Guided Technology Evolution (TRIZ Technology Forecasting)

Victor R. Fey, Eugene I. Rivin
30120 Northgate Lane, Southfield, MI 48076 USA
248-433-3075 ∑ Fax 248-433-1039

1. Introduction

Effective and efficient development of new generations of products and processes is the mighty weapon in the competitive struggle. Presently, there is no structured methodology to perform this extremely important activity and the prevailing approach is the "trial and error," somewhat enhanced by several "soft" technology forecasting techniques.

The Theory of Inventive Problem Solving (TRIZ in its Russian abbreviation) provides a powerful structured methodology for a directed development of new products/processes (Guided Technology Evolution). This paper describes a background and some fundamental notions of this methodology and illustrates them by some examples of product design evolution.

2. Why we need to forecast technology

Technology advancement is a principal impetus in economic development. Foreseeing technological advancements that will shape the future is of immense importance for many industrial, financial, or social enterprises, since they can be deeply influenced by emerging innovations.

Companies capable of undertaking technology forecasting can benefit in numerous ways, such as:

As global competition becomes more fierce, an ability to make precise and comprehensive forecasts of the impending evolution becomes of growing importance for economic well-being of many businesses.

3. Traditional technology forecasting techniques

Various technology forecasting methods [3, 8-10] have been developed over the last few decades. Several of them, such as linear extrapolation, morphological method, Delphi method, interlocking matrix, relevance tree, dynamic simulation model, have found some applications. While being different and generally useful, these techniques share the common philosophy and constraints:

To overcome above constraints, caused mainly by intuitive approach to innovation prediction, and make technology forecasting a practical tool for a long- term business development, a new approach, based upon a systematic logical analysis, has to be introduced.

4. Laws and Lines of Technological Systems Evolution

An analytical approach to technology forecasting has been developed by Genrikh Altshuller and his school within a framework of TRIZ [1, 2, 4-7, 11]. The theoretical foundation of the TRIZ technology forecasting is a set of the Laws or Prevailing Trends of Technological Systems Evolution revealed by analysis of hundreds of thousands of invention descriptions available in the world patent databases. These laws, along with other analytical and solution tools of TRIZ, can be used for a judicious analysis and evaluation of the future designs of the systems of interest.

The Laws of Evolution reflect significant, stable, and repeatable interactions between elements of technological systems and between the systems and their environment in the process of evolution. These Laws are listed below.

The Laws of Technological System evolution serve as "soft equations" describing the systemís "life curve" in the evolution space. If configuration of the current system is given, then configurations on the next stages of development can be reliably "calculated" using the system of these Laws.

The Laws of Evolution are very helpful for technology forecasting since they identify the most effective directions for the systemís development. For example, the Law of Increasing Flexibility states that technological systems evolve from rigid structures into flexible or adaptive ones. An illustration to this Law is evolution of aircraft structures that went from rigid wing designs to variable-geometry wing designs. A Law of Evolution delineates a general direction for further system transformation but says nothing about the details of this transformation.

The latter is addressed by a continuous study and development of the Lines of Technological Systems Evolution. These Lines describe more specifically the stages of the systems development.

This system of Laws and Lines of Evolution is illustrated below on the example of two Laws and the respective Lines of technology evolution.

4.1. Law of Transition to a Higher-Level System

This Law states that technological systems evolve in a general direction from mono-systems to bi- or poly-systems.

Systems usually originate as single objects - mono-systems. An example of a mono-system is a pencil. Mono-systems can be combined to form higher-level systems: bi-systems (i.e., pencil+eraser), or poly-systems (i.e., a set of more than two different pencils).

A higher-level system can be composed from similar or identical subsystems. Combining several mono-systems into such a homogeneous bi- or poly-system can enhance functional performance of each constitutive sub-system and develop a new and useful functional properties.

Transition to bi- and poly-systems (Fig. 1) represents a very important and very powerful trend of evolution. The following are examples of bi-systems which resulted in enhancement of functional properties of the original mono-systems:

These examples are based on combining identical components. In other cases, the component sub-systems can be similar but different in size, color, and/or functional properties. Examples of such systems are:

Such bi- and poly-systems are called shifted bi- and poly-systems.

Effectiveness of bi-systems and poly-systems may increase when their components are more diverse. Some examples of heterogeneous bi-systems comprised of diverse components are a wristwatch with a calculator; key ring with a pen knife; and a pencil with eraser. The latter case represents an important type of inverse bi-systems - a combination of components with opposite properties. An interesting application of combining components with opposite properties into a bi-system is suggested in a project of a "bi-greenhouse." In one section of this greenhouse, plants are growing that extract carbon dioxide from the surrounding air, while emitting oxygen. In the other section, other types of plants are growing, such varieties that extract oxygen from air and emit carbon dioxide. Such a greenhouse does not require an air-exchange system.

