Safety of machinery - Part 2: Examples of application

IEC TR 62998-2:2020 establishes guidance for the application of IEC TS 62998-1:2019.
It provides examples of:
– application for which SRS/SRSS are relevant,
– use of SRS/SRSS information from an application point of view,
– fusion of SRS into SRSS for given applications, and
– appropriate information for use for given applications.

General Information

Status
Published
Publication Date
13-Apr-2020
Current Stage
PPUB - Publication issued
Completion Date
14-Apr-2020
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IEC TR 62998-2
Edition 1.0 2020-04
TECHNICAL
REPORT
colour
inside
Safety of machinery –
Part 2: Examples of application
IEC TR 62998-2:2020-04(en)
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---------------------- Page: 2 ----------------------
IEC TR 62998-2
Edition 1.0 2020-04
TECHNICAL
REPORT
colour
inside
Safety of machinery –
Part 2: Examples of application
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.110; 21.020 ISBN 978-2-8322-7975-5

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 2 – IEC TR 62998-2:2020 © IEC 2020
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms, definitions and abbreviated terms ........................................................................ 7

3.1 Terms and definitions .............................................................................................. 7

3.2 Abbreviated terms ................................................................................................... 8

4 Applications for mobile robots .......................................................................................... 8

4.1 General ................................................................................................................... 8

4.2 SRSS on mail transport mobile robot ...................................................................... 9

4.2.1 Intended use .................................................................................................... 9

4.2.2 SRSS performance class determination ......................................................... 10

4.2.3 SRS limits of use and SRSS function ............................................................. 10

4.2.4 Safety-related requirements ........................................................................... 11

4.2.5 Object classes and physical properties .......................................................... 12

4.2.6 Sensing zones ............................................................................................... 13

4.2.7 Dependability under environmental influences ............................................... 15

4.2.8 Safety-related information .............................................................................. 16

4.2.9 Verification and validation .............................................................................. 17

4.2.10 Information for use of the SRSS .................................................................... 18

4.3 SRSS on cleaning mobile robot ............................................................................. 19

4.3.1 Intended use .................................................................................................. 19

4.3.2 SRSS performance class determination ......................................................... 20

4.3.3 SRS limits of use and SRSS function ............................................................. 20

4.3.4 Safety-related requirements ........................................................................... 21

4.3.5 Object classes and physical properties .......................................................... 22

4.3.6 Sensing zones ............................................................................................... 23

4.3.7 Dependability under environmental influences ............................................... 24

4.3.8 Safety-related information .............................................................................. 24

4.3.9 Verification and validation .............................................................................. 25

4.3.10 Information for use of the SRSS .................................................................... 26

5 Application for container handling equipment for harbour logistics ................................. 27

5.1 General ................................................................................................................. 27

5.2 SRSS for CHE ...................................................................................................... 28

5.2.1 Intended use .................................................................................................. 28

5.2.2 SRS limits of use and SRSS function ............................................................. 29

5.2.3 SRSS performance class determination ......................................................... 30

5.2.4 Safety-related requirements ........................................................................... 31

5.2.5 Object classes and physical properties .......................................................... 31

5.2.6 Sensing zones ............................................................................................... 32

5.2.7 Dependability under environmental influences ............................................... 34

5.2.8 Safety-related information .............................................................................. 34

5.2.9 SRSS performance class after fusion ............................................................. 34

5.2.10 Verification and validation .............................................................................. 34

5.2.11 Information for use of the SRSS .................................................................... 35

Bibliography .......................................................................................................................... 37

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IEC TR 62998-2:2020 © IEC 2020 – 3 –

Figure 1 – Outdoor scene ....................................................................................................... 8

Figure 2 – Mobile robot with 2 distinctive safety-related zones .............................................. 10

Figure 3 – Combination of three SRSs into an SRSS and SRSS functions ............................ 11

Figure 4 – Mounting positions and sensing zones of the SRS and safety-related zones

of SRSS ................................................................................................................................ 14

Figure 5 – Mounting positions and sensing zones of the SRS and safety-related zones

of SRSS ................................................................................................................................ 14

Figure 6 – Examples of measurement data for evaluation of coverage interval ...................... 17

Figure 7 – Test setup ............................................................................................................ 18

Figure 8 – CHE application ................................................................................................... 28

Figure 9 – Operation areas of CHE ....................................................................................... 29

