Collision Avoidance for Satellites in Formation Flight

Slater, Gary W.; Byram, Sharyl; Williams, Trevor

doi:10.2514/6.2004-5216

Cited by 14 publications

(16 citation statements)

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“…We remedy this situation by smoothing out the control discontinuity in a thin boundary layer neighboring the switching surface [31]. To do this, the sign function in the control law (5) can be replaced by a saturation function, thus the MTANCCA is given by…”

Section: Modified Control Law Designmentioning

confidence: 99%

Coordination control design for formation reconfiguration of multiple spacecraft

Zhou

Xia

2015

IET Control Theory & Applications

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This study investigates the high precision control design of formation reconfiguration for a group of spacecraft with obstacle/collision avoidance and unknown disturbances. First, by utilising the null-space-based method, a set of predesigned velocities are calculated for each spacecraft to perform the tasks with the obstacle/collision avoidance task has a higher priority. Second, a task-based adaptive non-singular fast terminal sliding mode coordination control algorithm (TANCCA) is proposed, which can guarantee all the spacecraft to implement the formation reconfiguration while avoiding obstacles/collisions under an unknown disturbed environment. To solve the chattering problem caused by the discontinuity of TANCCA, a modified TANCCA (MTANCCA) is then developed, which is continuous and chattering-free. Finally, the authors use the solution to the formation reconfiguration control problem for six spacecrafts in a circular Low Earth Orbit at 600 km altitude. The results of the simulation show that the MTANCCA is successful in achieving the obstacle/collision avoidance, disturbance rejection, fast convergence, and high control precision without any collisions or rules broken. IntroductionSpacecraft formation flying (SFF) means a group of spacecraft flying together with coupled dynamic states, and research in this area has become an increasingly popular subject in recent years. Formation with a definite configuration could deem to work as a virtual monolithic spacecraft, it will greatly enhance system performance by distributing the task from a monolithic spacecraft to several small spacecraft, especially for some capabilities which are unachievable for a single monolithic spacecraft [1]. Replacing large and complex spacecraft with an array of simpler micro-satellites can bring out new possibilities and opportunities of cost reduction, redundancy, and improve resolution aspects of onboard payload, thus SFF is a new method of performing space operations. In spaceflight, obstacle/collision avoidance is the process of preventing a spacecraft from colliding with any other spacecraft, object or space junk. In a tightly flying cluster of spacecraft, obstacle/collision avoidance is an essential concern while fulfilling specific and varied missions. Furthermore, the disturbance forces working on a spacecraft in orbit are mainly caused by gravitational perturbations, atmospheric drag, solar radiation, solar wind, and third-body perturbing forces [2]. Although the disturbances are small, they should not be ignored because over time large deviations will occur without any treatment. From the aforementioned, research on the problem of SFF with obstacle/collision avoidance and disturbances has important practical significance and application potential. During the past decade, many studies have been published on spacecraft obstacle or collision avoidance. Using the null-space-based (NSB) concept, Schlanbusch et al.[3] investigated the spacecraft formation and collision avoidance problem, and a cooperative control method was deve...

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Section: Modified Control Law Designmentioning

confidence: 99%

Coordination control design for formation reconfiguration of multiple spacecraft

Zhou

Xia

2015

IET Control Theory & Applications

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“…With the rapid practical applications for spacecraft formation missions, the importance of optimal cooperative control is worth investigating in the theoretical research and practical applications. [4][5][6] Optimal cooperative control has been identified as one of the most important cases to consider for cooperative control in SFF system, 7,8 where the goal is to select optimal cost functions to obtain performance index and to predict the system state in real time. Due to this fact, many control algorithms have been presented to solve this problem by combining the optimal methods with cooperative control.…”

Section: Introductionmentioning

confidence: 99%

Optimal cooperative control for formation flying spacecraft with collision avoidance

Lin

Shi

2019

Science Progress

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This article investigates optimal cooperative control algorithms for spacecraft formation flying system that can guarantee collision avoidance between spacecrafts. By selecting potential functions to avoid collisions and constructing index cost functions to describe optimal control, the optimal control algorithms based on the state-dependent Riccati equations, which only require local information vectors, are presented that can guarantee the formation spacecraft to track the reference trajectory without collisions and achieve optimal performance states. Finally, the corresponding proof analysis by Lyapunov stability theory shows that the closed-loop system for spacecraft formation flying is asymptotically stable. The simulation results demonstrate the effectiveness of the proposed optimal cooperative control algorithms with desired control objectives, including trajectory tracking, formation optimality, and collision avoidance.

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“…where KðEÞ is the integrand matrix, whose specific expression is given in the appendix [29]. Then, combining equations (22), (31), (32), and (34), C 2 ðtÞ can be directly calculated as follows:…”

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confidence: 99%

An Analytical Method for Calculating Short-Term Space Interception Probability

Ding

Yang

et al. 2019

International Journal of Aerospace Engineering

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For small unguided space interceptors, the interception probability is an important index to evaluate their strike capability. However, the Monte Carlo (MC) based simulation method not only consumes a lot of computation time but also theoretically lacks interpretability. In this regard, this paper proposes an analytical method that can quickly and accurately calculate the short-term space interception probability. Firstly, by considering the effect of perturbation force on spacecraft as the effect of external force acceleration, the analytical calculation formula of the short-term state error covariance propagation of space target and interceptor is deduced. Next, by projecting the state error and rotating the coordinate system, the joint error distribution of the target and the interceptor in the calculation coordinate system at the time of closest approach (TCA) is obtained. Thereby convert the calculation of the space interception probability into the integral of the 2-dimensional probability density function in the circular domain. Then, the Laplace transform and Taylor expansion are used to obtain the exact power series expression and the maximum truncation error of the integral calculation, and the analytical calculation of the short-term space interception probability is realized. Finally, the effectiveness of the proposed method is verified by a simulation example. The proposed method can directly calculate the space interception probability according to the initial state error distribution of the target and interceptor, and the whole calculation process does not contain double integral operation. The proposed method has high computational efficiency, is suitable for on-orbit calculation, and provides effective support for the rapid evaluation of the strike capability of the space interceptor.

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Collision Avoidance for Satellites in Formation Flight

Cited by 14 publications

References 0 publications

Coordination control design for formation reconfiguration of multiple spacecraft

Coordination control design for formation reconfiguration of multiple spacecraft

Optimal cooperative control for formation flying spacecraft with collision avoidance

An Analytical Method for Calculating Short-Term Space Interception Probability

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