Fault tolerant carrier frequency tracking for closed loop measurement systems

2003 ◽  
Author(s):  
N. Kero ◽  
H. Nachtnebel ◽  
H. Pommer ◽  
T. Sauter
Keyword(s):  
Carrier Frequency ◽  
Closed Loop ◽  
Fault Tolerant ◽  
Frequency Tracking ◽  
Measurement Systems ◽  
Loop Measurement

Implementation and Performance Assessment of a Vector Tracking Method Based on a Software GPS Receiver

2011 ◽  
Vol 64 (S1) ◽  
pp. S151-S161 ◽  
Author(s):  
Sihao Zhao ◽  
Mingquan Lu ◽  
Zhenming Feng
Keyword(s):  
Global Positioning System ◽  
Carrier Frequency ◽  
Gps Receiver ◽  
Tracking Loop ◽  
Frequency Tracking ◽  
Tracking Method ◽  
Global Positioning ◽  
Vector Tracking ◽  
Tracking Loops ◽  
And Performance

A number of methods have been developed to enhance the robustness of Global Positioning System (GPS) receivers when there are a limited number of visible satellites. Vector tracking is one of them. It utilizes information from all channels to aid the processing of individual channels to generate receiver positions and velocities. This paper analyzes relationships among code phase, carrier frequency, and receiver position and velocity, and presents a vector loop-tracking algorithm using an Extended Kalman filter implemented in a Matlab-based GPS software receiver. Simulated GPS signals are generated to test the proposed vector tracking method. The results show that when some of the satellites are blocked, the vector tracking loop provides better carrier frequency tracking results for the blocked signals and produces more accurate navigation solutions compared with traditional scalar tracking loops.

scholarly journals Comparing the Performance of Reference Trajectory Management and Controller Reconfiguration in Attitude Fault Tolerant Control

2018 ◽  
Vol 151 ◽  
pp. 04008
Author(s):  
Rouzbeh Moradi ◽  
Alireza Alikhani ◽  
Mohsen Fathi Jegarkandi
Keyword(s):  
Control Problem ◽  
Closed Loop ◽  
Fault Tolerant ◽  
Dynamic Performance ◽  
Fault Tolerant Control ◽  
Spacecraft Attitude ◽  
Reference Trajectory ◽  
System Behavior ◽  
Closed Loop System ◽  
Reference Trajectories

Reference trajectory management is a method to modify reference trajectories for the faulty system. The modified reference trajectories define new maneuvers for the system to retain its pre-fault dynamic performance. Controller reconfiguration is another method to handle faults in the system, for instance by adjusting the controller parameters (coefficients). Both of these two methods have been considered in the literature and are proven to be capable of handling various faults. However, the comparison of these two methods has not been considered sufficiently. In this paper, a controller reconfiguration mechanism and a reference trajectory management are proposed for the spacecraft attitude fault tolerant control problem. Then, these two methods are compared under the same conditions, and it is shown that the proposed controller reconfiguration has better performance than the proposed reference trajectory management. The reason is that the controller reconfiguration has more variables to modify the closed-loop system behavior.

scholarly journals High Speed, High Temperature, Fault Tolerant Operation of a Combination Magnetic-Hydrostatic Bearing Rotor Support System for Turbomachinery

2004 ◽  
Author(s):  
Mark Jansen ◽  
Gerald Montague ◽  
Andrew Provenza ◽  
Alan Palazzolo
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Closed Loop ◽  
Fault Tolerant ◽  
Active Vibration Control ◽  
Control Algorithms ◽  
Displacement Sensors ◽  
Rotor Support ◽  
Active Vibration ◽  
Speed Computer

Closed loop operation of a single, high temperature magnetic radial bearing to 30,000 RPM (2.25 million DN) and 540°C (1,000°F) is discussed. Also, high temperature, fault tolerant operation for the three axis system is examined. A novel, hydrostatic backup bearing system was employed to attain high speed, high temperature, lubrication free support of the entire rotor system. The hydrostatic bearings were made of a high lubricity material and acted as journal-type backup bearings. New, high temperature displacement sensors were successfully employed to monitor shaft position throughout the entire temperature range and are described in this paper. Control of the system was accomplished through a stand alone, high speed computer controller and it was used to run both the fault-tolerant PID and active vibration control algorithms.

