| Bionic robotic fish is a new type of highly efficient,highly maneuverable underwater operation and delivery vehicle.Currently,most of the carriers carrying robots are submarines,and less research is conducted on the carriers for bionic robotic fish.Submarines are often used for offshore salvage exploration,which has low operating efficiency,poor maneuverability,and limited working time.Therefore,the research on the use of vectors as bionic robotic fish remains to be further studied.This paper is to explore the problem of the balance characteristics of the robot hand bionic robotic fish system(Manipulator Bionic Robot Fish System,MBRFS)in different attitude operations in water environment,with the Manipulator-Bionic Robotic Fish Mechanism(MBRFM)as the research object.For MBRFS,where the carrier is in a free-floating state,the specific research contents are as follows:1)The three dimensional software is applied to design and assemble the body of the bionic robot fish,the manipulator with four degrees of freedom,the connecting mechanism,the snorkeling mechanism and the attitude balancing mechanism.MBMFS pose matrix motion equations are deduced through the MBFM spatial6-DOF motion method and the transformation between coordinate systems.Based on the establishment of the carrier coordinate system,the characteristics of the space movement and the conversion relationship between the two coordinate systems,the external forces and various external moments of the MBRFS during the movement were obtained.2)The joint space trajectory planning of MBRFS is performed using the polynomial interpolation method to avoid the appearance of singular position and joint limit angle.The virtual prototype model of the system was built to deduce the working scene of the sinking,suspension and ascending.Through the kinematic analysis of the mechanical structure of its grasping mechanism,the operating space of the end-effector is deduced.3)The kinematics simulations are carried out on the MBRFS virtual model such as sinking,grabbing and placing levitation and ascending postures.The simulated curves of angular displacement,angular velocity and angular acceleration of each joint of the carrier and grab mechanism can be applied to analyze the variation of the joint variables under the different attitude operation of the system in real time.It is concluded that the angular displacement of the carrier and the joint extension of the manipulator are the factors affecting the attitude balance of the system.4)Based on the hydrodynamic theory of the water environment,the CFD model is used to simulate the flow field of the MBRFS model.The influence of water resistance on the instantaneous equilibrium of the MBRFS system during the sinking and rising attitude is studied.The velocity cloud chart and turbulence energy cloud chart obtained from fluid simulation showed that the pressure in front of the carrier in the fluid is larger and the velocity tends to decrease.The resistance and resistance coefficients of MBRFS in the direction of Y and Z are different when sinking and ascending attitude,and the resistance in Y direction is greater.Therefore,the resistance in the fluid has a certain influence on the attitude balance of the underwater operation system.This paper analyzed the theoretical analysis of MBRFS dynamics and solved the problem of parameter determination in the overall design of MBRFM.Through the planning of the posture trajectory of the mechanism,the design accuracy of MBRFS is improved.By analyzing the water resistance caused by the operation under different postures,it is concluded that the resistance under water environment has a certain influence on the posture balance of MBRFS.The above research will provide reference for the development and application of MBRFS. |
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