Robotics Industry

As the efficiency of robot applications generally increases, the closer human and machine are able to work together. Static safeguards are increasingly reaching their limits. The trend is moving away from full enclosures for robot cells in favour of human-robot collaborations (HRC), which manage without guards where possible, but still guarantee operator safety. In practice, each application requires a separate safety-related assessment.

Robots are classed as partly

completed machinery in terms of

the Machinery Directive. The two

standards ISO 10218 “Safety of

Industrial Robots” Part 1:

“Robots” and Part 2: “Robot

systems and integration” are

available for detailed safety

requirements. Both parts are

published as EN ISO 10218-

1:2011 and EN ISO 10218-2:2011

and are listed as harmonised C

standards under the Machinery

Directive 2006/42/EC. Part 2:

“Robot systems and integration”

also contains information on

collaborative operation, and there

is an accepted de facto

requirement for all safety

functions to meet Category 3 / PL

d of EN ISO 13849-1.

When planning an HRC

application, robot selection is an

important element for the systems

integrator. Various methods can

be applied to verify and validate

safety requirements, including

visual inspections, practical tests

and measurements. The systems

integrator has to verify or validate

over 200 points in all. The status

of the standards is clear,

therefore. In practice, however,

the question remains as to

whether an HRC can be

implemented safely with this

standards framework.

There is some guidance found in

HSE’s guidance document

HSG43. The Technical

Specification ISO/TS 15066:

“Robots and Robotic Devices –

Collaborative industrial robots” is

intended to demonstrate the ways

forward and is due for publication

by the end of 2015.

Steps toward a safe HRC application

When the normative specifications

are implemented, the fact that

robot cells are classified as a

machine under the Machinery

Directive means that each step of

the conformity assessment

procedure must be completed. It

should be noted that the robot

itself is only regarded as partly

completed machinery; it is not

until the end effector or the

necessary tool for the respective

application is in place that the

robot achieves a specific purpose

and must then be regarded as

final machinery. The integrator or

user becomes the manufacturer of

the machinery and is responsible

for the safety-related inspection,

including CE marking.

En Route to Robot Safety

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The efficiency of robot applications increases, the closer human and machine are

able to work together.

Sophisticated solutions for press retrofit increase availabilityEn Route to Robot Safety

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One of the most important points

en route to achieving a safe robot

application is to produce a risk

analysis in accordance with

EN ISO 12100. On robot

applications, the challenge for the

“risk assessment” is the

dissolution of the boundaries

between what used to be clearly

separate work areas for human

and machine. The operator’s

movement must be considered in

addition to the hazards emanating

from the robot. However, these

cannot always be calculated in

terms of speed, reflexes or the

sudden approach of additional

people.

Based on the risk analysis, the

next steps are the “safety

concept” and “safety design”,

including component selection.

The results from the “risk

analysis” and “safety concept” are

used to document the selected

safety measures in the “risk

assessment” and to implement

these in the “system

implementation”. This is followed

by the “validation”, in which the

previous steps are re-examined.

Validation is essential for proving

that machines are safe.

The checklists in EN ISO 10218-2

provide additional guidance for

robot applications. By attaching

the CE mark, the integrator

ultimately confirms that the robot

cell and its assured properties

meet all the legal requirements of

the Machinery Directive 2006/42/

EC when used in accordance with

its intended purpose.

Selection of robot and safety components

A wide range of robot systems is

available on the market, which are

suitable for various application

areas. Although they form the

basis of a safe robot application,

a safety-related assessment of

the application and any additional

components and systems is

always required in order to

implement a safe HRC.

In future we will need safety

systems that are considerably

more intelligent so that work areas

in which human and machine

collaborate can be designed

safely, even without guards. These

systems may be part of the actual

robot control system, for

calculating the robot’s movements

safely for example. This enables

the path of the robot arm to be

calculated in advance. In many

cases however, safe motion

functions such as these will not

be enough to achieve the safety

objective. Combinations will often

be needed, which will include

near-field protection (e.g. tactile

safety sensors, such as those

exhibited by Pilz at the

Automatica exhibition in June

2014), personal protection

equipment (safety goggles and

clothing) and safe sensor

technology for monitoring the

detection zone, such as the safe

3D camera system SafetyEYE

from Pilz, for example. This is able

to monitor warning and detection

zones safely in 3D.

