Yuxia Ji, Li Chen, Jun Zhang, Dexin Zhang and Xiaowei Shao
The purpose of this paper is to investigate the pose control of rigid spacecraft subject to dead-zone input, unknown external disturbance and parametric uncertainty in space…
Abstract
Purpose
The purpose of this paper is to investigate the pose control of rigid spacecraft subject to dead-zone input, unknown external disturbance and parametric uncertainty in space maneuvering mission.
Design/methodology/approach
First, a 6-Degree of Freedom (DOF) dynamic model of rigid spacecraft with dead-zone input, unknown external disturbances and parametric uncertainty is derived. Second, a super-twisting-like fixed-time disturbance observer (FTDO) with strong robustness is developed to estimate the lumped disturbances in fixed time. Based on the proposed observer, a non-singular fixed-time terminal sliding-mode (NFTSM) controller with superior performance is proposed.
Findings
Different from the existing sliding-mode controllers, the proposed control scheme can directly avoid the singularity in the controller design and speed up the convergence rate with improved control accuracy. Moreover, no prior knowledge of lumped disturbances’ upper bound and its first derivatives is required. The fixed-time stability of the entire closed-loop system is rigorously proved in the Lyapunov framework. Finally, the effectiveness and superiority of the proposed control scheme are proved by comparison with existing approaches.
Research limitations/implications
The proposed NFTSM controller can merely be applied to a specific type of spacecrafts, as the relevant system states should be measurable.
Practical implications
A NFTSM controller based on a super-twisting-like FTDO can efficiently deal with dead-zone input, unknown external disturbance and parametric uncertainty for spacecraft pose control.
Originality/value
This investigation uses NFTSM control and super-twisting-like FTDO to achieve spacecraft pose control subject to dead-zone input, unknown external disturbance and parametric uncertainty.
Details
Keywords
This purpose of this paper is to describe the course of information literacy given by the Chongqing University library to cultivate university students' information awareness…
Abstract
Purpose
This purpose of this paper is to describe the course of information literacy given by the Chongqing University library to cultivate university students' information awareness. Up‐to‐date information retrieval skills, comprehensive document skills and innovative thinking are encouraged.
Design/methodology/approach
Adopts a range of innovative teaching/learning methodologies using modern teaching methods and materials; and combines these with scientific and technical consultation and patent agent cases. Describes how this course has been brought into the university undergraduate and graduate teaching plan.
Findings
The utilization rates for documents and resources in the library have improved; and many other social benefits have been achieved.
Originality/value
Will guide others wishing to set up an information literacy education course and enhance the information literacy of university students.
Details
Keywords
Martin Aruldoss, Miranda Lakshmi Travis and V. Prasanna Venkatesan
Business intelligence (BI) has been applied in various domains to take better decisions and it provides different level of information to its stakeholders according to the…
Abstract
Purpose
Business intelligence (BI) has been applied in various domains to take better decisions and it provides different level of information to its stakeholders according to the information needs. The purpose of this paper is to present a literature review on recent works in BI. The two principal aims in this survey are to identify areas lacking in recent research, thereby offering potential opportunities for investigation.
Design/methodology/approach
To simplify the study on BI literature, it is segregated into seven categories according to the usage. Each category of work is analyzed using parameters such as purpose, domain, problem identified, solution applied, benefit and outcome.
Findings
The BI contribution in various domains, ongoing research in BI, the convergence of BI domains, problems and solutions, results of congregated domains, core problems and key solutions. It also outlines BI and its components composition, widely applied BI solutions such as algorithm-based, architecture-based and model-based solutions. Finally, it discusses BI implementation issues and outlines the security and privacy policies adopted in BI environment.
Research limitations/implications
In this survey BI has been discussed in theoretical perspective whereas practical contribution has been given less attention.
Originality/value
A comprehensive survey on BI which identifies areas lacking in recent research and providing potential opportunities for investigation.