Development of fault tolerant control systems for industrial applications

In this report, the development of fault tolerant control systems for industrial applications is presented

Development of fuzzy neuron controllers for industrial applications

Two distinctive approaches are studied in this report to design neuro-fuzzy control systems for industrial applications. The first is a direct neuro-fuzzy control approach where the control is completely determined by fuzzy inference, and it requires no model of the system under control. The second approach adopted is a neuro-fuzzy scheduling approach. Information on the system model (even though it might not be accurate) is used to design conventional controllers at various operating points.RP 20/9

Development of robust digital controllers for industrial applications

This report presents some new frequency domain criteria to check the stability property of perturbed linear systems with perturbations in weighted Lp domains which is the most useful class of structured perturbations.RP 13/9

Performance study of close-loop power control algorithms for a cellular CDMA system

Performance of a reverse link code-division multiple-access (CDMA) system with fast close-loop power control algorithms is studied. It is found that if fast close-loop power control algorithm functions effectively, the speed of the mobile unit is in the range such that its Doppler frequency is less than one tenth of the power control updating rate. This paper also proposes a new predictive power control algorithm with better performance in terms of system capacity than the conventional and adaptive step size algorithms. An increase in system capacity as high as 22% compared with the conventional algorithm can be achieved depending on the mobile velocity

A Multi-Path Compensation Method for Ranging in Wearable Ultrasonic Sensor Networks for Human Gait Analysis

Gait analysis in unrestrained environments can be done with a single wearable ultrasonic sensor node on the lower limb and four fixed anchor nodes. The accuracy demanded by such systems is very high. Chirp signals can provide better ranging and localization performance in ultrasonic systems. However, we cannot neglect the multi-path effect in typical indoor environments for ultrasonic signals. The multi-path components closer to the line of sight component cannot be identified during correlation reception which leads to errors in the estimated range and which in turn affects the localization and tracking performance. We propose a novel method to reduce the multi-path effect in ultrasonic sensor networks in typical indoor environments. A gait analysis system with one mobile node attached to the lower limb was designed to test the performance of the proposed system during an indoor treadmill walking experiment. An optical motion capture system was used as a benchmark for the experiments. The proposed method gave better tracking accuracy compared to conventional coherent receivers. The static measurements gave 2.45 mm standard deviation compared to 10.45 mm using the classical approach. The RMSE between the ultrasonic gait analysis system and the reference system improved from 28.70 mm to 22.28 mm. The gait analysis system gave good performance for extraction of spatial and temporal parameters

Ultra-Wideband (UWB) microwave imaging for breast cancer detection

Microwave imaging using ultra-wideband (UWB) signal is an extension to UWB radar applications where the imaging system is used to view unobtrusively inside the human body. The proposed plan focuses on the research and development of the UWB-based clinically-oriented imaging device. An antenna array is illuminating the breast by transmitting an UWB pulse. The backscatter signal is recorded at each element of the array. Upon encountering a tumor, significant backscatter signal arises due to the significant dielectric contrast. The scattered signals are then processed to form an image map that indicates the location and size of malignant tumors. The proposed approach is attractive to patients because both ionizing radiation and breast compression are avoided, resulting in safer and more comfortable exams. It also has the potential to be both sensitive and specific, to detect small tumors, and to be less expensive than methods such as magnetic resonance imaging and nuclear medicine. The imaging process is expected to be very rapid. In a nutshell, this approach used together with film-screen mammography can significantly improve detection and limit false positive findings. With the UWB-base breast imaging maturing and more clinical studies, this approach could replace film-screen mammography

Design of reliable controllers for symmetric composite systems: Primary contingency case

This paper discusses the reliable controller design problem for symmetric composite systems composed of several identical subsystems. A reliable controller design procedure is presented in terms of the solutions to the Algebraic Riccati Equations. The order of these AREs is much lower than that of the symmetric composite system. The resulting closed-loop system is reliable in that it provide guaranteed internal stability and H∞ performance when all sensors and actuators are operational as well as when the sensors or actuators of a prescribed subsystem experiences an outage.link_to_subscribed_fulltex

Ultra-wideband real-time dynamic channel characterization and system-level modeling for radio links in body area networks

Reliable on-body wireless network design needs to incorporate the natural body movements. However, existing models are static or pseudo-dynamic models. In this work, the lack of a comprehensive channel model for a moving body is addressed. A dynamic radio channel around the human body is statistically analyzed and modeled. Important parameters of the channel are estimated from measured data and compared with the model prediction. Simulations show that the model can predict the parameters of a system working in a dynamic body area network with 92% accuracy