The Rise of “Cobots” and Its Safety Considerations

Industrial robots are transforming factories, production facilities and manufacturing plants around the world. Incorporating new collaborative robots (cobots) has allowed companies to boost productivity, improve quality and reduce costs. In fact, it is expected that the robotics industry will reach 2.6M units deployed worldwide by 2019 (World Robotics Report 2016, IFR). Some of the examples of robot applications include pick and place, harsh environments and assembly line.

With such a growth in robotics and a wide array of applications, it is vital to consider safety to ensure overall safety, including protecting the purchaser and ensuring compliance with regulatory matters. Safety considerations, risk assessment, and mitigation include ISO/TS 15066, constructional and workspace evaluation, functional safety, and cybersecurity.

Safety Considerations, Risk Assessment and Mitigation

The most popular type of cobot today is Power and Force Limited (PFL) robot, with the power and force limited by design. Quasi-static contact and transient contact are two types of contact between an operator and part of a robot system.

What is important to remember is about the quasi-static contact is that there is a risk that an operator body part can be clamped between a moving part of a robot system and another fixed / moving part of the robot cell. To improve safety and reduce risk, manufacturers should consider contact force and pressure, speed limits, physical and design characteristics and a redesign of the operator area (including a repositioning of the work area).

Transient contact, on the other hand, is when the robot manipulator collides with an operator in free space. To improve safety in transient contact situations, manufacturers should consider inertia of the robot (and workpiece), contacted body part, and relative mass along with speed limits and physical characteristics.

The Need For Risk Assessment

One important standard for risk assessment is ISO/TS 15066 that was established over a six-year period by representatives of 24 countries to address the safety of collaborative robot applications. ISO/TS 15066 addresses the limit criteria on mechanical loading for both transient and quasi-static contact, and risk assessment should be according to EN/ISO12100.

What Manufacturers Should Lookout For During Construction

It is also crucial to consider safety during construction evaluation. Safety considerations during the construction evaluation include: electrical - fire and shock hazards, mechanical safety and endurance - moving parts, pressure, and batteries, UL 1740, EN 60204-1 and NFPA 79 and function - safety devices and abnormal conditions.

To ensure that the cobot will be able to function properly, it must be tested to verify safe functioning in the intended environment. Temperature, altitude, humidity, and electromagnetic compatibility (EMC) can affect cobots.

Functional Safety

Whether the technology relies on already approved off-the-shelf parts or custom technology, a functional safety evaluation must be performed. Terms such as “safety rated”, “fail safe” or “functional safety analysis” are applied to a control system meant to protect employees or other cobot operators. These control systems can include safety rated stop and protective stops, slow speed functions, limited force functions, person detection, etc. A custom safety controller can be complex, so it is imperative that a qualified 3rd-party performs the functional safety evaluation.

Cybersecurity

Technological advances including sensors, smart technologies, and cameras facilitate cobot connectivity to the Industrial Internet of Things (IIoT), enterprise resource planning (ERP) systems, and warehouse management systems. Networked control systems are used to monitor and manage efficiency, automation, and maintenance of cobots. This connectivity (often through corporate network or even the internet) poses a cybersecurity concern.

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