Effectiveness of bi- and poly-systems can be enhanced in the process of their convolution. The first steps of this process involve elimination of redundant auxiliary components. This leads to forming a partially convoluted bi- or poly-system. For example, a double-barreled gun has only one butt; and a multi-boiler power station may have less smoke stacks than boilers.

The next step of evolution is a transition to a completely convoluted bi- or poly-system when one system performs two or more functions.

Fig. 1. Lines of evolution "mono-bi-poly"

Example 1

Protective suits for emergency rescue workers in mines have a cooling system and an oxygen-supply system. It was proposed by Genrikh Altshuller to combine these two systems by using liquid oxygen. First, the oxygen is used in the cooling system, and then,

after its temperature increases during the cooling process, it is used for breathing. This combination has resulted in significant weight reduction and allowed for increasing the resource of the system between recharging the life support gear.

4.2 Law of Increasing Flexibility

According to this Law, in the course of evolution, technological systems develop from rigid structures to flexible and adaptive ones.

Line of Increasing Flexibility

Fig. 2

A new technological system developed to solve a specific problem, performs in a specified environment, at specified regimes, etc. Its design reflects, accordingly, the specific needs that this system has to satisfy. It is characterized by rigidly defined connections between its components that usually prevent the system from adapting to the changing environment. Such a system demonstrates feasibility of the main design concept. It performs satisfactorily the main task for which it was developed, but its application environment, as well as performance parameters are limited. Studies of evolution of numerous systems have demonstrated that a typical process of evolution involves phases during which the structure of the system is becoming less rigid and more adaptable to the changing environment. This trend is universal; it can be easily recognized in many commonly used systems.

For many systems increasing flexibility usually begins with replacement of stationary components with moving ones, replacement of a rigid linkage or a rigid structure by a segmented linkage/structure connected by hinges, replacement of rigid components with flexible ones such as hydraulic and pneumatic systems, introduction of nonlinear components, etc. The more advanced stages in the increasing flexibility process are characterized by using physical and chemical effects and phenomena, by implementing servo-controlled systems, etc.

Example 2: Evolution of car suspension

Suspension for axle Both wheels are combined regardless of different road conditions
Independent suspension Each wheel responds to its road conditions
Interconnected suspension Motions of all wheels are adapting to road conditions under individual wheels
Semi-active suspension Damping forces in each strut are adapting to road and motion (braking) conditions
Active suspension Develops forces in accordance to road and motion conditions
Active suspension with forward sensing Develops forces in accordance with anticipated road conditions

Another Line of Increasing Flexibility is shown below:

Fig. 3

4.3 Examples of a technological system evolution

Principal points of evolution along both the Mono-Bi-Poly Line and Line of Increasing Flexibility can be illustrated by various designs of two systems as reflected in the U.S. patents: a) hair comb/brush and  b) varifocal lens system.

The principal developments of the comb/brush system were studied along two directions:

4.3.1 Transition to bi- and poly-system


A typical hair comb or brush

Single-function homogeneous bi-system

Use of two combs for assisting in hair trimming

Single-function homogeneous partially convoluted bi-system

U.S. Patent 5,067,502 describes a hair trimming guide composed of two identical combs sharing one handle

Single-function shifted bi-system

  1. A set of two combs each having differently distanced teeth
  2. A set with a comb and a brush

Partially convoluted single-function bi-system

  1. One comb handle supports two rows of differently spaced teeth
  2. U.S. Patent D384208: combined brush and comb

Heterogeneous bi-system
  1. Use of both hair curler (heater) and comb/brush for hairdressing
  2. U.S. Patent 3,861,407 describes a hair dye applicator that consists of a hair comb attached to a container with dye
  3. Use of both hair cutter and comb/brush for hair trimming
  4. Use of both hair blower and comb/brush for hairdressing
  5. Use of both hairdresser's hand and comb to style hair.
Partially convoluted heterogeneous bi-system
  1. U.S. Patent 4,217,915: to facilitate curling and waving of hair during brushing, the hair brush has an electrical heating element so that hair can be dried, straightened, or curled by contact with the heated body while being brushed
  2. U.S. Patent 4,090,522 (evolution of the U.S. Patent 3,861,407): the comb itself serves as a container for the fluid
  3. U.S. Patent 4,346,721: hair brush with hair cutting blade
  4. U.S. Patent 4,023,578: combination of a hair blower and brush
  5. U.S. Patent 4,766,914: hairdresser glove
Poly-function partially convoluted heterogeneous system U.S. Patent 4,709, 475 (evolution of the U.S. Patent 4,346,721): combination comb, hair trimmer and safety razor ; U .S. Patent 5,622,192: comb having spraying and massaging means

