Supersonic Trajectory Optimization

Completed TRL 3 (started at 2, targeting 3)

Description

We will apply both emerging and industry-standard trajectory optimization tools to solve the minimum-fuel optimal control problem. Initially, we will use dymos, an open-source Python code built on top of OpenMDAO, and POST2. We will start by using the energy-state approximation to simplify the minimum-time-to-climb problem (few equations of motion, few controls to solve for) and build up to the minimum-fuel-turn for a point mass (several equations of motion and several controls). In addition to framing the problem itself, another challenge will be modeling the F-18 aerodynamics and propulsion system with just enough fidelity as to predict the aircraft motion and fuel-used, but not so much complexity as to be unsolvable in a reasonable amount of time.

Once optimal trajectories are prototyped, they will be flown in 6-DoF, piloted simulation. In addition to checking the accuracy of the predicted aircraft motion and fuel cost, the trajectories will be evaluated for real-world practicality. Ideally, the trajectories will follow a few simple rules. If not, pilots might require cues from a flight director instrument, or the tracking task might need to be automated altogether with a closed-loop guidance system.

Benefits

The objectives are to solve for and validate minimum-fuel supersonic flight test trajectories. Motivated by the Low Boom Flight Demonstrator Mission, the goal is to maximize the number of sonic boom test points achievable per sortie. Using the F-18 as a surrogate, the first tasks are to construct a simplified model, optimize trajectories using readily-available software, and evaluate in the piloted sim. Optimal trajectories that enable additional test points or otherwise yield significant fuel savings will be flight-tested. The sensitive fuel flow meter from 853 will be transplanted (e.g. to 868, or 846) in order to quantify fuel savings and performance more accurately than is feasible with production hardware. If successful, the approach is immediately applicable to the Low Boom Flight Demonstrator Project.

Details

Technology area	Flight Vehicle Systems
Program	Center Innovation Fund: AFRC CIF (AFRC CIF)
Lead organization	Armstrong Flight Research Center, Edwards, CA
Start date	2020-10-01
End date	2021-09-30

Project contacts

Listed on TechPort itself — the most direct way to ask about this specific project.

Matthew J Boucher — matthew.j.boucher@nasa.gov

How to get involved

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