Guijie Liu

A Review of Artificial Lateral Line in Sensor Fabrication and Bionic Applications for Robot Fish

Lateral line is a system of sense organs that can aid fishes to maneuver in a dark environment. Artificial lateral line (ALL) imitates the structure of lateral line in fishes and provides invaluable means for underwater-sensing technology and robot fish control. This paper reviews ALL, including sensor fabrication and applications to robot fish. The biophysics of lateral line are first introduced to enhance the understanding of lateral line structure and function. The design and fabrication of an ALL sensor on the basis of various sensing principles are then presented. ALL systems are collections of sensors that include carrier and control circuit. Their structure and hydrodynamic detection are reviewed. Finally, further research trends and existing problems of ALL are discussed.

Dynamics Modeling and Control Simulation of an Autonomous Underwater Vehicle

ABSTRACT Liu, G.; Chen, G.; Jiao, J., and Jiang, R., 2015. Dynamics modeling and control simulation of an autonomous underwater vehicle. A dynamics model of an open-shelf Autonomous underwater vehicle (AUV) is described in this paper. The virtual prototype technology and the control simulation software are used to build the virtual prototype model of AUV, and AUV dynamic location control arithmetic is simulated based on analyzing motion and hydrodynamic mathematical model of the virtual prototype. The simulation results indicate that the virtual prototype system has the function of simulation demo and performance validation, and can provide one kind of new method for AUV graphic simulation, and has very important practical meaning on AUV design and control research.

Impulse absorption by horizontal magnetic granular chain

The granular medium is known as a protecting material for shock mitigation. We study the impulse absorption of an alignment of magnetic spheres placed horizontally under a non-uniform magnetic field. The phenomenon of the wave dispersion is presented. This system can absorb 85% ∼ 95% (88% ∼ 98%) of the incident peak force (energy) under the applied magnetic field strength in 0.1 T ∼ 1.0 T. The shock attenuation capacities are enhanced by the increment of field strength. With an intelligent control system, it is conceivable that the magnetic granular chain may offer possibilities in developing adaptive shock protectors.

Tunable isolator based on magnetorheological elastomer in coupling shear–squeeze mixed mode:

In this article, the systematic design, construction, and testing of a novel tunable isolator based on magnetorheological elastomers in coupling shear–squeeze mixed mode have been studied. The influence of magnetic particle volume fraction on field-induced properties of magnetorheological elastomer isolator is studied, and the performance of vibration mitigation of magnetorheological elastomer isolator is evaluated experimentally. The results show that the frequency-shift property of magnetorheological elastomer isolator is linearly proportional to the magnetic particle volume fraction and applied current, and vibration mitigation capacity of magnetorheological elastomer isolator is remarkably enhanced by increasing the applied current. The design of magnetorheological elastomer isolator in coupling mixed mode may provide a new insight for using magnetorheological elastomers in vibration reduction applications.

Analysis and Forecast of Hydrodynamic Simulation for Small Autonomous Underwater Vehicle

According to the high cost and tedious work of model test method for fluid’s velocity issue around Autonomous Underwater Vehicle (AUV), this paper has found out the convenient simulation way by building the relationship of simulation results for AUV with rotating propeller and that with stationary propeller. Under different flow velocity and propeller speed conditions, hydrodynamic simulation for a small AUV model has been carried out to establish the relationship of drag coefficient for the two conditions mentioned above. The result demonstrates that margin of drag coefficient under the two conditions tends to be a fixed value. The analysis of actual running resistance of small AUV can be obtained only by studying that of stationary one base on the result. Numerical simulation method can be well used in the fluid’s velocity analysis instead of the model test method.

Dislocation Evaluation of Fe Twist Grain Boundary Based on Molecular Dynamics

The grain boundary and dislocation motion characteristics on the atomic scale are significant for the study of material failure mechanisms. In the present work, by theoretical analysis and numerical simulation, the most stable phase of Fe crystal under given conditions is confirmed. Distribution of dislocation potential under different torsion angles is studied for BCC-Fe (001) twist grain boundary. The dislocation motion in Fe (001), Fe (110) and Fe (111) twist grain boundary under tension, compression and shear loading are also investigated.

Research on flow field perception based on artificial lateral line sensor system

In nature, the lateral line of fish is a peculiar and important organ for sensing the surrounding hydrodynamic environment, preying, escaping from predators and schooling. In this paper, by imitating the mechanism of fish lateral canal neuromasts, we developed an artificial lateral line system composed of micro-pressure sensors. Through hydrodynamic simulations, an optimized sensor structure was obtained and the pressure distribution models of the lateral surface were established in uniform flow and turbulent flow. Carrying out the corresponding underwater experiment, the validity of the numerical simulation method is verified by the comparison between the experimental data and the simulation results. In addition, a variety of effective research methods are proposed and validated for the flow velocity estimation and attitude perception in turbulent flow, respectively and the shape recognition of obstacles is realized by the neural network algorithm.

Tunable evolutions of shock absorption and energy partitioning in magnetic granular chains

In this paper, we investigate the tunable characteristics of shock waves propagating in one-dimensional magnetic granular chains at various chain lengths and magnetic flux densities. According to the Hertz contact theory and Maxwell principle, a discrete element model with coupling elastic and field-induced interaction potentials of adjacent magnetic grains is proposed. We also present hard-sphere approximation analysis to describe the energy partitioning features of magnetic granular chains. The results demonstrate that, for a fixed magnetic field strength, when the chain length is greater than two times of the wave width of the solitary wave, the chain length has little effect on the output energy of the system; for a fixed chain length, the shock absorption and energy partitioning features of magnetic granular chains are remarkably influenced by varying magnetic flux densities. This study implies that the magnetic granular chain is potential to construct adaptive shock absorption components for impulse...

Computer Simulation of AUV Navigation System Using Fish Lateral Line Sensing Mechanism

Based on the study of fish lateral line sensing mechanism, integrated fluid dynamics, boundary layer theory, coupling theory and so on. To establish a neural network model similar to the fish neuromas model. After the numerical calculation and simulation analysis to simulate fish lateral line system, we can get the conclusions to apply to autonomous underwater vehicle (AUV) navigation and target recognition. Provided a new method for AUV navigation and environment perception. Computer simulation results presented that based on the fish lateral line sensing mechanism to build a perception model, AUV can identify a new water condition distinguishably. This discovery can be used in navigation and positioning of AUV.

The Research about the Vibroacoustic Characteristics of the Surface Cracked Plate

Vibration characteristics of surface cracked plate are studied from the view of structural intensity .Line-spring model of the surface crack is put forward based on fracture mechanics. The relationship of the additional angle and displacement with the crack parameters is derived. The concept of additional structural intensity is presented and the additional structural intensity’s expression of shell finite element is deduced. The change regulars between structural intensity and vibration parameters with crack’s parameters are concluded by using ANSYS and MATLAB software, the simulation results are matched with the trend of theoretical formula.