Human-robot collaboration: the five biggest challenges

Modern collaborative robots make it possible to efficiently automate production processes for which, until recently, this was still considered impossible. Thanks to the close collaboration between robot and human, even flexible and complex substeps can be implemented with high productivity. This requires dynamic safety solutions and concepts, however, in order to overcome the challenges relating to protecting the interaction between humans and robotics. Safety is the utmost priority, in particular for direct human-robot collaboration (HRC), i.e. when both are active in the same workspace at the same time. The comprehensive portfolio of sensors from SICK offer innovative and intelligent solutions for this with sensor technologies for Robot Vision, Safe Robotics, End-of-Arm Tooling and Position Feedback. We have identified the five biggest challenges of HRC and present a ground-breaking new safety solution.

Many industry sectors are increasingly facing a dilemma: On the hand there is a shortage of skilled workers, and on the other hand production capacities need to be expanded and the manufacturing quality assured. A full automation with a complete redesign of the process is not always practical and economical, however. A progressive automation of subprocesses does, in some cases, offer a solution to the problem. It involves partially automating manual workstations using collaborative robots, or converting them into hybrid workstations. Thanks to the many advantages of partial automation, the development of human-robot collaboration is gaining further momentum. But as humans and robots work ever more closely together, the requirements on safety change to.

State-of-the-art in human-robot collaboration

Cobots have revolutionized the robot market. The simplicity with which they can be integrated and programmed now generally allows a problem-free implementation of robotics applications. At the same time, cobots are safe. Thanks to the already integrated safety functions, such as safe force and speed monitoring and a collaborative design of the robot arm with no sharp corners or edges, they are ideally suited for close collaboration with humans. What does pose problems, however, is the tool or workpiece area, which in many cases is not automatically protected as well by the protective measures incorporated into the cobot. Not least for this reason, a true, safe, efficient and productive human-robot collaboration has not yet achieved the expected acceptance. In order to operate HRC applications safely, certain pressure limit values must not be exceeded at potential crush points. When the contact surfaces are small, e.g. at tool or workpiece edges, these limit values can – if at all – only be adhered to through drastic limitation of the robot speed. It may also be necessary to use expensive collaborative tools. HRC applications are therefore often neither adequately efficient and safe to implement, nor productive to operate. Many operators shy away from these limitations, make do without the benefits of HRC, and protect the application in the traditional manner, e.g. using enclosures or safety laser scanners.

There is also the issue of acceptance by the operators, i.e. those who work in close collaboration with the robots on a day-to-day basis. All the currently available protective measures only take effect when contact or crushing has already occurred. It is clear that humans would feel uneasy about that and not fully trust the safety application.

Industries are increasingly using collaborative robots to automate efficiently and safely despite labor shortages.

Five challenges of human-robot collaboration

For automaters and system manufacturers and operators, robot-assisted automation of individual work steps is indispensable to remain competitive. We have closely examined the five biggest challenges that arise in relation to this:

1. A robot application should be simple, fast and cost-effective to construct.

To adapt a robot relatively quickly to the manual workstations of today, there is no looking past cobots: They are quickly installed, easy to use after a short induction, and also comparatively cost-effective to buy. A cobot, with its integrated safety functions and inherently safe design, also satisfies the basic prerequisites for a collaborative partnership between human and robot.

2. The collaborative application should be freely accessible without an enclosure.

Operators often need to check individual work steps or the work results and, if necessary, be able to take corrective actions without the work process of the robot being interrupted by the traditional protective devices used to detect the presence of people. That is why only an unrestricted collaboration between human and robot can open up new possibilities for efficient production processes.

Industries face five challenges in human-robot collaboration, including simple and cost-effective robot applications.

3. How does the HRC application achieve the required productivity and efficiency on the one hand, as well as the necessary risk reduction?

To ensure a productive protection of the collaborative application, you need safety measures for the protection of people that focus on the hazardous area of the tool and allow the protective fields to be minimized:

a. Risk assessment and safe engineering

Productivity begins at the engineering phase: To efficiently design and implement the safety concept, the risks associated with the interaction between humans and robots must be identified, evaluated, and reduced in a targeted manner for the specific application.

b. Safety vs availability

Interruption-free, productive operation of the robot in order, on the one hand, to ensure safety in a collaborative application approach and, on the other hand, achieve a level of productivity that makes it economical to operate the robot.

c. Costs of the safety solution

The costs of the safety solution must be in reasonable proportion to the costs of the overall application.

