Research On The Key Techniques Of Path Planning For Pond Shrimp And Crab Farming

Pond shrimp and crab farming is an important part of aquaculture and has high economic value.But the most labor-intensive work in aquaculture is the feeding of shrimps and crabs.Large-scale pond farming has increased the working intensity and time of workers.Because of the physiological characteristics of shrimp and crab,the activity ability of shrimp and crab in water is not as strong as that of fish.In order to reduce the feeding cost,reduce the time spent by feeding and make the feeding process more consistent with the foraging ability of shrimp and crabs.The other purpose is to make the breeding process standardized and digitized.In this paper,the structure and control system of the feeding vessel are optimized,and the problems of the electric power and loading capacity of the feeding vessel as well as the pond environment in reality are comprehensively considered.Finally,the light feeding vessel is designed with the strategy “one charge and two replenishment”."One charge and two replenishment" refers to that the feeding vessel fills the battery for a time before feeding work,and replenishes the feed bin,and feeds the ship for a second replenishment midway,referred to as "one charge and two replenishment".In order to fit the foraging characteristics of shrimp and crabs,feeding is needed not only around the large pond,but also in the middle area.Therefore,a large pond needs reasonable path planning.So,this paper mainly studies the path planning in the feeding process of the feeding vessel.Because of the low precision of single point positioning,the error of the feeding ship traveling along the planned path is large.In order to obtain low cost and high precision positioning for fishery application,to achieve better operation.The relative positioning method is studied to periodically correct the position deviation of feeding vessel and improve the positioning accuracy.The main work of this paper is as follows:(1)Design and improve the feeding vessel.Through the paper patent and market research,summed up the existing structure characteristics of the feeding ship,determined that the feeding vessel hull for catamaran structure,plastic material,large shell integrated molding,battery and control part is placed near the front of the control box.This structure is conducive to the stability of the hull.The silo has reduced silo capacity compared to the market’s large feeder boats to better ensure that the feeder boats can operate smoothly in open and incline water under full and no load of feed.The feeding boat is propelled by paddle wheel.In this paper,the feeding vessel combined with the obstacle avoidance algorithm can avoid the dense area of aquatic plants.According to the demand of the feeding vessel,the hardware of the feeding ship was designed,and STM32 L was selected as the main control chip of the feeding vessel.For the navigation control system of the feeding vessel,the selection,performance and communication mode of GPS positioning module and electronic compass module are mainly introduced.Finally,a communication network system between the feeding vessel and the shore is designed based on LoRa communication.(2)According to the actual demand,a reasonable pond area and environment were designed,and on this basis,the pond was rasterized in combination with the width of the feeding plate of the feeding boat.In view of the large area of the pond,when the pond filling material points have been confirmed,through boustrophedon decomposition method to decompose of grid environment,set up a list of all subdomain in the corner of the four points,each traversal over an area,point to the current point in the update list of Euclidean distance,looking for the nearest point,as the starting point of the next area,and then use the A~* algorithm to plan out the shortest distance,then for feeding requirements,design the reasonable feeding strategy,and use genetic algorithm to design the loading path,finally realizes the ponds covering and filling material.The algorithm and feeding strategy for a pond with no fixed feeding point are similar to those for a pond with a fixed feeding point,but the feeding area needs to be found during path planning.(3)For the pond environment,single point GPS positioning error is large,the deviation of feeding boat along the planned path is large,if the differential positioning is used,the cost will increase.In this paper,the design is different from the traditional single point GPS positioning mode,with periodic GPS relative positioning technique to correct positioning error to improve the positioning precision of the feeding vessel.Using LoRa technology,it can obtain stable signal in the large pond environment,and finally travel along the path planned by the path planning.The low cost and high precision performance of the proposed algorithm is verified by LoRa surface communication and localization experiment.