater clamping experiment of the gripper is carried out,and the gripper can carry out stable and reliable underwater clamping operation for objects of different shapes and weights in a certain range.(5)According to the functional requirements of submersible sampling jellyfish,the control circuit of the prototype is designed and completed.The underwater clamping swimming experiment of the prototype is carried out.When the sampled jellyfish holds 250 g weight underwater and the umbrella cavity maintains the contraction frequency of 0.25 Hz,the floating swimming speed can reach 16 mm.The results show that the sampled jellyfish has good swimming performance on the premise of realizing the requirement of underwater stable clamping. |
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