Simulation Study On Magnetic Fluid-solid Coupling Drive Of Bionic Ascidian Soft Robot

With the massive development of resources and the continuous improvement of the strategic position of the ocean,underwater soft robots have become a hot research topic in the field of bionics.The existing underwater robot driving methods mostly use propeller propulsion,At present,most of the existing underwater robots were driven by propellers,which are complicated in structure,large in size and disturbed by close observation of Marine life.This paper proposes a bionic ascidian soft robot based on ascidian.The magnetic fluid-solid coupling driving method is employed to make the upper and lower sides of the bubble structure attract each other to simulate water jet propulsion.There is no motor when driving,reducing the noise of movement and simplifying the structure.This paper proposed a bionic sea squirt soft robot based on ascidian structure and motion mechanism,It is composed of a soft shell and multiple soft bubble structures,and each soft bubble structure can achieve independent extrusion deformation movement.Analyze its driving method,design the driving actuator of the soft robot.The driving actuator is composed of a soft bubble structure,an electromagnetic coil and a magnet.The electromagnetic coil and magnet are wrapped by soft materials on the upper and lower sides of the bubble structure.By controlling the on-off state of the electromagnetic coil,the actuator realizes the suction and opening of the bubbles,and then drives the soft robot to move.The electromagnetic properties of actuators driven by soft robot are analyzed.Based on Maxwell's electromagnetic theory,the working principle of the actuator is analyzed,and a three-dimensional finite element simulation model is established.Simulate and analyze the magnetic field performance and electromagnetic force generated by two sets of actuators with different working conditions.Through the comparison of the results,a better actuator structure and the best electromagnetic force are obtained.The propulsion performance of bubble structure of sea squirt soft robot is analyzed.Based on the fluid-solid coupling theory,the motion mechanism of the soft robot is analyzed,and a three-dimensional finite element model of the bubble structure is established.Numerical simulation and calculations are carried out.The simulation results show that the bubble structure has cyclically fluctuating propulsive force during extrusion deformation.The propulsive force data is calculated to obtain the propulsive force.In addition,the distribution characteristics of the pressure field and velocity field of the surrounding fluid and the vortex structure during the extrusion deformation of the bubble structure are analyzed,and the propulsion mechanism and flow field coupling effect of the extrusion deformation of the bubble structure are studied.The overall motion performance of the bionic sea squirt soft robot is analyzed.The steady state analysis of the soft robot was carried out,and the mechanical model of propulsion performance was established.The relationship between velocity and time,displacement and time was studied through the calculation of the mechanical model.The results show that thedrag coefficient decreases and becomes stable with the increase of the velocity.Finally,the bubble structure parameters are optimized.The influence of the new bubble structure on the propulsion of the software robot is analyzed,Through the analysis and comparison with the original bubble structure,it is concluded that the new bubble structure's propulsion efficiency is higher than the original bubble structure,and the stability of the movement is improved.In this paper,the shape of the soft robot of sea squirt is designed and its structure is simplified from the biological point of view.The magneto-fluid-solid coupling mode is adopted to drive,which reduces the noise and improves the environmental adaptability.The motion mechanism of the bionic sea squirt soft robot is analyzed by numerical simulation,which provides a theoretical basis for the further design and development of the bionic soft robot in the future and provides a theoretical basis for the optimization design.