Smart Machines & Factories spoke to Roberta Nelson Shea, Universal Robots’ chief technical compliance officer, who gives insights into the challenges and importance of compliance in a robotic company.
Compared to traditional industrial sectors, robotics is a relatively young field. Robotics has only been used in a workplace environment for the last 40 years. Furthermore, technology in this field is yet advancing incredibly fast and thus, compliance needs to be adaptable to keep pace with these rapid changes. Another challenge is how to convey the myriad facets of compliance comprehensibly to end customers and integrators to clear up issues such as: When is a robot system really compliant? And what are the requirements to which the robot and robot system have to comply?
The first thing, which has to be clarified for the topic of compliance, is always in what industry and for which purpose will this robot system be used. Compliance requirements differ from application to application, e.g EMC thresholds, temperature, indoors / outdoors, performance or accuracy and work environment. The robot is the arm or manipulator with its controller, while the robot system is the robot plus the end-effector for the intended application or use. For other work environments, e.g electronics, pharma-production or foods, there could be additional requirements, such as cleanroom use or wash-down.
Depending on the application and industry, there are very different expectations. This is also true for compliance in a safety context, especially when it comes to human-robot-collaboration without additional safeguards (“cage-free”).
Challenges for compliance in robotics
Roberta Nelson Shea, Universal Robots’ chief technical compliance officer, explained that Universal Robots robot arms are mountable in many different ways, e.g. to a wall, upside-down or on top of a table or mobile platform, and can be equipped with various end-effectors, the manufacturer faces further challenges: Will the robot system remain compliant for collaborative and cage-free use after the addition of end-effector and parts?
Roberta Nelson Shea says: “First, some questions need to be answered. The parameters needed – payload, reach, performance, etc. – have to be clarified for both, the robot and the additions which make a robotic system. From a compliance point of view, many different additional factors exist when a cage-free collaborative application is desired. All of these need to be taken into account. At Universal Robots, we tackle this challenge in two ways: First, we only guarantee compliance of our ‘partial machine’ – i.e. the robot arm – to enable its use in collaborative applications. Second, we emphasize to our distributors and to the end customers that a risk assessment is required to make the robot application (robot + addition) compliant, e.g. to safety standards and technical specifications such as ISO/TS 15066.”
Furthermore, manufacturers need to be precise in their communication with their customers and partners. Robot manufacturers can only guarantee the compliance of their product to their specifications and approvals. These can be that the robot is accurate to the tenth of a millimetre or that the robot arm complies to be used in accordance with ISO/TS 15066 including Annex A. This Annex A covers a range of force and pain threshold values, which a collaborative robot system can be used without guards and protective devices. Nelson Shea explains: “As a manufacturer, we do our utmost to inform our distributors and end-customers about the intended use as comprehensively as possible. However, our robots are being used in many different sectors that we cannot cover all the applications, our partners and end customers might come up with. Nevertheless, we are pleasantly surprised with all the imaginative applications developed by our customers so far and will come up with in the future.”
Who is responsible to test for compliance?
Manufacturers worldwide do their utmost to ensure compliance of their products to the intended use and to as many use cases as they can envision, if reasonable. However, just as robotic technology is ever advancing, so is the ingenuity of integrators and end users. Therefore, as inventive integrators will uncover unprecedented ways to use and develop robot applications, they have to ensure that the complete application complies with applicable requirements. For cage-free collaborative applications, these requirements depend on the robot’s work environment, force values, shape and weight of the end-effector and part and the maximum permissive speed of the robot to remain within selected pressure and force values.
There is no unified means to test whether an application meets the free-space values and many have come up with their own testing methods. This results in different forces being measured. Thus, differences can arise in determining the appropriate limits which each robot should be configured so that the application complies in order to be deemed cage-free collaborative applications. Nelson Shea concludes: “Therefore, compliance managers need a common and comprehensively accepted tool to measure and simulate the quasi-static and transient contact values for a given application speed. These are some of the next challenges for standardisation to aid in the compliance collaborative and “cage-free” robotics technology.”
For further information please visit: www.universal-robots.com