Reading 6.3: Control, regulation and cybernetics
The problem of controlling the steam engines of the industrial revolution brought into being the first machines that were controllers. Prior to that humans had always performed the function of control – the helmsman of the ship maintaining its course, the householder regulating the amount of material for the fire maintaining the warmth of the house, the owner regulating his factory, the magistrate regulating behaviour. The science of cybernetics arose from the Second World War where the problem of shooting down a fast moving aeroplane proved too difficult for the majority of gunners. Just as in the case of the steam engines, the task was beyond humans. Because human reaction times were too slow, a machine-based solution was required. The science of cybernetics arose from these beginnings, but it was soon realised that these regulation and control problems were common to different disciplines – engineering, business and management, medicine, psychology, psychiatry and, last but not least, the natural environment and ecology.
Whilst most of us are familiar with the idea of cybernetics connected with machines and robotics, the originators of the science of cybernetics did not think of it like this – they defined cybernetics as ‘the science of control and communication in the animal and machine’ (Wiener, 1948).
Any system will have some characteristic that you seek to control, usually some indicator will describe a characteristic, and there will be some desired value for the characteristic which you seek to achieve. In many cases this will be an output of the system. In order to perceive whether the characteristic or goal is or is not achieved you must have a means of sensing this, so the first essential component of a control system, is a means of sensing where you are. The signal from the sensors must be fed to some means of comparing where you are to where you want to be, the goal you wish to achieve, so the second essential component is a comparator. The comparator makes the comparison and must produce as a result a signal to a means of making an adjustment, an actuator. The actuator then is a means of effecting a change in the system to move it towards the desired goal. These three subsystems then are the essential components of a control system, together with some outside means of knowing what the ultimate goal might be (see Figure 6.2).
Applying this to an animal managing its environment, you can see that the essential features are present. Figure 6.3 illustrates in simple form the animal managing its environment.
The situation is of course much more complex than I am able to illustrate, but here I envisage the eye acting as a sensor, the brain acting as comparator, with a goal either built in by genetic structure, or as a result of prior experience, and the legs acting as actuators to change the environment.