ISO 5109:2023

DRAFT INTERNATIONAL STANDARD
ISO/DIS 5109
ISO/TC 20/SC 16 Secretariat: ANSI
Voting begins on: Voting terminates on:
2022-08-04 2022-10-27
Evaluation method for the resonance frequency of the
multi-copter UA by measurement of rotor and body
frequencies
ICS: 49.020
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ISO/DIS 5109:2022(E)
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ISO/DIS 5109:2022(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 5109
ISO/TC 20/SC 16 Secretariat: ANSI
Voting begins on: Voting terminates on:

Evaluation method for the resonance frequency of the
multi-copter UA by measurement of rotor and body
frequencies
ICS: 49.020
COPYRIGHT PROTECTED DOCUMENT
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ii
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PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022

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ISO/DIS 5109:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test method . 2
4.1 Concept of test method . 2
4.1.1 Hammering method . . 2
4.1.2 Excitation table method . 3
4.2 Concept for an operation frequency . 4
5 Measurement of natural frequency and operation frequency . 4
5.1 Natural frequency . 4
5.1.1 Natural frequency measurement. 5
5.2 Operation frequency. 5
5.2.1 Operation frequency measurement . 5
5.2.2 Thrust force measurement . 5
6 Evaluation of resonance .6
6.1 Operating frequency and natural frequency overlapping . 6
iii
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ISO/DIS 5109:2022(E)
Foreword
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This document was prepared by Technical Committee ISO/TC 20, Subcommittee SC 16, Testing and
Evaluation.
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iv
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ISO/DIS 5109:2022(E)
Introduction
This standard defines the correlation between the excitation frequency caused by rotor rotation and the
resonance frequency of the main body in the design of the multi-copter UA, and suggests the evaluation
method to define the design requirements of the multi-copter UA to prevent damage due to resonance.
Typical applications for evaluation of resonance of UA are ;
a) measuring the natural frequency of UA ;
b) measuring the thrust forces and rotor rotating frequency ;
c) determining the modal properties of UA(natural frequency, damping and mode shape) ;
d) checking the resonance between main body and rotor rotating frequency ;
e) evaluation of the effect on UA after resonant frequency analysis.
v
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DRAFT INTERNATIONAL STANDARD ISO/DIS 5109:2022(E)
Evaluation method for the resonance frequency of the
multi-copter UA by measurement of rotor and body
frequencies
1 Scope
This standard provides a method for evaluating the resonance vibration frequency of multi-copter UA
only. The frequency of the rotor means the frequency within the operating frequency range, and the
frequency of the main body means the global mode frequency. This standard specifies a method to
avoid design of UA that the resonance occurs generated by the coincidence of the natural frequency of
the UA body and the rotational frequency of the rotor.
This standard relates to multi-copter UA weighing less than 150kg.
2 Normative references
ISO 21384-2:2019, Unmanned aircraft systems – Part 2 : Product systems
ISO 21384-3:2019, Unmanned aircraft systems — Part 3: Operational procedures
ISO 21384-4:2019, Unmanned aircraft systems – Part 4 : Vocabulary
ISO 21895:2020, Categorization and classification of civil unmanned aircraft systems
ISO 7626-2:2015, Mechanical vibration and shock — Experimental determination of mechanical mobility
— Part 2: Measurements using single-point translation excitation with an attached vibration exciter
ISO 7626-5:2019, Mechanical vib
...