水下无人系统学报

Research on Vibration Environment of Lightweight Torpedo Borne Equipment Based on Modal Superposition Method

ZHANG Yi-wen, YIN Shao-ping, WANG Zhi-jie, GUO Jun, ZHANG Zhi-min, GAO Shan

2016, 24(6): 401-406. doi: 10.11993/j.issn.1673-1948.2016.06.001

[Abstract](1001) [PDF 1840KB](412)

Abstract:
The vibration environment of lightweight torpedo borne electronic equipment is investigated to solve the problem of complex vibration environment and lack of vibration data, this study establishes a calculation model of the torpedo′s electronic cabinet based on finite element method, and calculates modal data, such as natural frequency and vibration modes, by using the software ANSYS Workbench. Comparing the calculated data with the modal testing data, the model is proved to be correct. The modal superposition method is employed to predict the vibration environments of the torpedo borne equipment based on this model. The prediction results show that the equipment assembled on baffle plate is subjected to a harsher vibration environment. So an improved design scheme is proposed to reduce the root mean square of vibration data by more than 40% comparing with the original design, which infers that the improved design scheme can be applied to the structure design of a lightweight torpedo.

Effect of Pump-jet Propulsor Duct on Sound Field of Rotor

LU Ding-ding, FU Jian

2016, 24(6): 407-411. doi: 10.11993/j.issn.1673-1948.2016.06.002

[Abstract](947) [PDF 1786KB](503)

Abstract:
The sound field generation and propagation of a pump-jet propulsor is quite different from that of a propeller because of the existence of the duct. In order to understand the sound performance of the pump-jet propulsor for its acoustic optimization design, the point source model and boundary element method are used to forecast the sound field of rotor in the duct, and the effect of the duct on the sound field is analyzed. The characteristic of rotor sound field in the duct is similar to that of the propeller, and the directivity of wide-band acoustic source level shows 8 shape. The incident sound field and scattering sound field of the rotor are quite different due to the scattering effect of the duct, resulting a remarkable effect of the duct on the sound field of the rotor in radial direction, and a neglectable effect in axial direction.

Design and Performance Analysis of a Multi-resonant Broadband Tonpilz Acoustic Transducer

TIAN Feng-hua, SONG Zhe

2016, 24(6): 412-416. doi: 10.11993/j.issn.1673-1948.2016.06.003

[Abstract](2079) [PDF 1614KB](503)

Abstract:
To broaden the working bandwidth of an acoustic transducer, improve its transmitting performance and reduce transmitting fluctuation, we designed a novel multi-resonant broadband Tonpilz acoustic transducer by using comprehensively the matching layer, the double exciting, the bending vibration, and slotting on the middle mass block, etc., employed the finite element method to conduct modal analysis of the transducer, and investigated the influences of the thickness of the matching layer and the size of the middle mass block on the performance of the transducer. Test verified that the working bandwidth of the transducer was 12 kHz ~ 42 kHz, the transmission voltage response(TVR) was greater than 140 dB, and the transmission voltage fluctuation in the frequency band was less than 6 dB. Calculation results were in good agreement with the test ones.

Selection of Auxiliary Samples for Reverberation Suppression via STAP

ZHAO Shen-dong, ZHOU Tian-zai, SHEN Jian-sen

2016, 24(6): 417-421. doi: 10.11993/j.issn.1673-1948.2016.06.004

[Abstract](1263) [PDF 1688KB](353)

Abstract:
A key link in space-time adaptive processing (STAP) is the estimation of covariance matrix, which depends on auxiliary samples near the sample to be detected. To ensure the estimation accuracy, sufficient independent identically distributed auxiliary samples are necessary. In this paper, the correlation of reverberation auxiliary samples, the identical distribution characteristic, and the selection of time point number are analyzed, and a corresponding valid scheme is given according to the characteristics of acoustic signal. As a result, a selection method of auxiliary samples for reverberation suppression via STAP is proposed through comprehensively considering the estimation precision of covariance matrix, the operand of adaptive processing, and the dimension-reduced STAP.

Design on Multi-excitation Broadband Tonpilz Transducer

HU Fu-ji, ZHANG Wen-bo, WANG Ming-zhou

2016, 24(6): 422-425. doi: 10.11993/j.issn.1673-1948.2016.06.005

[Abstract](1236) [PDF 1430KB](407)

Abstract:
Multi-resonant broadband Tonpilz transducer takes the way of coupling multiple vibration modes, so it broadens frequency band. In this paper, for the development of underwater acoustic signal technology, the equivalent circuit method and the finite element analysis method are used to analyze the performance of the double-excitation source multi-resonant transducer for bending vibration of the front cover plate. The results of these two methods are in good agreement. Moreover, the finite element analysis software ANSYS is employed to investigate triple-excitation source multi-resonant transducer. The results show that the frequency band of the double-excitation source multi-resonant transducer is effectively broadened, and the triple-excitation source multi-resonant transducer undergoes small influence of the mass thickness in its working frequency band. This study may provide reference for design of bandwidth and fluctuation of the multi-resonant broadband transducer.

