A computationally efficient safety assessment for collaborative robotics applications. (August 2017)

• Record Type: Journal Article
• Authors: Parigi Polverini, Matteo; Zanchettin, Andrea Maria; Rocco, Paolo
• Is Part Of: Robotics and computer-integrated manufacturing. Volume 46(2017)
• Page Start: 25
• Page End: 37
• Publication Date: 2017-08
• Subjects: Kinetostatic safety field -- Safety assessment -- Motion control -- Physical human–robot interaction -- Redundant robots; Robots, Industrial -- Periodicals; Computer integrated manufacturing systems -- Periodicals; Robotics -- Periodicals; Robots industriels -- Périodiques; Productique -- Périodiques; Robotique -- Périodiques; 670.285
• DOI: 10.1016/j.rcim.2016.11.002
• Languages: English
• ISSNs: 0736-5845

Abstract

Abstract: Safety during interaction with unstructured and dynamic environments is now a well established requirement for complex robotic systems. A wide variety of approaches focus on the introduction of safety evaluation methods in order to shape a consequent safety-oriented control strategy, able to reactively prevent collisions between the robot and potential obstacles, including a human being. This paper presents a new safety assessment, named kinetostatic safety field, that captures the risk in the vicinity of an arbitrary rigid body "source of danger" (e.g. an obstacle, a human body part or a robot link) moving in R 3 . The safety field depends on the position and velocity of the body but it is also influenced by its real shape and size, exploiting its triangular mesh. The introduction of a body-fixed reference frame in the definition of the field provides closed form computability and an effective computation time reduction, that allows for real-time applications. In particular, intensive computations, connected to the specific body geometry, can be performed only once and off-line, ensuring a fast and constant on-line computation time, independently of the number of mesh elements. Furthermore, we combine the safety field concept with a safety-oriented reactive control strategy for redundant manipulators. Our approach allows to enhance safety in several real-time collision avoidance scenarios, including collision avoidance with potential obstacles, self-collision avoidance and safe human–robot coexistence. The proposed control strategy is validated through experiments performed on an ABB FRIDA dual arm robot. Abstract : Highlights: A new safety assessment, named kinetostatic safety field, for robots in interaction with humans and the environment is proposed. The safety field is easily and efficiently computable for a moving rigid body, represented by a triangular mesh with arbitrary number of mesh elements, thus allowing for real-time applications. The safety field concept is combined with a safety oriented control strategy for redundant robots, experimentally validated on an ABB FRIDA dual arm robot.