Functionally Efficient Conceptual Design And Innovation Tools

Original Article

Proceedings of Virtual Concept 2006 Playa Del Carmen, Mexico, November 26th – December 1st, 2006

Functionally efficient conceptual design and innovation tools Martin E. Baltazar-Lopez, Jorge D. Flores-Porras, Eric F. Zenteno-Cardoso, Marco A. Miranda Ramírez

Centro Nacional de Investigación y Desarrollo Tecnológico, CENIDET Prol. Palmira Esq. Apatzingan, Cuernavaca, Mor. 62240, Mexico. Phone/Fax 52 777 312 76 13 E-mail : {baltazar, dflores05m,eric05m,mamr05m}@cenidet.edu.mx

Abstract: A design methodology founded on the research work done at the Institute for Innovation and Design in Engineering, has been applied to enhance the ability to design and innovate of neophyte engineers at National Research and Technological Development Centre (CENIDET) in Mexico. This methodology is based on the cognitive skills of abstraction, critical parameter identification, and questioning in order to obtain a functionally efficient conceptual design. Besides of teaching the design process to novice designers, the methodology inspires in them a design philosophy which enables them to perform engineering effectively and innovatively in any area of specialty. Some examples of this design philosophy are presented. Key words: Design methodology, Functional structure, abstraction, Innovation. 1- Introduction

When teaching engineering, the process of learning through real problems is a common practice. In some cases, in undergraduate curricula it is necessary to have exposure to industrial problems particularly on the last semesters of the course of study in which industrial partners provide some of their problems and industrial exposure first to the faculty and then to students as a form of knowledge and expertise. Faculty work with students to provide the information back to the industrial partners as a form of Technical expertise and design specific problems and thus as a solutions in which students are exposed to the design process, they can get real results and become potential employees for industrial partners.

However, by using a specific methodology, some times this idea of getting industrial expertise and industrial problems can be substituted for a solution of an everyday problem, based on the fact that not all the engineering problems come from industry, being this more accessible for students, nevertheless not less technically-challenging projects, and making these solutions of a real need a good starting point of their engineering design practice, some times those solutions have risen interest from industrial partners.

2- The Methodology

Research evidence has shown that engineering design is a process that can be developed and imparted to engineers [PB1,UE1,U1,F1,S1]. Also other research studies shows that certain differences exist between experienced and novice designers [G1,LS1]. Experienced designers come up with innovative solutions quickly in comparison to novice designers because they first identify and then attack core issues of a problem while neophyte engineers try to look at existing-solution schemes or model dependent solutions causing fixation of thinking and thus blocking the innovative process.

In CENIDET we try to use those research findings to increase our understanding of the design process as well as effective means for teaching that process. The conceptual design methodology used is based on the techniques taught at Texas A&M University’s former Institute for Innovation and Design in Engineering (IIDE) [B1,KB1] which provided to industry continuing education customized workshops on - In reality, this approaching of Industry and schools, as partners design innovation. to solve problems, in Mexican institutions is very incipient. - In the mechanical engineering department of CENIDET, one of the goals is to exposure the students to real engineering practice. This is not always an easy task. In part because there is a lack of confidence from possible industrial partners because there is not such culture of University-Industry partnership in Mexico.

P95 VC InCo2006

-1-

The core of this approach is a design philosophy based on Abstraction, Critical Parameter Identification, and Questioning. The aims of the methodology are: • To provide an understanding of the creative processes whereby the effect of a product can be evaluated

Copyright of Virtual Concept

Virtual Concept 2006

Functionally efficient conceptual design

Figure 1: Abstraction Process.

• • •

To provide an understanding of innovation not only in an industrial context but in every day life To introduce a number of innovation techniques, particularly based on abstraction and questioning To introduce a number of advanced design techniques to enable the innovation process to be executed and managed .

