Keynote Student

Modelling and control of bioinspired multi-body AUV with CFD flow analysis

  • wright, marvin (Strathclyde University)
  • Xiao, Qing (Strathclyde University)
  • Yue, Hong (Strathclyde University)
  • Post, Mark (University of York)

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To support a better understanding of the fundamental flow mechanisms and further the development of corresponding optimal control strategies for bio-inspired autonomous underwater vehicles [1], this research applies a combined approach in developing a multi-body dynamic and control model within a high fidelity CFD environment. The detailed CFD flow information at every time instance provides detail of the unsteady flow around a robotic fish body enables investigation into energy-efficient gaits and motion patterns. The simulation is set up using the software interface between the commercial finite volume method based CFD tool Ansys Fluent and an in-house developed user-defined function. By using Fluent, the simulation takes advantage of the GUI’s usability and stability. The comprehensive and continuously developed in-house code [2] captures the multi-body dynamics and kinematics of a swimmer using the Newton-Euler equations [3]. For the current study the focus lies on rigid elements serially connected by 1DoF rotating joints to mimic Body-Caudal Fin (BCF) swimming, either as a continuous body with interpolated surface bending or as discreet, rigid elements. The undulating body motion created via synchronised joint actuation is set to dynamically adapt to velocity and Line-of-sight (LOS) reference signals. For a globally moving swimmer, high mesh quality is maintained by means of dynamic meshing. Correctness of the simulation was confirmed through extensive validation. To present the full capabilities of the simulation environment, detailed numerical results of the undulating body and surrounding fluid domain as well as tracking performance of the designed feedback controller will be presented in a case study. 1. Wright, M., et al. Multi-actuated AUV body for windfarm inspection: lessons from the bio-inspired RoboFish field trials. in 2020 IEEE/OES Autonomous Underwater Vehicles Symposium (AUV). 2020. IEEE. 2. Li, R., et al., A multi-body dynamics based numerical modelling tool for solving aquatic biomimetic problems. Bioinspiration & biomimetics, 2018. 13(5): p. 056001. 3. Porez, M., F. Boyer, and A. Belkhiri. A hybrid dynamic model for bio-inspired soft robots—Application to a flapping-wing micro air vehicle. in 2014 IEEE International Conference on Robotics and Automation (ICRA). 2014. IEEE.