Development Of Remote Mooring-force Detecting System For Floating Offshore Cage

With the demand for protein-rich seafood increases, seafood supply is increasinglydependent on aquaculture. In view of the existing serious water pollution, aquaculturedecline in quality and other issues in estuarine breeding, scale cage aquaculture was addedinto the "Twelfth Five-Year Plan". However, the risk of cage aquaculture is high, mooringfailure is prone to happen especially under the influence of typhoon, which would lead to seriousresult as fish deaths. All of these restrict the scale development of cage aquaculture. Therefore, thisresearch focused to develop a remote detection system of mooring force for floatingoffshore cages commonly used in south-china sea. The purposes of this thesis are toremotely and correctly measure the mooring force waveform and provide appropriatereal-time force measuring tools for the stress analysis of cage mooring system.The software of ANSYS was used to do modal analysis of floating cage framestructure and simulate the natural frequency of its various modes which would then betaken as the basis for system development.According to the actual needs of cage mooring force measurement, the idea waspresented in this thesis that cage mooring force remote detection system should be builtbased on ZigBee and GPRS.In this system, the sensor nodes are responsible for collecting force information ofthe cable, and then bring together the information collected by each sensor node to thecoordinator node. Coordinator node then sends data in a predetermined format to the Landmonitoring center where displays and saves the collected data through the GPRS network.The details are as follows:(1) According to aquaculture environment of offshore cage and existing wirelesscommunication technology, the approach of using ZigBee and GPRS technology to builddeep cage mooring force remote detection system was presented;(2) System hardware was design. By analyzing the mechanical characteristics of thecable, rally signal conditioning modules are designed; giving the details of the hardwaredesign of ZigBee modules;(3) Based on ZigBee protocol stack, system software was designed in detail. Thedesign of the coordinator node software, including setting up network and the design of aserial port to send and receive procedures. The design of senor node software, includingthe collection of pulling data, sending the data of node and the node receives the data which comes from the coordinator.(4) Based on the Visual Studio2010platform，the monitoring center software waswritten through the use of c#language, it Is mainly responsible for receiving data from thesensor nodes, and carrying on the display and preservation, it also send sensor nodescollect command and control the sensor node sampling frequency.This thesis had the following two innovations:(1) The remote testing system was designed as the tool of mooring forcemeasurement, which preliminary solved the problem that it is difficult in actual mooringforce measurement at present(2) Fully considering the hydrodynamic characteristics of the cages under waveaction, we targeted design the signal conditioning module which makes it undistorted inmeasuring Tension signals.The tests showed that the designed system could be used for timely detection of thecable force, and the system extension should be convenient，The feasibility of removing oradding check point according to the needs of actual engineering research would increasethe flexibility of tensile testing and reduce the cost of mooring force research. The testsystem developed in this paper provides important reference data for deep wateraquaculture research in Extreme sea conditions, such as the basis of data during thetyphoon.