As per the newspaper report, a person died after he went close to the robot arm of a machine. He went close to adjust a sheet that got dislodged when lifted by the robot arm.
It is normal practice to prohibit entry of personnel in robot working areas, as they do the work as per program.
It may not be practical to put proximity sensors on robot arms to stop robot movement as in that case their work output can be severely limited.
Instead, the entry to work area / reach of robots can be fenced and its entry door opening can be interlocked to stop operation.
http://timesofindia.indiatimes.com/world/europe/Robot-kills-man-at-Volkswagen-plant-in-Germany/articleshow/47904748.cms