Figure 10 – SRSS structure and safety-related functions ...................................................... 30

Figure 11 – Safety-related zones of SRSS ............................................................................ 32

Figure 12 – Mounting positions and sensing zones of the SRS, and safety-related

zones of the SRSS ................................................................................................................ 33

Table 1 – Safety-related requirements .................................................................................. 12

Table 2 – Example of confidence information for SRS ........................................................... 17

Table 3 – Information for use of the SRSS ............................................................................ 19

Table 4 – Safety-related requirements .................................................................................. 22

Table 5 – Information for use of the SRSS ............................................................................ 27

Table 6 – Safety-related requirements .................................................................................. 31

Table 7 – Environmental limits of SRSS ................................................................................ 34

Table 8 – Information for use of the SRSS ............................................................................ 36

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– 4 – IEC TR 62998-2:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY OF MACHINERY –
Part 2: Examples of application
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and

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The main task of IEC technical committees is to prepare International Standards. However, a

technical committee may propose the publication of a technical report when it has collected

data of a different kind from that which is normally published as an International Standard, for

example "state of the art".

IEC TR 62998-2, which is a Technical Report, has been prepared by IEC technical committee

TC 44: Safety of machinery – Electrotechnical aspects.
The text of this Technical Report is based on the following documents:
Enquiry draft Report on voting
44/849/DTR 44/865A/RVDTR

Full information on the voting for the approval of this technical report can be found in the report

on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

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IEC TR 62998-2:2020 © IEC 2020 – 5 –
This document is to be used in conjunction with IEC TS 62998-1:2019.

A list of all parts in the IEC 62998 series, published under the general title Safety of machinery,

can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
reconfirmed,
withdrawn,
replaced by a revised edition, or
amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

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– 6 – IEC TR 62998-2:2020 © IEC 2020
INTRODUCTION

Safety-related sensors are applied to machinery presenting a risk of personal injury. They

provide protection by causing the machine to revert to a safe condition before a person can be

placed in a hazardous situation.

IEC TS 62998-1:2019 is intended for use by safety-related sensor manufacturers and

integrators of safety-related sensors for the design of safety-related sensor systems used for

the protection of persons.

This document gives guidance for manufacturers and integrators on the application of IEC TS

62998-1:2019.
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IEC TR 62998-2:2020 © IEC 2020 – 7 –
SAFETY OF MACHINERY –
Part 2: Examples of application
1 Scope
This document establishes guidance for the application of IEC TS 62998-1:2019.
It provides examples of:
– application for which SRS/SRSS are relevant,
– use of SRS/SRSS information from an application point of view,
– fusion of SRS into SRSS for given applications, and
– appropriate information for use for given applications.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies.

For undated references, the latest edition of the referenced document (including any

amendments) applies.

IEC TS 62998-1:2019, Safety of machinery – Safety-related sensors used for protection of

persons
3 Terms, definitions and abbreviated terms
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 Terms and definitions
3.1.1
mobile robot
robot able to travel under its own control
[SOURCE: ISO 8373:2012, 2.13, modified – The note has been omitted.]
3.1.2
robot

actuated mechanism programmable in two or more axes with a degree of autonomy, moving

within its environment, to perform intended tasks
[SOURCE: ISO 8373:2012, 2.6, modified – Notes 1 and 2 have been omitted.]
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– 8 – IEC TR 62998-2:2020 © IEC 2020
3.2 Abbreviated terms
CHE container-handling equipment
ALARP as low as reasonably practical
LiDAR light detection and ranging
MOR meteorological optical range
TOF time of flight
SLAM Simultaneous Localization and Mapping
SRS safety-related sensor
SRSS safety-related sensor system
SCS safety-related control system
4 Applications for mobile robots
4.1 General

This example covers the integration and installation phase using fusion of three SRSs into an

SRSS in accordance with Clause 6 of IEC TS 62998-1:2019 to improve sensing zones and

safety-related zones in accordance with requirements for the intended use. The intended uses

are 2 different mobile robot types, in accordance with ISO 13482:2014, that operate

autonomously in a public area with limited access. The reader should be aware that the

following descriptions are not based on comprehensive analysis and are only examples for

mobile robotics.

NOTE ISO 13482:2014 covers mobile robots operating in an autonomous manner. For simplification, the term

"mobile robot" will be used from now on.

