| Micro underwater vehicles play an important role in marine resources exploration,ecological monitoring,civil rescue and military investigation.The underwater vehicle which imitates the design of aquatic biology has some biological movement and morphological characteristics.In addition to its small size,low cost and portability,it also has the characteristics of high propulsion efficiency,strong mobility and low noise.Therefore,it is of great significance and practical value to develop corresponding micro underwater vehicles for micro aquatic organisms.The diving beetles has excellent swimming ability and can crawl faster on land,which is an excellent material for the design of micro-submersible robots.The body structure of the dragon lice is closely related to the swimming characteristics.It is very important to explore the flow field characteristics of the structure and the motion characteristics of the foot of the dragon lice for the design of a new micro bionic underwater robot.In this paper,the motion and force of swimming foot of adult golden lice were analyzed,and the force characteristics of body and swimming foot of dragon lice were analyzed by numerical simulation.The details are as follows:1.The morphological structure and motion characteristics of biological prototypes were observed and analyzed.High-speed camera was used to photograph the movement characteristics of the swimming foot of the diving beetles during swimming.It was observed that the frequency and amplitude of the swimming foot of the dragon lice were different under different motion conditions.When the dragon lice escaped,the frequency of watering was high and the amplitude was small,and the speed was gentle and the swing amplitude was large during the cruise.By observing the joints of swimming feet,the structural parameters of swimming feet and the characteristics of swimming rigid hair were obtained.2.Establish swimming foot movement and stress model.The swimming foot was simplified,and the simplified model of foot mechanism was established.The relationship between force and structure of swimming foot was analyzed,and the influence of underactuated two-bar mechanism was simulated.The D-H parameter method is used to establish the motion model of the simplified swimming foot mechanism of the diving beetles and its trajectory is given,which is in good agreement with the trajectory of the biological prototype.According to the characteristics of swimming foot,an underactuated bionic drafting foot with simple structure is designed,which can stretch and close automatically with the change of flow resistance.3.The relationship between flow field characteristics and structure was analyzed by numerical simulation of biological body and swimming foot.The three-dimensional model of the diving beetles was scanned,and the edge contour of the horizontal and lateral sections of the organism was extracted.The flow field simulation analysis shows that the drag reduction of the body and the vertical vortex can be generated at the tail.The characteristics of different gaps in swimming bristles were analyzed,and it was found that small gaps could significantly block the flow.The flow field characteristics of the seamless plate and the gap plate with different gaps are compared.When the gap size is consistent with the rigid wool gap,the gap plate is more seamless with the upstream surface.4.A submersible robot imitating diving beetles was designed and manufactured.The force model of underwater vehicle is established.According to the characteristics of swimming feet,the quadruped distribution scheme of diving robot that can realize multiple motions is designed.The physical prototype was made and the experimental platform was built;The underwater motion experiment of swimming foot was carried out,and its motion characteristics were in line with the design expectations. |
