Optimal coplanar flight between orbits <opti- mal'nyy kompianarnyy polet mezhdu orbitani<
Optimization of coplanar flight between orbits
OPTIMIZATION↗
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Results for “FLIGHT OPTIMIZATION”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Dynamic Replanning of Low Noise Rotorcraft Operations
A new method for rapidly planning and dynamically replanning low noise rotorcraft flight operations is developed. A large database of rotorcraft maneuver segments is generated, and an acoustic cost is assigned to each segment by using a computationally efficient semiempirical rotorcraft noise modeling method that accurately models the changes in rotor noise caused by maneuvering flight. Combinatoric optimization techniques are then employed to combine these maneuver segments into a low noise optimal flight path. A simple heuristic for estimating the total acoustic cost required to reach the target location is developed and incorporated into the search algorithm, allowing the computation of low noise paths in seconds. A procedure for implementing an “anytime” version of the method is described, enabling feasible solutions to be dynamically replanned “on the fly”—i.e., in fractions of a second—and refined over time to a low noise optimal solution.
Greenwood, Eric↗
Applying optimization software libraries to engineering problems
Nonlinear programming, preliminary design problems, performance simulation problems trajectory optimization, flight computer optimization, and linear least squares problems are among the topics covered. The nonlinear programming applications encountered in a large aerospace company are a real challenge to those who provide mathematical software libraries and consultation services. Typical applications include preliminary design studies, data fitting and filtering, jet engine simulations, control system analysis, and trajectory optimization and optimal control. Problem sizes range from single-variable unconstrained minimization to constrained problems with highly nonlinear functions and hundreds of variables. Most of the applications can be posed as nonlinearly constrained minimization problems. Highly complex optimization problems with many variables were formulated in the early days of computing. At the time, many problems had to be reformulated or bypassed entirely, and solution methods often relied on problem-specific strategies. Problems with more than ten variables usually went unsolved.
Healy, M. J.↗
Powered flight trajectory optimization for lunar and interplanetary transfer.
Steepest descent method to compute powered flight trajectory optimization for lunar and interplanetary transfer
TRAJECTORY OPTIMIZATION↗
Optimal symmetric flight with an intermediate vehicle model
The present investigation is concerned with an examination of optimal symmetry flight on the basis of the intermediate vehicle model. The analysis is partly based upon an exploration of Euler solutions for the path-angle-as-control model carried out by Kelley (1958). The current analysis takes into account higher-order optimality conditions and 'chattering-control' phenomena. Attention is given to details regarding the intermediate vehicle model, the Legendre-Clebsch necessary condition, the conjugate-point test, and the numerical solution of the time-range problem. It is found that the flight path angle takes on the role of control variable in the model. From physical considerations, it can be seen that when a positive margin of thrust over drag exists, the maximum-range climb trajectory without time or fuel constraints has no proper maximum nor an upper bound.
Kelley, H. J.↗
Optimal symmetric flight with an intermediate vehicle model
The present investigation is concerned with an examination of optimal symmetry flight on the basis of the intermediate vehicle model. The analysis is partly based upon an exploration of Euler solutions for the path-angle-as-control model carried out by Kelley (1958). The current analysis takes into account higher-order optimality conditions and "chattering-control' phenomena. Attention is given to details regarding the intermediate vehicle model, the Legendre-Clebsch necessary condition, the conjugate-point test, and the numerical solution of the time-range problem. It is found that the flight path angle takes on the role of control variable in the model. From physical considerations, it can be seen that when a positive margin of thrust over drag exists, the maximum-range climb trajectory without time or fuel constraints has no proper maximum nor an upper bound.
Menon, P. K. A.↗
Parallel dynamic programming for on-line flight path optimization
Parallel systolic algorithms for dynamic programming(DP) and their respective hardware implementations are presented for a problem in on-line trajectory optimization. The method is applied to a model for helicopter flight path optimization through a complex constraint region. This problem has application to an air traffic control problem and also to a terrain following/threat avoidance problem.
Slater, G. L.↗
Overview of optimal trajectories for flight in a windshear
Optimal flight trajectories for the B-727, B-737, and B-747 aircraft in the presence of wind shear are studied. The takeoff problem and the abort landing problem are considered with reference to flight in a vertical plane. In the former, optimal trajectories are computed by minimizing the peak deviation of the absolute path inclination from a reference value; in the latter, optimal trajectories are computed by minimizing the peak value of the altitude drop. Numerical computations show that, for both the problems under consideration, the optimal trajectories of the three aircraft show the same qualitative behavior. Hence, it appears that the near-optimal guidance schemes developed for the B-727 can be extended to the other two aircraft, albeit with some quantitative modification.
