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The simulation turntable is an important device for the hardware-in-the-loop simulation of satellites or other spacecraft. It can simulate the movement attitude of the spacecraft in space such as roll, pitch, and yaw, and is widely applied in electromagnetic countermeasure, space shooting and other fields. This paper takes the on-orbit service spacecraft as the research object, studies the coordinate system transformation and implementation problems of ground simulation of spacecraft attitude based on the five-axis turntable, designs the coordinate system conversion process and verifies the effectiveness of the conversion process. The coordinate system conversion method studied in this paper can effectively realize the ground simulation of spacecraft attitude on the five-axis turntable, providing theoretical guidance and effective methods for solving the problems of attitude simulation in on-orbit service tasks, having more important guiding values for simulating experiments in the field of aerospace engineering such as rendezvous and docking.

This paper proposes a fuzzy gain scheduling backstepping sliding mode control (FGS-BSMC) approach for a class of uncertain strict-feedback nonlinear system. First, system description and problem formulation is given. Second, the FGS-BSMC is proposed to design the controller for the strict-feedback nonlinear system. A sliding mode control (SMC) is employed to construct the backstepping sliding mode control (BSMC) approach for design flexibility of backstepping control and robustness of SMC. In order to decrease chattering result from SMC, a fuzzy logic system (FLS) is designed to construct the FGS-SMC, in which the gain of sign function can be scheduled adaptively according to the fuzzy rules. Finally, a verification example is given to demonstrate the effectiveness the proposed FGS-BSMC. Simulation results illustrate that the FGS-BSMC decreases chattering effectively and has better control performance against BSMC.

Near-space autonomous airship represents a unique and promising platform for earth observation and surveillance that involve a long duration airborne presence. In this paper, a six-degrees-of-freedom dynamics model and maneuverability of a near-space earth observation platform are presented. First, the near-space earth observation platform is introduced, including the concept design, configuration, energy sources, propeller and payload. Second, reference frames and motion parameters of the platform are defined, and the kinematics equations describing the platform's dimensional motion are derived. The effects of gravity, buoyancy, added inertia, aerodynamics and thrust on the platform are incorporated into the dynamics analysis, and a dynamics model in vector form of the platform is derived based on Newton-Euler principle. Finally, a simulation program has been developed to implement the dynamics model and applied to analyze the maneuverability of the platform. It is hoped that this work is useful to support the evaluation of maneuverability and the development of control system for the near-space earth observation platform.

The near space autonomous airship represents a unique and promising solution for many applications ranging from surveillance, communication utilities and scientific exploration. In attempt to complete the various missions, the near space airship first requires an accurate control system for autonomous flight. This paper presents an improved sliding mode control method for autonomous flight, considering the characteristics of nonlinearity, strong coupling and uncertainty of an airship. Firstly, the dimensional motion mathematical model of an airship is derived, including kinematics and dynamics equations. Then the controller for autonomous flight is designed by use of an improved variable structure control method, which adopts the boundary layer sliding mode control approach. Finally simulation results illustrate the effectiveness of the proposed method. The proposed control method is robust to parameter uncertainties and external disturbances, and provides an effective approach to design flight control system of a near space airship.