Fast and Safe Trajectory Planning: Solving the Cobot Performance/Safety Trade-Off in Human-Robot Shared Environments

Palleschi, Alessandro; Hamad, Mazin; Abdolshah, Saeed; Garabini, Manolo; Haddadin, Sami; Pallottino, Lucia

doi:10.1109/lra.2021.3076968

Cited by 43 publications

(15 citation statements)

References 21 publications

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“…Alternatively, control barrier functions are considered in [23] to ensure safety without unnecessarily limiting the manipulator speed. In [24], the authors introduce a scheme for solving the performance/safety trade-off in collaborative workspace, which accounts for safety of a predefined set of points of interests on the robot based on the interaction/collision model of [25]. More recently, in [26], an integrated mixed-reality system for safety-aware humanrobot collaboration based on a deep learning approach and on the generation of a digital twin is adopted to compute the minimum safety distance in real time.…”

Section: Introductionmentioning

confidence: 99%

Enhancing fluency and productivity in human-robot collaboration through online scaling of dynamic safety zones

Scalera

Giusti

Vidoni

et al. 2022

Int J Adv Manuf Technol

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Industrial collaborative robotics is promising for manufacturing activities where the presence of a robot alongside a human operator can improve operator’s working conditions, flexibility, and productivity. A collaborative robotic application has to guarantee not only safety of the human operator, but also fluency in the collaboration, as well as performance in terms of productivity and task time. In this paper, we present an approach to enhance fluency and productivity in human-robot collaboration through online scaling of dynamic safety zones. A supervisory controller runs online safety checks between bounding volumes enclosing robot and human to identify possible collision dangers. To optimize the sizes of safety zones enclosing the manipulator, the method minimizes the time of potential stop trajectories considering the robot dynamics and its torque constraints, and leverages the directed speed of the robot parts with respect to the human. Simulations and experimental tests on a seven-degree-of-freedom robotic arm verify the effectiveness of the proposed approach, and collaborative fluency metrics show the benefits of the method with respect to existing approaches.

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Section: Introductionmentioning

confidence: 99%

Enhancing fluency and productivity in human-robot collaboration through online scaling of dynamic safety zones

Scalera

Giusti

Vidoni

et al. 2022

Int J Adv Manuf Technol

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“…In literature, minimum time path parametrization approaches have been proposed in [9,[31][32][33][34]. In particular, the method developed in [32] has been implemented in [35] with the constraints of the ISO 15066. With respect to the literature, the proposed approach shows three main differences and novelties:…”

Section: Introductionmentioning

confidence: 99%

“…With respect to [9,[31][32][33][34][35] we present a simpler formulation that defines a two-parameter ad hoc set of smooth parametrizations. Such a set does not have a fixed end-point along the path as a constraint, allowing us to compute the required point of the curve where the motion stops.…”

mentioning

confidence: 99%

Online Computation of Time-Optimization-Based, Smooth and Path-Consistent Stop Trajectories for Robots

Rojas

Giusti²,

Vidoni³

2022

Robotics

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Enforcing the cessation of motion is a common action in robotic systems to avoid the damage that the robot can exert on itself, its environment or, in shared environments, people. This procedure raises two main concerns, which are addressed in this paper. On the one hand, the stopping procedure should respect the collision free path computed by the motion planner. On the other hand, a sudden stop may produce large current peaks and challenge the limits of the motor’s control capabilities, as well as degrading the mechanical performance of the system, i.e., increased wear. To address these concerns, we propose a novel method to enforce a mechanically feasible, smooth and path-consistent stop of the robot based on a time-minimization algorithm. We present a numerical implementation of the method, as well as a numerical study of its complexity and convergence. Finally, an experimental comparison with an off-the-shelf stopping scheme is presented, showing the effectiveness of the proposed method.

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“…They were able to proof in user studies that the participants could finish their task more efficiently compared to the original baseline. A trajectory planning approach was taken by Palleschi et al in [14]. Using a visual perception system to gather position data of the operator, they also used an interaction/collision model from Haddadin et al [15] to permanently check the safety situation according to the ISO/TS 15066 standard.…”

Section: Introductionmentioning

confidence: 99%

Human–Machine Differentiation in Speed and Separation Monitoring for Improved Efficiency in Human–Robot Collaboration

Himmelsbach

Wendt

Hangst

et al. 2021

Sensors

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Human–robot collaborative applications have been receiving increasing attention in industrial applications. The efficiency of the applications is often quite low compared to traditional robotic applications without human interaction. Especially for applications that use speed and separation monitoring, there is potential to increase the efficiency with a cost-effective and easy to implement method. In this paper, we proposed to add human–machine differentiation to the speed and separation monitoring in human–robot collaborative applications. The formula for the protective separation distance was extended with a variable for the kind of object that approaches the robot. Different sensors for differentiation of human and non-human objects are presented. Thermal cameras are used to take measurements in a proof of concept. Through differentiation of human and non-human objects, it is possible to decrease the protective separation distance between the robot and the object and therefore increase the overall efficiency of the collaborative application.

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Fast and Safe Trajectory Planning: Solving the Cobot Performance/Safety Trade-Off in Human-Robot Shared Environments

Cited by 43 publications

References 21 publications

Enhancing fluency and productivity in human-robot collaboration through online scaling of dynamic safety zones

Enhancing fluency and productivity in human-robot collaboration through online scaling of dynamic safety zones

Online Computation of Time-Optimization-Based, Smooth and Path-Consistent Stop Trajectories for Robots

Human–Machine Differentiation in Speed and Separation Monitoring for Improved Efficiency in Human–Robot Collaboration

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