  In the application of underwater creature study, comparing with
propeller-powered ROVs and servo motor actuated robotic fish, novel biomimetic
fish robot designs with soft actuation structure could interact with aquatic
creatures closely and record authentic habitats and behaviours. This final
project report presents the detailed design process of a hydraulic soft
actuator powered robotic fish for aquatic creature study capable of swimming
along the 3D trajectory. The robotic fish is designed based on the analysis of
the pro and cons of existing designs. Except for the mechanical and electronic
designs and manufacturing method of crucial components, a simplified open-loop
control algorithm was designed to check the functionality of the application
board and microcontroller in the Proteus simulation environment. As the key
component of the robotic fish, Finite Element Method (FEM) simulations were
conducted to visualise the soft actuator's deformation under different pressure
to validate the design. Computational Fluid Dynamics (CFD) simulations were
also conducted to improve the hydrodynamic efficiency of the shape of robotic
fish. Although physical manufacturing is impossible due to the pandemic, the
simulations show overall good performance in terms of control, actuation, and
hydrodynamic efficiency.
