Source: https://www.tuv-sud-psb.ph/ph-en/resource-centre/publications/research-papers/meet-my-new-work-colleague-a-robot
Timestamp: 2020-02-22 22:59:04
Document Index: 98059107

Matched Legal Cases: ['art 1', 'art 1', 'art 2', 'art 2', 'arts 1', 'arts 1']

Functional Safety Conference FS 2017 - Stewart Robinson | TÜV SÜD Philippines
Principal Engineer and Functional Safety Expert
Collaborative Robots, sometimes referred to as cobots, are designed to work alongside humans in a “collaborative workspace”, an area where the robot and the human can perform tasks simultaneously.
Unlike more traditional machines, which are ‘caged’ by a guarding mechanism, collaborative robots often operate in the human-occupied workspace without safety fencing. However, not all collaborative robots are guard-free, depending on their function and related safety requirements. This paper explains the measures that are required to ensure that working with cobots is ‘safe’, including a description of the Functional Safety requirements.
A brief history of Industrial Robots
ISO 8373 defines an Industrial Robot as: “An automatically controlled, reprogrammable, multipurpose manipulator programmable in three or more axes, which may be either fixed in place or mobile for use in industrial automation applications.”
It is generally accepted that Industrial Robots date back to around 1960, General Motors installed their first Industrial Robot at the Trenton New Jersey plant in 1961. This was a “Unimate” robot arm developed by the company Unimation (name derived from Universal Automation). The inventor was George Devol. The robot weighed about two tons but was remarkably accurate, it was used for spot welding and handling die castings.
GM went on to install 66 more Unimates and other automotive manufacturers also became interested, notably Ford.
Industrial robot arms continued to evolve in the 1960's and 70's. The competition from companies around the world continued to produce a high demand for industrial robots. This spurred further research and technical development and items such as the development of the microprocessor helped to create cost-effective control systems that were still powerful.
In 1967 the Swedish company ASEA developed a robot for a spray painting application, this is accepted as the first successful story of a business developing a specific robot based on their needs. The company eventually became ABB who are still one of the leading manufacturers of robots in the world. This is only one example of when large companies began to develop their own industrial robots.
Development continued with other robot manufacturers entering the market and by the early 1980s it was said that a new manufacturer was entering the market each month. However later in the decade there were some setbacks that included some significant malfunctions, for example in 1988 there was a series of malfunctions at the GM Dodge plant near Detroit/Michigan that resulted in robots smashing windows and painting one another! This and other setbacks resulted in a downturn and it wasn’t until the first decade of the 21st century that robot supply regained mid 1980 levels. The global downturn in the late 2000’s was another setback but 2010 saw a huge upturn in demand and according to figures from the International Federation of Robotics (IFR) 2014 saw a 29% increase in the worldwide supply of Industrial Robots. Up from 178,000 in 2013 to 229,000 in 2015 (see Figure 2 IFR 2016 Report - Estimated worldwide supply).
It is estimated that by the end of 2015 more than three million Industrial Robots have been supplied worldwide. Of course many of the older ones will have been de-commissioned but the numbers are growing at a significant rate, so much so that IFR estimates that the year 2019 will see 414,000 robots supplied (see Figure 3 - IFR 2016 Report - Estimated yearly shipments).
Isaac Asimov's "Three Laws of Robotics" are of course from science fiction, however it is claimed that Asimov’s “I, Robot” was part of the inspiration for George Devol when he invented Unimate.
Besides the robot itself, the collaborative robot might include the ‘end effector’, that is the tool adapted on the robot arm with which the robot performs tasks, and the objects moved by it.
Unlike more traditional machines, which are ‘caged’ by a guarding mechanism, collaborative robots often operate in the human-occupied workspace without safety fencing. However, not all collaborative robots are guard-free, depending on their function and related safety requirements.
Cobots are expanding the possibilities of automation as they are often easier to deploy and use.