Transition to a bi-system can take place not only at the level of the whole product (comb/brush), but at the level of its components as well. For example, a fluid-dispensing comb suggested in U.S Patent 5,337,764 can be considered as a logical advancement of the design in U.S. Patent 4,090,522. The former has two fluid reservoirs (for different hair treatment fluids) removably attached to the body such that fluid communication is provided from the reservoirs to the teeth.

4.3.2 Increasing Flexibility of Mono-System

As one can see the process of increasing flexibility also goes on both at the level of the whole comb/brush and at the level of its components. Here are several examples:

U.S. Patent 4,116,205:

Foldable hair brush

U.S. Patent 4,475,563:

Hair brush with movable bristle rows

U.S. Patent 4,500,939:

Hair brush with a flexible base plate made of a plastic material

U.S. Patent 4,507,818:

Collapsible hairbrush

U.S. Patent 5,337,765:

Modular brush for user-selected hair streaking

U.S. Patent 5,584,088:

Rotating hair brush

4.3.3 Increasing Flexibility of Bi-System

Stationary/rigid bi-system

Flexible bi-system

U.S. Patent D 384,208: combined brush and comb

U.S. Patent D 309,217 features a combination brush/comb with retractable bristles

U.S. Patent 4,090,522: the comb serves as a container for the liquid medication. The liquid flow cannot be controlled.

U.S. Patent 5,339,839: a comb with fluid applicator made entirely of a flexible material which allows any portion of the container to be squeezed in order to force the liquid through the longitudinal passage and the linear passages and out of the linear passages at the tips of the teeth.

U.S. Patent 4,217,915: to facilitate curling and waving of hair during brushing, the hair brush has an electrical heating element so that hair can be dried, straightened, or curled by contact with the heated body while being brushed.

U.S. Patent 5,091,630 describes a hair curling apparatus with rotatable brush.

4.4.4 Discussion

The described above steps of evolution of the hair comb/brush are not always aligned in a chronological order. This is typical for, practically, any technological system. Some pioneering patent can be granted a hundred years ahead of its time, and most of the patents/inventions/solutions appear rather chaotically. However, major developments fit into basic steps of the Lines of Evolution. Accordingly, these steps can be applied to an existing product/process in order to develop a continuum of potential evolutionary changes in its design/structure. This process represents the TRIZ technological forecasting, or Guided Technology Evolution.

4.4.5. Evolution of varifocal lens systems

The type of Conventional varifocal (zoom) lens systems that is most commonly found in practice is the multi-element glass lens system that is optically structured so that its focus can be varied by changing the axial air spacing between its elements through the use of movable mechanical lens mounts.

Another type of variable focus lens systems utilizes a pair of optical refracting plates having surfaces that are specifically configured to selectively define, in combination, spherical lenses having different focal lengths as the plates are displaced with respect to one another.

All conventional varifocal lens systems share common fundamental drawbacks:

4.4.6. TRIZ analysis of the conventional varifocal lens systems

From TRIZ standpoint (Line of Increasing Flexibility), it is clear that the aforementioned drawbacks can be eliminated by transition from rigid lens systems based on glass elements (lenses and mirrors) to systems that may use elements made of other, more flexible materials.

The Line of Increasing Flexibility suggests that the lens systems should evolve through the following stages (Fig. 4):

  1. One rigid glass lens
  2. Two-lens varifocal system
  3. Multi-lens varifocal system
  4. Elastomeric varifocal lens system
  5. Liquid varifocal lens system
  6. Gas varifocal lens system
  7. Varifocal lens system using various fields (first of all, fields of electromagnetic nature)

Analysis of both patent databases and R&D literature, performed by The TRIZ Group, corroborates to a large extent this assumption. Stages 1-3 are represented by the conventional lens systems. Varifocal lens systems corresponding to stages 4-6 can be found in many recent patents and publications. Varifocal lens systems of stage 7 are not developed yet.

Fig. 4

4.4.7. Overview of non-conventional varifocal lens systems

Typical elastic lens system

The variable focus lens system of this type comprises a lens element formed of at least one transparent, homogeneous elastomeric material that is shaped to provide it with a predetermined focus length when the lens element is in relaxed or nearly relaxed state.

