Speed estimation for robotic fish using onboard artificial lateral line and inertial measurement unit

Many species of fish use the lateral line for underwater information extraction. In spite of the extensive work on artificial lateral line (ALL) and inertial measurement unit (IMU), the ALL and IMU are rarely used together to estimate the speed of robotic fish. Here we show that an artificial lateral line and an inertial measurement unit can be used cooperatively to estimate the speed of a swimming robotic fish. Based on the analysis of the robotic fish, we use an optimal information fusion decentralized filter algorithm to efficiently fuse the information of ALL and IMU for speed estimation. Our robotic fish has an artificial lateral line consisting of 11 pressure sensors and an inertial measurement unit. Experiments conducted with the freely swimming robotic fish demonstrate that the proposed scheme is able to efficiently estimate the robot speed with small errors in real time.