Modeling and Requirements Formulation for Submarine Control Surface Actuation Systems∗

This paper examines methods that can be adopted in early stage or retrofit design of actuator subsystems, and is motivated by the modern trend toward retrofitting legacy hydraulic actuation of submarine control surfaces with electromechanical systems. This problem highlights the familiar need designers have to relate system response requirements to selected subsystems to enable focused development of the latter. This paper shows the utility of adopting a model basis, and specifically uses a bond graph approach in combination with two-port immittance relations. Bond graphs benefit study of multidisciplinary systems and provide insight into system interconnection and causality. In combination with bond graphs, immittance functions enable key relations to be established based on the overall system description, and provide a way to specify response requirements. Immittance functions also enable adopting network synthesis methods, which are used in this paper to show how passive and active compensation can be integrated to benefit proposed actuation schemes. It is shown how this combination of methods provides designers with a systematic way of relating system response requirements to targeted subsystems. The methods described are demonstrated using a simplified control surface actuation problem, and simulation results of key static and dynamic requirements are presented. The derived passive and active compensation are used to augment conventional feedback controlled actuator models, and simulations demonstrate how compensation can reduce energy consumed by actuation subsystems. ∗Manuscript originally submitted December 1, 2009. Final draft submitted April 25, 2010. This work was supported by the Office of Naval Research through the Electric Ship Research and Development Consortium. †Corresponding author, R. Longoria is with the University of Texas, Department of Mechanical Engineering, 1 University Station C2200, Austin, TX 78712 USA (phone 512-471-0530, fax 512-471-8727, email: [email protected]). ‡J. LeSage is a graduate student at the University of Texas, Austin, TX USA. §W. Shutt is with the University of Texas, Applied Research Laboratories, 1 University Station F0252, Austin, TX 78712 USA.