Papers by Keyword: Sonar

Abstract: This paper presents the research of model-base design and control of Remotely Operated Vehicle (ROV) built in VietNam Automation & Mechatronics Laboratory (VIAMLAB). This is one of the most important types of underwater robots used in water environments for many purposes, especially for navy and marine industries. The design keeps our tethered ROV self-stabilized in the horizontal plane. It is also equipped with thrusters and sensor feedbacks, allowing 6 degrees-of-freedom motion. Moreover, cameras and grabber integrated into ROV support underwater survey tasks. In addition, the paper also simulates controllers with the main task of keeping depth for ROV. The controllers designed and surveyed here include: PID, optimal control (LQR), standard model control (MRAC) and combination controller between LQR and MRAC. The performance of the algorithm will be evaluated through simulation results using Matlab / Simulink.

Abstract: Luneburg lens is a gradient index lens that focuses the incoming wave to the opposite side of the lens without aberration. We developed a two-dimensional acoustic Luneburg lens by variable density method of space inside the lens. The lens is composed of hundreds of aluminum columns with various radii of less than 1cm. We tested the ability as sonar in the air. It focuses the incoming acoustic wave on the edge of the opposite side of the lens as well in the frequency range of 1,000Hz ~ 3,000Hz. It showed a dynamic response depending on the motion of the acoustic source. It could be a strong candidate of a next generation of sonar.

Abstract: At present, marine sonar instrument has been widely used in scientific research, engineering construction and environmental protection in the field of marine, but most instruments lack method of metrological verification, testing or calibration. Without standardized testing system, the quality of instrument cannot be guaranteed. This paper proposes a method to establish the system. It shows the main content of the system, especially testing platform, technical standards and testing plans in the system. The conclusion is given finally.

Abstract: in view of the current situation of ship has collision with sea mountain , design and develop the sonar of ship collision avoidance system based on PLC.its main purpose is to remind the crew in front of mountains and ship automatic collision avoidance. The design is based on the minimum distance of ship and mountain, put forward the system scheme: measure the two objects distance by sonar , using this system as the control core , the information is analyzed and calculated by this system. When the distance between ship and mountains is less than the minimum safe distance.so this system will alarm crews and as deceleration avoidance .

Abstract: In order to research the siltation problem of pressurized CSO chamber with the outlet pipe elevation higher than that of the inlet pipe, a 1:5 scale model was made of plexiglass for laboratory experiments. The velocity field of the CSO chamber was measured by PIV system. VOF and DPM models were adopted in the numerical simulation, and the results were applied to the comparison and analysis with the field inspection images obtained by SONAR system. Research results show that this special CSO chamber is liable to result in siltation in dry weather flow. The deposit location and shape of sediment depend on the flow field distribution. At low flow, there is low velocity eddy zone at the central region of CSO chamber, and then there is a bulge in the middle of sediment contour line in horizontal plane. With the increase of flow, the scouring force of middle region enhances, and then the sediment contour line tends to a straight line. Furthermore, there are relatively strong scour areas at both sides of inflow which result in the trend to be flat of sediment surface. These analyses are validated by field inspection of SONAR.

Abstract: For ensuring the safety of inland river shipping and avoiding super draft, it is of significance to propose a method to detect draft of inland departure ship. The real-time detection method on draft of inland departure ship is proposed, the measurement principle of ship draft is deeply analyzed, and the small scale experiment has been carried out. Experimental results show that as ship speed inicreases, the ship draft is of gradually declining tendency, and the measurement error is of gradually increasing tendency, the minium error is -4.2%, the maximum error is -11.4%. The results prove the possibility of this method , and also indicate that ship speed has large influence on measured ship draft.

Abstract: This paper has explored the design of three-dimensional imaging sonar software and its application to the hardware platform. In the process of designing, the software has been optimized in view of characteristics of the hardware structures and calculation of the TMS320C6416, and the specific optimization methods and effects have also been presented. It turns out that the effect of software optimization is obvious and the working system stable and reliable.