Robust Attitude Control Systems Design for Solar Sails (Part 1): Propellantless Primary ACS

Wie, Bong; Murphy, David M.; Paluszek, Michael; Thomas, Stephanie

doi:10.2514/6.2004-5010

Cited by 39 publications

(19 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For a baseline 40m square sailcraft, the cm/cp offset is assumed to be 0.25% of the square sail edge length and the magnitude of SRP force is given by 8.33x10 -6 N/m 2 multiplied by the area of the deployed sail membrane. 18 The effects of variation in these parameters are presented in Section V. Rearranging Eqs. (10a,b,c) and solving for the angular acceleration leads to the following system of governing ordinary differential equations in the body-fixed reference frame: Again, it is important to note that each of the equations of motion above (for a spinning square or e 1axisymmetric sailcraft under the influence of SRP) contains a newly added term which accounts for the variation in inertia that the vehicle will experience during the deployment process.…”

Section: Equations Of Motion Governing Deploymentmentioning

confidence: 99%

“…The inertias calculated above are 2082 kg-m 2 about the pitch and yaw (e 2 , e 3 ) axes and 3942 kg-m 2 about the roll (e 1 ) axis, whereas the corresponding published values are 2171 kg-m 2 and 4340 kg-m 2 (4.1% and 9.2% error, respectively). 18 It should be noted that Eqs. (16a,b,c) are approximations and a more rigorous dynamic model is necessary to predict the complex time dependence of the deploying sailcraft's inertia with higher accuracy.…”

Section: Time-dependent Principal Moments Of Inertiamentioning

confidence: 99%

“…One method to minimize the influence of SRP is to require that sail deployment occur edge-on to the Sun to reduce the amount of photons incident to the sail membrane. 18 Thus the magnitude of the external disturbance torque from SRP would be minimized, as would the possibility for instabilities induced by sail membrane deployment asymmetries (e.g., uncertain cm/cp offset). It is, however, not clear if this sequence is optimum since the solar sail would be statically stabilized by the incident SRP in a sun-pointing deployment.…”

mentioning

confidence: 99%

See 2 more Smart Citations

(Student Paper) Attitude Dynamics and Stability of Solar Sails During Deployment

LeFevre¹,

Jha²

2006

47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

0
0
0
0

View full text Add to dashboard Cite

The attitude dynamics of a solar sail spacecraft during deployment are critically important for overall mission success. To model these dynamics, equations of motion governing the deployment of a solar sail are developed and the stability of the predicted motion is evaluated. For this purpose, an expression is derived to calculate the principal moments of inertia as the solar sail is deployed. A typical 40 m x 40 m square solar sailcraft is considered with a center of mass vs. center of pressure (cm/cp) offset of 0.25% of the sail edge length, boom deployment rate of 2.5 cm/s, and maximum incident solar radiation pressure force density of 8.33x10 -6 N/m 2 . The dynamic simulations show that the sailcraft exhibits an exponential decay in the spin rate about its roll axis (perpendicular to the sail membrane). This behavior is accompanied by an increase in the pointing error of the sail membrane normal vector (i.e., thrust vector). Variations in the baseline parameters given above will alter the final pointing error. It is shown that uncertainty in the cm/cp offset produces the most severe increase in the pointing error. Adjustment of the boom deployment rate (and thus, the total time required for deployment) also significantly affects the pointing error induced by the deployment process. It is observed that the final pointing attitude error in most cases is significantly larger than the typical sailcraft specification of ±1 deg misalignment of the thrust vector. The capabilities of the attitude control system and the deployment parameters (e.g., initial spin rate, boom/sail deployment rate, and initial pointing attitude) must then be optimized to assure satisfactory deployment.

show abstract

Section: Equations Of Motion Governing Deploymentmentioning
confidence: 99%

Section: Time-dependent Principal Moments Of Inertiamentioning
confidence: 99%

mentioning
confidence: 99%

See 1 more Smart Citation
(Student Paper) Attitude Dynamics and Stability of Solar Sails During Deployment
LeFevre¹,
Jha²
2006
47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference
0
0
0
0
View full text Add to dashboard Cite
The attitude dynamics of a solar sail spacecraft during deployment are critically important for overall mission success. To model these dynamics, equations of motion governing the deployment of a solar sail are developed and the stability of the predicted motion is evaluated. For this purpose, an expression is derived to calculate the principal moments of inertia as the solar sail is deployed. A typical 40 m x 40 m square solar sailcraft is considered with a center of mass vs. center of pressure (cm/cp) offset of 0.25% of the sail edge length, boom deployment rate of 2.5 cm/s, and maximum incident solar radiation pressure force density of 8.33x10 -6 N/m 2 . The dynamic simulations show that the sailcraft exhibits an exponential decay in the spin rate about its roll axis (perpendicular to the sail membrane). This behavior is accompanied by an increase in the pointing error of the sail membrane normal vector (i.e., thrust vector). Variations in the baseline parameters given above will alter the final pointing error. It is shown that uncertainty in the cm/cp offset produces the most severe increase in the pointing error. Adjustment of the boom deployment rate (and thus, the total time required for deployment) also significantly affects the pointing error induced by the deployment process. It is observed that the final pointing attitude error in most cases is significantly larger than the typical sailcraft specification of ±1 deg misalignment of the thrust vector. The capabilities of the attitude control system and the deployment parameters (e.g., initial spin rate, boom/sail deployment rate, and initial pointing attitude) must then be optimized to assure satisfactory deployment.
show abstract

