Safety design and development of human-robot collaboration in cellular manufacturing

Abstract

The key challenge of this work is to research the safety design and development of a close range active human-robot collaboration system in which no governing safety standards and regulations are currently present. Active robot assistance in a human-centered cellular manufacturing system is very promising proposal, however safety is the uppermost consideration before this idea can be materialized. In this development, five main safety designs in both hardware and control levels have been proposed and discussed in this work. In the prototype system development, human area and robot area are setup as safe working areas but border crossing is allowed and monitored for safety. At the close region of collaboration, three safety robot working zones are defined by light curtains to control the behavior of the robot based on the collaboration requirements. The assisting mobile robot manipulators system is designed with additional safety control strategies in term of robot gripper speed and travel area to minimize the collaboration risks. Vision system by IP cameras is developed to monitor the human operator safety conditions by measuring the body posture and position. The overall control system is developed to coordinate the collaboration flow between the human operator and mobile robot manipulators system to ensure the safety of the assembly operation. Risk assessments are conducted to make evaluations before and after implementation of safety design into the prototype system. Various safety improvements are observed and discussed. It has proven that the safety designs can reduce the potential collaboration risks in the system.