Miele, A.↗
Optimal short-range trajectories for helicopters
An optimal flight path algorithm using a simplified altitude state model and a priori climb cruise descent flight profile was developed and applied to determine minimum fuel and minimum cost trajectories for a helicopter flying a fixed range trajectory. In addition, a method was developed for obtaining a performance model in simplified form which is based on standard flight manual data and which is applicable to the computation of optimal trajectories. The entire performance optimization algorithm is simple enough that on line trajectory optimization is feasible with a relatively small computer. The helicopter model used is the Silorsky S-61N. The results show that for this vehicle the optimal flight path and optimal cruise altitude can represent a 10% fuel saving on a minimum fuel trajectory. The optimal trajectories show considerable variability because of helicopter weight, ambient winds, and the relative cost trade off between time and fuel. In general, reasonable variations from the optimal velocities and cruise altitudes do not significantly degrade the optimal cost. For fuel optimal trajectories, the optimum cruise altitude varies from the maximum (12,000 ft) to the minimum (0 ft) depending on helicopter weight.
Slater, G. L.↗
Optimal short range trajectories for helicopters
An optimal flight path algorithm using a simplified altitude state model and an apriori climb-cruise-descent flight profile has been developed and applied to determine minimum fuel and minimum cost trajectories for a helicopter flying a fixed range trajectory. The performance model is based on standard flight manual data and is such that on-line trajectory optimization is feasible with a relatively small computer. The results show that the optimal flight path and optimal cruise altitude can represent a 10 percent fuel saving on a minimum fuel trajectory. The optimal trajectories show considerable variability due to helicopter weight, ambient winds and the relative cost trade-off between time and fuel. In general, 'reasonable' variations from the optimal velocities and cruise altitudes do not significantly degrade the optimal cost.
Slater, G. L.↗
Flight-test guidance for airbreathing hypersonic vehicles
A guidance solution for aerospace planes is given based on a family of energy-heading extremal solutions that can be used for feedback implementations. Test conditions are developed as steady-cruise solutions by means of energy-heading extremal solutions to a time/fuel-range flight-optimization problem. Feedback charts are derived that give control as a function of energy and heading-to-go, and the reduced-order model is compared to numerically optimized point-mass solutions for flight optimization. The energy-heading model is shown to provide feedback-control charts that yield fuel-efficient turn/acceleration maneuvers with significant weight-change as compared to the point-mass solutions. Such variables as Mach number, dynamic pressure, and lift are found to influence the solutions significantly.
Cliff, Eugene M.↗
STUDIES IN THE FIELDS OF SPACE FLIGHT AND GUIDANCE THEORY. INTRODUCTION
Guidance systems and flight optimization theory for space flight
FLIGHT OPTIMIZATION↗
THREE-DIMENSIONAL LOW-THRUST INTERPLANETARY TRAJECTORY OPTIMIZATION
Low thrust propulsion interplanetary trajectory flight optimization - guidance systems
FLIGHT OPTIMIZATION↗
Application of quadratic optimization to helicopter flight control.
Quadratic optimization applied to helicopter flight control design, assuming constant feedback gains and command step input with zero steady state error
Gray, D. L.↗
Optimal multistage rocket flight and other discontinuous variational problems
Discontinuous variational problems & optimal flight of multistage rockets
MULTISTAGE ROCKET↗
Peak-Seeking Optimization of Spanwise Lift Distribution for Wings in Formation Flight
A method is presented for the in-flight optimization of the lift distribution across the wing for minimum drag of an aircraft in formation flight. The usual elliptical distribution that is optimal for a given wing with a given span is no longer optimal for the trailing wing in a formation due to the asymmetric nature of the encountered flow field. Control surfaces along the trailing edge of the wing can be configured to obtain a non-elliptical profile that is more optimal in terms of minimum combined induced and profile drag. Due to the difficult-to-predict nature of formation flight aerodynamics, a Newton-Raphson peak-seeking controller is used to identify in real time the best aileron and flap deployment scheme for minimum total drag. Simulation results show that the peak-seeking controller correctly identifies an optimal trim configuration that provides additional drag savings above those achieved with conventional anti-symmetric aileron trim.
Hanson, Curtis E.↗
Optimal trajectories in atmospheric flight
Aspects of optimization theory and switching theory are discussed, taking into account the necessary conditions for extrema, a solution subject to constraints, the calculus of variations, the Pontryagin maximum principle, the canonical transformation, Contensou's domain of maneuverability, optimal switching, a junction with singular arc, and linearized singular control. Equations of motion are considered along with aerodynamic and propulsive forces, the general properties of optimal trajectories, flight in a horizontal plane, optimal coasting flight, supersonic cruise, the supersonic turn, supersonic maneuvers in a vertical plane, energy state approximation, a modified Chapman's formulation for optimal reentry trajectories, optimal planar reentry trajectories, and an optimal glide of reentry vehicles. Orbital aerodynamic maneuvers are examined, giving attention to aerodynamic capture, a change in the apogee, a change in the eccentricity, a change in the perigee, an orbital maneuver, an aerodynamic maneuver, and a combined maneuver.
Vinh, N. X.↗
Science and Technology of Low Speed and Motorless Flight, Part 1
The proceedings of the Third International Symposium on the Science and Technology of Low Speed and Motorless Flight are reported. Twenty-eight papers were presented in the areas of low speed aerodynamics, new materials applications and structural concepts, advanced flight instrumentation, sailplane optimal flight techniques, and self launching and ultralight glider technology. These papers are included in the document along with another paper, which was not presented, on proposed definitions for various categories of sailplanes and gliders.
Hanson, P. W.↗