The core of the methodology is formed by three skills: the ability to think on an abstract level; the ability to identify critical parameters; and the ability to question. 2.1- Abstract level thinking

Novice design engineers try to get related solutions while experienced designers get innovative solutions based on Once the students are familiar with the methodology, they can abstract thinking on analyzing the core issue of a problem. perform design effectively and innovatively in any area of specialty. Abstraction is the process by which a perceived need is progressively transformed from a colloquially expressed

P95 VC InCo2006

-2-

Copyright Virtual Concept

Virtual Concept 2006

Functionally efficient conceptual design

statement into a functionally precise definition, using In general, an engineering design process starts with the technically fundamental terms. This has been identified as one identification of a need. It then assists a designer to generate solutions to that need, to develop and implement systems or of the key skills required for a designer. components, and concludes with satisfactory qualification The importance of abstraction in increasing the insight that the and testing of a prototype. This whole process involves designer has into the problem and simultaneously expanding organizing and managing resources and people. Critical the solution space that can be explored. The abstraction process factors such as cost, safety, reliability, aesthetics, ethics, and to achieve the required level of abstraction for a given problem social impact are also considered during the design process. statement is summarized in Figure 1. A need statement describes the design task and it is Answering “yes” to all of the questions in Figure 1, can be composed of two parts: a) the main design function and b) used to evaluate whether abstraction has been achieved to the the main design constraint. required degree. The ultimate goal of abstraction is to simultaneously increase the insight into the problem and 2.3- Critical Parameter identification expand the solution domain, to obtain innovative and nontraditional solutions. The Critical Parameter Identification is the next systematic process by which a designer identifies the important issues in In the process of abstraction a need statement evolves from a a recognized need. Those issues can be physical, natural, colloquially expressed phrase to a technically precise sentence chemical, or mathematical concepts that are significant to the in a more abstract form. The solution-specific details are need. The Critical Parameter Identification and Abstraction eliminated and the terms qualitative. Through abstraction, the processes go parallel, along with questioning. Again there is final need statement should be simultaneously technically a difference on how experienced designers attack a problem precise, solution independent, general but not vague, and and quickly reach and address the core issue in the problem, allows a greater variety of possible solutions at the conceptual in comparison to neophyte design engineers. Thus it could be said that the rapid and skillful identification of critical stage. parameters is a characteristic of a good design engineer. 2.2 Need Statement

Karuppoor, et al [KB1] show the process of abstraction and how the need statement goes from a colloquial sentence to a Based on the definition of the word Design: “the process of more precise one an also the associated critical parameter creating a device or system to satisfy a need” thus the most evolves along with it at each stage of abstraction. important and one of the most critical parts in the design process is to define a need statement. The need statement Figure 2 shows the actions involved in identifying the critical should reflect the problem in question, and the implicit parameters for the design. Critical parameters are limiting constraints of the probable solution. conditions and gradients that address the change or a rate of

Figure 2: Actions involved in Critical Parameter Identification

P95 VC InCo2006

-3-

Copyright Virtual Concept

Virtual Concept 2006

Functionally efficient conceptual design

By Questioning, the designer’s thoughts are directed into new solution spaces and thus avoid fixation on existing solutions enabling the designer to be innovative and to consider issues that have not been thought of before and and considering problems in new and different perspectives.

change of a variable. A critical parameter is often determined by those limiting conditions at interfaces between the functional requirements of the design and the environment. Thus for an engineer it is not an easy task to minimize these rates of change and at the same time meeting the specified need.

3-Functional Analysis

2.4-Questioning

At this point of the design process it is necessary to have all the design specifications written and organized. This is done by the functional analysis. The functional analysis is carried out by using a chart known as functional structure.

Along with abstraction and critical parameter identification, questioning skills are required in a good design. For instance, questioning the constraint helps establish whether this is a real or a perceived constraint, or one that is being artificially imposed.

3.1-Functional Structure

Also by questioning it is possible to recognize the true need and from there innovative solutions that would not otherwise have been considered. This illustrates how the process of questioning is a subtle, yet powerful tool, in helping define the true need and opening up the solution space for further exploration.

Once a problem is declared into the need statement, several ideas come up into place. A common practice is to write down all those ideas however most of the times, those are not organized in a consistent way. The functional structure is a graphic way to organize and classify ideas into functions, restrictions, constraints, alternatives and concepts.

The effective designer, by questioning needs and assumptions, makes a conscious effort to be innovative and to not get fixated on certain ideas. Figure 3 shows the various questions that should be asked in relation to the need. These consist of the five “W” s (Why? What? …) and the “H” (How?) along with the opposite corresponding negative questions. The role of a designer at this stage is the one of a true researcher trying to find technically reasonable explanations by gathering of information and can use these questions to fully explore the task and gain insight into the true need. The question of How? encompasses all the other questions and is, in a sense, the means through which the answers to the W’s can be implemented.

