The control of approaching phase of the space rendezvous and berthing often uses the parallel approaching method based on the signal of the line of sight (LOS) position. The nonlinear sliding modal in the longitudinal control is improved by adding the coupled item and the damping item including the LOS angle. Its existence and stability are proved for the relative equations. The coupled multivariable nonlinear sliding modal of the LOS guidance is presented. The existence and stability are proved for the coordinated control.

A pinpoint autonomous navigation and control algorithm for lunar soft landing is presented in the paper. In the algorithm, first, the direction of landing spacecraft relative to the lunar center is determined according to the geometry relation of several ranging beams relative to the lunar surface. Second, attitude, velocity and altitude relative to the orbit reference frame are determined by combining the velocity vector provided by the velocimeter in the body reference frame. Third, the adaptive guidance and control method is selected based on the character of determined parameter. The algorithm can determine and control parameters of attitude, velocity and altitude based on direct measurement data and can improve the estimation and control accuracy of attitude, velocity and altitude, and can’t be affected by the inertial navigation error. Finally, the presented algorithms are validated by mathematical simulations.

Under more general conditions, the stability and the robustness of goldensection feedback control law are analyzed in this paper, and in the framework of hybrid identification,  the inputstate stable(ISS) property of the gradient project method used in  SISO and MIMO characteristic models is studied, and  the L2bound of estimated errors of characteristic parameters is obtained. The final results further generalize the former results and play very important roles in the stability analysis of entire hybrid system.

The single gimbal control moment gyro, used in spacecraft attitude control system, deserves special attention in recent years due to its large control torque. However, the singularity problem is the major constraint on rapid attitude maneuver, especially in a continuous maneuver process, the spacecraft should escape from singularity rapidly. In this paper, based on the angle between desired control torque and output torque from CMG, a new singularity measurement is introduced. An improved  singularity robust steering law are proposed, and a Gaussian function is adopted to determine the singularity robust coefficient. Simulation results demonstrate that compared with the traditional gradient null motion method, the proposed algorithm can finish attitude maneuver more quickly. It assures the singularityescape more rapidly and reduces attitude chattering magnitude.

For the predictive guidance with zero effort miss (ZEM) taken as a performance objective for exoatmospheric interception problem,the prediction accuracy of ZEM directly influences the completion of terminal intercept mission.  In this paper, a ZEM forecasting method based on the targetcentered orbit frame is introduced by using the linearized inverse square gravity model.The condition of ZEM occurrence is derived and one method for improving prediction accuracy of ZEM is also put forward,which can distinctly improve the prediction accuracy by choosing the initial orbit angular velocity.Moreover this method is compared with the one based on ECI frame by simulation.The results indicate that the improved one has higher accuracy and certain value to practical application.

The attitude and orbit control system（AOCS）is the critical subsystem of the satellite. According to different requirements for satellites, AOCSs have different configurations because of various sensors and actuators to be chosen. The characteristics of AOCS configurations being used are described in this paper, then a new internalbus based AOCS configuration is discussed which can be adapt to different requirements and be benefit to improve the system bandwidth.

The attitude control system constructed by a cluster of control momentum gyro (CMG) is the best choice to meet the rapid attitude maneuvering and accurate control requirements of today’s agile satellites. Meanwhile, the control accuracy, response speed as well as stability of the gimbal control assembly determine the CMG performance directly. Focusing on the high performance requirement for agile satellites, a high performance gimbal control method is proposed, by employing the permanent magnetic synchronous motor (PMSM) with the field oriented control (FOC) algorithm, and utilizing a gimbal rate observer to drive the gimbal mechanical assembly directly in this paper. In order to solve the problem that the resolving rate of normal angular sensors are difficult to meet the accuracy requirement, a Luenberg state observer is introduced to obtain the observed gimbal rate value in the extremely low rate condition. The observed value is introduced into the closed loop system of gimbal rate thereby. Theoretical analysis and simulation experiments have proved the validity of the proposed method. Then, a simulation work is done to aim at studying the effect of motor parameter drifting on the observed value. The simulation results have demonstrated the robust performance of the proposed observer based closedloop rate control system.

Baffle is an important stray light suppression assembly of optical imaging sensor used in autonomous rendezvous and docking (RVD). It gives much contribution to the sensor in extracting information of the object and improving the attitude determination accuracy.The Monte Carlo methodbased baffle design is described in this paper. Moreover, by means of optical simulation software the comparison between the simulation result of the design and the experiment result shows that the design method is effective.

The solenoid valve’s physical model is built based on Ansoft to gain interdependence of some variables in electromagnetic field. The simulation result of the Ansoft is led into the AMESim system model to realize the coupled simulation of electromagnetic structure, hydraulic system and mechanical movement. For the double seat solenoid valve, more accurate simulation analysis results of load characteristics, such as load response time and mass flow rate can be obtained.

The slip ring used to conduct electric signal for rotor is an important component of 200N·m·s control moment gyro (CMG). It is necessary to carry out the life test of the electric ring, because it determines the life of 200N·m·s CMG. The life test of conductive slip ring is presented in this paper. Purpose and object of the test, acceleration factor, test environment, test system configuration and failure criterion are described in detail. Electric noise, frictional torque and insulation performance are analyzed during the test, and the results show the performance of the conductive slip ring satisfies the need for 200N·m·s CMG after 4 million turns of test.

Considering the coordinate relationship among satellites of  Walkerδ constellation，a configuration maintenance strategy based on coverage performance is proposed in this paper. Coverage performance as a discriminant of strategy is obtained by an improved grid simulation method. According to the geometry relation between grid point subsatellite point，this improved method can be used to find those grids within coverage zone and obtain global coverage information. Considering J2 perturbation the nominal position of satellite is dynamic. In operation of constellation, when dissatisfied grids are found, the satellite with reduced coverage performance can be found according to its nominal positiion. The configuration maintenance will be accomplished after the target satellite is adjusted to its nominal position. A numeric simulation is given. The result demonstrates the effectiveness of the proposed strategy.

In the design of  filmcooled bipropellant thruster, the numerical simulation of the combustion chamber is a necessary step. In this paper, process of atomizing of the liquid propellant, breaking up of droplets, liquid film formation are taken into account, and the EDC combustion model and the realizable kε turbulent flow model are selected. Distributions of droplets, liquid film and static temperature are obtained by using the numerical simulation. At last, based on the analysis of simulation results, the working process in combustion chamber are interpreted, and two conclusions on the liquid film cooling are derived.