Consequently, more flexible production automation will become increasingly accessible to a wider number of businesses, including Small and Medium sized Enterprises (SMEs). However, they do present new safety concerns.
As well as manufacturing, there are many other sectors where such a collaborative operation delivers distinct advantages, including:
Medical (where robots are used during various medical procedures including surgery)
Healthcare (where robots perform tasks such as assistance with mobility)
Service (both domestic and professional applications)
Space (for example on the International Space Station)
Defence (robots assisting in bomb disposal and wearable robots for enhanced mobility)
The automotive industry has been the single largest driver of the robotics industry worldwide for decades. Today, automotive Original Equipment Manufacturers (OEMs), as well as other tier suppliers are making use of new collaborative robot technologies.
Enrico Krog Iversen, CEO - Universal Robots has said:
“The world's first collaborative robots entered the market in 2009. The new generation nicknamed cobots created a paradigm shift within the manufacturing industry: Large corporations as well as small and medium-sized companies are looking for new ways to optimize production processes in order to compete on a global scale.
The invention of cobots has made automation accessible for all. The cobots' ease-of-use, flexible deployment, human-robot-collaboration, space saving qualities, and their fast payback makes this new kind of robot attractive. The full potential of the global market of cobots is very far from being realized yet - we therefore expect increased demand in the next few years."
Standards progression
EN ISO 10218-1:2011 Robots and robotic devices — Safety requirements for industrial robots — Part 1: Robots. The Standard outlines the scope of Part 1 as follows – “This part of ISO 10218 specifies requirements and guidelines for the inherent safe design, protective measures and information for use of industrial robots. This part of ISO 10218 specifies requirements and guidelines for the inherent safe design, protective measures and information for use of industrial robots. It describes basic hazards associated with robots and provides requirements to eliminate, or adequately reduce, the risks associated with these hazards. . Requirements for robot systems, integration, and installation are covered in ISO 10218-2.”
EN ISO 10218-2:2011 Robots and robotic devices — Safety requirements for industrial robots — Part 2: Robot systems and integration. The Standard outlines the scope of Part 2 as follows – “This part of ISO 10218 specifies safety requirements for the integration of industrial robots and industrial robot systems as defined in ISO 10218-1, and industrial robot cell(s). The integration includes the following:
- The design, manufacturing, installation, operation, maintenance and decommissioning of the industrial robot system or cell;
- Necessary information for the design, manufacturing, installation, operation, maintenance and decommissioning of the industrial robot system or cell;
- Component devices of the industrial robot system or cell."
In order to ensure that humans are not exposed to unacceptable risks when working collaboratively the current standards describe four separate measures that can be used to provide risk reduction. It is required that at least one of these requirements needs to be fulfilled, in addition to having visual indication that the robot is in collaborative operation.
1. Safety-rated monitored stop - This measure requires that when it is detected that a human has entered the collaborative workspace, the robot shall be stopped. The stop condition should then be maintained until the human leaves the workspace.
There are various types of sensing devices that are used to detect a person but among the most commonly used type in this sort of application are ‘Area Scanners’. These are ‘AOPDDR - Active Opto-electronic Protective Device Responsive to Diffuse Reflection’
2. Hand guiding - In this mode the human can guide the robot at the end effector by hand. Additional requirements for safety include safe-limited speed monitoring, a local emergency stop, and the use of an enabling device, which is a three position device that has to be held in the centre position.
3. Speed and separation monitoring - In this mode, the robot must maintain a specified separation distance from the human and operate at a predetermined speed. This measure requires careful risk assessment and needs to take account of safety distances, which should include the consideration of approach speeds of parts of the human body as described in EN ISO 13855.
4. Power and force limiting by inherent design or control - In this mode the power and force of the robot actuators need to be monitored by safety related control systems to ensure that they are within limits established by a risk assessment.
