Aerospace Contrd and Application

Select Research on System Design of Lunar Rover

YANG Mengfei JIA Yang CHEN Jianxin

2008, 34(3): 3-6.

Abstract ( 26 )

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The state of the art of lunar exploration is briefly reviewed．Based on the concept and main functions of lunar rovers，system design including composition of subsystems，operational states and modes is analyzed and investigated．Finally，the key techniques of lunar rovers are proposed to give a reference to the engineering development．

Select A Method of Intelligent Adaptive Control for Spacecraft

SHEN Shaopin, WU Hongxin,

2008, 34(3): 7-11.

Abstract ( 30 )

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Intelligent adaptive control of spacecraft is an important part of intelligent autonomous control for spacecraft．In this paper，by taking the spacecraft with deployable and retractable flexible appendage as the object，the principle and method of intelligent adaptive control are researched SO as to realize the control target of high precision，high stability and strong adaptability．According to the characteristic model and the golden section adaptive control law，a parameter varying active adaptive control method based on the length of the flexible appendage is presented．This method combines the control of center rigid body with the active control of appendage．Numerical simulations show that by applying the parameter varying active adaptive control，the vibration of the attitude angle and modes can be rapidly suppressed and the overshoots are very small when the appendage deploys，retracts or is excited by resonance disturbances and that the designed controller excels other controllers．

Select Research on the Attitude Control of Active Suspension Rov

ZOU Dali, YANG Lei, QU Guangji

2008, 34(3): 12-16.

Abstract ( 28 )

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As compared with the passive suspension rover，the active one enhances the motion capabilities on irregular and unknown terrains．Due to the existence of redundantly actuated system of active suspension rovers，the control system is more complex．Base on the low speed of rover movement，the research on attitude control of the active suspension is conducted and a method for stability is proposed．The simulation in the ADAMS and MATLAB illustrates the effectiveness of the method and high stability of the rover movement．

Select Fault Diagnosis Method Based on a Decentralized Predictive Filter

LI Ji.

2008, 34(3): 17-22.

Abstract ( 27 )

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A new fault diagnosis method for a complex system with more than one type of faults is proposed in this paper．To distinguish different faults，two kinds of residuals generated from only one decentralized predictive filter are used，because they have different sensitivities to component/actuator faults and sensor faults．Even more，for a component or actuator fault，the source of it can be found exactly depending on the relationship between residuals and faults．And for a sensor fault，it can be detected and isolated easily by using the decentralized structure of predictive filters．To elaborate this method，a simulation for a satellite attitude determination system is presented．The simulation results demonstrate that the decentralized structure of predictive filters is more powerful than the centralized one in fault diagnosis and system reconfiguration．

Select ：Numerical Analysis of the Flow Resistance for Large Volume Surface Tension Tank

PAN Hailin, LI Yong, ZHAO Chunzhang, WEI Yanming

2008, 34(3): 23-29.

Abstract ( 16 )

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It is important to analyze the flow resistance of the tank，not only to provide the information to analyze the flow resistance of the whole propulsion system，but also to provide the standard for choosing the tank used in the parallel system．Through analyzing the flow resistance，the most important part contributing to the flow resistance of the tank can be found，which should be manufactured under more rigorous contr01．In the paper，the flow resistance of a large volume tank is analyzed．Firstly，the mathematic model of the flow resistance of the tank is established．Secondly，the model is used to analyze the flow resistance under a variety of operation conditions．Finally，the distribution of the flow resistance on the PMD of the tank under a variety of operation conditions is obtained，and the relation between the flow rate and the flow resistance is also obtained．

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Robust Control of Large Angle Maneuver for Multi-Body Spacecraft

YUAN Changqing, LI Junfeng, SHEN Ying,

2008, 34(3): 30-36.

Abstract ( 17 )

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This paper investigates the robust control of large angle maneuver for the multi-body spacecraft with model uncertainties．A nonlinear dynamics model with uncertainties is considered．An approximate pseudo-linear system is developed by using the inverse system method，and two linear robust controllers are designed through the mixed sensitivity H_∞optimization and the p synthesis method，respectively．A PD controller is used to eliminate the singularity during the mixed sensitivity H_∞optimization．Numerical examples of the central body and antenna tracking different targets are given．The simulation results demonstrate that both controllers are robust stable，and the robust performance of the μ controller is better than that of the H_∞controller．

Select Satellites Autonomous Navigation Based on Ultraviolet Sensors and Star Sensors

GUAN Yuexin, WEI Chunling,

2008, 34(3): 37-41.

Abstract ( 28 )

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An autonomous orbit determination method based on ultraviolet sensors and star sensors is presented．The accuracy of the measurements of the geocentric vector plays a key role in satellite navigation，but it is affected by the earth oblateness．With the earth oblateness taken into account，simulations are used todetermine the effect of the earth oblateness on the geocentric vector，and a compensation process based on satellite attitudes is proposed．The results show that the compensation process has high accuracy and can improve navigation accuracy effectively．

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Application of UML in Requirement Modeling of Spacecraft Attitude and 0rbit Control Software

SHI Yinghai

2008, 34(3): 42-45.

Abstract ( 41 )

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The unified modeling language(UML)and modeling are investigated．The architectures and interfaces of the components of spacecraft attitude and orbit control software are described，and the dependency relations between the components are analyzed．For the requirement analysis of spacecraft attitude and orbit control software，the functional requirements and the non-functional requirements are studied．The software models are presented，and the efficiency and reasonability of the UML are illustrated．

Select The Computer System Design Based on the SPARC Architecture Processor

SHI Lei, LIU Bo, ZHOU Kai,

2008, 34(3): 46-50.

Abstract ( 30 )

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This paper specifies the development of SPARC architecture and addresses the design of computer systems for spacecraft based on SPARC architecture．This paper puts emphasis OR the details of SPARC V8 architecture and lists the processors by using SPARC V8 architecture．Finally it raises a processor system designed with the indigenous chip BM3802．

Select A Method for Three Axis Attitude Control of Momentum Bias Satellite

WU Dan

2008, 34(3): 51-54.

Abstract ( 23 )

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A 2-Degree-of-Freedom(DOF)control wheel configuration in the roll/yaw plane is presented for the satellite attitude control．On the basis of analysis of environmental disturbance torques to some communications satellite platform，the wheel configuration is compared with the existing four-wheel pyramidal configuration according to parameters such as effect of biased momentum magnitude，storage capability，maximum momentum variation，reliability．It is concluded that the proposed configuration exceeds the four-wheel pyramidal configuration in performances．

Select On Attitude Quaternion

MA Yanhong, HU Jun

2008, 34(3): 55-60.

Abstract ( 45 )

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The quaternion calculation for spacecraft attitude determination is investigated in this paper，including the transformation between quaternion and the direction cosine matrix，the quaternion differential equation，the selection of time steps for integrating the quaternion equation，and the compensation methods for the noncommutativity error in high dynamic motion．The dual quaternion is also addressed．

Select Effect of Cavitation on the Transient Characteristics of Fluid Pipeline

ZHAO Chunzhang, LI Yong, PAN Hailin, WEI Yanming

2008, 34(3): 61-64.

Abstract ( 25 )

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Cavitation is a general phenomenon in fluid systems．It has an obvious effect on the transient characteristics of the fluid system．Cavitation model is taken into account for simulation of fluid systems，fluid properties such as density and bulk modulus are calculated in different pressures．The analytical models are developed by using the hammer and one-dimension fluid transient theory based on the finite difference method，in consideration of the cavitation，release and collapse of bubbles．The results are much closer to the actual physical process and provide guidance and reference for the design of fluid systems．