Just as is the case with autonomous vehicles, where there are “levels†of autonomy (from Level 0 where you drive to Level 4 where you can safely shave, apply makeup or otherwise let the vehicle do the driving), there are levels of collaboration between robots and humans.
Nachi Robotic Systems (nachirobotics.com) has developed four collaborative modes for their robots that meet the safety requirements of ISO 10218-1.  The first level is “Safety-Rated Monitored Stop.† Here a robot can be stopped in a safe position and the operator can step in and load, unload or perform other tasks without the need for the robot motor power to be shut down.  This is a time save, given that the conventional restart procedures aren’t necessary.
Then there is “Direct Teach.† This is what it sounds like: the operator can program the robot by moving the robot without the need for a teach pendant.  Rather, there is a joystick that allows the user to move the robot to points in space as required.  This means that programming time can be sped up compared to the norm.
The third mode is “Speed and Separation Monitoring.† There are safety-rated sensors used to detect human presence within the robot’s space.  The robot operates at full speed when the human is in the “green†zone; reduced speed in the “yellow†zone; and at a full stop when the human moves into theÂ
“red†zone.
Finally, stage four, or what’s often thought as a “collaborative robot.† Here, motor power and force are limited so that a human worker can work side-by-side with the robot.  In the event that the robot contacts the worker, then it simply stops before injury occurs.  Â
