RLV landing section guidance law acquiring method based on sliding-mode control theory

Abstract

A RLV landing section guidance law acquiring method based on a sliding-mode control theory comprises steps of: calculating a height deviation and a lateral distance deviation according to an RLV landing section nominal trajectory; then, selecting an appropriate sliding-mode surface according to the tracking deviation of the nominal trajectory, and equivalently converting a RLV three-degree-of-freedom kinetic equation into a form described by the sliding-mode surface; and finally, designing the guidance law by using a Lyapunov method. In the design process, by analyzing aerodynamic data, the uncertainty upper bound of a guidance circuit is obtained and a compensation term is introduced to suppress the uncertainty so that the guidance system has asymptotic stability to the uncertainties such as disturbance. The method can overcome the influence of the uncertainty of the RLV guidance system so as to improve guidance precision, converts an original second-order system into a first-order system by introducing the sliding-mode control method, thereby achieving a visual design process.

Description

technical field [0001] The invention relates to a method for obtaining guidance law of RLV landing section based on sliding mode control theory. Background technique [0002] Reusable launch vehicles (RLV) are space shuttle vehicles that combine the features and functions of spacecraft and aircraft. They can stay in orbit to complete various space tasks, and can also return safely and accurately like an airplane. ground. Due to its reusable characteristics, RLV will become a highly reliable carrier for human beings to explore the universe at a low cost and a military weapon for competing for space supremacy. Therefore, the major powers in the world continue to invest huge resources in its research and development, and conduct new research and exploration. [0003] The return and re-entry phase of the RLV is usually divided into the initial re-entry phase, the terminal energy management phase, and the approach and landing phase. Go-around capability, if the guidance or con...

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Problems solved by technology

[0003] The return and re-entry phase of the RLV is usually divided into the initial re-entry phase, the terminal energy management phase, and the approach and landing phase. Go-around capability, if the guidance or control method is unstable or cannot meet the accuracy requirements, it may cause the RLV to fail to land safely, and even lead to catastrophic consequences

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