Motion Control of Robotic Fish Under Dynamic Environmental Conditions Using Adaptive Control Approach

In this paper, we propose a novel robust adaptive control technique to steer the direction of attack of the robotic fish swimming under influence from varying environmental conditions. Due to complex nature of robot motion hydrodynamics, it is difficult to predict the true dynamics of the system with good accuracy. Hence, a discrete-time adaptive control technique is proposed, which can effectively track a reference even if the robot system's model parameters might vary over time due to physical variations in the system. Rigorous theoretical convergence analysis on the closed-loop system confirms that the reference tracking error will asymptotically be bounded within a prescribed limit. Furthermore, the adaptive control approach is experimentally verified to produce desirable performance under significant variations in payload and drag force on the robotic fish. The latest results, thus, signify that the proposed control algorithm can efficiently control the robotic fish motion in complex underwater environments.