An Energy-based Approach for the Integration of Collaborative Redundant Robots in Restricted Work Environments

To this day, most robots are installed behind safety fences, separated from the human. New use-case scenarios demand for collaborative robots, e.g. to assist the human with physically challenging tasks. These robots are mainly installed in work-environments with limited space, e.g. existing production lines. This brings certain challenges for the control of such robots. The presented work addresses a few of these challenges, namely: stable and safe behaviour in contact scenarios; avoidance of restricted workspace areas; prevention of joint limits in automatic mode and manual guidance. The control approach in this paper extents an Energy-aware Impedance controller by repulsive potential fields in order to comply with Cartesian and joint constraints. The presented controller was verified for a KUKA LBR iiwa 7 R800 in simulation as well as on the real robot.