Chih-Chen Liu, Ph.D. student
Department of Mechanical Engineering
National Cheng Kung University
Tainan, 701 TAIWAN
Lecture, Department of Mechanical Engineering
Far East College, Tainan, TAIWAN
Jahau Lewis Chen, professor
Department of Mechanical Engineering
National Cheng Kung University
Tainan, 701 TAIWAN
Abstract
The 40 inventive principles and contradiction table of TRIZ
techniques are a good method for solving engineering innovative design problem
with system contradictions. This paper describes an inventive design method for
the designer to solve engineering innovative design problem without
contradiction information by using TRIZ 40 inventive principles. Some examples
will illustrate the usefulness and convenience of proposed approach.
Introduction
When a design engineer tries to solve an innovative design
problem, it is usually a system incompatibility or conflict design problem. As
the designer changes certain parameters of the system in his design problem, it
might make other parameters bad. Traditionally, the design engineer makes
compromise with this kind of contradiction situations and restricts himself on
performing innovative design tasks. The TRIZ method [1-3] is an available tool
for the designer to handle this conflict conditions during the innovative design
problem solving process. One of the TRIZ techniques was developed in the former
Soviet Union by Altshuller, who had analysis over 400,000 patents to build the
contradiction table and 40 inventive principles [1-7]. For using this technique
in innovative design problem solving, the designer needs to first find
corresponding contradictions for his problem at hand. Next, the designer matches
the meaning of each contradiction with two appropriate parameters from 39
engineering parameters that defined in the TRIZ contradiction table [8-9]. The
designer can find 3-4 most frequently used principles for solving engineering
innovative design problem from contradiction table when he confirms the
parameters of contradiction for an engineering system. However, sometimes the
designer only knows how to improve one parameter of this system, but doesn’t
know or can’t predict the corresponding contradiction parameter of this system.
Furthermore, for some contradiction conditions, TRIZ contradiction table doesn’t
recommend any inventive principles. Therefore, the contradiction table is
useless in helping the designer finding suitable inventive principles and
solving his innovative design problem. There are several techniques in TRIZ that
do not require a definition of a contradiction - the System Operator, the Ideal
Final Result, and the 76 Standard Solutions all work without explicit
definitions of a contradiction. This paper describes an inventive design method
for the designer to solve engineering innovative design problem without
contradiction information by using the 40 inventive principles. Some examples
will illustrate the usefulness and convenience of proposed approach.
Improving “Accuracy of Measurement”
The CCD laser measured instrument can quickly and accurately
survey complex 3D curved surfaces. However, it also has some limitations, such
as the object’s color is red or black. In this situation, the light is absorbed;
there is no true reflection from the measured object when a red laser is shot at
the object, so an inaccurate image is formed. Figures 1 and 2 show estimated
results of a red Kitty model. As can be seen in the figures, there are many
defects. For improving this quality of measurement problem, we tried TRIZ method
and found a corresponding improving parameter “accuracy of measurement”.
However, this is only one parameter that we can find for improving our problem.
It is very difficulty for us to discover the corresponding contradiction
parameters for this problem. Hence, there was really no way to directly use TRIZ
contradiction table to find inventive principles that would solve this problem.
Fig. 1. Result of measuring red Kitty model (data points) Fig.
2. Result of measuring red Kitty model (shading)
At first we tried to find ways to improve “accuracy of
measurement” parameter with corresponding TRIZ inventive principles. It is tried
to find possible problem solving techniques from those known inventive
principles. In other words, we considered all possible inventive principles for
improving “accuracy of measurement” parameter and examined them one by one based
on the information of TRIZ contradiction table. As a result, some inventive
principles have high frequency of appearances, such as #32 “change the color”
(21 times), #28 “replacement of a mechanical system” (18 times), #6
“universality” (11 times) . . . etc. These results, in particular principles
were seen more often, show to be a potentially effective problem solving
technique. In addition, one can find other possible solutions with TRIZ
contradiction table by looking from another angle of this problem to avoid
parameter “accuracy of measurement” deterioration. Some inventive principles,
such as #28 “replacement of a mechanical system” (17 times), #32 “change the
color” (14 times), #26 “copy” (11 times) . . . etc., were found by this approach
to be also a potentially effective problem solving technique.
Improving “accuracy of measurement” parameter is active
problem trouble-shooting, moreover avoiding “accuracy of measurement” parameter
deterioration is passive problem solving. No matter whether active or passive,
both approaches have positive significance once the problem itself is formulated
correctly. Putting them together, we obtained the following inventive
principles, such as #28 (35 times), #32 (35 times) . . . etc. The inventive
principle #32 “change the color” is very suitable in solving this problem. The
quality of measurement was improved successfully as a result of the color of
measured object (the Kitty model) was changed from red to yellow. The improved
results can be seen in Figures 3 and 4. Another inventive principle #28
“replacement of a mechanical system” can also be another kind of feasible
technique for this problem. Based on principle #28, this problem can be solved
by using the contact type 3D measured instrument for measurement of the original
red Kitty model.
Fig. 3. Result of measuring yellow Kitty model (data points)
Fig. 4. Result of measuring yellow Kitty model (shading)
Single Engineering Parameter and Inventive Principles
Previous case study provides a method for the designer by
using one engineering parameter to improve system performance. Moreover, it
doesn’t matter whether or not the presence of contradiction parameter is known.
First , this method examines all corresponding inventive principles associated
with each “improving parameter” in the TRIZ contradiction table. Particular
principles were seen a number of times. This situation can be explained as that
the inventive principles will make improvements to a certain “improving
parameter” in the system, possibly corresponding with other “avoiding
degeneration parameter” types. Hence, for certain inventive principles appeared
more often, indicating that it is a good one to try in solving innovative design
problem.