While EN ISO 10218 already contained some guidance on the use of collaborative robots, with the rapid pace of technological development, it was widely acknowledged that this guidance needed to be enhanced.
Consequently, a Technical Specification (ISO/TS 15066 Robots and robotic devices — Safety requirements for industrial robots - Collaborative operation) was published in 2016 to deal specifically with this situation. The document is a Technical Specification, as more application knowledge is needed before publishing a finalised collaborative robot standard.
The design of the collaborative work space
The design of the collaborative operation
- Minimum separation distance and maximum robot speed
- Static (worst case) or dynamic (continuously computed) limit values
- Safety-rated sensing capabilities
Methods of collaborative working
- Safety-rated monitored stop
- Hand-guiding
- Speed and separation monitoring
- Power and force limiting (biomechanical criteria!)
- Collaborative/non-collaborative
- Different methods of collaboration
Operator controls for different applications
The methods of collaborative working ‘speed and separation monitoring’ and ‘power and force limiting’ are particularly elaborated on in ISO/TS 15066. This includes recommendations for ‘biomechanical limits’ of pain thresholds for specific parts of the human body.
The rationale for creating biomechanical limits was established in conjunction with testing conducted by the University of Mainz (Germany). Testing was conducted using 100 healthy adult test subjects on 29 specific body areas, and for each of the body areas, pressure and force limits for quasi-static contact were established evaluating onset of pain thresholds.
There are also working groups of the standards organisations reviewing various aspects of human-machine interactions, which will also inform the development of future standards. But for now, EN ISO 10218 Parts 1 and 2, and the ISO/TS 15066 specification defines the safety requirements for the sphere of collaborative robots, with the the most relevant published guidance being contained in EN ISO 10218
In all four of the measures described above, the safety related control system that provides this functionality needs to meet either:
Safety Performance Level d (PLd), with Category 3 architecture (the identified level to which the safety related parts of a control system resist faults and their subsequent behaviour if a fault occurs) outlined within the standard EN ISO 13849, or
Safety Integrity Level 2 (SIL 2) with hardware fault tolerance (HFT) 1, as set out in EN [IEC] 62061.
One of the best known manufacturers of cobots is the Danish company Universal Robots (UR). This table is from their published functional safety data, the values have been tested and verified by TÜV Nord Cert GmbH.
Published in 2012, a Health & Safety Executive (HSE) Research Report, (RR906) - Collision and injury criteria when working with collaborative robots, also offers some useful guidance.
The introduction to the HSE report states that “this study explored the safety, reliability and evidence for the force limits defined by the draft TS 15066, and of the methods for testing them. It also addressed whether the proposed approach in the draft TS 15066 is likely to adequately protect people from the risks. Risk assessment of potential collision scenarios, human reliability and behaviour issues, and equipment failure modes and rates are discussed, as is the adequacy of personal protective equipment against collision injuries.”
The cobot sees the dawn of robotic systems that can safely interact with human workers while effectively performing simple industrial tasks. While the advent of the cobot offers exciting possibilities for industry, some end-effectors may create hazards, especially as contact between the collaborative robot and the operator can lead to the possibility of collision.
It is therefore vital that a complete risk assessment is undertaken before a cobot is deployed, as you would with any machinery in the workplace. This must cover the intended industrial workplace, with the basis for this risk assessment being EN ISO 10218 Parts 1 and 2, alongside the Machinery Directive.
It is a concept that is promoted as a “German strategic initiative to take up a pioneering role in industrial IT which is currently revolutionizing the manufacturing engineering sector”.
Industry 4.0 creates what has been called a "smart factory". Within the modular structured smart factories, cyber-physical systems monitor physical processes, create a virtual copy of the physical world and make decentralised decisions. Over the Internet of Things, cyber-physical systems communicate and cooperate with each other and with humans in real time, and via the Internet of Services, both internal and cross-organizational services are offered and used by participants of the value chain.
The use of collaborative robots can be considered to be part of the fourth industrial revolution.