Observation and control
In the 20th century, the great period of the technology and control of motion, starting from Newton’s laws of motion Kalman’s systems theory approach has been developed: the theoretical and practical calculation method of controllability combined from the observations about system changes and the preliminary knowledge about system processes.
It is a precondition for observability that we must be able to examine the behaviour of the system going backwards, that is to be able to deduce the basic state from the current state. This experience is important because it serves as a basis for predicting the future behaviour of the system and for designing control in a way that it is partly built on previous relations and partly to detect the changes expected to occur in the next control phase. The condition of controllability means that the system must be able to reach the target state that is to go through all interim states. (The conditions of controllability and observability were discussed on page 51 where continuous processes were described using state variables.)
The Kalman filter, which is based on the observation and control of states, made its major debut in controlling flying objects, measuring, estimating and controlling their states throughout the entire trajectory from the starting point to the destination, while filtering out all disturbances. Today, nearly all complex systems use these conditions, as target tracking is a basic concept in the operation of all systems; even the position tracking of our cell phones works this way.