Fuzzy Thermal Alarm System for Venus Express

Abstract

In the aerospace field, where satellites and spacecraft contain numerous components that require constant, yet indirect, surveillance of large amounts of data, monitoring tools give the operators constant access to the state of the machinery, facilitating prompt and appropriate responses to any problems that may arise. The objective of developing a Venus Express alarm system (Steel, 2006) is to monitor the thermal characteristics of each spacecraft face with respect to spacecraft altitude relative to the sun’s position. A thermal alarm monitoring tool assumes particular importance in the Venus Express mission as the spacecraft will be subject to high levels of solar radiation due to its proximity to the sun. In the space context, in particular for missioncontrol purposes, fuzzy inference systems provide a suitable technique to build this type of alarm system because the knowledge is imprecise or partial, going beyond the use of traditional, that is, crisp, methods (Ribeiro, 2006). Furthermore, the fuzzy linguistic approach used (Mendel, 2001; Ross, 2004) allows for an effective complement to human operators by creating systems that can support their actions in case of any fault detected.

Key Terms in this Chapter

Alarm System: It is a monitoring system that provides alarms in case of some faulty component.

Fuzzy Inference Systems: These are rule-based systems capable of drawing conclusions from given uncertain evidence to reach a decision using approximate reasoning.

Fuzzy Sets: Fuzzy sets is a set theory approach in which set membership is less precise than having objects strictly in or out of the set.

Linguistic Variable: It is a mathematical representation of semantic concepts that includes more than one term (fuzzy set)

Choquet Integral: The Choquet integral is a mathematical method for aggregating criteria that allows selecting an alternative that takes into account synergies between criteria.