Model of operating technical system (useful system)

Technical objects are created to produce a useful product, which is achieved by performing a function. The excavator excavates a pit. The plane, train, ship, and vehicle carries cargo. The pen makes signs on paper. The factory produces planes etc.

In short, it is possible to say that:

The function of a technical object is expressed in an action aimed at changing the state of tangible objects. 

The function can be imagined as interaction of three components – the object being machined, the tool, and the action performed by it. The tool acts upon the object being machined, converts it, and producesthe product – the result of performing the function.

When analysing and designing, it is efficient to consider technical objects in the operation mode and to make models of technical systems demonstrating interaction of components during performance of the necessary action. It is possible to call such a technical system an “operating” one. If we go back to the analogy with the patent law, this model refers us to something like a “machine at work.”

Examples of potentially operational technical systems are the telephone, excavator, pen, computer, chip factory, stick for knocking off apples, screw, satellite navigation system etc.

Examples of functioning technical systems: a person talking on the telephone, a locked lock, a factory producing chips, a flying aircraft, a working computer etc.

The purpose of the system operation is to produce a useful product. To this end, it is created, its operation is supported. Therefore, such a system can be called a useful system.

The useful-system model has an extended set of components. Besides G.S. Altshuller's system “core” (an engine, transmission, tool, control), it includes an energy source and an object being machined. The system operation results in a useful product.

• The “object being machined” is the component which is machined with the tool and converted into a useful product.
• The “tool” directly acts upon the object being machined.
• The “energy source” provides energy for the system operation.
• The “engine” converts energy into the type required for the tool operation.
• The “transmission” is responsible for transferring this energy from the engine to the tool.
• The “control” ensures coordinated operation of all components of the system.

The relations of these components are shown in the figure.

It is important to note that all of the system components listed are not necessarilyseparate technical assemblies and parts. The “engine”, “transmission”, “control” are the roles of the system components, their “functions”. The same component can have two or more roles at the same time, each role is performed by a part of the component in the case. Conversely, several components can have the same role. In other words, when creating a system, it should be taken into consideration that the device can be imagined not only as a set of components but also as a set of functional modules.

System controllability

The system controllability should be mentioned separately.

The controls act upon all the other components of the system adapting its parameters to the operating conditions. Three levels of such adaptation can be discriminated.

The initial adaptation of the system parameters to certain average operating conditions which is carried out at the design and production stages. This adaptation can be static: a vehicle is stable both when standing and moving. An example of dynamic adaptation is a bicycle stable in motion only.

Periodic adaptation which is carried out from time to time during the system operation through compensatory adjustments.

The final adaptation of the system parameters to the changing operating conditions for which it is necessary to provide for the possibility of online control, i.e. a quick and relatively simple change in the system parameters when its operating conditions change.

Example. Pencil as a set of functional modules

The regular pencil includes a graphite bar (pencil lead), a wooden body, and a layer of paint on its surface.  If we intend to create an operating technical system, it would be better to imagine the pencil as several functional modules:

1. The writing part per se: the tip of the pencil lead which leaves a trace on paper.
2. The spacer: the pencil part from the pencil lead to the hand holding the wrist of the writer in the right position.
3. The holding part: the place where the hand and the pencil come into contact.
4. The reserve: the pencil part under the hand which is not directly involved in work but shortens as the pencil lead wears.

As we can see, when the pencil works its modules perform a variety of functions but their composition is almost the same: the pencil lead, the wooden body, and the paint. The useful system for making a trace on paper will be as follows:

Simplest useful system

Technical devices can vary from a factory where thousands of workers assemble a plane of hundreds of thousands of parts to the simplest hand-held tool, e.g. a hammer driving nails.

To work with a problem, it is necessary to concentrate on the issue without studying the machine in full detail. The action happening at the place should be considered, and it should be understood participation of which components ensures completion of the action. These components make up the so-called simplest useful system.

The simplest useful system has only one energy conversion on the path from the energy source to the tool (both the energy type and the energy flow parameters can convert).

The simplest useful system is determined through the product – the result of its action. Knowing that the product is an object converted which is being machined, we find the first system component. The rest of the components are identified through an analysis of their functional roles.

Example. Air brush as the simplest system.

