In this paper, the nonzero-sum pursuit-evasion (PE) game control problem is studied for a class of linear spacecraft control systems subject to the complete information case and incomplete information case. The incomplete information includes the cost functions and the control inputs. In practical confrontation situations, due to the incomplete information constraints, it is impossible for the pursuer and the evader to build up the exact opposite cost function. Hence, a nonzero-sum game framework is utilized to describe the PE game problem of the double-spacecraft system. First of all, under the complete information case, the nonzero-sum PE game control strategy is designed by solving the coupled Riccati recursions. Then, aiming at the incomplete information case, a control gain estimator is established, which lays the foundation for the control strategy design of the pursuit spacecraft. On the basis of the estimated control gain, the pursuit control strategy is solved by using the standard discrete-time Riccati recursion. In order to further get rid of the system information, a Q-learning-based control gain is designed for the pursuit spacecraft. Finally, a numerical example on the PE spacecraft system is provided to verify the effectiveness of the proposed PE game control strategies.

This paper puts forward a coordinated formation control scheme for multiple fixed-wing unmanned aerial vehicle (UAV) systems with external nonlinear disturbances including not only the drag force and uncertain lateral force, but also the drag, lift, and lateral forces caused by wake vortices. A novel distributed finite-time extended state observer is designed to estimate both the unmeasurable states and uncertain external nonlinear disturbances of each fixed-wing UAV. In particular, an event-triggered mechanism is employed to reduce the burden of communication networks among multiple fixed-wing UAVs. Meanwhile, an inter-trigger output predictor, replacing the classic zero-order holder, is adopted to obtain cooperative errors between two consecutive triggering moments. Furthermore, a composite distributed controller is proposed to mitigate uncertain disturbances, enabling the coordinated formation flying of multiple fixed-wing UAVs.Finally, two illustrative simulation scenarios are discussed to verify the performance of the presented coordinated formation control scheme.

On-orbit removing tumbling targets is a critical research issue for future space missions. Repeated tentative contacts by the robot can be used to eliminate the rotational motion of a tumbling target. The elimination process depends on the accuracy of the information provided by a motion estimator, which is not discussed in conventional research. Additionally, there are few literatures that examine how to reduce the number of contacts to increase mission safety. To solve these issues, a coupling framework of a navigation method and a detumbling controller is designed in this paper. In particular, the relative navigation method, which incorporates the momentum transfer information and the visual guidance, is developed to estimate states of the target. The combination of two types of information ensures that the estimator can be used continuously in free-floating and contact modes without the need for measuring interaction forces. By modifying an optimal controller, a detumbling controller is designed. A sufficient condition is established such that the robot can achieve the goal of detumbling the target under the influence of estimation errors. Finally, a numerical example is provided to illustrate the effectiveness of the designed framework.