Searching for design

contradictions and

conflicts with DSM

Method exemplified using a case study of the EU robot competition 2010

Professor Eric Coatanéa

18/06/2010

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System dynamic model

Eurobot 2010

Oranges

Tomatoes

Earns of Corn

H. Ears

of corn

(our)

H. Tomatoes

(our)

Harvesting

Oranges

(Our)

H. Oranges

(Opponent)

H. Tomatoes

(Opponent)

H. Earns of corn

(Opponent)

Dispending

Zone (our)

Dispending

Zone

(opponent)

Dispending

Zone

(opponent)

Technical

knowledge

(Our)Budget

(Our team)

-

-

-

-

-

Opponent

moving

robot

Static

own

robot

moving

robotAvoid

Number of team

members (Our)

Power

required

(W)

+

Remaining

time

Energy used (W)

Detection

time (t)

Software

complexity

(lines)

Available

resources

Beacons

Grey

raised

zone

Fixed

trees

moving

robot

Climb

moving

robotMove

Detection

signal

sent

Detect

Obstacle

or fruit

detected

+

+

+

-+

+

Development time

Match duration (t=90s)

+

-

RefereeTomatoes, corns

and fixed tree

possible locations-

++

Control unit

treatment

power

+

+

+

+

+

Distance

(m)

Number of

acc./dece.

cycles

Speed

required

acceleration

and

-

Weight

collected

-

+

+

Weight

robot

+

Development

time

+

+

Autonomy

-

-

3/74

Construction and Analysis of the System dynamic model

Analysis of the system of interest

It is difficult to analyze the existing interactions and find the loops in

such a graph!

What do we want to do with such type of System Dynamic

model?

1- We would like to clarify what are the design problems that we

should solve in priority?

What is a design problem?

1- A contradiction related to a performance

2- A target that cannot be attained

3- A conflict between performances

Engine + transmission + tank

Cruising Range

Weight

Body

More E&T

permits M

More W constraints CD

Passengers and luggageDevelopment and

manufacturing cost

+-

4/74

Analysis of the system of interest

What are the types of contradictions that we can find in

a system dynamic model?

1- Several factors influencing in an opposite manner a performance

parameter.

Efficient and

developed

educational

systemEducated citizens

Salary level

+

Price level of local

companies

products

+

+

High quality products

+

Plus factor

Minus factor

Selling products+

-Contradicting factors

Performance parameter

Construction and Analysis of the System dynamic model

5/74

Analysis of the system of interest

What are the types of contradictions that we can find in

a system dynamic model?

2- A parameter is influencing in an opposite manner different

performance parameters.

Efficient and

developed

educational

systemEducated citizens

Salary level

+

Price level of local

companies

products

+

+

High quality products

+

Minus factor

Plus factor

Selling products+

-Contradicting factors

Performance parameters

Margin

+

Construction and Analysis of the System dynamic model

6/74

Examples

Contradictions

Some countries would like to

have military planes forces

available far from home country

(possibility to have fast air

support and intervention). This

requires the use of special plane

and boats (expensive).

Contradiction ?

Plus factor: Fast and distant air

support

Minus factor: Cost (requires special expensive

boats and special planes)

7/74

One way to solve partially the contradiction consists of developing

vertical take-off and landing planes

Contradictions

Prototype: Lockheed XFV-1(tail-sitter)

Take-off and landing on the tail

Contradiction ?

Plus factor: Vertical direction of

the fuselage

Minus factor: Visual control and

guidance especially during landing

Examples

8/74

Answer 1 to vertical take-off and landing contradiction

Contradictions

One contradiction solved (Vertical

take-off and landing without need

for runway and visual control and

guidance) but another

contradiction created!

Plus factor: Vertical take-off and

landing without runway and visual

control

Minus factor: Huge energy

consumption during landing and

take-off (limit greatly range of

the planes)

AV-8B Harrier II

New contradiction

Examples

9/74

Answer 2 to vertical take-off and landing contradiction

Contradictions

+

Bell/Agusta

BA609

Examples

10/74

Definition

Contradiction: “Model of a system conflicts that puts incompatible

requirements on functional properties” [M.A. Orloff, Inventive Thinking

through TRIZ]

Contradictions

11/74

Some types of contradictions

- Organizational properties vs. complexity of implementation,

Contradictions

12/74

Some types of contradictions

- Function A vs. Function B (incompatibility of functions)

Contradictions

To provide flame (oxidizer + fuel) To be used under water

13/74

Some types of contradictions

- Technical properties vs. cost,

Contradictions

14/74

Some types of contradictions

- Technical properties vs. complexity of production

Contradictions

15/74

Some types of contradictions

- Technical properties vs. complexity of use,

Contradictions

Autogiro

16/74

Some types of contradictions

Physical property A vs. Physical property B (incompatibility of physical

properties),

Contradictions

17/74

Architectural definition of the

system dynamic model

Analysis of the system of interest Problem formulation

(system location,

environment, goals,

system service functions)

Solution synthesis (architectural

definition of the system dynamic

model)

Solution (system dynamic model

and analysis)

Solution Verification

(verification of the viability of the model via quick

sensitivity analysis)

Confirmation

Verification

and validation planning

Oranges

Speed

required

(m/s)

Budget

(Our team)

Power

required

(W)

Stock

Flow

Converters

Causal link

+

If Speed INCREASE(DECREASE) then

Power INCREASE(DECREASE)

