Research On The Control System Of A New Type Submersible Offshore Cage

With the development of economy and the improvement of living standards,people’s demand for aquatic products is also increasing.This demand not only includes the quantity of aquatic products,but also includes their quality,which makes the traditional extensive breeding methods gradually unable to meet the market,and the offshore harbor breeding is gradually saturated,and the focus of aquaculture begins to shift to the offshore sea area.However,the cage breeding in the open sea needs to resist the disturbance of strong wind and waves,and the floating anti-wind and wave cage is easy to be damaged.Therefore,a submersible offshore cage that can avoid wind and waves is proposed.With the development of automation technology and computer science,experts and scholars have begun to explore the way of intelligent Marine aquaculture equipment,and submersible offshore cage is one of the important directions.Taking the submersible offshore cage control system as the research object,this paper mainly studies the following contents:This paper analyzes the shortcomings of several existing offshore cage,and puts forward a new type of submersible pneumatic disc-shaped cage,carries on the overall design of the new submersible cage,and analyzes the working process of the cage in detail.The structure and function modules of the cage are designed,the working mode of the cage is analyzed,and the control system is designed under the overall requirements of the cage.The mathematical model of underwater motion of cage was established,and the dynamic analysis was mainly carried out in the body-fixed coordinate system fixatively connected with cage.The transformation relationship between earth-fixed coordinate system and body-fixed coordinate system was deduced,and the 6-dof dynamic equation mathematical model of underwater motion of cage was established.Based on the mathematical model of the underwater movement of the cage,the state equation of the third-order system was obtained by referring to the air supply blowing equation of the cage ballast tank.Based on Lyapunov stability criterion,the controller was designed by backstepping method.In order to overcome the interference of complex environment,sliding mode control was introduced to obtain the final feedback control law.The control system is simulated in Simulink simulation software,and the motion trajectory,error and control signal curve of cage system are obtained,and the simulation results are briefly analyzed.After completing the algorithm research,the software and hardware parts of the swooping cage control system are built,including the upper computer software program,the lower computer controller,peripheral circuit,pneumatic circuit,sensor,etc.,and the cage actuator is controlled by PWM signal.Define the data communication protocol,complete the data communication between the controller units,build the remote sea and land communication of the cage,realize the remote monitoring of the cage condition,and carry out the preliminary reliability test in the laboratory.Finally,under the guidance of similarity theory,the cage model was designed and made,and the function test was carried out in the test pool.The working mode of the cage was simulated,the test data was obtained,and the test results were analyzed.The test results also show the reliability and stability of the cage under various working modes,which provides technical support for sea trial.