Design And Experiment Of Mobile Water Quality Monitoring System For Pond

Pond is the main form of aquaculture in China.High quality water quality monitoring is the basis of green production.Due to the great difference of water quality in different positions and depths of ponds,the traditional fixed position water quality monitoring method can not obtain comprehensive and accurate data.The design of mobile hull with lifting water quality monitoring sensor can effectively solve this problem.Crab culture is an important type of aquaculture.On the basis of the actual conditions of the waterways and water purification areas in the new type of pond recirculating water crab culture,a mobile monitoring system for aquaculture was developed,including unmanned ship,driving system,lifting device,autonomous navigation and other designs.Relevant experiments were developed,and the expected results were achieved.The main research contents are as follows:(1)Demand analysis and overall scheme design for water quality monitoring of circular crab pond.Based on the features of the recirculating water culture model and the ecological culture model of self-purification in pond,three features of the model were analyzed.For the sake of testing the effectiveness of this model,combined with these three features,a mobile water quality monitoring system with lifting function,low cost and high efficiency is proposed,and the overall scheme and effect diagram are formed.(2)The structure design of movable water quality monitoring system.According to the demand of water quality monitoring in aquaculture pond,the construction scheme of water quality monitoring platform and the structural design of each device were completed.It was determined that each device would be carried by unmanned ship.Combined with the control system,the mobile water quality monitoring was realized,and the functional modules were reasonably arranged.The mechanical structure of the unmanned ship and the control box was designed,and the single hull is 1.1m × 0.18 m ×25m,PE material fully closed blow molding,wall thickness 4mm.The propeller was driven by 12 V DC brush motor,shaft drive and propeller.The pitch of propeller is 60 mm.The lifting system was designed.The lifting structure was composed of a stepping motor,a driving pulley,an idler and a fixed bracket.The bottom of the water quality sensor was fixed with one side of the rope,and the other side of the rope was connected with the idler and the driving pulley.The driving pulley was driven by the positive and negative rotation of the stepping motor to realize the lifting operation of the water quality sensor.(3)Design of mobile water quality monitoring platform control system.According to the performance requirements of pond water quality monitoring and control,the overall design and test of the control system functions were carried out,including the remote control algorithm of unmanned ship,the control scheme design of lifting system,the autonomous navigation control system of GPS + electronic compass,the design and implementation of automatic navigation path planning,and the design of water quality data acquisition system;Complete the design and development of the control board,including the design of the control board schematic diagram,the design and implementation of the board function program and the production of the control board.(4)Field test and reliability analysis of pond.The mobile water quality monitoring device was used as the test object,and the pond was tested in the pond of Shanghai Baodao Crab Industry Co.,Ltd,Chongming District,Shanghai.There were many groups of strips of water grass gaps in the pond.The pond test conditions were more in line with the actual water quality collection device,and the test results were more authentic.The navigation accuracy and lifting capacity of the monitoring device are tested.When the monitoring device navigates independently,the average speed is 1.1m/s,the maximum linear yaw is 0.8m,the maximum turning yaw is 0.5m,and the average sampling time of each monitoring point is 2min,and the performance is relatively stable,especially in the windy environment,which has been verified,which significantly reduces the labor intensity.After 30 days of testing,the process reveals that the mobile water quality monitoring system has good reliability,and can meet the needs of the actual aquaculture pond field water quality monitoring.