The image on the left shows a well working robot in action. It can be realized within a robot challenge. The rules for the challenge are known and it's possible for a programmer team to program a robot which is working inside the specification. Notable examples are soccer playing robots, self-driving cars, delivery drones and even biped robots. On the first look the programmer in the challenge have solved the issue, because the demonstrated behaviors shows, that the robot is capable of doing a task autonomously, that means without human intervention.
The problems will become visible if the task is not encapsulated in a synthetic challenge but should be solved in a real world application. A typical example is a self-driving car which travels on the road or a pick&place robot used at the assembly. Usually a human operator is needed who observes the robot during operation. The interesting point is, that even the robot has succeed in the synthetic challenge he will fail in the real world applications. That means, the human operator of a pick&place robot is under heavy stress while the robot is doing a pick&place task.
In the right picture the desired situation is shown in which a robot masters a task without a human operator. Not a single case is known in which a robot is capable of doing so. It's not possible to remove the human operator from the loop, because then the task is not longer fulfilled. Surprisingly this is true for all robotics domain like self-driving transport vehicles, pick&place robots and household robots. The technology works only if nobody cares. If it's a real world situation without a human operator in the loop, the robot isn't able to handle the task by it's own. The problem is not located within the robot's programing but it has to do with tasks which are highly complicated. A robot is only needed for task which are done in the past by humans. The idea is to transfer work from a human operator to a robot. A robot won't be confronted with repetive easy to solve tasks, because these problems can be automated with classical techniques like CNC machines. Only task which are harder to automate are transfered to robots.
Unfortunately, a robot is not able to handle complicated problems by it's own. It's a human level problem which can only be solved by humans in the loop. It's not possible that a robot supports the human in the task. What robotics engineers are doing is to assume that a task can be easily automated. The best example is a transport vehicle which drives on a straight line. In a challenge the robot is doing a great job, and exactly such a device is needed in a factory for solving a transport problem. The assumption is, that the technology would work in a real world application similar to the demonstration in the robotic challenge. The problem is, that in real world use case the human operator has to move next to the vehicle all the time to ensure that the robot is doing the task the right way. As a result, the human operator won't save time and energy but monitoring the robot is more complicated than doing the job by it's own. That is the reason, why all the factories are not using robots.
Or let me explain the situation from a different perspective. In a synthetic robot challenge for example in Robocup, many human operators are available. A team of specialists is monitoring the robot all the time. In a real world use case, these human operators are not available. And exactly this produces a new kind of situation. The problem is, that a human operator who monitors a robot can't removed from the setup because than it's not guaranteed what the robot is doing. A robot can't decide by it's own if he is working inside the specification.
The only way for ensure a high productivity is to take a human operator out of the loop. This can be realized by separation of humans and robot and with execution monitoring. The idea is, that no human operator is needed which monitors what the robot is doing, but the machine is working autonomously. A monitoring device is a machine which operates independently from the robot. It's main objective is to detect in which case the robot is wrong. Then the device will stop the robot and a human operator is needed. From an abstract perspective a monitoring device defines two different situations. Either the human operator can relax and leave the robot, or the human operator is needed because the robot has made a mistake. Real world application of robotics means, that for a certain amount of time, no human operator is needed. This is equal to increase the productivity.