Design,Analysis And Experiment Of Squid-like Underwater Robot Based On Origami Bellows

The bionic underwater robot imitates the swimming mode and physiological structure of natural underwater creatures,and has broad application prospects in scientific and military fields such as underwater resource investigation and development,underwater reconnaissance and early warning,underwater equipment maintenance,and underwater ecological environmental protection.Compared with the traditional propeller-driven underwater robot,the bionic underwater robot has better adaptability in the underwater environment,can pass in complex environments and narrow spaces,has high concealment performance when swimming,and low noise.At present,the bionic underwater robot mainly adopts the swimming mode of fin or torso motion propulsion and jet propulsion,which is widely used in science and military fields.However,at present,the bionic underwater robot swimming by jet propulsion still has the problems of low propulsion,slow response speed and inflexible steering action.Therefore,in this paper,a bionic squid underwater robot is designed based on origami bellows.The main contents are as follows:An underwater robot was designed based on origami bellows imitation squid swimming method.The robot consists of a pulse jet mechanism and a fin wave mechanism.The motion characteristic of the pulse spray mechanism is to use origami bellows to axially expand and contract to change the internal volume,complete the repeated process of water storage and spray to achieve the pulse propulsion function;the fin wave mechanism uses streamlined semicircular fins.The structure swings back and forth to realize the fin wave propulsion function.Based on hydrodynamic analysis,a jet propulsion model and a fin wave propulsion model were established,prototypes were made,and an experimental test system was set up for performance testing.The test results show that the maximum propulsion force of the pulse jet mechanism is 0.8 N,and the driving speed of the underwater robot is 2.8 cm/s at a driving voltage of 12 V,a frequency of 0.2 Hz,and a duty cycle of 50 %;the fin wave mechanism drives the underwater robot steering,the maximum steering angular velocity is 36 °/s,and the minimum steering radius is 10 cm.When the underwater robot adopts the composite swimming method,the maximum swimming speed is 10.5 cm/s.In order to solve the problems that the underwater robot designed with origami bellows still has a small propulsion force and a small amount of water spray during a single motion cycle.It is necessary to analyze the performance of origami bellows and propose optimization for the design of origami bellows method.By analyzing the relationship between the size parameters of origami bellows and the performance of the underwater robot,the unit maximum storage water volume model of the underwater robot was established from the size parameters of origami bellows.Analyze the folding movement process of origami bellows,and use the response surface method to establish an estimation model that reflects the mechanical properties of origami bellows.Using the structural parameters of origami bellows as variables,the performance index value of origami bellows was obtained based on the mechanical performance estimation model of origami bellows and the unit maximum storage water model,and a multi-objective optimization model was established.The Pareto was obtained using the MOGA genetic algorithm the optimal solution set is selected from the Pareto optimal solution set.A prototype of an underwater robot is made for experimental testing.The experimental results show the feasibility of optimizing the design of origami bellows of the underwater robot and the effectiveness of the optimization method.In order to further improve the steering performance and movement stability of the squid-like underwater robot,the underwater robot is improved based on the flexible fin structure,and the deformation mode of the flexible fin structure is simplified according to the structural characteristics of the flexible fin structure.The flexible fin structure is affected by inertial force and fluid dynamics,and will generate corresponding flexible deformation when swinging in water.This flexible deformation can affect and improve the performance of the underwater robot.Assemble the underwater robot and build an experimental test system,use various materials,aspect ratios and shapes to make flexible fin structures,and conduct experimental tests on the steering performance of the underwater robot based on the flexible fin structure.The influence of the design parameters of the flexible fin structure on the steering performance of the underwater robot is analyzed.The experimental results show that when the flexible fin structure of the underwater robot is made of polypropylene plastic,the aspect ratio is selected between 1.5-1.75,and the shape is fin-shaped,the steering performance of the underwater robot is the best.In order to enhance the environmental adaptability of the underwater robot based on origami bellows imitation squid swimming method,an underwater robot was designed based on the pneumatic soft actuator.The multi-cavity type pneumatic soft actuator used can satisfy the kinematic performance of the underwater robot while making the overall structure of the underwater robot more compact and lightweight.Based on the Yeoh constitutive model and the principle of moment balance,a bending deformation model of a multi-cavity pneumatic soft actuator is established.Make a multi-cavity type pneumatic soft actuator and perform performance test analysis.The pneumatic soft actuator can realize the morphological change from the straight state to the 180 ° bending state,the driving of the underwater robot origami bellows can be realized.Make prototypes of underwater robots,build experimental test platforms,and test the performance of underwater robots.The experimental results show the feasibility of the underwater robot.