A DSP Implementation Method of Multi-point Real-Time Receiving and Transmitting Scale Target Simulator

ZHAO Jun-jie

2016, 24(6): 426-430. doi: 10.11993/j.issn.1673-1948.2016.06.006

[Abstract](1264) [PDF 1657KB](348)

Abstract:
In underwater acoustic countermeasure there is a big difference between the single-receiving multi-transmitting scale target simulator and the real submarine echo. In this paper, an implementation method of multi-point real-time receiving/transmitting scale target simulator based on advanced digital signal processor(ADSP) is presented. This method adopts the multi-point receive-transmit mode and the multi-channel signal parallel real-time detection and processing to improve the target simulator's simulation fidelity of underwater target in terms of the space echo characteristics and the time/frequency domain characteristics. Test results show that the minimal time delay of the system can be controlled less than 10 ms, and the difference between time delay simulation and target strength simulation is reduced, thus the echo frequency of each highlight is more close to the real submarine echo frequency. This study may provide reference for further optimization of the scale target simulation technology.

Simulation on Closed-loop Control of Torpedo Turbine Rotary Velocity

MA Liang, YANG Cheng-shi, ZHANG Xiao-yi, LU Jun, CHEN Gang, HAN Yong-jun

2016, 24(6): 431-437. doi: 10.11993/j.issn.1673-1948.2016.06.007

[Abstract](1160) [PDF 486KB](878)

Abstract:
To realize speed variation of a torpedo in a wide range, the nonlinearity and the remarkable variation of parameters due to the speed and depth variations in wide range are considered for a certain type of turbine engine system of thermal propulsion torpedo. The models of fuel-variable pump, combustion chamber and engine are established to obtain the nonlinear and dynamic characteristics of the system as well as the system parameters in different conditions. Further, a closed-loop control strategy of rotary velocity is drawn up, and the proportion-integral-derivative(PID) control algorithm with variable parameters is adopted to implement rotary velocity control simulation of the turbine engine. Simulation results indicate good performance of the closed-loop control of turbine engine rotary velocity.

Dynamic Simulation of Closed Cycle Power System for UUV

BAI Jie, DANG Jian-jun, LUO Kai, LI Dai-jin

2016, 24(6): 438-443. doi: 10.11993/j.issn.1673-1948.2016.06.008

[Abstract](1228) [PDF 1664KB](536)

Abstract:
The closed cycle power system based on Li/SF6 heat pipe reactor is investigated for the purpose of designing high energy density power system of unmanned underwater vehicle(UUV). The moving boundary models of an evaporator and a condenser are established based on mass conservation and energy conservation equations with dividing their heat exchangers into different areas. The steady state model of a turbine and the dynamic model of a liquid trap are established. And the dynamic model of the whole system is built. With step change of the inlet water flow rate of the evaporator, the dynamic characteristics of the key components of the system are obtained by simulation. The results show that with the increase in the inlet water flow rate, the pressure in the tube rises up, the temperature at evaporator outlet decreases, the turbine power output gets higher, and the phase zone lengths of the evaporator and condenser change. When the flow rate decreases, the above behaviors change on the contrary. These models may be applicable to design of UUV power system and its control strategy.

Influences of Magnetizing Modes on Exciting Force Waves of Permanent Magnet Brushless DC Motor

FAN Xiao-bo, HU Li-min

2016, 24(6): 444-449. doi: 10.11993/j.issn.1673-1948.2016.06.009

[Abstract](1293) [PDF 1666KB](425)

Abstract:
In order to reduce the vibration and noise of the permanent magnet brushless DC motor(PM BLDCM) for underwater vehicle, a finite element analysis model is established for PM BLDCM to investigate the difference between an electromagnetic exciting force waves of PM BLDCM with two different magnetizing modes. And the distribution characteristics of flux density of air gap for parallel and radially magnetizing modes in both no-load and load conditions are obtained and compared. Then, the electromagnetic forces are derived via the Maxwell stress tensor, and the electromagnetic force waves of PM BLDCM in both no-load and load conditions are simulated. The influences of two magnetizing modes on electromagnetic force waves are analyzed, and the distribution characteristics of the waves are achieved. The results show that in no-load and load conditions the electromagnetic exciting force waves are quite different, so the influence of load on exciting force waves must be considered in analyzing the influence of magnetizing mode on the exciting force waves; and compared with in parallel magnetizing mode, the amplitude of the main frequency increases in radially magnetizing mode but the amplitudes of other frequencies reduce.

