Design of automatic and uniform feeding system carried by workboat and effect test for raising river crab

Abstract: In order to solve the feeding problem in river crab aquaculture such as high labor intensity, low automation and non-uniform feed distribution, an automatic air propeller driven feeding system carried by a workboat and uniform feeding method was proposed. The system is mainly composed of a workboat driven by air propellers, automatic feeding device, ARM (advanced RISC machine) main controller, GPRS (general packet radio service) communication module and GPS (global positioning system) navigation device. A air propeller driven device was designed to solve the effect of waterweeds intertwine with underwater propellers of common workboat on sailing, and an automatic feeding device equipped with the flow velocity controllable bait feeder, distance adjustable thrower and quantity of feed in the bin measurable device was designed to solve the problem of non-uniform distribution of the feed. The ARM S3C2440 was used for the control system which could perform automatic uniform feeding by receiving task information through the GPRS communication module M590, modeling for the thrower of the automatic feeding device, motion of the feed particle and cumulative distribution of feed on the water, creating a target function for cumulative distribution density, using genetic algorithm (GA) to solve the optimal operation parameters such as flow velocity of the feeder, speed of the rotary table, feed sector angle, speed of the workboat and distance between adjacent feeding travel of trajectory planning which optimal value of distance between adjacent feeding travel was 8.21 m, feed sector angle was 80°, the workboat speed above and below the feeding travel were both 0.43 m/s, flow velocity of the feeder was 32.01 g/s, speed of the rotary table was 1480 r/min when the expected value of distribution density was 9 g/m2, and implementing trajectory tracking by GPS navigation device BD982. We conducted simulation of oblique throwing movement, feed average cumulative distribution density and distribution density variance, feeding contrast test between feeding device and artificial on the ground and feeding test on pond respectively. The results showed that the automatic feeding system can obtain good uniform feeding effect by working with the optimal operation parameters. The feed distribution uniformity of the automatic feeding system carried by workboat can be increased by three times than that with the artificial feeding, compared with the feed distribution density set value, the feed average distribution density relative error was 5.11%. In order to adapt the river crabs nocturnal habits, the automatic feeding can be performed in the night, one automatic feeding system carried by workboat could fine management about 6.67 hm2 crab pond which was equivalent to feeding with five rural labor force so that it would save manpower and increase efficient utilization of the feed. The automatic feeding system carried by workboat could make the feed utilization rate improved by more than 15%, resulting feed saving by more than 15% and crab output per unit area increased by more than 20%. At the same time, the automatic feeding system carried by workboat could perform timing; quantitative and uniform feeding which ensured that river crabs grow with equal size, as such improved the production and aquaculture area use efficiency. This research provides technology reference for further study of automatic uniform feeding on the whole pond in river crab aquaculture and other aquaculture needing for feeding along the pond or on the whole pond.