4. How does HRC achieve the desired ergonomics in the workplace and the acceptance of the collaborating humans?

Current protective measures for collaborative applications are based on contact-based technologies. These allow a hand or other body part of the human to be touched or crushed, whereby the forces arising are monitored and, if limit values are exceeded, a stop is triggered. This can lead to potential acceptance problems with the operators. The protective measures should therefore be implemented by contactless means.

5. When is HRC economical?

To be able to operate the robot application economically, it must be efficient and productive in operational use – in conjunction with the necessary risk-reducing measures. The cost-effectiveness already begins before operation: With the selection of suitable and efficient protective measures that ensure the safety of people on the one hand and suit the project budget in regard to purchasing costs as well as validation and commissioning effort on the other.

Industries are increasingly using robots to work continuously and productively while ensuring safety and cost-effectiveness.

Smooth PRC processes using End-of-Arm-Safeguard (EOAS)

SICK has investigated these challenges thoroughly and offers an optimal solution to them with its End-of-Arm-Safeguard (EOAS). The world first EOAS technology, developed jointly with Universal Robots (UR), maintains the balance between productivity and safety for collaborative applications. EOAS is installed directly on the robot flange, creates a cone-shaped protective field around the tool and workpiece, and thereby effectively protects this area. The robot constantly carries the sensor and protective field with it, so the contactless protective device only ever acts where an actual crush risk from the tool and workpiece exists.

Industries are increasingly using robots with End-of-Arm-Safeguard (EOAS) to balance productivity and safety in collaborative applications.

When the protective field of the EOAS is interrupted, the robot immediately stops its movement depending on the situation. As soon as the protective field is clear again, the robot can automatically resume its movement. In contrast to human-robot collaboration applications that are protected based on the force and pressure limiting function of the robot, a robot with EOAS generally achieves higher speeds because these functions can be implemented differently in the tool area when using EOAS.

Contactless protective measure – efficient and economical

End-of-Arm-Safeguard allows the contactless protection of human-robot collaboration applications in the tool area. Due to the small protective field, it makes new enclosure-free and therefore openly accessible HRC applications possible: Humans can work with the cobot at the same time and in the same workspace. Safety is assured, the robot is stopped even before crush situations in the tool/workpiece area arise. Special collaborative grippers, design changes in the vicinity of the tool (rounding of corners/edges, incorporation of protective covers, etc.) or extremely slow crawling speeds of the cobots are usually no longer necessary.

The mandatory validation of the protective measures for HRC applications also becomes significantly easier because the hazardous points that are protected with the EOAS now no longer need to be validated through time-consuming pressure and force measurements. This can lead to significant cost savings. The comparatively small protective field also has the advantage that it doesn't occupy any productive areas, thereby supporting the economical use of the factory hall.

To enhance efficiency and acceptance in human-robot collaboration, industries are increasingly using robots with End-of-Arm-Safeguard (EOAS) for contactless measures.

EOAS creates acceptance and trust

EOAS places a local protective field around the workpiece and the gripper. In contrast to previously used protective measures based purely on force and power limitation, this ensures crushing no longer occurs. The human can therefore move about freely and easily in the immediate vicinity of the active robot and collaborate closely with it. In this way, the EOAS increases the acceptance of the human-robot collaboration, creates trust, and improves the working conditions.

Intuitive configuration and installation as well as fast engineering

With EOAS, a new safety solution is available that allows a targeted risk reduction in HRC applications – without overshooting the mark.

End-of-Arm-Safeguard is installed directly on the robot flange, is embedded fully in the robot safety system of Universal Robots via the special EOAS Safety URCap and can be intuitively and quickly configured using the UR Teach Pendant. A true plug and play system. The EOAS system is currently designed for Universal Robots applications and shall also be available for other systems in future.

EOAS has the potential to be a true gamechanger in the cobot sphere. With its many advantages, it enables the industry to finally implement safe HRC applications not only in niche applications, but also across the board.

Safety systems

Collision protection around the gripper for safe human-robot collaboration

End-of-Arm-Safeguard