Human Error Recovery for a Human/Robot Parts Conveyance System

The study wncems a human e m r recovery function for efficient human/robot collaborative parts conveyance tasks, which has not been discussed so far in construction of human/robot coe&atence sys-infewnce updater which allows a robot to judge whether the goal intended to reach by the opemtor is w m c t or not, from incomplete trajectory data sequence of the robot endtip maneuvered by the op-emtor. Experimental results showed that Q use of the proposed inference updater reduced the task execution time even when human e m r occumd in a task, which demonstrate the usefilness of the up-dater. t e m. W e propose a human operational intention EQT assemble lint ~ Figure 1: IhStratiOn Of Skill-Assist for parts aS-' sembly tasks 1 Introduction We have developed human coexistence robots called " Skill-Assist " [l] which assist human workers in reflecting their skills, and introduced them to practical assembly lines. Figure 1 illustrates a simplified image of the Skill-Assist which has almost the same industrial mission as Cobots do [2], but an additional positioning mechanism and a control structure are installed. In such human/robot coexistence systems, it is inevitable to maintain the system reliability for securing the safety of human operators and avoiding a lowering of task efficiency. Redundant mecha nisms of enhancing the reliability of robots have been proposed in various aspects. A survey paper [3] introduces many redundant mechanisms on fault detection and tolerance schemes mainly focused on low-level robot controllers. Some other recent studies of interest include such proposals as: (a) a fault tolerant joint structure with redundant allocation of dual actuators for each joint of the space shuttle remote manipulator [4]. (b) failuretolerant inverse kinematics schemes proposed for kinematically redundant robots experiencing locked joint failures [5]. (.)an approach to using commercial-off-the-shelf products for designing a fault-tolerant bus architecture comprised of two different types of busses [6]. (d)construction of fully redundant (dual) signal process sequences under functional safety, starting from joint angle and endtip force sensors to the computation of dynamics and torque output for impedance control of a robot [7]. In the case of developing human/robot coexistence systems, however, we should not only pay our attention to the reliability of robot operation but also discuss the reliability on a human opera-2004