Aiming at the practical engineering problems of complex spacecraft operation environment and unknown errors in ground modeling, a method of modeling spacecraft control system by fusing mechanism and data is proposed based on the idea of digital twin. The deviation between mechanistic models and physical entities is modeled by mining information from ground test data and in orbit telemetry data through LSTM networks. Then the mechanistic models and data driven models are combined to obtain highly accurate systemlevel and component –level models. Simulation results of typical components of spacecraft control systems show that the model constructed by this modeling method can provide more accurate portrayal of multi dimensional characteristics, effectively improve the accuracy of control system modeling， which lays an important foundation for accurate performance evaluation and intelligent health management of spacecraft control systems in orbit.

Autonomous orbit determination for a two satellite system with modelling errors is concerned in this paper．The performance of the autonomous orbit determination system is greatly affected by these errors in the dynamic model．One way to deal with these errors is treating them as unknown biases and estimating them with dynamic states together. Based on k order local weak observability theory, sufficient and necessary conditions of k order local weak observability are mathematically proved for the orbit determination system with modelling errors. The Extended Kalman Filter is applied to estimate the orbital states and systematic errors simultaneously．Simulation results show that the estimation algorithm is effective when the modeling errors are constant or slow time varying vectors.

The problem of maintaining control is investigated for the hybrid propulsion spacecraft formation around the planet centered displaced orbit. Firstly, the dynamics model of spacecraft formation near a planetary suspension orbit is established, and then the relative motion equation of spacecraft formation is derived via linearizing the model. In terms of control strategy, an integral sliding mode formation flight controller is designed, which can maintain and control formation configuration via adjusting the size of solar pressure and inter satellite Coulomb force. The controller has the characteristics of fast response and little dependence on system model. Finally, the numerical simulation shows that the proposed control method can achieve formation keeping control near the hovering orbit of the planet under the condition of disturbance.

An underactuated Control method is proposed for the stabilization control of the postcapture combination with state constraints. First, On the basis of establishing the dynamic model of the tethered system, the auxiliary function is designed to ensure the state constraints, and an underactuated controller is designed based on the energy method. Then, it is mathematically proved that the system state satisfies the constraints and can converge to the expected value. Finally, the designed controller is verified by simulation and compared with the traditional hierarchical sliding mode controller. The simulation results show the superiority of the designed controller with smaller attitude angle change range, less convergence time and higher control accuracy during the control process.

High value failed satellites are key targets for in orbit service and generally have large flexibility and residual angular momentum. Using robotic arms to directly capture the target has the risk of collision. If the contact detumbling is used to reduce the target angular velocity in advance, the success rate of the service satellite to capture the target can be greatly improved. Aiming at the problem of contact detumbling control of non cooperative failed satellites with flexible vibrations, a flexible vibration suppression method based on the characteristic model is proposed. Firstly, the characteristic model of the flexible vibration angular velocity is established based on the contact dynamic equation. Then the adaptive flexible vibration suppressor based on the characteristic model is designed. Finally, the numerical simulation is carried out. The simulation results show that the method can effectively suppress the flexible vibration of the target during the detumbling process.

Due to the limitation of system resources, the embedded operating system in the spacecraft does not have the file system module. The system task completes the reading and writing of external storage devices by directly calling the I/O interface. However, with the complexity of space missions, the equipment without a file system will have a large performance bottleneck. Therefore, the development of a safe and reliable file system is an urgent issue for space embedded systems. The space embedded operating system is a typical safety critical system, and every module integrated in the system needs to undergo rigorous testing to ensure that it will not cause malfunctions during operation. The use of formal verification technology can strictly guarantee the correctness of a certain system module mathematically. Therefore, the formal technology is used to verify the correctness of its internal logic according to the requirements of space vehicle file system in this paper.

In order to make the stepper motor reach the rated speed or target angle as soon as possible and avoid out of step, it is necessary to design the acceleration and deceleration profiles, such as trapezoid, S shape and so on. The traditional method of fixed design speed curve is only suitable for the situation that the target position, direction, initial speed, maximum limited speed and acceleration of the stepper motor have been determined in advance and will not be changed before the motor reaches the target position. In many applications of stepper motor, sometimes it is necessary to modify the operation parameters temporarily, and sometimes the initial speed cannot be determined in advance. At this time, it is necessary to modify the designed speed curve temporarily, which is very complex. In this paper, the tracking differentiator method based on ADRC theory is used to solve the problem of frequently modifying the speed curve. The method can optimize the complexity of the algorithm and reduce the amount of calculation. The algorithm is verified on STM32 micro controller, and has been applied in the control of manipulator driven by stepper motor.

In order to meet the requirement of inserting the oil gun into the incendiary agent and oxidant injection port at the same time during the orbital filling process of the space manipulator，a compliance control method of manipulator is proposed. The proposed method can meet the requirement that two relatively independent structural parts on the same part contact the shaft hole at the same time in the process of plug in control. First, the insertion and extraction process and contact state of the biaxial hole are analyzed; then, a compliance controller based on impedance control is designed, which realizes the smooth and autonomous cooperation of the plugging process under the action of contact force feedback; finally, the application effect of the compliance control method is verified by simulation experiments.The compliance control method proposed in this paper has practical value and application prospect under the requirements of specific space operation environment. This method provides a certain theoretical and application basis for the remote operation of space on orbit service robotic arms and the development of intelligent operation technology.