Alignment Method for SINS-Tachometer Integration Based on Reverse Navigation Algorithm

ZHANG Fu-bin, DONG Quan-wei

2016, 24(6): 450-457. doi: 10.11993/j.issn.1673-1948.2016.06.010

[Abstract](1781) [PDF 2276KB](415)

Abstract:
Tachometer is cheap, and it can measure autonomous underwater vehicle′s relative axial velocity to surrounding water during high speed navigation, so it becomes an auxiliary device for alignment of strap-down inertial navigation system(SINS). In this paper, a method for integrating SINS and tachometer is proposed. The data from tachometer are used to correct the infor-mation collected by inertial sensors, and the information obtained from the system is processed forward and backward alternately according to the idea of reverse solution. By increasing processing times of sampled data during the period of alignment, the alignment accuracy and performance of the system can be enhanced. Simulation result shows that the SINS-tachometer integration can realize rapid alignment and satisfy the requirement for alignment accuracy. The proposed method may be applied to an AUV formation, coordinative mission of multiple vehicles, topographic survey and seabed chart drawing, etc.

Simulation on Information Fusion Theory of Network-Torpedo Integrated Navigation

ZOU Qi-ming, WAN Ya-min, CAO Meng

2016, 24(6): 458-462. doi: 10.11993/j.issn.1673-1948.2016.06.011

[Abstract](1143) [PDF 1616KB](402)

Abstract:
To meet high accuracy requirement of network-torpedo navigation and to ensure high fault tolerance of the navigation system, an inertial navigation system(INS)/Doppler velocity system(DVS)/global position system(GPS) federated Kalman filter scheme is proposed based on information fusion theory. The system equations of INS/DVS, INS/GPS, and INS/DVS/GPS and the measurement equations are established, and the multi information fusion of different integrated navigation patterns is studied by using the non-feedback reset federated Kalman filter to satisfy the accuracy requirement of network-torpedo navigation. Simulation results show that the design of the non-feedback reset federated filter is effective in greatly reducing the error of each navigation parameter and achieving high accuracy of underwater long-range integrated navigation for the network-torpedo.

Dynamic Simulation of Torpedo′s Electric Servo Actuator

SHI Jin-qi, ZHANG Qin-geng, WANG Li-wen, YANG Hong-kai, ZHAO Xiong-hui, LI Jun

2016, 24(6): 463-468. doi: 10.11993/j.issn.1673-1948.2016.06.012

[Abstract](1042) [PDF 2119KB](595)

Abstract:
A mechanical system model of torpedo′s electric servo actuator is established based on the multi-body dynamics software RecurDyn to reflect the transmission characteristics of electric servo actuator, and an electric actuator control system model is established with Matlab/Simulink. Then, coordinated modeling of transmission mechanism and control system of the electric servo actuator is conducted. Compared with traditional design methods, this coordinated simulation analysis method can accomplish kinematic and dynamic analyses of a servo actuator according to real working condition in early design of its physical prototype to obtain actual transmission characteristics, thus to optimize the design and improve design efficiency.

Effect of Homing Range on Lightweight Torpedo's Anti-submarine Operation Efficiency

CHEN Jing, HE Xin-yi, LEI Lei, GAO He

2016, 24(6): 469-474. doi: 10.11993/j.issn.1673-1948.2016.06.013

[Abstract](1401) [PDF 1931KB](405)

Abstract:
In conventional evaluation of lightweight torpedo's anti-submarine operation efficiency, the homing range is taken as the constant input parameter, which influences the evaluation accuracy. Therefore, this paper analyzes the relation between homing range and irradiation angle. Adopting the multi-highlight model and the torpedo homing range prediction model based on the grid search method, this paper contrastively analyses the target detection probability via simulation experiment for two different situations: 1) taking the homing range as input parameter, and 2) taking the estimated value of homing range in actual battlefield environment as input parameter. The results suggest that in order to more really reflect battlefield situation, the real homing range be taken as the input parameter for evaluation of the torpedo's anti-submarine operation efficiency according to situations of ourselves and the enemy and hydrological condition.

Analysis and Application of Wake Homing Torpedo's Potential Attack Area

ZHAO Xiang-tao, KOU Zhu, MEN Jin-zhu

2016, 24(6): 475-478. doi: 10.11993/j.issn.1673-1948.2016.06.014

[Abstract](3311) [PDF 1166KB](413)

Abstract:
To use a suspended depth charge to intercept a torpedo under the condition of knowing the parameters of bearing, velocity and range estimation of a wake homing torpedo, a conception of torpedo's potential attack area is proposed, and theoretical derivation is performed to obtain the potential attack area of the torpedo. Subsequently, the analysis method is used to solve the shooting and aiming point of the interception array of the suspended depth charges. The proposed method may provide reference for improving the probability of a suspended depth charge intercepting a wake homing torpedo.

2016 Vol. 24, No. 6

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