Abstract：Comparing to traditional satellites, space solar power stations have large size. The influences of higher order gravitational force and torque to the orbital and attitude motion should be considered carefully. The influences of higher order gravitational force and torque to the orbital and attitude motion of a sun Tower space solar power station working in the earth’s gravitational field which the oblateness of earth is considered will be studied in this paper. Firstly, the gravitational potential function will be expanded in a Taylor series up to fourth order; Secondly, the gravitational force and torque of a solar power station will be derived and the equations of the attitude and orbital motion of solar power station are given. At last, the influence of the higher order gravitational force and torque to the orbital and attitude motion will be analyzed by numerical simulation. The result shows that the influence of the higher order gravitational force to the orbital motion can reach the order of 100m and the influence of the higher order gravitation torque to the attitude motion is small enough to be neglected.

Based on active vibration isolation and precision pointing control of ultra quiet platform for high precision spacecraft in the future, considering the dynamic characteristics of flexure jointed ultra quiet platform, as well as the effect of base and payload disturbances, the general dynamic model of ultra quiet platform is built. Then the decoupled force control method is derived, and the highly coupled multiinput and multioutput system for ultra quiet platform is converted into singleinput and singleoutput linear time invariant system so that the interaction of different struts is eliminated. The method also greatly simplifies the controller design. On this basis, the numerical simulation analysis and verification are made. The simulation results show that the decoupling force control method using a general dynamic model can achieve good control effect for active vibration control of ultra quiet platform, which is simple and easy to implement.

A fault detection method based on hierarchical stochastic gradient algorithm is presented for sensor fault. Compared with the leastsquare identification algorithms, stochastic gradient(SG) identification algorithm has less computational load. The fault detection method is proposed based on stochastic gradient algorithm for the system with limited computing power. The analysis reveals that the higher estimation accuracy of identification algorithm, the higher estimation accuracy of detection method. To improve the accuracy, the hierarchical identification principle is used firstly, and then the unknown true parameters of residual are replaced by the latest estimation. The calculation loads analysis of the proposed algorithm is given. In addition, a simulation example is employed to show the advantage of the proposed approach in sensor fault detection.

The design of roll control is presented under the certain dynamic pressure condition that aerodynamic rudder is completely used for attitude control, via the analysis of stability and control characteristic on reentry of hypersonic vehicle. According to the rollloop structure, the relationship between rollloop performance index and control parameters is analyzed, and the rudder bandwidth is estimated. On this basis, the minimum rudder bandwidth in different flight feature points is given. In addition, with the help of the simulation results, the effects of time constants, damping ratio and delay time of the rudder system on the performance of roll control quality are studied.

Sharp corners may appear in robotic arm’s trajectory planning by using general interpolation method. In order to eliminate the sharp edges and make the machine arm have a continuous velocity and acceleration under non uniform motion state, a new circularconnectionmean linear interpolation method is proposed. Then, a quadratic interpolation is performed, under which the acceleration and deceleration have good smoothness. A simulation about the algorithm is made under the environment of MATLAB. The optimal planning path can be obtained via performing the algorithm and selecting the adjustment fitting degree. Finally, the good feasibility of the algorithm is confirmed in the robot arm’s trajectory planning.

The problem of spacecraft attitude control is investigated in this paper. To solve this problem, a finitetime sliding mode control strategy is proposed based on a finitetime timevarying sliding manifold in the present of uncertainty and external disturbance．The stabilization is proved and the parameter selection method is given. By using the proposed control strategy, the closedloop system is asymptotically stable and the convergence time is finite. In addition, the attitude tracking error can converge in a given time. Consequently the dynamic response of the closedloop system is determined by the sliding mode dynamics. Numerical simulations are finally provided to illustrate the performance of the control strategy.

A parallel process and faulttolerance method is presented for the multiple redundancy GNC system of aerospace vehicle. Via parallel design, the input information acquisition ability is improved. The processing ability can be improved by parallel processing of GNC controller core module. Based on the fault tolerant design of system input and output, the redundant GNC system has complete fault tolerance ability. The presented method can be applied widely.

Based on the traditional hardwareintheloop (HIL) simulation system of spacecraft attitude and orbit control system (AOCS), a new simulation system is designed and realized for validation of timeconsuming and high accuracy space orbit control mission. In this system, an approach is proposed, which can accelerate process of simulation experimentation by super realtime running of program in dynamics simulator. The implement planning, structure, components and working principle of the system are introduced. Then the two key problems are detailed, including exploring of the realtime & super realtime orbit and attitude dynamics model, and synchronization for states of hardware tested and test equipment. The system has been applied for development of AOCS successfully; its validity is illustrated by an instance.

The spacecraft control software is becoming more complex and huge now, which requires higher software reliability and security and leads to higher demands on both reliability design and measure of spacecraft control software. In this paper, a reliability design method, which is suitable for space application, is given and analyzed. Based on a certain aerospace combined with concrete examples of the reliability measure, the software design is proposed.

The gravity gradient torque of Chang’e5T spacecraft is analyzed during surrounding the EarthMoon. Based on the analysis, the actual quality characteristic is acquired via utilizing the onorbit data. A method of bias attitude in pitch is also designed to achieve the attitude of gravity gradient trim. The onorbit flight proves that the method can reduce the gravity gradient of the spacecraft and extend the unloading period.

 The technique of the star map simulation is widely used to test star identification algorithms and the performance of star sensor on the ground．A novel approach of star map simulation is put forward in this paper, considering satellite orbit motion and effect of image shift．The simulation procedure consists of four steps： firstly， searching the navigator stars that appearing in the field of view throughout the whole sky. Dividing index method is proposed to accelerate the selecting velocity. Secondly, the accurate positions of selected guide stars on the image plane of star sensor are derived by constructing a pinhole model. Thirdly, gray values for simulating star image pixels are evaluated according to the 2D Gaussian distribution law．In order to simulate the star image accurately and actually， the image shift should be considered．Finally, noises made by stray light and circuits are added in order to simulate the orbit environment vividly. In a world, the approach proposed here is with the merit of high speed, nice accuracy, and good reality and so on.