At hypersonic speeds, the rules of flight begin to change. Air behaves differently, temperatures rise to extremes and even small uncertainties in data can lead to major instability. Professor Raúl Ordóñez is tackling these challenges head-on through two grant awards.
The grants, awarded as Small Business Technology Transfer (STTR) projects, connect university research with businesses to develop real-world applications. Both are also in partnership with GoHypersonic, Inc., a Dayton-based company, which specializes in the research and design of advanced hypersonic vehicles and propulsion systems.
“My first project, which is sponsored by the Office of Naval Research, involves using pressure sensors on an aircraft body to be able to to estimate things like the angle of attack and the side slip angle, which are typically very difficult to accurately measure,” Ordóñez said.
At hypersonic speeds, traditional measurement systems become less reliable. Angle of attack and sideslip angle are typically measured using GPS-supported systems but those methods can fail under extreme heat, pressure or signal disruption.
This project uses pressure sensors embedded along the aircraft. These sensors detect subtle changes in airflow pressure, which can then be translated into data. Ordóñez’s work involves developing algorithms that take pressure sensor data, together with data from inertial measurement units (IMUs), and convert it into control actions. IMUs are devices that contain accelerometers and gyroscopes to track angular motion.
Ordóñez’s design ensures the aircraft behaves as intended. This design includes feedback systems, nonlinear dynamics and estimation techniques that can function reliably even when data is incomplete or noisy. Unlike GPS, IMUs are self-contained, but they come with their own challenges on hypersonic vehicles.
“If you have an aircraft, you typically would have an IMU on it,” Ordóñez said, “You can use this to figure out the various angles of the aircraft. But this turns out to be a difficult problem at high speeds and accelerations, especially when the aircraft is undergoing different conditions.”
Testing these sensors’ materials and components is also a critical part of the project. The University of Dayton Research Institute is helping to simulate the thermal conditions experienced at high Mach numbers on the sensors, evaluating whether they can survive and perform under such extremes.
His second project, sponsored by the Missile Defense Agency, involves control design for a new class of next-generation hypersonic vehicles capable of very fast maneuvers at extreme combinations of altitude and speed. The nature of the vehicles and the conditions where they need to operate make for a challenging control design problem.
Hypersonic technology is advancing rapidly. Nations are investing heavily in vehicles capable of traveling at extreme speeds with high maneuverability, making them difficult to detect, track, or intercept using conventional systems.
Rapid acceleration, vibration and thermal stress can diminish sensor accuracy. Estimating the aircraft’s orientation requires advanced estimation methods, often combining multiple data sources to improve reliability. This is where Ordóñez’s expertise in systems dynamics and mathematical modeling becomes essential.
In modern defense scenarios, GPS signals can be jammed or spoofed, rendering traditional navigation systems ineffective. Developing alternative methods is essential for ensuring aircraft can operate independently. These systems must be self-contained and resistant to external interference.
“There are increasing global threats that are developing their own sort of hypersonic technologies,” Ordóñez said, “So these sensors might be a good way to combat those threats.”