Two different mobile robots operate on a certain university campus with buildings to achieve:

transport of in-house mail items among office buildings of the university, and
cleaning of pavements of the university.

Figure 1 shows the typical outdoor pavement of a university campus. Person(s) being present

or approaching the safety related zone(s) of an SRSS should be detected and the safety-related

control system should initiate appropriate reaction of the mobile robot.
Figure 1 – Outdoor scene
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IEC TR 62998-2:2020 © IEC 2020 – 9 –
4.2 SRSS on mail transport mobile robot
4.2.1 Intended use

The intended use should be determined (see 6.2.1 of IEC TS 62998-1:2019) by the integrator.

It is defined by the following selected example items:

1) The mobile robot is a Type 1.1 robot specified in ISO 13482:2014 with a weight of 30 kg

and size of length: 500mm × width: 500mm × height: 600mm.

2) The mobile robot automatically navigates the pavement connecting the university office

buildings. The path of the robot is predetermined according to the map created by SLAM

technology [1] and physical constraints. The map includes position information for objects

that are fixed along the pavement, such as guardrails, building walls, trees, etc. By referring

to the map, the robot determines its own restricted space (ISO 13482:2014, 3.18.2) while

moving.
3) The mobile robot moves during daytime on non-carriageways where:
a) light vehicles such as bicycles are not allowed to enter;
b) wheelchairs can enter;

c) pavements are smooth paved with slopes of up to 5 degrees in some areas, as shown

in Figure 1;

d) standing or walking people on the pavements are adults and/or children. Children under

and including 3 years are assumed to be controlled and children from 4 years up to

including 10 years are assumed to be accompanied by adults. An adult might not

accompany children over 10 years up to 14. For the purpose of this example, the speed

of a person towards the mobile robot is assumed to be between 0 mm/s and 800 mm/s

if the person enters into the safeguarded zone.

NOTE The speed in this example deviates from ISO 13855:2010 under the assumption of different human

behaviour in this application. For other applications, faster or slower speeds might be more appropriate. On

the campus, people are informed by organizational measures and warning signals that running is not

allowed in the areas where mobile robots are present. Other examples of properties are given in 4.2.4.

4) The mobile robot:

a) is intended to make a protective stop when a standing or walking person comes into the

protective stop zone (see Figure 2);

b) is intended to reduce the speed when a standing or walking person moves into the

safeguarded zone (see Figure 2);

c) is driven with a speed up to 700 mm/s reduced by the safety related speed control

function down to 300 mm/s;

d) can reduce speed within 0,5 s from 700 mm/s to 300 mm/s, and another 0,2 s to reduce

to zero speed;
e) is intended to be used in the daytime.
5) The outdoor environmental conditions during operation:
a) can be up to 10 mm/h precipitation;
b) can have light interference representing daytime.
___________
Numbers in square brackets refer to the Bibliography.
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– 10 – IEC TR 62998-2:2020 © IEC 2020

The mobile robot has two distinctive zones, in accordance with ISO 13482:2014. The protective stop zone, where

the mobile robot performs a protective stop, and the safeguarded zone, where a safety-related speed control function

is performed when a safety-related object is detected. In accordance with IEC TS 62998-1:2019, the protective stop

zone and safeguarded zone would be safety-related zone(s).
Figure 2 – Mobile robot with 2 distinctive safety-related zones
4.2.2 SRSS performance class determination

In the chosen approach, using ISO 13482:2014 the required performance level of the safety

functions of a Type 1.1 mobile robot is PL b, in accordance with ISO 13849-1:2015. The safety

functions include the protective stop function, the safety-related speed control function, the

hazardous collision avoidance function, and the travel surface detection function in accordance

with ISO 13482:2014, which will be initiated by the SRSS.

The required performance class of the SRSS corresponding to PL b is the sensor performance

class B specified in IEC TS 62998-1:2019.
4.2.3 SRS limits of use and SRSS function

The SRSS consists of three SRSs defined by the manufacturer as follows (see Figure 3).

