First Ever Flight Demonstration of Zero Propellant Maneuver(TM) Attitute Control Concept

Bedrossian, Nazareth; Bhatt, Sagar; Lammers, Michael L.; Nguyen, Louis; Yin, Zhaohua

doi:10.2514/6.2007-6734

Cited by 38 publications

(26 citation statements)

References 6 publications

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“…For those fulfilling the constraints, we can decide which one is more optimal by defining a certain quantity to be minimized, the cost function. The formulation of this optimal control problem then becomes Minimize Jx⋅; u⋅; t f R t f 0 h ⊤ w h w dt subject to _ xt 2 6 6 6 6 6 6 6 6 6 6 6 6 6 4 3 7 7 7 7 7 7 7 7 7 7 7 7 7 5 xt 0 r 0 ; v 0 ; σ 0 ; ω 0 ; h w0 ; δ 0 xt f r F ; v F ; σ F ; ω F ; h wF ; δ F jω i tj ≤ ω MAX i 1; 2; 3 jh wi tj ≤ h wMAX i 1; 2; 3 ju i tj ≤ τ MAX i 1; 2; 3 (22) where the state and control spaces are given by X: fr; v; σ; ω; h w ; δ ∈ R 17 : kωk ∞ < ω MAX ; kh w k ∞ ≤ h wMAX g…”

Section: Optimal Control Problemmentioning

confidence: 99%

“…This concept is known as zero-propellant maneuver (ZPM) [18], owing to the possibility of maneuvering a spacecraft without the need for propellant to desaturate the reaction wheels. Using pseudospectral (PS) methods for the solution of the optimal guidance problem [19][20][21], Bedrossian et al [22,23], and Bhatt et al [24] successfully applied this approach to several slews of 90 and 180 deg in the International Space Station without saturation of its CMGs. PS methods have been proven to be an efficient and robust way to provide solutions to complex continuous-time optimal control problems [25], like the one that arises from the formulation of the ZPM.…”

mentioning

confidence: 99%

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Perigee Attitude Maneuvers of Geostationary Satellites During Electric Orbit Raising

Prieto

Roberts

2017

Journal of Guidance, Control, and Dynamics

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When full-electric orbit-raising trajectories begin in a classic geostationary transfer orbit with low initial perigee altitude, the need for deployed solar arrays to power the propulsion system significantly increases the aerodynamic and gravity gradient torques. In fact, the torque magnitudes in the first few perigee passages may become a challenging requirement for the attitude control system. Apart from oversizing actuators, other solutions may include the need for a backup thruster system or raising the perigee altitude, implying mass penalties and cost. This paper presents the design of an optimal attitude maneuver at the perigee that can be undertaken using nominal reaction wheels. Attitude paths avoiding saturation of the wheels while dumping accumulated momentum are obtained performing a physically consistent modeling of aerodynamic torques and using pseudospectral methods to solve the trajectory optimization problem. The optimization of solar array positions is also explored to further constrain the problem or improve the maneuver performance. Resulting mass and cost savings can be significant, which could be used for additional payload or to significantly extend the operational life of the satellite.

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Section: Optimal Control Problemmentioning

confidence: 99%

mentioning

confidence: 99%

Perigee Attitude Maneuvers of Geostationary Satellites During Electric Orbit Raising

Prieto

Roberts

2017

Journal of Guidance, Control, and Dynamics

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“…O VER the last decade, pseudospectral (PS) methods for optimal control have moved rapidly from theory [1][2][3] to practice [4][5][6][7][8][9][10][11][12] to flight application [13,14]. The flight application onboard the International Space Station marks one of the many milestones in the recent developments [15][16][17][18] in PS methods for optimal control theory.…”

Section: Introductionmentioning

confidence: 99%

Spectral Algorithm for Pseudospectral Methods in Optimal Control

Gong

Fahroo

Ross

2008

Journal of Guidance, Control, and Dynamics

165

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Recent convergence results with pseudospectral methods are exploited to design a robust, multigrid, spectral algorithm for computing optimal controls. The design of the algorithm is based on using the pseudospectral differentiation matrix to locate switches, kinks, corners, and other discontinuities that are typical when solving practical optimal control problems. The concept of pseudospectral knots and Gaussian quadrature rules are used to generate a natural spectral mesh that is dense near the points of interest. Several stopping criteria are developed based on new error-estimation formulas and Jackson's theorem. The sequence is terminated when all of the convergence criteria are satisfied. Numerical examples demonstrate the key concepts proposed in the design of the spectral algorithm. Although a vast number of theoretical and algorithmic issues still remain open, this paper advances pseudospectral methods along several new directions and outlines the current theoretical pitfalls in computation and control.

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“…As exemplified by its experimental and flight applications in national programs [6][7][8][9][10], it is not surprising that the Legendre PS method has become the method of choice [11][12][13][14][15][16][17][18][19] in both industry and academia for solving optimal control problems. Efforts to improve the Legendre PS methods by using either other polynomials [20][21][22] or point distributions [23,24] have not yet resulted in any rigorous framework for convergence of these approximations [24,25].…”

Section: Introductionmentioning

confidence: 99%