A Four Quadrant Finite Dimensional Thruster Model

This paper reports two speci c improvements in the nite-dimensional nonlinear dynamical modeling of marine thrusters. Previously reported four-quadrant models have employed airfoil theory considering only axial uid ow and using sinusoidal lift/drag curves. First, we present a thruster model incorporating the e ects of rotational uid velocity and inertia on thruster response. Second, we report a novel method for experimentally determining non-sinusoidal lift/drag curves. The model parameters are identi ed using experimental thruster data (force, torque, uid velocity). The models are evaluated by comparing experimental performance data with numerical model simulations. The data indicates that thruster models incorporating both reported enhancements provide superior accuracy in both transient and steady-state response.