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Distributed track and balance measurement with bias correction

IP.com Disclosure Number: IPCOM000240708D
Publication Date: 2015-Feb-19
Document File: 8 page(s) / 491K

Publishing Venue

The IP.com Prior Art Database

Related People

Patrik Moravek: INVENTOR [+4]

Abstract

Health and Usage Monitoring Systems (HUMS) diagnose the health of critical components during flight hours for safe operation of the vehicles. Communication between HUMS control unit is the most important aspect for HUMS. For this, wireless communication is preferable over wired communication as it reduces weight, time for installation and overall cost of the system. In track and balance measurement, precise alignment of data from the sensors is required. Clock distribution is not possible in wireless communication so it is problematic to achieve data alignment within distributed systems. This paper proposes a novel method for aligning the data from two or more sensors in a wireless distributed HUMS. Time interval between the start and the end of the execution interval is measured and the frequency and clock drift is precisely indicated. Proper alignment of sample data is possible as it has the knowledge of precise oscillator frequency relative to the control unit and derived sampling rate.

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Distributed track and balance measurement with bias correction

Patrik Moravek, Jan Beran, David Kubat and Tomas Tesarik ABSTRACT

Health and Usage Monitoring Systems (HUMS) diagnose the health of critical components during flight hours for safe operation of the vehicles. Communication between HUMS control unit is the most important aspect for HUMS. For this, wireless communication is preferable over wired communication as it reduces weight, time for installation and overall cost of the system. In track and balance measurement, precise alignment of data from the sensors is required. Clock distribution is not possible in wireless communication so it is problematic to achieve data alignment within distributed systems. This paper proposes a novel method for aligning the data from two or more sensors in a wireless distributed HUMS. Time interval between the start and the end of the execution interval is measured and the frequency and clock drift is precisely indicated. Proper alignment of sample data is possible as it has the knowledge of precise oscillator frequency relative to the control unit and derived sampling rate.


1. Introduction

Health and Usage Monitoring System (HUMS) in rotorcraft measures vibration for detection of any progressive defects in critical components and also suggests possible corrective action. Typical applications of on-board HUMS include monitoring of transmission and engine vibration, rotor tracking and balancing, shaft balancing, gear box monitoring and rolling bearing monitoring. HUMS comprises a number of sensors such as tachometers and accelerometers and data acquisition systems. These sensors are placed in close proximity to critical components such as rotor blades and drive shafts to sense the performance of the components. The data acquisition system

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collects this measured data and stores it in a storage device. Early detection and rectification of defects helps to increase the operational safety of the vehicle. Furthermore it reduces the maintenance cost and fuel consumption and improves the vehicle performance and reliability. The components can be scheduled for maintenance in time in case any discrepancy is noticed in measured data of a specific component. In state-of-the-art wired installations, these sensors are connected to HUMS with connectors and wires, resulting in disadvantages such as increase in weight, installation time and cost of the HUMS.

The problem highlighted above can be overcome by using a wireless interface between the sensors and the HUMS. But there are certain problems associated with this wireless interface. In HUMS, track and balance measurements are used to monitor status of rotors as unbalanced rotors can cause undesirable vibrations. Precise alignment (accuracy shall be smaller than 1 ┬Ás) of the accelerometer and the tachometer is required for this measurement which is problematic to achieve within distributed systems containing wirelessly connected sensors...