There are means for supporting the lens element along and perpendicular to its optical axis and for applying radial tensile stress around the periphery of the lens element (as shown, for example, in U.S. Patent 4,444,471, Figs 2, 3)

Fig. 5

Fig. 6

The preferred embodiment of the variable focus lens system is shown in Fig. 5. The lens system comprises four major elements, an integrally formed, elastomeric optical member 12, a two-part clamp 20, a circular bezel 38, and a cylindrical tubular member 40. The optical member 12 is a three-part structure comprising a central lens element 14, a circular flexible membrane 16, and a circular toroidal edge 18. On the outer surface of the tubular member 40 there are two grooves 72 (Fig. 6) that are spaced 18--degrees apart into which slidabli fit a corresponding pair of tongues 30 extending forwardly parallel to the optical axis, OA, from the clam front section 22. Clockwise rotation of bezel 38 about axis OA causes the tubular member 40 to displace axially along axis OA, so that the forward edge of the tubular member 40, comprising the rollers 66, contacts the flexible membrane 16 at a predetermined radial distance away from the peripheral edge of the lens element 14. As the tubular member 40 is displaced along axis OA, it leading edge operates to apply a force to the flexible membrane 16 in the direction parallel to axis OA.. The radial stress thus created is uniformly distributed about the periphery of the lens element 14 and operates to alter its shape (Fig. 3), so that the focal length of the lens element 14 can be changed in a continuous manner.

Typical liquid lens system

In a typical fluid lens system (as suggested, for example, in U.S. Patent 4,466,706, Fig. 7), a variable shape/volume chamber is filled with an optically clear fluid, having a specified refraction coefficient, the pressure of which is regulated by adjusting the volume of the chamber. The latter is closed at opposite ends by resilient optically clear diaphragm elements that bend or budge with varying degrees of curvature responsive to pressure changes induced in the fluid.

Typically, a pair of axially adjustable telescoping sleeves defines a chamber. The opposite outer ends of the chamber are closed by a pair of relatively thin resilient optical discs formed of available plastic material. The discs alter their curvatures in response to changes in the fluid pressure.

Fig. 7

Typical gas lens system

In these systems, gas pressure changes correlate with movements of the lens through magnification changes. Changing the pressure of the high refraction index gas leads to changing the focal length of the gas lens, and, as a result, to changing the focal length of the whole lens assembly. Fig. 8 (as represented in U.S. Patent 4,732,458) is a schematic representation of a gas zoom lens 10. Lens 10 comprises a first lens group 22 (A, B) and a second lens group 24 (C, D). Separating the negative meniscus elements B, C is a cavity 26 filled with a heavy high refraction index gas. Connected to the cavity 26 is a piston/cylinder assembly 30. Piston 32 is adapted to move up and down within cylinder 34 raising or lowering, respectively, the pressure of the gas in the cavity 26.

Fig. 8

4.4.8 Major design problems of the non-conventional (fluid) varifocal lenses

There is a growing need for large telescopes, projection lenses, aerial camera lenses, satellite camera lenses, and concentrating lenses for solar energy devices that can be met by lenses formed by liquids and gases. Despite many potential uses of the latter (mostly, because of their low cost), they have two major design restrictions:

  1. Waves and ripples resulting from vibrations introduced by the surrounding
    environment and/or mechanisms.
  2. The varifocal lens must have a quick response to make it suitable for various applications. Quick response varifocal lenses can be designed by using a highly rigid material. However, because of the pressure applied to the operating liquid or gas, the use of transparent elastic films made of a rigid material results in the generation of harmful aberrations.

These problems are not overcome in the existing proposed designs.

4.4.9. TRIZ approach to resolving the design problems of the non-conventional
(fluid) varifocal lenses

From TRIZ standpoint, further promotion of the fluid varifocal lenses is possible by advancing their structure farther along the Line of Increasing Flexibility (Fig. 1). This suggests the following design changes:

  1. To use magnetic and electric fields as means to control structural properties of fluid lenses.
  2. To replace conventional optically clear fluids with optically clear fluids susceptible to magnetic and/or electric fields.
  3. To use materials exhibiting non-linear mechanical/optical properties.

5. Comparison between traditional and TRIZ technology forecasts

The traditional and TRIZ forecasts can be distinguished by their respective outcomes. A conventional technology forecast is concerned with calculating the probability that a particular parameter of the system of interest reaches certain level by the specified point in time. A TRIZ forecast results in developing of an array of design modifications of the system that may advance it along its S-curve.