As its name implies the functional structure must clearly specify the main function and also sub-functions that the device being designed must perform. Also all possible constraints that will limit our solution space. The functions are organized in such hierarchical way that the main function and main constraint are at the first level after the need statement, which in turn would be the header of the chart. Going down to next level are the subfunctions and secondary constraints, at the lower levels are the alternatives and finally the concepts. When forming this functional structure a questioning process is carried out.

Why ?

Why not?

What?

What not?

How? When

TRUE NEED

How

When not?

Who not?

Who

Where

Where Figure 3: Questioning process to get the “true” need.

P95 VC InCo2006

-4-

Copyright Virtual Concept

Virtual Concept 2006

Functionally efficient conceptual design

Figure 4: Function Structure

4-Conceptual Design

The design itself demands creativity making the engineers and designers in inventors. Also the design is an iterative process making necessary to look upon alternatives when striving for an optimal solution design. The design requires attention to the details. In many cases the details make the difference between success and failure. How it is defined a design need is reflected in the solutions. A good need definition allows the conception of innovative solutions at the functional structure. Design can be viewed as an iterative movement between the two knowledge domains achieved through the use of the two thinking modes, form concept space to configuration space and vice versa. The conceptual space implies a generalization or abstraction of specific information to fundamental concepts which in turn fosters divergent thinking. On the other side, a particularization or configuration of abstract principles or concepts fosters convergent thinking. This it is necessary to count of a large sample of functional alternatives which eventually will evolve into conceptually different solutions.

Identify the critical design issues early.

•

Start early in the design process.

•

Get “divorced” often.

•

Consider design alternatives at each stage

•

Consider fundamental principles.

•

Continually reexamine assumptions.

Also some activities are implicit in the conceptual design • Idea Generation o •

•

Identify ideas.

Concept Development o

At the conceptual design it is necessary to have at least three conceptually different alternatives. Understanding as different those solutions which have fundamentally different principles or physical effects Also the keys for a good conceptual design can be summarized as follows:

P95 VC InCo2006

•

Develop three conceptually different and viable solutions.

Concept Evaluation o

Evaluate the solutions against the need.

o

Create a single design incorporating good features.

5-Case Study

Handicapped people in Mexico who has the necessity to use wheelchairs for mobility find out in many occasions the problem to bridge the gap over steps, curbs, and raised landings that are not accessible or do not count on an

-5-

Copyright Virtual Concept

Virtual Concept 2006

Functionally efficient conceptual design

•

appropriate ramp. Thus a necessity arises to design a device to be able to transport a non-electrical wheelchair from the inferior level to the step or curb and vice versa.

•

5.1-Need:

It is required of a device that allows people who use wheelchairs to accede with autonomy to steps or curbs that do not count on access ramp.

• •

5.2-Constraints:

• • • •

It must be a relatively simple mechanism It has to be of low cost (in comparison to the price of the wheelchair) That can be operated easily by the handicapped person Adaptable to any non-electrical wheelchair.

5.4-Main function:

To raise wheelchair to a step, curb or sidewalk that is not accessible. 5.5-Main restriction: With autonomy

5.3-Need Analysis, Important questions:

•

• •

Where is it needed? In any place with unevenness (standard height of step, curb or sidewalk) that does not count on an access ramp When it is needed? At the moment that the people mentioned above require to bridge the gap over a step or curb. How is it needed? It is required a relatively light device, cheap and functional. Is really needed? Yes, because not always there are access ramps to the steps, curbs or sidewalks or some person who can help.

5.6-True

need: To raise a wheelchair, with autonomy to a step, curb or sidewalk that is not accessible.

What is needed? It is required a device that allows the handicapped people who use wheelchairs to accede to steps or curbs that do not count on an appropriate ramp and without help from a third person. Why it is needed? Because handicapped people cannot accede with autonomy to steps and curbs without an appropriate ramp. Who needs it? Handicapped or Injured people who use wheelchairs that they require of autonomy for mobility.

5.7-Functional Structure

Based on the generic fuction structure of figure 4 and the concepts in relationship to the functional analysis, two functional structures were developed for this case.

