Flatness-based trajectory planning for electromagnetic spacecraft proximity operations in elliptical orbits

Zhu, Yanbo; Cai, Weiwei; Lee, Yang; Huang, Huan

doi:10.1016/j.actaastro.2018.08.031

Cited by 7 publications

(5 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reason for such change is that the hybrid magnetic bearing-rotor system is realized by differential control. The control system adjusts the system current according to the rotor position offset signals detected by the sensor [ 27 ]. In addition, the material of the magnetic bearing is affected by the magnetic saturation performance, which brings a maximum value for the corresponding regulation current of the system.…”

Section: Resultsmentioning

confidence: 99%

Performance for rotor system of hybrid electromagnetic bearing and elastic foil gas bearing with dynamic characteristics analysis under deep learning

Sun

2021

PLoS ONE

View full text Add to dashboard Cite

The bearing-rotor system is prone to faults during operation, so it is necessary to analyze the dynamic characteristics of the bearing-rotor system to discuss the optimal structure of the convolutional neural network (CNN) in system fault detection and classification. The turbo expander is undertaken as the research object. Firstly, the hybrid magnetic bearing-rotor system is modeled into the form of four stiffness coefficients and four damping coefficients, so as to analyze and explain the dynamic characteristics of the system. Secondly, the ambient pressure is introduced to analyze the dynamic characteristics of the elastic foil gas bearing-rotor system based on the changes in the dynamic stiffness and dynamic damping of the gas bearing. Finally, the CNN is introduced to be applied in the detection of faults of bearing-rotor system through determining the parameters of the constructed CNN. The results show that the displacement of the rotor increases and the stiffness decreases with the acceleration of the speed of the electromagnetic bearing. The maximum displacement of the rotor can reach 135μm, and the maximum stiffness can be reduced to 35×105N/m. Increase of ambient pressure causes enhancement of main stiffness of the gas bearing, and the main damping decreases accordingly. Analysis of the classification accuracy and loss function based on the CNN model shows that the convolution kernel size of 7*1 and the batch size of 128 can realize the best performance of CNN in fault classification. This provides a data support and reference for studying the dynamic characteristics of the bearing-rotor system and for the optimization of CNN structure in fault classification and detection.

show abstract

Section: Resultsmentioning

confidence: 99%

Performance for rotor system of hybrid electromagnetic bearing and elastic foil gas bearing with dynamic characteristics analysis under deep learning

Sun

2021

PLoS ONE

View full text Add to dashboard Cite

show abstract

“…Likewise, the location and length of the rotation window for obstacle 2 can also be computed. Note that the same linear technique as conventional RH method, that is, equation (15), is applied to addressing the obstacle avoidance constraint in the rotation window, while the adjacent beginning and final hyperplane constraints keep unchanged outside the window. Accordingly, the angular velocity ω of hyperplane is adjusted to γ tot divided by L window .…”

Section: Improved Rh Methodsmentioning

confidence: 99%

“…The second method converts collision avoidance problem into an optimization problem with path constraints and then solved it by nonlinear programming (NLP) algorithms. Limited by onboard computing resources, multiple approaches have been studied in aerospace systems to improve online computational efficiency, including differential flatness method, 14,15 pseudospectral method, 16,17 and inverse dynamics optimization method. 18,19 Among the existing approaches, model prediction control (MPC) method has attracted increasing attention due to its conceptual elegance and significant advances in real-time applicability.…”

Section: Introductionmentioning

confidence: 99%

Online collision avoidance trajectory planning for spacecraft proximity operations with uncertain obstacle

Zhang

Cai

Lee

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

Self Cite

View full text Add to dashboard Cite

The spacecraft relative motion trajectory planning is one of the enabling techniques for autonomous proximity operations, especially in the increasingly complicated mission environments. Most traditional trajectory planning methods focus on improving the performance criteria in the deterministic conditions, whereas various uncertain elements in practice would significantly degrade the trajectory performance. Considering the uncertainties underlying the collision avoidance constraints, this paper suggests a model predictive control based online trajectory planning framework in which the obstacle information in higher-precision would be consistently updated by the onboard sensor. To improve the computational efficiency of the online planning framework, the rotating hyperplane (RH) technique is utilized to transform the nonlinear ellipsoidal keep-out zone constraints into convex formulations. And the concept of rotation window is introduced to eliminate the unexpected mismatch between the spacecraft motion and hyperplane rotation in the conventional RH method, which in sequence improves the RH method’s capability for multiple obstacle avoidance problem. Moreover, a three-dimensional (3-D) extension strategy is proposed to simplify the computation procedure when applying the RH method for a 3-D collision avoidance problem. Numerical simulations are carried out to validate the performance of the proposed online trajectory planning framework in addressing the uncertain collision avoidance constraints.

show abstract

“…However, the direct method develops fast, given its large convergent domain, and requires no initial guessing of coordination variables [16]. As one of the direct methods, the pseudospectral method [17] has been widely adopted [18] because of its high computation efficiency [19] and ability for attaining real-time optimal trajectory [20]. The pseudospectral method includes the Chebyshev pseudospectral method (CPM), the Legendre pseudospectral method (LPM) [21], the Gauss pseudospectral method (GPM), and the Radau pseudospectral method (RPM).…”

Section: Introductionmentioning

confidence: 99%

Multi-Scenario Trajectory Optimization for Vertical Takeoff and Vertical Landing Vehicles Using the Gauss Pseudospectral Method

Liu¹,

Li²,

Han³

et al. 2022

Aerospace

View full text Add to dashboard Cite

Vertical takeoff and vertical landing (VTVL) vehicles, based on throttling liquid rocket engines, are attracting increasing attention for their validation of guidance and control techniques during landing. However, validation requires the vehicle to fly in a special trajectory with multiple constraints. Propellant consumption should be carefully calculated for the purpose of carrying more experimental devices during the flight, which makes conducting minimum-propellant trajectory optimization a necessity. This study focuses on the optimization of VTVL vehicles based on a throttling liquid rocket engine. Three flight scenarios applicable to this vehicle are proposed, namely, VTVL vehicles without horizontal movement, VTVL vehicles with horizontal movement, and vertical takeoff and autonomous landing with horizontal movement. Trajectory optimization using the Gauss pseudospectral method (GPM) was conducted during the abovementioned flight scenarios. The results show that the GPM provides excellent solutions for trajectory optimization in the different scenarios. In VTVL vehicles with horizontal movement, vertical takeoff, and autonomous landing with horizontal movement scenarios, the thrust appears in a similar bang–bang control. Meanwhile, in VTVL vehicles without a horizontal movement scenario, the thrust appears like a segmented bang–bang control, which we call regulative bang–bang control. Moreover, by introducing the thrust derivative into the optimization objective using a weighted method, thrust fluctuation can be restrained. To ensure the compatibility of switching the flight among the three scenarios, the carried propellant mass should be decided based on the third flight scenario.

show abstract

Flatness-based trajectory planning for electromagnetic spacecraft proximity operations in elliptical orbits

Cited by 7 publications

References 19 publications

Performance for rotor system of hybrid electromagnetic bearing and elastic foil gas bearing with dynamic characteristics analysis under deep learning

Performance for rotor system of hybrid electromagnetic bearing and elastic foil gas bearing with dynamic characteristics analysis under deep learning

Online collision avoidance trajectory planning for spacecraft proximity operations with uncertain obstacle

Multi-Scenario Trajectory Optimization for Vertical Takeoff and Vertical Landing Vehicles Using the Gauss Pseudospectral Method

Contact Info

Product

Resources

About