Novel collision detection index based on joint torque sensors for a redundant manipulator

Lee, Sang-Duck; Kim, Young-Loul; Song, Jae-Bok

doi:10.1109/iros.2013.6697023

Cited by 5 publications

(1 citation statement)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The PFL mode ensures that the cobot does not exceed the biomechanical limit values listed in ISO/TS 15066 when being in physical contact with humas [5]. This ability is typically realized by safety-rated functions that monitor the force and/or torque [6,7], paired with functions that limit the maximum speed [8,9]. The force and/or torque monitoring function is intended to detect collisions and to stop the robot immediately.…”

Section: Introductionmentioning

confidence: 99%

Modeling the Contact Force in Constrained Human–Robot Collisions

Herbster,

Behrens,

Elkmann

2023

Machines

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

Modeling the Contact Force in Constrained Human–Robot Collisions

Herbster,

Behrens,

Elkmann

2023

Machines

View full text Add to dashboard Cite

show abstract

Collision detection for safe human-robot cooperation of a redundant manipulator

Lee

Song

2014

2014 14th International Conference on Control, Automation and Systems (ICCAS 2014)

View full text Add to dashboard Cite

Human-robot cooperation have a potential risk of collision between a human and a robot, and collision detection is one of the most practical solutions to ensure human safety during this cooperation. However, collisions during human-robot cooperation cannot be reliably detected using conventional collision detection methods because collision forces and intended interaction forces cannot be distinguished from each other. In this study, we propose a collision detection method that can be used to distinguish collisions from intended task force at the end-effector. To this end, we developed a collision detection index that is decoupled from the intended external force applied for human-robot cooperation. The proposed method was verified through several experiments, and experimental results show that collisions can be detected regardless of the presence of physical contact between humans and robots for cooperati on.

show abstract