R.P.G. Collinson and A.R. Essex
GYROSCOPES are widely used in flight test instrumentation for measurement of angular rate of rotation.
The automatic pilot is probably the first application the layman thinks of in terms of electronics and flight control. However, the extensive part now played by electronics in…
Abstract
The automatic pilot is probably the first application the layman thinks of in terms of electronics and flight control. However, the extensive part now played by electronics in achieving good handling/controllability and performance is becoming increasingly important as the technology is now sufficiently mature for extensive use to be made of automatic control techniques.
Jafar Keighobadi, Mohammad‐Javad Yazdanpanah and Mansour Kabganian
The purpose of this paper is to consider the process of design and implementation of an enhanced fuzzy H∞ (EFH∞) estimation algorithm to determine the attitude and heading angles…
Abstract
Purpose
The purpose of this paper is to consider the process of design and implementation of an enhanced fuzzy H∞ (EFH∞) estimation algorithm to determine the attitude and heading angles of ground vehicles, which are frequently affected by considerable exogenous disturbances. To detect the changes of disturbances, a fuzzy system is designed based on expert knowledge and experiences of a navigation engineer. In the EFH∞ estimator, the intensity bounds of disturbances affecting the measurements are updated using a heuristic combination of three change‐detection indices. Performance of the proposed estimator is evaluated by Monte‐Carlo simulations and field tests of three kinds of vehicles using a manufactured attitude‐heading reference system (AHRS). In both simulations and real tests, the proposed estimator results in a superior performance compared to those of the recently developed and standard H∞ estimators.
Design/methodology/approach
Design, implementation and real tests of the EFH∞ estimator are considered for an AHRS specialized for vehicular applications. In the AHRS, three‐axis accelerometers (TAA) and three‐axis magnetometers (TAM) may be affected by large disturbances due to non‐gravitational accelerations and local magnetic fields. Therefore, the design parameters of EFH∞ estimator including the theoretic bound of disturbance intensity and the attenuation level are adaptively tuned using a fuzzy combination of three change‐detection indices. Once a sensor is affected by an exogenous disturbance, the fuzzy system will increase the scale factor of the corresponding measurement disturbance to place more confidence on the data of the AHRS dynamics including measurements of gyros with respect to the data coming from the TAA and TAM.
Findings
An intelligent fault detector is proposed for considering changes of disturbances to adjust the upper bounds of the estimator's disturbances and the length of data to update the fuzzy system inputs. The EFH∞ estimator is suitable to attenuate the effects of disturbances changes on accurate estimation of the attitude and heading angles, intelligently.
Originality/value
The paper provides a fuzzy state estimator for adaptively adjusting the theoretic disturbance matrices according to the actual intensity of the disturbances affecting the AHRS dynamics and the measurement sensors.
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Rzeszów University of Technology has undertaken the task of designing and providing of equipment to a flying laboratory. This paper presents basic design principles of the…
Abstract
Rzeszów University of Technology has undertaken the task of designing and providing of equipment to a flying laboratory. This paper presents basic design principles of the Inertial Reference Unit (IRU) which employs measuring signals from the Fiber Optic Gyros (FOG), accelerometers and electronic compass module. A microcomputer follows the algorithm of complementary filtration for of calculating the Euler angles for the aircraft attitude (pitch, roll and heading), angular rates, and linear accelerations. The correction systems that minimize error of the steady‐state measuring have been employed. The results of computer simulations, lab tests and selected flight tests have also been presented. The Inertial Reference Unit μIRU‐1 was tested in flight on board of the general aviation aircraft PZL‐110 “Koliber”. It has been confirmed that metrological properties of the system are appropriate for the purposes of teaching process. Currently, a modified version of the unit is being prepared. The new IRU is planned as a main reference unit for integrated flight control system of general aviation aircraft.
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Ch. Hajiyev and O. Akgun
In this study, Integrated Air Data – Doppler Navigation System is developed and presented. Air Data System and Doppler Radar have different advantages and disadvantages in…
Abstract
In this study, Integrated Air Data – Doppler Navigation System is developed and presented. Air Data System and Doppler Radar have different advantages and disadvantages in applications in flight control and navigation systems. The reason of this integration is to achieve the best combination of the features and eliminate the disadvantages of these systems. As a consequence of this integration via Kalman filtering, an integrated navigation system with high accuracy of airvehicle velocity and position and with high measurement frequency is attained. On basis of this integrated system, the possibility to estimate accurate and real time inflight wind speed is explained.
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This chapter provides an extensive review of literature on the interaction between and interdependence of informal and formal working practices in various workplace settings. The…
Abstract
This chapter provides an extensive review of literature on the interaction between and interdependence of informal and formal working practices in various workplace settings. The aim of the chapter is to elucidate the organisational, managerial, human relations and social factors that give rise to informal work practices and strategies, on the shop-floor not only at workers and work group levels but also at supervisory and managerial levels. This chapter helps the reader to understand the informal work practice of making a plan (planisa) in a deep-level mining workplace.