Researchers are developing robots to operate offshore oil platforms. A lot of things have to be thought out carefully when human actions are replaced by robot movements. Sensors are one aspect of this. Another is the matter of operations that involve contact, such as when a robot has to pick up something from the floor. Contact operations are a particular challenge, because the robot is very strong and it can easily destroy the equipment with which it comes into contact, unless we keep its strength fully under control. The robot is similar to a computer, in that it does exactly what it is told. Unlike a human being, it will not stop moving by itself or move aside if it collides with something else.