“…Since these characteristics, the capability of the linear approaches to represent realistically the dynamics and the coupling effects is limited [2]. In the past few years, nonlinear methods, such as sliding-mode control [2,3], robust control [4] and dynamic inversion control [5] are developed for hypersonic vehicles, and the corresponding controllers work well in simulations or applications. But these methods need precise analytical model to design controller.…”

Section: Introductionmentioning
confidence: 99%

A neural network adaptive inverse controller for hypersonic vehicle
Wang
¹
,
Liu
²

2010
2010 International Conference on Information, Networking and Automation (ICINA)
2
0
0
0
View full text Add to dashboard Cite

A structure of nonlinear adaptive inverse controller based on Radial Basis Function (RBF) network is proposed to control a hypersonic vehicle with highly nonlinear and strong coupled states. Different from conventional adaptive inverse controllers, the proposed one is constructed by one main controller called Trimmed Adaptive Inverse Controller and two compensators called Attitude Angle Compensator and State Compensator respectively. The Extended Minimum Resource Allocating Network (EMRAN) algorithm is adopted to train the RBF network on-line and off-line. The simulation results show that proposed adaptive inverse controller could lead the hypersonic vehicle to trace the expect input rapidly and steadily, and could adapt the different flight condition by online learning.

show abstract

“…The square sail concept, adopted by NASA and ESA, was also considered in previous studies [9,10]. Several ground validation experiments have been conducted on the deployment, modal testing [11], and attitude control system [12][13][14] among others. However, the size of the sail tested is limited by the size of the vacuum chamber available.…”

mentioning
confidence: 99%

Transfer Trajectories Design for a Variable Lightness Solarcraft
Gong
¹
,
Li
²
,
Baoyin
³

2009
Journal of Spacecraft and Rockets
2
0
4
0
View full text Add to dashboard Cite

A new configuration of sailcraft that can adjust its lightness number is proposed in this paper. The new-concept sailcraft can evolve along different displaced solar orbits passively. Transfer trajectories between different displaced orbits are investigated, and two different strategies are employed to complete the transfers. When the initial and final orbits are close to each other, a linear model is used to generate an analytical control law first and it is corrected differentially to control the nonlinear model. The transfer accuracy at the target point can be specified in the differential corrections process. Numerical examples are employed to validate the control method over the transfer arc. The results show that the convergence becomes worse as the distance between the two orbits increases until the iteration process does not lead to the desired result when the distance between two orbits is outside the linear range. For these cases, a direct optimization method is employed for transfer trajectory design. The transfer trajectory is divided into segments, and the control law is assumed constant over each segment. Then, the design problem is transformed into a parameter optimization problem. A genetic algorithm and a conjugate gradient method are combined to achieve the desired results. The method proposed in this investigation proved efficient over the range of cases considered. Nomenclature C m = center of mass of the sailcraft C p = center of solar radiation pressure of the sailcraft F 1 = resultant solar radiation pressure force exerted on S 1 and S 2 F 2 = resultant solar radiation pressure force exerted on S 3 and S 4 h i = distance from the apex to the center of mass of S i (i 1, 2, 3, 4) L = length of the boom used to support the payload M t = total mass of the sailcraft m b = mass of bus m p = mass of payload n = force vector along the sail normal axis n i = unit normal vector of S i n s = unit normal vector of solar light O = the intersection point of S i (i 1, 2, 3, 4) O i= the mass center of S i (i 1, 2, 3, 4) P 1 = center of pressure of S 1 and S 2 P 2 = center of pressure of S 3 and S 4 r = distance from the sail to the sun r AB = vector from point A to point B r C m C p = vector from point C m to C p S i = area of a specific sail (i 1, 2, 3, 4) in the cone configuration consisting of four sails z 0 = displacement of the displaced orbit i = angle between n s and n i c = lightness number of the whole sailcraft s = lightness number of the sail 1 = angle between S 1 and S 2 2 = apex angle of S 1 and S 2 1 = angle between S 3 and S 4 2 = apex angle of S 3 and S 4 = the costate of the optimal control = solar gravitational constant = density of the sail, kg=m 2 0 = radius of the displaced orbit = the deviation from the equilibrium position in the direction perpendicular to the plane formed by r 0 and z ! 0 = angular velocity vector of the sailcraft

show abstract

Robust Attitude Control Systems Design for Solar Sails (Part 1): Propellantless Primary ACS

Cited by 39 publications

References 9 publications

(Student Paper) Attitude Dynamics and Stability of Solar Sails During Deployment

(Student Paper) Attitude Dynamics and Stability of Solar Sails During Deployment

A neural network adaptive inverse controller for hypersonic vehicle

Transfer Trajectories Design for a Variable Lightness Solarcraft

Contact Info

Product

Resources

About