“Control of a Buoyancy-Based Pilot Underwater Lifting Body”

Authors: Finn Haugen,
Affiliation: Telemark University College
Reference: 2010, Vol 31, No 2, pp. 67-77.

Keywords: Underwater, buoyancy, air lift, position control, cascade control, feedforward control, disturbance, estimation, Skogestad model-based controller tuning

Abstract: This paper is about position control of a specific small-scale pilot underwater lifting body where the lifting force stems from buoyancy adjusted with an air pocket in the lifting body. A mathematical model is developed to get a basis for a simulator which is used for testing and for designing the control system, including tuning controller parameters. A number of different position controller solutions were tried both on a simulator and on the physical system. Successful control on both the simulator and the physical system was obtained with cascade control based on feedback from measured position and height of the air pocket in the lifting body. The primary and the secondary controllers of the cascade control system were tuned using SkogestadĀ“s model-based PID tuning rules. Feedforward from estimated load force was implemented in combination with the cascade control system, giving a substantial improvement of the position control system, both with varying position reference and varying disturbance (load mass).

PDF PDF (1123 Kb)        DOI: 10.4173/mic.2010.2.3

[1] Fossen, T. (1994). Guidance and Control of Ocean Vehicles, John Wiley and& Sons Ltd.
[2] Franklin, G. Powell, J. (1980). Digital Control of Dynamic Systems, Addison-Wesley.
[3] Goodwin, C., Graebe, S., Salgado, M. (2001). Control System Design, Prentice-Hall.
[4] Haugen, F. (2010). Advanced Dynamics and Control, TeachTech.
[5] Otterblad, S. Dovertie, R. (1985). Lifting body for diving, US Patent number 4,498,408.
[6] Skogestad, S. (2003). Simple analytic rules for model reduction and pid controller tuning, Journal of Process Control, 13(4):291--309 doi:10.1016/S0959-1524(02)00062-8

  title={{Control of a Buoyancy-Based Pilot Underwater Lifting Body}},
  author={Haugen, Finn},
  journal={Modeling, Identification and Control},
  publisher={Norwegian Society of Automatic Control}