1. SRS1: a 2D LiDAR suitable to be used up to PL b, in accordance with ISO 13849-1:2015,

which allows the detection of persons and other safety-related objects and the measurement

of their positions and velocities with high accuracy. The systematic capabilities are

assessed in accordance with IEC TS 62998-1:2019. The sensing zone is up to a radius of

7 000 mm, and a viewing angle of 270°. The detection capability is given for safety-related

objects with the properties: minimum size 40 mm × 40mm; minimum object reflectivity 5 %;

maximum object speed 1 600 mm/s. The response time is 0,05 s. Use in indoor and outdoor

environmental conditions is possible within defined limits.

2. SRS2: a TOF camera suitable to be used up to PL b, in accordance with ISO 13849-1:2015,

which allows detecting parts of 3D volumes of persons, road surface, and other safety-

related objects using 3D imaging technology. The systematic capabilities are assessed in

accordance with IEC TS 62998-1:2019. SRS2 is capable of measuring the position and

velocity of objects within the 3D sensor coordinate system. The sensing zone is up to

4 000 mm and vertical and horizontal field of views angle of 60° and 70°, respectively. The

detection capability is given for safety-related objects with properties: minimum size

40 mm × 40 mm × 40 mm; minimum object reflectivity 5 %; maximum object speed

1 600 mm/s. The response time is 0,05 s. It is possible to distinguish a paved road surface

and other objects three-dimensionally. Use in indoor and outdoor environmental conditions

is possible within defined limits.
3. SRS3: the same specification as SRS1.
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IEC TR 62998-2:2020 © IEC 2020 – 11 –
Figure 3 – Combination of three SRSs into an SRSS and SRSS functions
The target applications require four SRSS functions (see Figure 3):

• Safety-related function 1: to detect persons and hazardous objects in the protective stop

zone for initiating the protective stop function specified in ISO 13482:2014, 6.2.2.3.

• Safety-related function 2: to detect persons and hazardous objects and to provide their

positions and velocities as safety-related information for the safety-related speed control

function and/or the hazardous collision avoidance function specified in ISO 13482:2014,

6.4 and 6.5.2.1.

• Safety-related function 3: to detect the geometry of the travel surface of the robot as

specified in ISO 13482:2014, 6.5.3. When a travelable surface is observed in the

travelling direction of the robot, the robot can move forwards. If the robot moves

backwards, the road surface that it has already travelled is definitely present, so this

function is not required.

• Automation related function: to provide 3D point cloud with timestamp in the robot

coordinate system for SLAM.
4.2.4 Safety-related requirements

The SRSS safety-related requirements should be specified by the integrator (see 6.2.1 of

IEC TS 62998-1:2019) based on the intended use. For example, see the requirements defined

in Table 1.
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– 12 – IEC TR 62998-2:2020 © IEC 2020
Table 1 – Safety-related requirements
Term Requirement Details
SRSS performance class B See 4.2.2
Intended to be integrated from SRS
of the same performance class B
Demand rate of SRSS safety 10/h
related function(s)
SRSS response time 0,1 s
SRSS detection capability e.g. Person related properties: See 4.2.5
Sizes representing a 4-year-old
person in an upright position.
Minimum reflection value 5 %
Speed 800 mm/s
e.g. Hazardous object properties:
Sizes representing wheelchair
Minimum reflection value 5 %
Speed 800mm/s
SRSS sensing zones e.g. Safety related zones See 4.2.6
2-dimensional; 360° with S = 656
mm and S = 1 255 mm;
3-dimensional; vertical and
horizontal field of view 60°; with S
= 656 mm and S = 1 255 mm;
4.2.5 Object classes and physical properties

The SRSS detection capability should be specified by the integrator in accordance with 6.2.3

of IEC TS 62998-1:2019. The following specific examples are considered.
Object classes to be analysed are:
1) objects used to perform the person detection function;
a) supervised children up to and including 3 years;
b) accompanied children between 4 years and including 10 years;
c) unaccompanied children between 11 years and including 13 years;
d) adult persons from 14 years.
2) objects used to perform the hazardous object function;
a) wheelchairs.
3) objects used to perform the automation related function
a) landmarks used for navigation.

Furthermore, only the properties of an accompanied standing or walking child will be analysed

for the safety-related function 1 and safety related function 2.

For safety related function 2, the limit that SRS2 detects is the forearm of a 4-year-old child.

The simplified shape is estimated as cylinder with a diameter of 40 mm or more and a length of

200 mm.

NOTE 1 The 5th percentile value of the hand width and the hand length of a Japanese 4-year-old child is 49 mm

and 107 mm respective
...

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