Hua Song’s research while affiliated with Beihang University and other places

This article proposes a fault diagnosis method for closed-loop satellite attitude control systems based on a fuzzy model and parity equation. The fault in a closed-loop system is propagated with the feedback loop, increasing the difficulty of fault diagnosis and isolation. The study uses a Takagi-Sugeno (T-S) fuzzy model and parity equation to diagnose and isolate a fault in a closed-loop satellite attitude control system. A fully decoupled parity equation is designed for the closed-loop satellite attitude control system to generate a residual that is sensitive only to a specific actuator and sensor. A T-S fuzzy model is used to describe the nonlinear closed-loop satellite attitude control system. With the combination of the T-S fuzzy model and fully decoupled parity equation, the fuzzy parity equation (FPE) of the nonlinear system can be obtained. Then this article uses a parameter estimator based on a Kalman filter to identify deviations and scale factor changes from information contained in the residuals generated by the FPE. The actuator and sensor fault detection and isolation simulation of the three-axis stable satellite attitude control system is provided for illustration.

With the rapid development of trenchless technology, measurement-while-drilling systems draw extensive attention. At present, measurement-while-drilling systems are generally based on magnetic surveying technology or single-accelerometer measurement. In that case, the accuracies of these measurement-while-drilling systems are limited. In this article, a new measurement-while-drilling system with redundant accelerometers based on inertial technology is presented to improve the measuring performance of attitude, especially the measuring accuracy of roll. To reflect the influence of electromagnetic interference, the credibility estimation could be got by comparing the same attitude angles from the accelerometer and magnetometer. The calculation algorithm and experimental data are given in this article. Compared with traditional measurement-while-drilling systems, this new measurement-while-drilling system obtains better anti-disturbance property, higher measuring accuracy, and more reliable calculated results.

The navigation problem of the lifting reentry vehicles has attracted much research interest in the past decade. This paper researches the navigation in the blackout zone during the reentry phase of the aircraft, when the communication signals are attenuated and even interrupted by the blackout zone. However, when calculating altitude, a pure classic inertial navigation algorithm appears imprecise and divergent. In order to obtain a more precise aircraft altitude, this paper applies an integrated navigation method based on inertial navigation algorithms, which uses drag derived altitude to aid the inertial navigation during the blackout zone. This method can overcome the shortcomings of the inertial navigation system and improve the navigation accuracy. To further improve the navigation accuracy, the applicable condition and the main error factors, such as the atmospheric coefficient error and drag coefficient error are analyzed in detail. Then the damping circuit design of the navigation control system and the damping coefficients determination is introduced. The feasibility of the method is verified by the typical reentry trajectory simulation, and the influence of the iterative times on the accuracy is analyzed. Simulation results show that iterative three times achieves the best effect.

The horizontal directional drilling technology is widely used to lay the underground pipelines. These pipelines are of small or medium diameters with a dip angle ranging from 10° to 20°, special pipelines to 30°. In-pipe robot is commonly used to detect the pipeline fault. A new type of telescopic in-pipe robot is designed in this article, which is driven by step motor and screw, and supported by wheels. The robot has advantages of waterproof grade of IP68, stable motion state, and larger traction force. The speed is between telescopic robots and wheeled robots. Through force analysis and calculation, its maximum climbing angle is larger than 35°. The robot has good passing ability through the pipelines with bends. The inertial technology is used to locate the robot under the condition of disturbances. The pipeline fault detection algorithm based on the visual identification technology is designed to detect the pipeline fault. It can not only achieve autonomic positioning but also detect the pipeline fault.

Typical wheeled or tracked robot could hardly apply to middle or small diameter underground pipelines laid by trenchless technology. Aiming at this kind of pipeline’s characteristics, this paper puts forward a basic structure of telescopic in-pipe robot. To provide necessary theoretical basis for the device selection, the mechanical model and force analyzing are given in detail. The speed of robot, as well as the motor torque of locking mechanism, could be expressed as the function of the robot’s structural parameters. As a result, the robot’s structural parameters take influence on its performance. In order to achieve the best performance, it is necessary to use the multi-objective optimization method to select these parameters. Using the genetic algorithm toolbox, the optimal solution of these parameters was obtained. Based on this, the motor torque of locking mechanism is minimum while the speed of the robot is maximum.

In the paper, a new method is proposed for the hot issues of the fuel-saving of the inland navigation. Firstly, the thought of segmentation is used to construct the model of fuel consumption in the inland navigation, which takes a whole grasp of the voyage. Then, we use the nested adaptive genetic algorithm and sequential quadratic approximation (SQP) method respectively to plan out the optimal distribution of speed in order to reach the lowest fuel consumption. Also, simulation of the two methods were carried out and compared. According to result analysis, the more appropriate sequential quadratic approximation method is selected. Finally, the optimal speed distribution and the lowest fuel consumption is obtained, which is with guiding significance for the sailing crew. More importantly, the method can be applied to any navigation and any ships.

In the paper, a new method is proposed for the hot issues of the fuel-saving of the inland navigation. Firstly, the thought of segmentation is used to construct the model of fuel consumption in the inland navigation, which takes a whole grasp of the voyage. Then, we use the nested adaptive genetic algorithm and sequential quadratic approximation (SQP) method respectively to plan out the optimal distribution of speed in order to reach the lowest fuel consumption. Also, simulation of the two methods were carried out and compared. According to result analysis, the more appropriate sequential quadratic approximation method is selected. Finally, the optimal speed distribution and the lowest fuel consumption is obtained, which is with guiding significance for the sailing crew. More importantly, the method can be applied to any navigation and any ships.

With the development of urban infrastructure, the trenchless technology has been widely applied in many applications, especially in the field of pipeline or subway construction. In these applications, the attitude and position information of the bit is indispensable in the process of drilling. Currently, measurement-while-drilling (MWD) systems are generally based on radiolocation or single accelerometer measurement. In that case, the precision of these MWD systems is limited due to the presence of disturbances. Aiming at this defect, a new MWD system - with multiple sensors and based on inertial technology - is developed in this paper. Note that the measuring range of angle of traditional method is limited. We propose a new while-drilling unit which contains two 3-axis accelerometers fixed on two different planes with a certain angle as redundancy. With the help of the temperature sensor and geomagnetic sensor in the while-drilling unit, temperature compensation and credibility estimation are available. The attitude and position information of the bit, as well as the credibility, is calculated by ARM microprocessor. The method of data calculation is also described in detail. Compared with traditional the MWD system, this new MWD system obtains a better anti-disturbance property and can produce more reliable measurements.