Layered robotic system safety with lessons learned from automatic pedestrian doors

Early approaches to robotic system safety employed mechanical barriers to physically isolate robotic systems from their human operators. Modern collaborative applications for robotic systems, however, are driving the replacement of these physical barriers with other approaches to robotic system safety. This paper begins with a brief discussion of the elements comprising a robotic system and an admission that the robotics engineer can no longer rely on the ever-increasing density of microprocessors to solve problems through sheer computing power. The paper then discusses an automatic pedestrian door example system. Though perhaps not immediately obvious, automatic pedestrian doors are examples of robotic systems. People and automatic doors have been operating in the same workspace for decades and there are lessons to be learned from this experience. One of them being that even single-axis collaborative robotic systems present complex safety challenges. Systems with multiple robots and tens, if not hundreds, of axes will be exponentially more complex. Finally, the paper overviews a layered approach to collaborative robotic system safety. This approach is rich enough to the address the complexity of the problem domain, yet still computationally manageable by distributing the computing load across multiple layers.