[Question] Why does "action" exist?

[ipc-robot]

I am a beginner and I am very confused about it. What I can understand is that during my entire operation, I sampled at fixed time intervals. It's like a signal being collected by a letter. I only have to observe and what does action mean? Many data sets in the project have data with the column title action. Moreover, according to the expression of the project, action means the goal of the movement. However, this goal never seems to match the results in the observation. It looks like the robot never moves to its target. I was completely confused.