Integration of sensor, control and

actuator technology opens up

new freedoms when it comes to

planning dynamic process cycles

and work areas in which human

and robot interact safely.

Ultimately a safe HRC application

is the result of several factors:

interplay between normative

framework conditions and a

complex risk analysis on this

HRC requires intelligent safe control systems such as the 3D camera system

SafetyEYE

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basis, selection of a robot with the

relevant safety functions,

selection of appropriate,

additional safety components and

finally, validation through a

systems integrator.

The development of new

technologies for safe human-

robot interaction is one of the key

research areas at Fraunhofer IFF.

Seven years ago they launched a

research project in which a

service robot was developed for

fetch and carry services in

laboratories in life science

companies. It very quickly

became clear that human-robot

collaboration within the same

workspace will only be possible if

the issue of safety plays a central

role, open questions are resolved

and new technologies are

developed. The human must not

be injured by the robot. A

distinction is made between hard

safety and soft safety.

Hard safety is defined as

technologies that comply with the

safety requirements from the

standards and can be certified.

These are technologies such as

tactile sensor technology for

detecting contact between human

and robot, as well as other

technologies for detecting

approach such as the SafetyEYE,

and for the restriction of speed

and force.

Technologies that help to create

higher acceptance and simplify

interaction between humans and

robots, such as the projection of

warning and detection zones on

to the workspace around the

robot, are regarded as soft safety.

This is of particular interest with

dynamic warning and detection

zones, which are calculated online

based on robot movements.

The main areas for HRC in the

future will be in industrial

applications; and not just in the

field of small robots but also on

high load systems. But there will

be some challenges with regard

to safety; firstly, there isn’t one

safe robot or one safe sensor

technology that covers every

eventuality, in terms of safety.

There will be a range of

technologies and these must

safety certified. It’s the job of the

integrator to describe the hazards

and implement solutions, based

on a risk analysis. For example,

contact with humans should be

ruled out generally where there

are hot workpieces or sharp tools.

In this case it makes sense to

detect the coming together of

human and robot using tactile

floors, laser scanners or camera

systems. It depends on the

respective scenario and

environment.

Practical guidance for system integrators

To simplify implementation of the

normative specifications for

human-robot collaborations (HRC)

and demonstrate the ways

forward, the international

standards committee ISO/TC 184/

SC2 WG3 was tasked with

developing a Technical

Specification (TS). As a member

of this international standards

committee, Pilz is working actively

with robot manufacturers,

integrators, notified bodies such

as BG and other automation

companies to formulate this

specification.

The current draft ISO/TS 15066

“Robots and Robotic Devices –

Collaborative industrial robots”

substantiates solutions for safe

human-robot collaboration in an

industrial environment. A body

area model has been defined in

the Annex to the Technical

Specification (TS). The model

defines points in the

corresponding body areas, with

details of the respective pain

threshold. Once ISO/TS 15066

has been published, these pain

threshold values can be applied

as validation for safe HRC. The

Via software, warning zones and detection zones can be configured quickly and

easily on the PC using the SafetyEYE Configurator.

Pilz Automation Technology

3 Little Colliers Field, Corby, Northants, NN18 8TJ

Tel: +444 (0)1536 460766 Fax: +44 (0)1536 460866

sales@pilz.com, www.pilz.com

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body area model provides details

of the respective pain threshold

for each part of the body (e.g. on

the head, hand, arm or leg), which

marks the start of the pain

threshold. If the application

remains within these thresholds

during any encounter between

human and robot, then it complies

with the standard. The Technical

Specification currently has the

status of Committee Draft.

Publication is planned for the end

of 2015.

In the service of robot safety

As a complete supplier, Pilz offers

services as well as products and

systems for safe robot

applications. The company

supports users with a services

portfolio that is tailored to the

individual life phases of a robot

system: from process analysis to

Risk Assessment, engineering and

CE Marking. A specific training

package on robot safety

completes the range of services.

Pilz also offers technical

components and systems that

can be used to implement human-

robot applications safely,

including sensor, control and drive

technology – most innovative of

which is its 3D camera based

SafetEYE system, the PNOZmulti

with motion monitoring, and the

PSS 4000 automation system with

the ability to monitor many robot

axes.

A safe robot application can only be achieved if the safety concept is

implemented using the right choice of robot and its safety functions, combined

with intelligent safety components