Control simulation model for X-ROTOR concept

A control model of the X-Rotor concept, suitable for prototyping controller designs, supporting controller analysis and design and assessing the effectiveness of controllers in meeting design objectives is presented. The complexity of the model is minimised whilst retaining sufficient detail to capture the essential dynamic properties. The model is designed using MATLAB/ Simulink.

The control model consists of three main components, the wind model, the primary rotor aerodynamics and structural dynamics and the power take-off (including secondary rotor dynamics).

The wind model is adapted from that described in (Gala Santos, 2018), and consists of an effective wind field that contains appropriate frequency components up to six times the rotational frequency of the primary rotor. The primary rotor aerodynamics use the outputs from a bespoke double multiple streamtube (DMS) model (validated against the higher fidelity ‘CACTUS’ lifting line model) to populate a look-up table approach. The outputs of the DMS model and its validation against the CACTUS model are presented. The primary rotor structural model includes compliant upper blade dynamics and semi-compliant lower blade dynamics.

The power take-off dynamics include modelling of the secondary rotors using an actuator disc model. The model is validated against the BEM tool ‘QBlade’. The power train of the power take-off is modelled as a semi-compliant shaft connected to a direct drive generator. Illustrative simulation results are presented that show that the essential dynamic properties of the X-Rotor concept are simulated within the control model.