Flexible Satellite Attitude Maneuver Control Using Pulse-Width Pulse-Frequency Modulated Input Shaper

2006 ◽  
Author(s):  
Jinpeng Yuan ◽  
Di Yang ◽  
Hongtao Wei
Keyword(s):  
Pulse Width ◽  
Pulse Frequency ◽  
Satellite Attitude ◽  
Input Shaper ◽  
Attitude Maneuver

scholarly journals Spacecraft vibration reduction using pulse-width pulse-frequency modulated input shaper

1997 ◽  
Author(s):  
Gangbing Song ◽  
Nick Buck ◽  
Brij Agrawal ◽  
Gangbing Song ◽  
Nick Buck ◽  
...  
Keyword(s):  
Pulse Width ◽  
Vibration Reduction ◽  
Pulse Frequency ◽  
Input Shaper

scholarly journals Spacecraft Vibration Reduction Using Pulse-Width Pulse-Frequency Modulated Input Shaper

1999 ◽  
Vol 22 (3) ◽  
pp. 433-440 ◽  
Author(s):  
Gangbing Song ◽  
Nick V. Buck ◽  
Brij N. Agrawal
Keyword(s):  
Pulse Width ◽  
Vibration Reduction ◽  
Pulse Frequency ◽  
Input Shaper

Pulsed-DC Electrospray for Biopolymer Particle Production

2009 ◽  
Vol 1239 ◽  
Author(s):  
Cho-Hui Lim ◽  
Kiersten R Schierbeek ◽  
Michael E Mullins
Keyword(s):  
Pulse Width ◽  
Particle Production ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Process Conditions ◽  
High Duty Cycle ◽  
Pulsed Dc ◽  
High Pulse ◽  
Long Pulse ◽  
Frequency Pulse

AbstractPLLA microparticles were successfully fabricated via pulsed-DC electrospray. In this study, we investigated the effect of the pulsed voltage characteristics (e.g. pulse frequency, pulse amplitude and pulse width) on the particle’s size. We found that pulse frequency, pulse amplitude, pulse width, and the combinations of these factors had a statistically significant effect on the particle’s size. The process conditions to obtain smaller particles with uniform shape and size are a low pulse frequency, high pulse amplitude, and long pulse width (or a high duty cycle).

scholarly journals Dynamic Sliding Mode Controller with Variable Structure for Fast Satellite Attitude Maneuver

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Gao Shan ◽  
Li You ◽  
Xue Huifeng ◽  
Yao ShuYue
Keyword(s):  
Convergence Rate ◽  
Attitude Control ◽  
Sliding Mode ◽  
Variable Structure ◽  
System Stability ◽  
System State ◽  
Satellite Attitude ◽  
Satellite Attitude Control ◽  
Attitude Maneuver ◽  
Mode Parameter

In order to deal with the low convergence rate of the standard sliding mode in satellite attitude control, a novel variable structure sliding mode is constructed in this paper by designing the update law of the sliding mode parameter. By implementing this method, the advantage such as simple structure and strong robustness of the standard sliding mode are maintained and the system convergence rate is largely improved. The fixed sliding mode parameter is modified, and the update law is designed. When the system state is away from the sliding mode surface, the parameter is fixed, and when the system state approaches the sliding mode surface, the parameter begins to update. The constraint on control torque and angular velocity is taken into consideration, and the constraint on control parameters is given to ensure that the system state do not exceed its upper bound. System stability is proved by the Lyapunov stability theorem, and the superiority of the proposed controller is demonstrated by numerical simulation.

scholarly journals Optimal Factorization of the State-Dependent Riccati Equation Technique in a Satellite Attitude and Orbit Control System

2021 ◽  
Vol 20 ◽  
pp. 98-107
Author(s):  
Alessandro Gerlinger Romero ◽  
Luiz Carlos Gadelha De Souza
Keyword(s):  
Control System ◽  
Riccati Equation ◽  
The State ◽  
Linear Control ◽  
Control Techniques ◽  
Orbit Control ◽  
Satellite Attitude ◽  
Modified Rodrigues Parameters ◽  
State Dependent ◽  
Attitude Maneuver

The satellite attitude and orbit control system (AOCS) can be designed with success by linear control theory if the satellite has slow angular motions and small attitude maneuver. However, for large and fast maneuvers, the linearized models are not able to represent all the perturbations due to the effects of the nonlinear terms present in the dynamics and in the actuators (e.g., saturation). Therefore, in such cases, it is expected that nonlinear control techniques yield better performance than the linear control techniques. One candidate technique for the design of AOCS control law under a large maneuver is the State-Dependent Riccati Equation (SDRE). SDRE entails factorization (that is, parameterization) of the nonlinear dynamics into the state vector and the product of a matrix-valued function that depends on the state itself. In doing so, SDRE brings the nonlinear system to a (nonunique) linear structure having state-dependent coefficient (SDC) matrices and then it minimizes a nonlinear performance index having a quadratic-like structure. The nonuniqueness of the SDC matrices creates extra degrees of freedom, which can be used to enhance controller performance, however, it poses challenges since not all SDC matrices fulfill the SDRE requirements. Moreover, regarding the satellite's kinematics, there is a plethora of options, e.g., Euler angles, Gibbs vector, modified Rodrigues parameters (MRPs), quaternions, etc. Once again, some kinematics formulation of the AOCS do not fulfill the SDRE requirements. In this paper, we evaluate the factorization options (SDC matrices) for the AOCS exploring the requirements of the SDRE technique. Considering a Brazilian National Institute for Space Research (INPE) typical mission, in which the AOCS must stabilize a satellite in three-axis, the application of the SDRE technique equipped with the optimal SDC matrices can yield gains in the missions. The initial results show that MRPs for kinematics provides an optimal SDC matrix.

Parametric Analysis of Laser Beam Percussion Drilling for Thin Titanium Alloy Sheet Using Yb: Yag Fiber Laser

2021 ◽  
pp. 1-24
Author(s):  
Mohit Singh ◽  
Sanjay Mishra ◽  
Vinod Yadava ◽  
J. Ramkumar
Keyword(s):  
Laser Beam ◽  
Fiber Laser ◽  
Pulse Width ◽  
Peak Power ◽  
Laser Pulses ◽  
Pulse Frequency ◽  
Alloy Sheet ◽  
Power Pulse ◽  
The Individual ◽  
Percussion Drilling

Laser beam percussion drilling (LBPD) can create high density holes in aerospace materials with the repeated application of laser pulses at a single spot. In this study, one-parameter-at-a-time approach has been used to investigate the individual effect of peak power, pulse width and pulse frequency on geometrical accuracy and metallurgical distortion during LBPD of 0.85[Formula: see text]mm thick Ti–6Al–4V sheet using 200[Formula: see text]W Yb:YAG fiber laser. It has been found that the output parameters behave differently at the higher and lower values of a particular input process. The increase of pulse width from 1 to 1.50[Formula: see text]ms increases hole taper by 20% whereas the same corresponding change from 1.50 to 2.00[Formula: see text]ms reduces the taper by 20%. The increase of pulse frequency from 10 to 50[Formula: see text]Hz reduces hole circularity by 40% but the same proportionate change from 50 to 90[Formula: see text]Hz reduces circularity by 79%. Increase of peak power from 1.70 to 2.0[Formula: see text]kW increases hole taper by 8% but the corresponding increase from 2 to 2.30[Formula: see text]kW is 143%.

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