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Propose a plan of slight space debris observation via space-based imaging radar system previously designed. Based on the idea of differential orbit scan, the investigation focuses on the analyses of orbital scanning period, space area segmentation, radar parameters design and echoes record. In order to cope with weak signals detection, pulse accumulated arithmetic is considered. But because of the...
Performance of conventional Kalman filter, which is used in integrated navigation system, depends on precise system model and accurate observation data. Inaccuracy system model or truseless observation data will cause low precision of Kalman filter, and even lead to divergence. So a new adaptive Kalman filter based on evolutionary artificial neural networks is used in this system. The algorithm is...
The double inverted pendulum system is a less-driven, multi-parameter, highly nonlinear system. The sliding mode controller is designed to make the double pendulum stable at the upright equilibrium position. But, it is difficult to determine the sliding surface in design, which is the key to the performance of the control system. The improved genetic strategy is applied to search the optimal sliding...
The well-known direct torque control (DTC) is a very simple control method for inverter-fed AC drives, which characterized by fast dynamic response, structural simplicity, and low sensitivity to parameter changes. Attempts to combine DTC with SVM have led to new ways. This paper presents a new robust DTC-SVM for high performance induction machine drives. Simulation studies have been carried out for...
Robust adaptive neural network control and backstepping design are considered. An adaptive neural network controller is established for a uncertain nonlinear output feedback system. The controller regulates the output to a neighborhood of origin by properly choosing design parameters, and keeps all signals of the closed-loop bounded.
In order to reduce the useless power of the missile-loaded hydraulic actuator, a new scheme that a variable-speed pumping source (VPS) is equipped on the missile-loaded hydraulic actuator is proposed in this study. Simulations in time-domain, frequency-domain and useless power are performed for the proposed scheme, and the results demonstrate that the new scheme is feasible. On the one hand, the performance...
An inter-satellite ranging system in formation is designed. It can be applied to measure relative distance with the help of GPS constellation or independently works when GPS is invisible. Details of this design are represented, including its architecture, hybrid TDMA/FDMA technique and ranging precision analysis. And, a probabilistic algorithm is proposed to improve ranging precision from plusmn30...
In this work, an adaptive output feedback attitude control design method is investigated for a three-axis-rotational maneuver and vibration stabilization of a spacecraft with flexible appendages. The proposed controller ensures the asymptotic fulfillment of the objectives in the case of rest-to-rest maneuvers in present of uncertain inertia parameter uncertainty and disturbances. Also, it is assumed...
The integrated test system for an avionics ground experiment system is designed based on full requirements analysis to signals tested. Complex bus signals and functional signals are tested, analyzed and diagnosed in test system so as to guarantee ground experiment of integrated avionics system right. The multithreading technique is adopted in test software development and implementation. Finally,...
Based on the theory and semi-empirical formulas, the surface heating flux of warhead at zero attack angle under aerodynamic heating is calculated by using reference enthalpy method, and the equilibrium curves of temperature for radiation of wall are obtained, by which the anti-thermal effects of blunt leading edge is proved in this paper. At the same time, the anti-thermal effects of thermal protection...
A new discrete reaching law which is true of the ldquosix charactersrdquo given by Gao Wei-Bing is introduced in this paper. Then the control law is designed by using the discrete reaching law, and the method how to design a variable structure control of discrete system with time-delay is also introduced; It is manifested that the discrete control system with time-delay which is designed by the proposed...
A novel scheme for boiler combustion control system is proposed, where the firing rate demand is represented by furnace temperature distribution (FTD). In this scheme, the firing rate is defined to be FTD which characterizes the status of combustion directly. A real-time FTD shape control system is formulated and applied to boiler combustion control. FTD is fed back to combustion controller and adjusted...
In nonsmooth analysis, a well known result is that every asymptotically controllable system can be stabilized by means of some (discontinuous) feedback law in the sense of closed-loop system sampling (also referred to as sample-and-hold). The key points rely on the partition of interval and the construction of the feedback law based on the partition by pointwise optimization. Regarding the latter,...
Aerial target under the daytime condition shows complex imaging characteristics, like misshapen and blurred edges, even flickering and discontinuous imaging, which becomes a bottleneck of target detection and tracking in imaging tracking system. This paper presents a novel algorithm for detecting and tracking aerial targets with blurred and flickering imagery. Firstly, point spread function (PSF)...
Turbopump is a high-fault-rate component in Liquid Rocket Engine (LRE). In this paper, the reasons of the typical fault of turbopump rotor blade abruption and abscission are analyzed. And, by the method of dynamic analysis, the vibration features of the fault are studied to select the frequency features diagnosing effectively the fault. Then, the extraction method of the features is researched. By...
In this paper, two methods are introduced to estimate the position and speed of permanent magnet synchronous motors (PMSM). They are based on EMF and MRAS. The first method estimates the back electromotive force (EMF), then calculates rotor position and speed. In the second method, the model of PMSM is reference model and motor current is adjustable model. The derivation process and the simulation...
The method of two degrees-of-freedom Hinfin loop-shaping was applied to aero-engine control system in this paper, which could improve the tracking performance while maintaining stability robustness rather than the traditional one degree-of-freedom robust controller. A method to select the weight function in the loop-shaping procedure was proposed to select the desired shaping weights automatically...
The paper proposes a non-singular terminal sliding mode control for a class of uncertain chaotic systems based on backstepping method. Through defining the error variables between the states of chaotic system and virtual feedback variables, a special non-singular terminal sliding mode and the control strategy are proposed. Then verified that the proposed control method can guarantee the error variables...
This paper proposes an angular invariant feature for registration procedure to perform reliable matching between a given model shape and a data shape. The feature is defined by a k-dimensional vector with k angles between the normal vector of each point and its k-nearest-neighbors individually. The feature is invariant to scale transformation, rotation transformation. Particularly, when we register...
A new predictive guidance law for moving-mass actuated reentry vehicle is presented in this paper. The proposed approach is based on the fact that lateral force is formed in a plane which is perpendicular to the reentry vehicle velocity. Particularly, the nominal impact point is defined as the impact point generated by zero lift trajectory. The virtual displacement is defined as the tiny change of...
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