Design And Path Tracking Of Mobile Water Quality Monitoring System For Crab Culture

The quality of the water environment directly affects the health of river crabs.In order to ensure the yield and benefit of river crabs,the water quality of crab ponds must be tested regularly in the breeding process.The crabs have strong territorial awareness,not evenly distributed in the whole waters of aquaculture ponds.Due to the poor fluidity of aquaculture water,when the water quality deteriorates,it is difficult to detect anomalies at fixed measurement points accurately and timely.Therefore,for the disadvantages of small range,poor flexibility and high cost of fixed multi-points detection,this paper designs a water quality monitoring system for river crab culture based on unmanned ship,which can realize the large-scale automatic inspection of the culture pond.The path tracking algorithm is studied to ensure that the monitoring ship can navigate safely according to the target path.The main contents of this paper are as follows:A.By analyzing the domestic and international research status of water quality monitoring,unmanned operation ship and path tracking,the design of mobile water quality monitoring system for crab culture is completed.Based on the overall demand,the overall structure and working principle are given.The specific scheme of each part is designed as well as path tracking research ideas which are elaborated in detail.B.The path tracking error model of water quality monitoring ship is constructed.According to the kinematic analysis in inertial reference frame and body-fixed frame,the kinematic model of water quality monitoring ship is established.By analyzing the motion principle of water quality monitoring ship,the kinetic model of water quality monitoring ship is obtained.Considering the model difference and wind wave interference,the interference effect is analyzed.For the research of path tracking,the path tracking error model of the monitoring ship is established.C.A fixed-time path tracking controller is proposed.Based on the simplified linear tracking error model,the fixed-time controller is designed and the stability analysis is given.The controller is not constrained by the initial state,and it also can make the ship track the desired path quickly.On this basis,an extended state observer(ESO)is designed for online estimation and feedforward compensation for wind and wave disturbance to improve the tracking accuracy.The effectiveness of the proposed algorithm is verified by simulation.D.The software and hardware design of the mobile water quality monitoring system for crab culture is completed.The hardware circuit of the shipboard control system is designed.Based on the hardware design,the functions of parameter acquisition,communication analysis and motion control are realized.The remote monitoring system is established by integrating database,server and client to realize the data acquisition and function control of the monitoring ship.The experimental results show that the tracking accuracy of the water quality monitoring ship is improved,the maximum error of straight-line section is less than 0.2m,the maximum error of turning path is less than 0.6m.Combined with PC client test and verification,the results show that the monitoring system is stable,which can realize the mobile detection of the target pond and the effective storage of data.