scholarly journals Fast and stable photoacoustic gas spectroscopy by frequency tracking of a quartz tuning fork in closed loop detection

2020 ◽  
Author(s):  
Maxime Duquesnoy ◽  
Raphaël Lévy ◽  
Jean-Michel Melkonian ◽  
Guillaume Aoust ◽  
Myriam Raybaut ◽  
...  
Keyword(s):  
Closed Loop ◽  
Tuning Fork ◽  
Quartz Tuning Fork ◽  
Frequency Tracking ◽  
Loop Detection

Fuzzy fault-tolerant containment control for multi-agent systems with unknown nonlinear dynamics

2021 ◽  
pp. 014233122110430
Author(s):  
Malika Sader ◽  
Fuyong Wang ◽  
Zhongxin Liu ◽  
Zengqiang Chen
Keyword(s):  
Closed Loop ◽  
Control Method ◽  
Fault Tolerant ◽  
Nonlinear Function ◽  
Loop System ◽  
Multi Agent Systems ◽  
Closed Loop System ◽  
Containment Control ◽  
Agent Systems ◽  
Multi Agent

This paper studies the containment control problem for a class of nonlinear multi-agent systems (MASs) with actuator faults (AFs) and external disturbance under switching communication topologies. To address this problem, a new fuzzy fault-tolerant containment control method is developed via utilizing adaptive mechanisms. Furthermore, a sufficient condition is obtained to guarantee the stability of the considered closed-loop system by the dwell time technique combined with Lyapunov stability theory. Unlike the traditional method to estimate the weight matrix, the fuzzy logic system is used to estimate the norm of weight vectors. Thus, the difficulty that the unknown nonlinear function cannot be compensated for when the actuator produces outage or stuck fault is solved. Compared with the existing controllers for nonlinear MASs, the proposed controller is more suitable for the considered problem under the influence of AFs that are detrimental to the operation of each agent system. Besides which, the closed-loop system is proven to be stable by using the developed controller, and all followers converge asymptotically to the convex hull formed by the leaders. Finally, an example based on a reduced-order aircraft model is presented to verify the effectiveness of the designed control scheme.

A closed-loop system for frequency tracking of piezoresistive cantilever sensors

2013 ◽  
Author(s):  
Hutomo Suryo Wasisto ◽  
Qing Zhang ◽  
Stephan Merzsch ◽  
Andreas Waag ◽  
Erwin Peiner
Keyword(s):  
Closed Loop ◽  
Loop System ◽  
Closed Loop System ◽  
Frequency Tracking ◽  
Cantilever Sensors

Research on reference fiber for closed-loop measurement of Spectral Survey Telescope

2020 ◽  
Author(s):  
Shipeng Duan ◽  
Jiale Zuo ◽  
Mengtao Li ◽  
Zhigang Liu ◽  
Hongzhuan Hu ◽  
...  
Keyword(s):  
Closed Loop ◽  
Spectral Survey ◽  
Loop Measurement

Robust attitude fault-tolerant control for unmanned autonomous helicopter with flapping dynamics and actuator faults

2018 ◽  
Vol 41 (5) ◽  
pp. 1266-1277 ◽  
Author(s):  
Kun Yan ◽  
Mou Chen ◽  
Qiangxian Wu ◽  
Ke Lu
Keyword(s):  
Closed Loop ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Loop System ◽  
System Stability ◽  
Actuator Faults ◽  
Closed Loop System ◽  
Attitude Tracking ◽  
Control Scheme ◽  
Autonomous Helicopter

In this paper, an adaptive robust fault-tolerant control scheme is developed for attitude tracking control of a medium-scale unmanned autonomous helicopter with rotor flapping dynamics, external unknown disturbances and actuator faults. For the convenience of control design, the actuator dynamics with respect to the tail rotor are introduced. The adaptive fault observer and robust item are employed to observe the actuator faults and eliminate the effect of external disturbances, respectively. A backstepping-based robust fault-tolerant control scheme is designed with the aim of obtaining satisfactory tracking performance and closed-loop system stability is proved via Lyapunov analysis, which guarantees the convergence of all closed-loop system signals. Simulation results are given to show the effectiveness of the proposed control method.

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