Time

required

(s)

Number

collected

(n)-

H. Oranges

(Our)

18/74

System dynamic model

Analysis of the system of interest

Oranges

Tomatoes

Earns of Corn

H. Ears

of corn

(our)

H. Tomatoes

(our)

Harvesting

Oranges

(Our)

H. Oranges

(Opponent)

H. Tomatoes

(Opponent)

H. Earns of corn

(Opponent)

Dispending

Zone (our)

Dispending

Zone

(opponent)

Dispending

Zone

(opponent)

Technical

knowledge

(Our)Budget

(Our team)

-

-

-

-

-

Opponent

moving

robot

Static

own

robot

moving

robotAvoid

Number of team

members (Our)

Power

required

(W)

+

Remaining

time

Energy used (W)

Detection

time (t)

Software

complexity

(lines)

Available

resources

Beacons

Grey

raised

zone

Fixed

trees

moving

robot

Climb

moving

robotMove

Detection

signal

sent

Detect

Obstacle

or fruit

detected

+

+

+

-+

+

Development time

Match duration (t=90s)

+

-

RefereeTomatoes, corns

and fixed tree

possible locations-

++

Control unit

treatment

power

+

+

+

+

+

Distance

(m)

Number of

acc./dece.

cycles

Speed

required

acceleration

and

-

Weight

collected

-

+

+

Weight

robot

+

Development

time

+

+

Autonomy

-

-

19/74

- Place the variables in a Design Structure Matrix (DSM)

Influence of:

variables

On variables

Analysis of the system of interest

Construction and Analysis of the System dynamic model

A

B

A B

1

20/74

- Let’s consider the following relationships, Can you build the

associated DSM?

40-40C

+5

+2

+3

C

-3-2Is influenced

4

4

Influence (absolute)

0-2B

+10A

BAA

B

C

-2

-4

+1+3

Influence of:

Influence On:

1: Weak influence

2: Average influence

3: Strong influence

4: Very strong influence

Analysis of the system of interest

+2

Construction and Analysis of the System dynamic model

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- If B is a performance variable

A

B

C

-2

-4

+1+3

Influence of:

Influence On:

B is influenced by contradictory

influences, (Visible in column B).

B is providing contradictory

influences to A and C, Visible in

line B).

Analysis of the system of interest

Construction and Analysis of the system dynamic model: Contradictions of

type 1 and 2

+2

40-40C

+5

+2

+3

C

-3-2Is influenced

4

4

Influence (absolute)

0-2B

+10A

BA

22/74

- Indirect influences and loops: raise the power of the matrix

0-40C

+2

+3

C

0-2B

+10A

BA

0-40C

+2

+3

C

0-2B

+10A

BA

-80+8C

-6

+2

C

-100B

-12-2A

BA

Analysis of the system of interest

Construction and Analysis of the system dynamic model

A

B

C

-2

-4

+1+3

+2

What is the meaning of the value -10

in column B, line B?

23/74

- By continuing raising the power of the matrix, the most influential

variables are determined but also the most influenced variables

Analysis of the system of interest

Construction and Analysis of the system dynamic model

24/74

- Finding the conflicting loops require in this case to raise the matrix

below to power 4.

A

B

C

-2

-4

+1+3 Influence

of:

Influence On:

Analysis of the system of interest Construction and Analysis of the system dynamic model: Conflicts of type 1

and 2

-2

Cl.

2

Cl.

1

Cluster 2Cluster 1

0-200-20D

+30+1000E

00-4000F

0

-2

0

D

0

0

0

E

0

0

0

F

0-40C

0

+3

C

Is influenced

Influence (absolute)

0-2B

+10A

BA

D

Cluster 1

Cluster 2

E

F

-2

-4

+1+3

-2

25/74

Analysis of the system of interest

Oranges

Tomatoes

Earns of Corn

H. Ears

of corn

(our)

H. Tomatoes

(our)

Harvesting

Oranges

(Our)

H. Oranges

(Opponent)

H. Tomatoes

(Opponent)

H. Earns of corn

(Opponent)

Dispending

Zone (our)

Dispending

Zone

(opponent)

Dispending

Zone

(opponent)

-

Static

own

robot

moving

robotAvoid

moving

robot

Climb

moving

robotMove

Remaining

time Detection

time (t)

Detection

signal

sent

Detect Obstacle

or fruit

detected+

+

+

Weight

collected

(B) Tomato

harvesting

Construction and Analysis of the system dynamic model: Conflicts of type 1

and 2

It is important to give names to loops

in order to see if they have a real

importance on the system

26/74

From Anticipation to Action: A handbook of Strategic prospective, Michel Godet, Dunod Editor, 1991.

System Thinking: Managing Chaos and Complexity: A platform for Designing Business Architecture, J.

Gharajedaghi, Elsevier B.H., 2006.

Business Dynamics-Systems Thinking and modeling for a complex world, John D. Sterman, Irwin- Mc graw-

Hill Editor, 2000.

Ingéniérie et intégration des systèmes, J.P. Ménadier, Hermès editor, 1998.

Inventive Thinking through TRIZ, M.A. Orloff, 2nd Edition, 2006.

Engineering of creativity: Introduction to TRIZ Methodology of Inventive Problem Solving, S.D. Savransky,

CRC Press, 2000.

Main References for part 1

27/74

Thank you

Questions?