Next, the same procedures were applied to each “avoiding
degeneration parameter” in another dimension of the TRIZ contradiction table.
The corresponding inventive principles were examined and accounted for their
number of appearances. The use of those principles by the designer means that it
can improving a system’s parameters and can avoid the deterioration of certain
“parameters” simultaneously. As before, certain inventive principles appeared
many times show that using those principles will give the designer a good try to
solve innovative design problems.
Finally, combination of both parts together and summing up
the number of appearances of all of the principles constructs a table for single
engineering parameter and inventive principles, as shown in Table 1. The
vertical axis is the TRIZ 39 parameters that the designer wanted to improve. The
horizontal axis shows the frequency of appearances of each parameter’s
corresponding principles. Table 1 classifies inventive principles into different
ranks, such as A (more than 19 times), B (between 16 to 18 times), C (between 13
to 15 times), D (between 10 to 12 times), E (between 7 to 9 times), F (between 4
to 6 times) and G (between 1 to 3 times), according to the number of appearances
in the contradiction table for each parameter. Those principles appearances most
frequently (ranked at A, B, or C in Table 1) will have a better chance at
success in solving inventive design problem. Therefore, the designer can solve
engineering innovative design problem without contradiction information by
choosing suitable TRIZ inventive principles based on information in Table 1.
Table 1. Table for single engineering parameter and inventive
principles
Examples
1. First Example
The first example is the research methodology of this study.
The aim of this paper is to develop an inventive design method to solve
innovative design problem without knowing its contradiction information by using
TRIZ inventive principles to improve the system’s engineering parameters or
solve the engineering innovative design problem. The authors hope to improve or
modify parameter “convenience of use” in the TRIZ contradiction table. Three
principles associated with the “convenience of use” parameter with the highest
appearance rates were found from Table 1. According to the order of appearance
rate, they are #01 “segmentation”, #13 “inversion”, and #02 “extract”,
respectively. These three inventive principles are exactly the same approaches
as what the authors used to produce Table 1 and the TRIZ inventive design method
without contradiction information. If authors could have used Table 1 at the
beginning of this study (it didn’t existed at that time) to solve the problem
mentioned above, then we would have greatly decreased the time and energy spent
through trial and error method.
2. Second Example
Beverage cans are daily necessities in the modern world with
lots of uses. The designer wants reduce the consumption of cans and lower the
cost of production and environmental impact burden. One of the contradictions
discovered by the designer [9] is the improving parameter of “length of
nonmoving object” in conflict with the avoiding deterioration parameter of
“tension/pressure”. From TRIZ contradiction table, there are three corresponding
inventive principles:
#01 “segmentation” (breaking the cans surface by
crushing it under pressure),
#14 “spheroidality” (the top of the can is assembled
with curved lines and not straight ones), and
#35 “transform the physical/chemical state” (the
material is made of higher intensity steel alloy).
Looking at it another way, the designer only have the concept
of reduced can consumptions and he doesn’t know the possible deterioration
contradictions. Based on the “length of nonmoving object” parameter, the
designer can find the corresponding first five inventive principles from Table 1
as follows:
#35 “transform the physical/chemical state”,
#28 “Replacement of a mechanical system”,
#14 “spheroidality”,
#26 “copying”, and
#01 “segmentation”.
Inventive principles #35, #14, and #01 are the same as the
principles come from traditional TRIZ method [9]. Therefore, even though the
designer doesn’t know the system’s contradiction information, he can still use
Table 1 to find suitable TRIZ inventive principles to solve his own innovative
design problems. Furthermore, inventive principles #28 and #26 may give the
designer other opportunity to find good solution approaches for his inventive
design problem.
3. Third Example
The design purpose of the product “early stage of warning
light” is to strengthen the warning function. The system parameter to be
improved is “brightness”. By using Table 1, one can find three corresponding
inventive principles:
#19 “periodic action” (change the lights flashing style),
#32 “change the color” (change the light’s color to red
or yellow), and
#01 “segmentation” (add a lot of little lights around the
edge of the sign).
4. Fourth Example
The contradiction condition for “smart car” design problem
[10,11] is “small cars have convenient size but can’t absorb the energy of
impact”. Although every designer hopes to design compact cars that are
convenient for urban use (for example: easy parking or taking up less road
space), there is fear that a small car will not be able to stand up to the
impact by a traffic accident, particularly that the engine might injure the
passengers.
In this example, the designer wants to improve the cars usage
of road space, especially engine and engine compartment size. That is to say, to
improve the “area of moving object” parameter (during a collision the engine and
engine compartment are considered moving objects). The first two corresponding
inventive principles for this parameter from Table 1 are #15 “dynamicity” and
#17 “shift to a new dimension”. These two principles match the best solution
strategies on Reference 11.
Conclusions
There are several techniques in TRIZ that do not require a
definition of a contradiction - the System Operator, the Ideal Final Result, and
the 76 Standard Solutions all work without explicit definitions of a
contradiction. The present paper described an inventive design method for the
designer to solve engineering innovative design problem without contradiction
information by using the 40 principles. A single parameter inventive principles
table (Table 1) was established in this study. This table is very useful for the
designer in situations where it is unknown whether there is a contradiction and
some parameters need to be improved. When the designer uses Table 1 to solve his
innovative design problems, he should use the top of the list of the principles
in Table 1 in order to be faster and more successful, but there is no guarantee
that it is the best. The successful examples demonstrate the effectiveness of
proposed method. Especially, as seen in the explanation of first example, this
paper uses TRIZ methods to solve problems of TRIZ (innovative design problems
without contradiction information).
Acknowledgements
This study is supported by a grant from the National Science
Council, Taiwan, Republic of China, grant number: NSC89-2212-E006-169.
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