A Mission Architecture for On-Orbit Servicing Industrialization

Rousso, Patrick; Samsam, Sanaz; Chhabra, Robin

doi:10.1109/aero50100.2021.9438404

Cited by 10 publications

(8 citation statements)

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“…Space robots can replace or assist astronauts in various on-board/offboard activities, and it is particularly important for space robots to recognise astronaut commands [4]. Facial expression recognition by astronauts is a widely used method of human-robot interaction in space that does not rely on the highly intelligent capabilities of space robots, and it can effectively combine the decision-making capabilities of humans with the precise operational capabilities of space robots to improve their operational capabilities [5][6][7]. The accuracy of the astronaut's facial expression recognition and the size of the expression recognition model are important indications of the increased efficiency of space robots.…”

Section: Introductionmentioning

confidence: 99%

Multiscale Feature Fusion Attention Lightweight Facial Expression Recognition

Zhang

2022

International Journal of Aerospace Engineering

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Facial expression recognition based on residual networks is important for technologies related to space human-robot interaction and collaboration but suffers from low accuracy and slow computation in complex network structures. To solve these problems, this paper proposes a multiscale feature fusion attention lightweight wide residual network. The network first uses an improved random erasing method to preprocess facial expression images, which improves the generalizability of the model. The use of a modified depthwise separable convolution in the feature extraction network reduces the computational effort associated with the network parameters and enhances the characterization of the extracted features through a channel shuffle operation. Then, an improved bottleneck block is used to reduce the dimensionality of the upper layer network feature map to further reduce the number of network parameters while enhancing the network feature extraction capability. Finally, an optimized multiscale feature lightweight attention mechanism module is embedded to further improve the feature extractability of the network for human facial expressions. The experimental results show that the accuracy of the model is 73.21%, 98.72%, and 95.21% on FER2013, CK+ and JAFFE, respectively, with a covariance of 10.14 M. Compared with other networks, the model proposed in this paper has faster computing speed and better accuracy at the same time.

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Section: Introductionmentioning

confidence: 99%

Multiscale Feature Fusion Attention Lightweight Facial Expression Recognition

Zhang

2022

International Journal of Aerospace Engineering

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“…Therefore, protecting the safety of space assets in face of these threats is critical for cleaning space. Many studies have been done to find a way out, e.g., space situational awareness, on-orbit servicing and so on [5][6][7][8][9][10][11][12]. Developing on-orbit servicing vehicles with corresponding GNC (guidance, navigation and control) systems used to handle the space debris, inactive satellites and military vehicles threating to the space asset is the most effective method for safety.…”

Section: Introductionmentioning

confidence: 99%

Incomplete Information Pursuit-Evasion Game Control for a Space Non-Cooperative Target

et al. 2021

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Aiming to solve the optimal control problem for the pursuit-evasion game with a space non-cooperative target under the condition of incomplete information, a new method degenerating the game into a strong tracking problem is proposed, where the unknown target maneuver is processed as colored noise. First, the relative motion is modeled in the rotating local vertical local horizontal (LVLH) frame originated at a virtual Chief based on the Hill-Clohessy-Wiltshire relative dynamics, while the measurement models for three different sensor schemes (i.e., single LOS (line-of-sight) sensor, LOS range sensor and double LOS sensor) are established and an extended Kalman Filter (EKF) is used to obtain the relative state of target. Next, under the assumption that the unknown maneuver of the target is colored noise, the game control law of chaser is derived based on the linear quadratic differential game theory. Furthermore, the optimal control law considering the thrust limitation is obtained. After that, the observability of the relative orbit state is analyzed, where the relative orbit is weakly observable in a short period of time in the case of only LOS angle measurements, fully observable in the cases of LOS range and double LOS measurement schemes. Finally, numerical simulations are conducted to verify the proposed method. The results show that by using the single LOS scheme, the chaser would firstly approach the target but then would lose the game because of the existence of the target’s unknown maneuver. Conversely, the chaser can successfully win the game in the cases of LOS range and double LOS sensor schemes.

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“…Due to the randomness of the added perturbation in the simulation, we computed the actual trajectory under the obtained optimal control input multiple times. The average distance between the two satellites at the final time of mission is calculated to be almost 4 km, with this distance changing in the range [3,5] km. Table 8.2 summarizes the averaged classical orbital elements in each intermediate orbit to compare with those corresponding to the reference trajectory.…”

Section: Case Studymentioning

confidence: 99%

Section: Case Studymentioning

confidence: 99%

“…The highly increasing demand for OOS operations suggests the necessity to move towards industrialization, whose main challenge is the design of an efficient mission architecture for continuous supply of multiple services to a number of target satellites (hereafter called target). The phase of a servicing mission that mostly contributes to fuel and time consumption is the long-range rendezvous [5]. Further, considering the target's orbital motion in the long-range rendezvous will provide solutions that can decrease the duration and the required fuel in the short-range rendezvous.…”

Section: Introduction 11 Motivationmentioning

confidence: 99%

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An Evolutionary Framework for Multi-Objective Trajectory Design and Robust Model Predictive Control in Long-Range Rendezvous Missions

Samsam¹

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This thesis presents an optimization architecture for on-orbit servicing mission design in the long-range rendezvous phase. We develop a methodology to generate Pareto Optimal trajectories for long-range rendezvous of a servicing satellite with a moving target. The methodology employs a multi-impulse shape-based trajectory planning algorithm for in-plane orbit transfer, based on the two-body problem. We first derive the necessary and sufficient conditions that determine the set of smooth impulsive trajectories connecting the servicing satellite to the orbiting target. The Pareto Optimal trajectories from this set are then obtained using a constrained multiobjective optimization algorithm developed based on the Non-dominated Sorting Genetic Algorithm-II (NSGA-II). Transfer time and control effort are the two Pareto cost functions that are considered in the multi-objective optimization. To reduce the risk of collision in populated orbits and to remain in an orbital regime, we include restrictions on orbital elements as part of the constraints. Further, a maximum available impulse is considered as an upper-bound for velocity changes in an impulsive trajectory. The number of impulses along with the location of the first impulse in the parking orbit and the orbital parameters of the intermediate orbits form the set of design variables. We demonstrate the superiority of the developed trajectory planner by comparing its results with those obtained from another multi-objective evolutionary algorithm called the Multi-Objective Genetic Algorithm and an optimal Lambert approach. In an on-orbit servicing mission, a solution from the Pareto frontier set of optimal trajectories may be selected based on the mission requirements.To robustly follow the generated reference trajectories in a J 2 -perturbed orbital environment, we propose a Nonlinear Model Predictive Control (NMPC) scheme. The control signals are velocity increments at the time of applying each impulse, and the variable horizon is considered to be the time difference between every two impulses in the reference trajectory. To avoid singularities, the equinoctial orbital elements are used in the process model that includes the secular and first-order long-periodic effects iii

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A Mission Architecture for On-Orbit Servicing Industrialization

Cited by 10 publications

References 50 publications

Multiscale Feature Fusion Attention Lightweight Facial Expression Recognition

Multiscale Feature Fusion Attention Lightweight Facial Expression Recognition

Incomplete Information Pursuit-Evasion Game Control for a Space Non-Cooperative Target

An Evolutionary Framework for Multi-Objective Trajectory Design and Robust Model Predictive Control in Long-Range Rendezvous Missions

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