Feeding of large-scale fish farms: Motion characterization of a pneumatic rotor feed spreader

This study presents a wireless attitude heading and reference system (AHRS) adapted for use in marine environments where it was used to characterize the motion of a pneumatic rotary feed spreader representative of designs commonly utilized in large-scale salmon aquaculture. The attitude of the spreader affects the distribution of feed pellets over the cage surface and may have significant influence on the feeding efficiency of fish. Measurement and analysis of the motion were performed over a range of different airspeeds. The results suggested that an angular momentum originating from the connection between the spreader and the feed supply pipe may cause a substantial roll offset. At low airspeeds the yaw angle of the outlet pipe appeared to be most influential on the roll and pitch of the spreader. At higher airspeeds the rotational velocity became increasingly influential. The roll and pitch of the spreader may explain the non-uniform surface pellet distribution observed in a separate study.