The pneumatic air brush has  a container with compressed air (receiver), pipes, a nozzle. When the operator presses the valve, air leaves the receiver, passes along the pipes, and flows out of the nozzle at a high speed. Paint is fed to the air stream. Air picks up the paint, splits it into microdroplets forming the so-called spray cone.

Useful product: the cone of sprayed paint.

The minimum composition of the system is as follows

“Object being machined”: paint.

“Tool”: air flow in the nozzle.

“Energy source”: compressed air in the receiver.

“Engine”: the place where compressed air is released from the receiver, where its potential energy turns into the kinetic energy of the moving air.

“Transmission”: pipes which transmit the moving air from the receiver to the nozzle.

“Control”: air start valve and the operator.

Constructing the model of the simplest useful system is an important action when solving problems. With this model, we revise the composition and operation of the facility being analysed, we can revise the components involved in the performance of flawed operations of the process and their roles, can determine sets of components during which operation harmful products are produced, and finally the system model helps us get the idea of solving the problem. The importance of understanding how the system model is created for various facilities cannot be overstated, therefore we would provide several other examples.

Example. Model of the useful system for a metal cutter 

The cutter is driven by an electric motor via shafts and reducing gearboxes and cuts a metal layer off a stationary workpiece.

The energy flow is as follows.

Electricity is supplied from the grid, is converted into rotation in the motor, then it is transmitted to the cutter itself, and arrives at the cutting tips machining the part.

The system model per se is as follows:

Example. Model of the useful system for the turning machine

The workpiece being machined turns itself in the turning machine. The cutting tool is fixed relative to the machine body (no lateral motion of the cutting tool is taken into consideration for the sake of clarity).

The facilities are quite similar, they have the same principle of operation: metal cutting with hard-alloy components. However, the system model is more difficult to construct in this case. Indeed, the cutting tool plays the active role but it is fixed. Where does energy come from?

Energy can arrive at the cutting tool from one possible source only – from the rotating part.

What is the engine in this model then?

Energy comes from the rotating part and passes through the cutting tip into the body of the cutting tool. Since the cutting tool and its mount are made of a strong and rigid material, energy dissipates partially and converts into heat but most of it is reflected and returned to the cutting-tip point. A certain energy ring which ensures cutting of the workpiece metal is formed. The model of the useful system is as follows:

Useful systems of any complexity can be constructed of the simplest systems like of bricks.

Example. Vehicle as a set of two simplest systems

A vehicle carrying cargo can be imagined as a set of two simplest useful systems . 

In one of them, the “engine” (the vehicle engine) converts fuel energy into the crankshaft rotation. Further, this rotation is transmitted to the axes (in this system, it is the “tool”) which act upon the wheels making them rotate. The result is the system for turning the wheels. However, the wheels rotation is not enough for the vehicle movement.

For the vehicle to start moving, another energy conversion is required: the wheels rotation moment should be converted into a force moving the vehicle forward along the road. The “engine” in this case is the rotating wheels pressed by the vehicle weight against the road. Energy is transmitted via the vehicle frame to the “tool” – the body. The body keeps the cargo (“object being processed”). This system can already carry cargo.

Before proceeding, one important terminology reservation should be made. The terms “system” and “technical system” are actively used both among engineers and in the TRIZ. At the same time, both constructs of thought and quite tangible objects can be meant. Specifically, when we talk about analysis and modelling, the technical system is a cognitive picture of a real object. If we refer to development of technical systems or to experimental verification of solutions, then the tangible devices are the systems in the case. Besides, the term “technical system” can be confused with the concept of the “engineering system”, i.e. a system which includes components of machines. This is fundamentally wrong because the inventive problem in the general theory of analytical independent thinking (GTAIT)-TRIZ can be stated for any activity. It is, of course, engineering as understood by the engineers as well as problems related to management, promotion, sales etc. Against this background, the technical-system components can includes both parts of machines and teams of workers, cash flows and flows of materials, software components, and other types of components. In this case, we can refer to “social”, “business”, “managerial”, and other systems where certain sets of components performing a “technique” and producing a certain product as a result are considered.

It is inexpedient to introduce new concepts, to disrupt the terminology established, so further on in the text we will simply use the terms “system”, “useful system” or “harmful system” believing that it is a system arranged according given on this page. We hope that the reader will understand depending on the context to which system – engineering, social, business or any other – we refer.