1 October 2018 – 30 September 2019
Total award $154,759
Due to their design, rotorcraft are inherently sensitive to gust and turbulence in hover and transition. With their relatively low disk loading, they are sensitive to gusts when compared with aircraft; that disk loading is the major design parameter affecting turbulence. As the disk loading increases with forward flight, the sensitivity to turbulence dries. Along with disk loading, Center of Gravity (CG) also plays a major role in gust tolerance. Most rotorcraft have a low CG which acts as a pendulum and has the effect of creating added stability. However, modern VTOL designs tend to have a very high CG location which makes them highly sensitive to gusts and turbulence.
The technical objectives of this work are to:
- Investigate and develop a control law and associated control system to that allows a VTOL vehicle to sense and correct for gust and turbulence induced instabilities
- Design and build a sub-scale demonstrator.
- Testing the sub-scale demonstrator under full control in the Oran W. Nicks Low Speed Wind Tunnel, and in the outdoor environment of the Vehicle System & Control Laboratory’s UAS test site at the TAMU RELLIS Campus.
The basic control law will be a disturbance rejection enhanced version of the Proportional Integral Filter – Control Rate Weighting – Nonzero Setpoint (PIF-CRW-NZSP) control law structure. The PIF-CRW-NZSP controller is a multi-input multi-output (MIMO) optimal control methodology that permits low-pass filtering (smoothing) of feedback signals. It also permits the rate of servo actuation to be adjusted by the designer. This is effective in preventing actuators from hitting and riding their rate limits, which often produces poor performance and can lead to pilot induced oscillations (PIO). Control allocation will be used as needed to distribute the modulation of the gimballed rotors for the disturbance rejection capability.
Working with me on this project are:
-Zeke Bowden, MENG AERO
-Blake Krpec, AERO
-Christopher Leshikar, AERO