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The Method of State Space Description for Flight Process of Manned Spacecraft: 

The Method of State Space Description for Flight Process of Manned Spacecraft

Content: 

Why is the method of state space description introduced ? Basic Idea State Space Model of Manned Spacecraft Decomposition of the State Space State Transition Function and State Transition Matrix Application Conclusions Content

Why is the method of state space description introduced ?: 

Why is the method of state space description introduced ? Flight control is the important and key technology used to insure the safety of cosmonauts in manned space missions. The basis and precondition of implementing the flight control on spacecraft is the state. No state, no flight control. ■ How to monitor the states of spacecraft and diagnose its failures in order to sustain the activities of flight control in the mission process is the fatal problem that must be solved by a space control center. ■ Manned spacecraft has the following characteristics: complicated system configuration, large numbers of parameters, multi-mode controls, complex mission operations, rapid state transitions, etc. Facing this kind of spacecraft, solving the problems of monitoring and diagnosing is difficult and complicated. ■ Of all problems to be solved, how to describe and express the flight process of spacecraft in order to monitor its states and diagnose its failures is the number one difficulty.

Basic Idea: 

Basic Idea Firstly, the state of spacecraft is considered to be decomposed. That is, the whole state of the spacecraft can be decomposed into layer-states according to some rules. For different purposes, the decomposed states can include different layers, from sys-state, sub-state, …, until to para-state. Secondly, we can construct the state vector of every layer-state and confirm the value range of each state vector according to the experience from real missions and then build the state space of whole spacecraft. Thirdly, we can confirm the state transition functions and the state transition matrixes of the flight control process according to the control sequence acted on the spacecraft. Finally, we can describe the whole flight control process of manned spacecraft. The flight control process is described by the state track which is derived from the course that state vectors change their values in state space according to state transition matrixes in order of time.

State Space Model of Manned Spacecraft: 

State Space Model of Manned Spacecraft

State Space Model of Manned Spacecraft (Continuous 1): 

State Space Model of Manned Spacecraft (Continuous 1)

Slide7: 

State Space Model of Manned Spacecraft (Continuous 2)

Decomposition of the State Space ——the Six-layer Decomposition Framework : 

Decomposition of the State Space ——the Six-layer Decomposition Framework

Slide9: 

State Transition Function and State Transition Matrix A) On-off state switch and its state transition function

Slide10: 

State Transition Function and State Transition Matrix (continuous 1)

Slide11: 

State Transition Function and State Transition Matrix (continuous 2)

Slide12: 

Application The idea and method of state space description for the flight process of manned spacecraft can be applied to solve problems like following: State prediction of manned spacecraft State monitoring of manned spacecraft Failure diagnosing of manned spacecraft The flight control process of manned spacecraft based on the idea and method of state space description can be shown as fig. 5.

Slide13: 

Application (Continuous)

Conclusions: 

Conclusions Facing the characteristics of manned spacecraft of large numbers of parameters, complex mission operations, rapid state transitions, etc., the idea and method based on state space description was introduced to describe and express the flight process of manned spacecraft in order to solve the problems such as state prediction, state monitoring, failure diagnosing, and so on. This paper built the universal and discrete state space model of manned spacecraft, discussed the orthogonal decomposition of state space, gave the six-layer decomposition framework, probed into the state transition function and the state transition matrix in depth, and gave the general form of state transition matrix for manned spacecraft. The state of spacecraft can be decomposed into layer-states. For different purposes, the decomposed states can include different layers. The most typical decomposing form is the six-layer model. The flight control process that can be measured and monitored in a real space mission is discrete. The direct causation that leads to state transition is the

Conclusions (Continuous) : 

Conclusions (Continuous) control acted on the manned spacecraft. The form of state transition matrix is related to the control operations directly besides the choosing of state vector. If the state space was decomposed then the state transition matrix must have the form of blocked matrix. If the decomposition is orthogonal then this matrix must be diagonal. Only the matrixes of the bottom layer (parameter layer) are not diagonal. If there is not coupling existed between any two parameters, then the bottom matrixes will also degenerate to diagonal matrixes. The results of this paper can be effectually applied to solve problems such as state prediction, state monitoring and failure diagnosing. The idea and method of state space description for manned spacecraft is prevalent. This method has more significance in theory than in practice. For successful applications in real missions, some particular problems must be solved, such as how to extract eigenstate and eigenevent from the state space of manned spacecrafts, how to identify and monitor the eigenstate and the eigenevent in flight control process, etc.

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