Modeling the Contact Force in Constrained Human–Robot Collisions
Collaborative robots (cobots) become more and more important in industrial manufacturing as flexible companions, working side by side with humans without safety fences. A key challenge of such workplaces is to guarantee the safety of the human co-workers. The safeguarding Power and Force Limiting, a...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-10-01
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| Series: | Machines |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-1702/11/10/955 |
| _version_ | 1827720581777195008 |
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| author | Sebastian Herbster Roland Behrens Norbert Elkmann |
| author_facet | Sebastian Herbster Roland Behrens Norbert Elkmann |
| author_sort | Sebastian Herbster |
| collection | DOAJ |
| description | Collaborative robots (cobots) become more and more important in industrial manufacturing as flexible companions, working side by side with humans without safety fences. A key challenge of such workplaces is to guarantee the safety of the human co-workers. The safeguarding Power and Force Limiting, as specified by ISO 10218-2 and ISO/TS 15066, has the objective to protect humans against robot collisions by preventing the robot from exceeding biomechanical limits. Unintended contact such as collisions can occur under unconstrained spatial conditions (a human body part can move freely) or constrained spatial conditions (a human body part is pinched). In particular, collisions under constrained conditions involve a high risk of injury and thus require the robot to stop immediately after detecting the collision. The robot’s speed has a significant influence on its stopping behavior, though, and thus on the maximum collision forces that the robot can exert on the human body. Consequently, a safe velocity is required that avoids the robot from exerting forces and pressures beyond the biomechanical limits. Today, such velocities can only be ascertained in costly robot experiments. In this article, we describe a model that enables us to determine the contact forces of a cobot as they occur in constrained collisions. Through simulations, it becomes possible to iteratively determine the maximum safe velocity for a specific contact hazard that occurs under constrained spatial conditions. Experimental tests with different cobots confirm the results of our model, albeit not for all robots. Despite the mixed test results, we strongly believe that our model can significantly improve the reliability of assumptions made today during the planning of cobots. |
| first_indexed | 2024-03-10T21:06:32Z |
| format | Article |
| id | doaj.art-0bf7763d71f1441d8285bd9962d71bd1 |
| institution | Directory Open Access Journal |
| issn | 2075-1702 |
| language | English |
| last_indexed | 2024-03-10T21:06:32Z |
| publishDate | 2023-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Machines |
| spelling | doaj.art-0bf7763d71f1441d8285bd9962d71bd12023-11-19T17:08:35ZengMDPI AGMachines2075-17022023-10-01111095510.3390/machines11100955Modeling the Contact Force in Constrained Human–Robot CollisionsSebastian Herbster0Roland Behrens1Norbert Elkmann2Robotic Systems, Fraunhofer IFF, Sandtorstr. 22, 39106 Magdeburg, GermanyRobotic Systems, Fraunhofer IFF, Sandtorstr. 22, 39106 Magdeburg, GermanyRobotic Systems, Fraunhofer IFF, Sandtorstr. 22, 39106 Magdeburg, GermanyCollaborative robots (cobots) become more and more important in industrial manufacturing as flexible companions, working side by side with humans without safety fences. A key challenge of such workplaces is to guarantee the safety of the human co-workers. The safeguarding Power and Force Limiting, as specified by ISO 10218-2 and ISO/TS 15066, has the objective to protect humans against robot collisions by preventing the robot from exceeding biomechanical limits. Unintended contact such as collisions can occur under unconstrained spatial conditions (a human body part can move freely) or constrained spatial conditions (a human body part is pinched). In particular, collisions under constrained conditions involve a high risk of injury and thus require the robot to stop immediately after detecting the collision. The robot’s speed has a significant influence on its stopping behavior, though, and thus on the maximum collision forces that the robot can exert on the human body. Consequently, a safe velocity is required that avoids the robot from exerting forces and pressures beyond the biomechanical limits. Today, such velocities can only be ascertained in costly robot experiments. In this article, we describe a model that enables us to determine the contact forces of a cobot as they occur in constrained collisions. Through simulations, it becomes possible to iteratively determine the maximum safe velocity for a specific contact hazard that occurs under constrained spatial conditions. Experimental tests with different cobots confirm the results of our model, albeit not for all robots. Despite the mixed test results, we strongly believe that our model can significantly improve the reliability of assumptions made today during the planning of cobots.https://www.mdpi.com/2075-1702/11/10/955human–robot collaborationrobot safetyphysical contactpinchingrobot modeling |
| spellingShingle | Sebastian Herbster Roland Behrens Norbert Elkmann Modeling the Contact Force in Constrained Human–Robot Collisions Machines human–robot collaboration robot safety physical contact pinching robot modeling |
| title | Modeling the Contact Force in Constrained Human–Robot Collisions |
| title_full | Modeling the Contact Force in Constrained Human–Robot Collisions |
| title_fullStr | Modeling the Contact Force in Constrained Human–Robot Collisions |
| title_full_unstemmed | Modeling the Contact Force in Constrained Human–Robot Collisions |
| title_short | Modeling the Contact Force in Constrained Human–Robot Collisions |
| title_sort | modeling the contact force in constrained human robot collisions |
| topic | human–robot collaboration robot safety physical contact pinching robot modeling |
| url | https://www.mdpi.com/2075-1702/11/10/955 |
| work_keys_str_mv | AT sebastianherbster modelingthecontactforceinconstrainedhumanrobotcollisions AT rolandbehrens modelingthecontactforceinconstrainedhumanrobotcollisions AT norbertelkmann modelingthecontactforceinconstrainedhumanrobotcollisions |