Safety-optimizing method of human-care robot design and control

Safe planning for human-robot interaction

“…17 Several authors consider an a priori evaluation of the workspace to determine motion parameters within the various zones of the workspace. 9, 13 Nokata et al 18 use a danger index based on the distance and velocity between the human and the manipulator end effector to plan a safe path for a planar manipulator. Chen and Zalzala 19 use the distance between the robot and any obstacles as a measure of ''safeness'' in the cost function for path planning for mobile manipulators.…”

“…Planning is thus used to improve the control outcome, similar to using smooth trajectory design to improve tracking. 21,22 Herein, a similar approach to Nokata et al 18 is considered. However, in order to address safety in unstructured environments, the whole arm configuration of the manipulator, rather than only the end-effector state, is considered in the planning stage.…”

“…14,18 In this work, an index similar to the danger index of Nokata et al 14,18 is proposed, and applied to configuration space planning of the robot motion. By selecting safer configurations at the planning stage, potential hazards can be avoided, and the computation load for hazard response during real time control can be reduced; cf.…”

“…These can include the relative distance between the robot and the human, the robot stiffness, the robot inertia, end effector movement between contiguous configurations, or some combination of these measures, similar to those proposed by Ikuta and Nokata. 14 Nokata et al 18 use the danger index to find an optimum safe path, however, only the end effector point trajectory with respect to the human is considered. Herein, a safe path for the entire robot structure is planned, explicitly planning the robot posture.…”

Online Hazard Analysis for Autonomous Robots

“…In addition to these, a number of safety standards for robotics have been developed; most notably ISO 10218-1 [12] and ANSI /RIA R15.06 [2]. As discussed by Nokata et al [21] and Desantis et al [5], the methods currently employed by robotic designers are not appropriate for designing safe robots operating in unstructured environments. This is due to the high complexity associated with a system that must adapt to changes in its environment and perform actions which cannot always be anticipated during development.…”