Thus, the main benefits of the TRIZ forecasting are the following:

6. Steps of the TRIZ technology forecasting (Guided Technology Evolution)

TRIZ forecasting consists of four major phases:

  1. Analysis of the system's evolution

    Study of the history of the system and its position on its "life curve" (S-curve).

  2. "Road mapping"

    Application of the Laws and Lines of Technological Systems Evolution to forecast functional and structural alterations in the system

  3. Problem formulation

    Formulation of engineering problems to be solved so as to achieve targets set at the
    previous phase

  4. Problem solving

    Solving the formulated problems by using powerful analytical and solution tools of TRIZ

6.1 Analysis of the system's evolution

Evolution of technological systems can be illustrated by an S-shaped (Fig. 9) curve reflecting changes of the system's benefit-to-cost ratio with time since the inception of the system. In phase 1 the system's development is relatively slow. Phase 2 features a fast development, usually associated with a commercial implementation of the system and perfecting of the manufacturing processes. Then the pace of development eventually slows down (phase 3) and stalls (phase 4). Sometimes the system enters phase 5 of degradation. In some cases, the system undergoes "renaissance" (phase 6), which can be sparked by availability of new materials, of new manufacturing technology, and/or by development of new applications. When system A in Fig. 9 is approaching the conclusive phases 3 and 4 of its development, usually a new system B having a higher performance potential is already waiting in the wings.

The length and slope of each segment on the system's life curve depends not only on technological but also on economic and on human factors. The common sense (in the hindsight!) suggests that a new system B in Fig. 9 should start its fast development when development of the system A begins slowing down. However, frequently development of system B is delayed by special interest groups which have large investments into the existing technology, job security, etc., associated with the old system.

Analysis performed by Altshuller demonstrated that inventive activity correlates closely with the S-curve. A typical function "number of inventions per unit time ?? time" for a system (Fig. 10) has two peaks. The first peak occurs near point a on the S-curve thus indicating the beginning of mass implementation of the new system. The second peak coincides with the end of the system's "natural life" (around point g ) and is associated with efforts (usually futile in the long run) to extend the systemís life, to compete with the new evolving system.

Fig. 11 shows the level of inventions at different stages of the systemís life. At the beginning, inventions creating the basis for a new system are usually of a high level (i.e., high degree of novelty). This level gradually declines and then rises again in the process of implementation of the system, when many problems associated with manufacturing and marketing must be solved. After this peak, the levels of inventions drop again.

Fig. 12 illustrates dynamics of change of average economic effectiveness of a technological system in different periods. The first inventions that lay foundation for the system , notwithstanding their high technical level, do not bring profit since the system exists only on paper as a promising concept. The rewards for the inventions grow in the course of implementation of the system. At the stages when the system is in mass production, even small improvements may result in significant economic rewards.

It is usually feasible to collect information needed to plot the above curves. Analysis of these curves helps one to determine position of the system of interest on its S-curve.

Three typical cases may exist:

  1. The system has not progressed up to point a , Fig. 9. Position of this point should be determined by forecasting the potential of the system as compared with the competing systems. The condition associated with point a develops only when deterioration of the preceding system begins. The existing system deters development of the new competing system.
  2. If the system evolves between points a and b, the forecast should determine physical limits of the system based on the objective factors (e.g., strength of materials, heat producing capacity of fuels, various barriers such as speed of sound for airplanes, manufacturing costs, etc.). An array of conceptual modifications of the system that may provide for its advancement up to point  and b should be conceived.
  3. The system has passed point  and b (or point g). In this case, the forecasting process is, in
    essence, a search for a new system that may succeed the existing system.

6.2 "Road mapping"

After the history of the system's evolution and its position on S-curve have been established, the Laws and Lines of Evolution are applied to foresee (conceptually) the possible future designs of the system. Analysis of the state-of-the-art of the present system allows one to determine the current stage of the systemís evolution and identify the next stages. At this phase, application of various Lines of Evolution enables identification of the missing steps and feasible future steps of development.

6.3 Problem formulation

As a rule, transition from one stage of evolution to the next stage is accompanied by formulation of design and/or production problems to be resolved. For example, the need to increase flexibility of a system by introducing electromagnetic field can contradict the requirement for the design simplicity. Thus, to make the next step in the systemís evolution, a conflict between increasing flexibility and design complexity has to be overcome.

Since the forecasting is carried out along several Lines of Evolution that represent different Laws, usually there are many engineering problems, which are to be formulated and resolved.



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