Development of an Autonomous Modular Swimming Robot with Disturbance Rejection and Path Tracking

Here we present the development of an autonomous modular swimming robot. This robot, named μBot 2.0, was upgraded from our previous robot platform μBot and features onboard computing, sensing, and power. Its compact size and modularity render the robot an ideal platform for studying bio-inspired robot swimming. The robot is equipped with a micro controller in its head that communicates with external computers through Bluetooth Low Energy (BLE) and sends motor commands to the body segments via Inter-Integrated Circuit (I2C) protocol. Each body segment has a customized printed circuit board (PCB) that receives commands and controls the electromagnetic actuator for generating body movements. The robot head is also equipped with an Inertial Measurement Unit (IMU) to measure its heading and a battery for power. In this work, a μBot 2.0 with three actuators was assembled and the swimming performance was tested. The robot actuators were activated via rhythmic motor input from a central pattern generator (CPG). Experimental results showed that the swimming speed was highly sensitive to the frequency of the motor input, with a maximum swimming speed of 130 mm/s (equivalent to 0.7 body length per second) at 6 Hz. The robot also had the capability to correct its heading with IMU feedback and follow desired paths using a line-of-sight (LOS) guidance law with an overhead camera. Our results demonstrate the effectiveness of the robot's design and its potential in a variety of aquatic applications.