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The purpose of this paper is agile attitude control design with the novel three-dimensional (3D) magnetically suspended wheel (MSW) that is the preferred type for agile maneuvering compared to conventional control moment gyro due to frictionless, low vibration and long lifetime. This system does not require a separate steering law for pyramid arrangement to derive tilt angles. It is also conducting an agile maneuver with high accuracy despite the high-frequency disturbances.

In this paper, a disturbance observer-based attitude stabilization method is proposed for an agile satellite with a pyramid cluster of the novel 3D magnetically suspended wheel actuator. This strategy includes a disturbance observer and a linear quadratic regulator controller. The rotor shaft deflection of MSW is actively controlled to reduce vibration and producing gyro torque. The deflection angle of the pyramid cluster MSWs considered as control parameters. The closed-loop stability is proved by using the Lyapunov strategy. The efficiency and performance of the offered method verified by numerical simulation via MATLAB/SIMULINK software.

According to simulation results, the disturbance observer-based control controller stabilized the system with high accuracy and optimal tilt angles without any extra steering law equation. Hence, the system speed is increased, and the system error is minimized without separate steering law.

The magnetically suspended wheel is a new kind of inertia actuator for attitude control that has several benefits such as frictionless, high-speed rotor, clean environment and low vibration compared to the traditional wheel. It has complex nonlinear dynamics that cause have complicated controller design. The proposed strategy stabilizes the system and conducting an agile maneuver with high precision despite the high-frequency disturbances. It is applicable for some missions requiring high accuracies, like Earth observation and the solar observation mission that require a very accurate pointing control and a long lifetime.

This paper is the initial paper to design a pyramid array for magnetically suspended wheels. Compared to other research, this method doesn’t need a separate steering law of the MSWs cluster and presented optimal tilt angles with less computational. Also, it designs a disturbance observer-based controller for this system that proposed high accuracy and agile stabilization.

IN covering British activities in the inertial guidance field, it is appropriate to include a brief picture of developments in the historical sense so that British achievements can be seen in perspective especially with regard to the state‐of‐the‐art in the United States. We will also deal with the application of inertial navigation systems to the civil field for, although at the moment every production inertial quality system in service is being operated in a military rôle, civil aviation is on the threshold of adopting inertial techniques.

This paper aims to investigate the attitude control pointing improvement for a small satellite with control moment gyroscopes (CMGs) using the active force control (AFC) method.

The AFC method is developed with its governing equations and integrated into the conventional proportional-derivative (PD) controller of a closed-loop satellite attitude control system. Two numerical simulations of an identical attitude control mission namely the PD controller and the PD+AFC controller were carried out using the MATLAB^®-SimulinkTM software and their attitude control performances were demonstrated accordingly.

Having the PD+AFC controller, the attitude maneuver can be completed within the desired slew rate, which is about 2.14 degree/s and the attitude pointing accuracies for the roll, pitch and yaw angles have improved significantly by more than 85% in comparison with the PD controller alone. Moreover, the implementation of the AFC into the conventional PD controller does not cause significant difference on the physical structure of the four single gimbal CMGs (4-SGCMGs).

To achieve a precise attitude pointing mission, the AFC method can be applied directly to the existing conventional PD attitude control system of a CMG-based satellite. In this case, the AFC is indeed the backbone for the satellite attitude performance improvement.

The present study demonstrates that the attitude pointing of a small satellite with CMGs is improved through the implementation of the AFC scheme into the PD controller.

THE demands of war have created an increasing necessity for very strict inspection of component parts of aero and other internal combustion engines ; more particularly with the former, as more and more power is demanded from them.

THE generic term “reprographic” is intended to cover all the methods of making copies or reproductions and also the equipment related to these processes. The steady growth of all these methods has resulted in a close relationship between them, so that it is now almost impossible to refer to one without the other, especially where economics are being considered.

‘FOG in Channel: Continent isolated!’ Those were once the headlines in a national newspaper which thus succinctly, although with unintentional irony, expressed the British sense of complacency. Making allowance for an element of exaggeration, the incident contained enough truth to make its point. The new alignments of industry and commerce which are now taking place mean that this country cannot afford to retain even a vestige of such an attitude.

Recent advances in nano and picosatellite missions and future such missions require faster and accurate pointing accuracies using reaction wheels for attitude control purposes. The ability to put one or three reaction wheels on the spacecraft in the 1‐20 kg range enables new classes of missions. The purpose of this paper is to present the detailed design, analysis, and construction of a miniature reaction wheel prototype. The designed pico‐reaction wheel promises to fulfill the need for low cost, low mass, low power, high reliability, and high‐accuracy attitude control systems for applications such as communications, remote sensing, and space science.

Details about the design, analysis and development of pico‐reaction wheel are discussed. The development status of the system is outlined and the working prototype of the device is described and some preliminary test results are given. Requirements specifications, design and analysis and finite element analysis are covered.

A fully functional prototype has been developed and testing has been conducted that demonstrated the effectiveness of the device. The pico‐reaction wheel offers a new attitude control system implementation strategy for pico and nanosatellite missions that can help to significantly reduce the spacecraft costs. The key to our success has been to design the reaction wheel from ground‐up for simplicity.

The designed pico‐reaction wheel satisfied all the constraints and requirements. Furthermore, its advantages include scalability and modularity by virtue of using commercial‐off‐the‐shelf components. A pico‐reaction wheel has been successfully designed and is now available to pico and nanosatellite builders at a cost that is consistent with low‐cost research missions.

REGRETTABLY, we do not seem to have found the solution to the problem of taking up the slack in British industry. Work study is a widespread industrial practice today, but can it now be said that its extended use will take up the slack in wasted effort which, in terms of a 5% production increase, would put a vastly different complexion on the production front.

Introduces papers from this area of expertise from the ISEF 1999 Proceedings. States the goal herein is one of identifying devices or systems able to provide prescribed performance. Notes that 18 papers from the Symposium are grouped in the area of automated optimal design. Describes the main challenges that condition computational electromagnetism’s future development. Concludes by itemizing the range of applications from small activators to optimization of induction heating systems in this third chapter.

‘THE most interesting years of my industrial life’ is the way the writer of this column would describe the three and a half years of office as editor of Time and Motion Study.