Trend of increasing controllability

Trend of increasing controllability is a trend of engineering system evolution according to which as engineering system evolves, it develops more ways in which it can be controlled.

Overview

Alongside the trend of uneven development of system components, the trend of increasing controllability serves as a mechanism of the trend of increasing coordination.

The term control refers to actions aimed at adjusting the values of system parameters to align them with the changing parameters of the supersystem and the surrounding environment.

Mechanisms of the trend of of increasing controllability

A sub-trend of the trend of increasing controllability is the trend of increasing dynamization. Additionally, the trend has two mechanisms of its own which state that as a system evolves:

The level of control within the engineering system increases

According to this mechanism, systems follow the path outlined below as they develop:

At first, the system is uncontrolled, meaning it lacks its own control block (e.g., office lighting that is manually switched on and off by staff). Once a control block is introduced, the system begins to control itself – initially through a fixed program (e.g., a lighting system with a built-in timer that turns lights on and off at set times). A more advanced system allows intervention to the fixed program (e.g., switching to a weekend mode or adjusting on/off times based on day length). The next stage is externally controlled system (e.g., a building manager monitoring room occupancy and manually switching lights based on presence).

Eventually, the system reaches full self-control – for instance, motion or presence sensors detect whether people are in the office, and the system automatically adjusts lighting accordingly. Here, it is possible to distinguish between macro-level control and micro-level control.

An example of macro-level control is a system equipped with special sensors that detect environmental parameters and adjust lighting accordingly (e.g., turning lights on or off based on the human presence or daylight levels).

In micro-level control, there are no separate components for detecting external conditions. Instead, the system uses specific materials or physical phenomena to respond directly to changes, without the need for prior detection. A good example is a check valve, which operates purely based on the force of the flowing medium acting on a movable part inside the valve. The valve opens and closes automatically, without the use of sensors, electronics, or external signals – just as long as there is appropriate flow and pressure of the working fluid.

The number of controllable states increases

This sub-trend states that as a system evolves, the number of controllable states increases in the following way:

An example is sound parameter control in systems designed for audio playback. Early phonographs had only one fixed volume level (single state), as there was no way to adjust it during playback. Over time,step switches were introduced that allowed users to choose from a few discrete volume levels. The next stage brought smooth volume adjustment, offering a wide range of infinitely variable states. Modern devices now feature digital potentiometers, enabling precise control not only of volume but also of tone, channel balance, and equalization – significantly increasing the number of controllable states (multiple ranges).