To raise a wheelchair, with autonomy to a step, curb or sidewalk that is not accessible

Allows horizontal mobility.

Vertical displacements of the wheelchair

Advance over flat floors without raised landings

Raise a non accessible step, curb or sidewalk

Using a motorized device

Maintain user’s autonomy

Allowing mobility to user without help of another person

Using a manual device

Figure 5: Initial Functional Structure

P95 VC InCo2006

-6-

Copyright Virtual Concept

Virtual Concept 2006

Functionally efficient conceptual design

To raise/lower a wheelchair, with autonomy to a step, curb or sidewalk that is not accessible.

Allows displacement horizontal/vertical

Allows horizontal displacement for normal mobility conditions

Maintain user’s autonomy

Vertical displacements of the wheelchair

Raise/lower a non accessible step, curb or sidewalk

Advance over flat floors without raised landings

Using a motorized device

Hydraulic System

Allowing mobility to user without help of another person

Electric System

Using a manual device

Movable arms

Telescopic Ramp

Manual Lift

Figure 6: Modified Functional Structure 5.6-Critical Parameter Identification

After analyzing all the involved aspects in functions and constrains to obtain a suitable solution, the functional structure evolves (and could be possible that the need statement changes in the process) into a modified or second functional structure. From the functional structure several conceptual alternatives emerged:

After a rain storming some Critical parameters were identified: • Height difference in steps, curbs or sidewalks (150 to 200mm aprox) •

Maximum force to be exerted to the mechanism

•

Telescopic Ramp

•

Dimensions

•

Hydraulic system

•

Weight

•

Movable arms

•

Cost

•

Electric system

•

Manual lift

With the need statement and the information from critical parameters a initial functional structure is developed. As mentioned before a systematic way of organize ideas and relate them to the solution as functions, constraints or alternative concepts is necessary. A graphic way of doing that is a organization chart known as Functional Structure where the process of questioning is carried out at the same time that the functions, sub functions and constraints are arranged in a hierarchical levels from top to bottom. At the lower level of the functional structure there should be at least three conceptually different design alternatives, to be evaluated at next design stage. The final functional structure is obtained after an iterative process and evolution of the need statement.

P95 VC InCo2006

In table I are shown all the considered conceptual alternatives evaluated against a datum or reference. After a matrix evaluation of the critical parameters of each of those concepts it was determined that the hydraulic mechanism presented more advantages over the rest of the alternatives, and also the movable arms mechanism had several advantages over the ramp however when considering manufacturing costs, these two options were surpassed by the telescopic ramp mechanism. In the process the conceptual design activities of Fig. 7 were carried out.

-7-

Copyright Virtual Concept

Virtual Concept 2006

Functionally efficient conceptual design

Figure 7: Layout of the Conceptual Design Activities

Critical Parameter

Telescopic Hydraulic Movible Electric Manual Ramp System arms System lift

Cost

-

-

-

-

Size

+

I

-

+

Weight

-

I

-

I

Manoeuvrability

+

+

+

+

Strength

+

I

-

I

I

-

-

I

Energy consumption

+

-

-

+

Maintenance

-

-

-

-

Manufacture

-

-

-

-

Total (+)

4

1

1

3

Total (-)

4

5

8

3

Life cycle

DATUM

Table I. Concept Matrix Evaluation

P95 VC InCo2006

-8-

Copyright Virtual Concept

Virtual Concept 2006

Functionally efficient conceptual design

Figure 8: Model of wheel and the telescopic mechanism Based on these results, and applying de designer criteria, the telescopic ramp was chosen to be developed as a prototype.

triple slider mechanism with a folding end ramp, deployed in place with a single degree of freedom. The ramp mechanism implemented on a wheelchair is shown in Figure 9. Because the simplicity of the mechanism’s linkage, the manufacturing cost is low, making it affordable for the majority of users of this kind of wheelchairs.

5.7-Telescopic Ramp Mechanism

A wood model, Fig. 8, was constructed to illustrate the movements involved in the mechanism. It consists of a

Figure 9: Ramp Mechanism implemented on the wheelchair

P95 VC InCo2006

-9-

Copyright Virtual Concept

Virtual Concept 2006

Functionally efficient conceptual design

6- Conclusions

[G1] Glegg, G.L.,The Design of Design, Cambridge University Press, Cambridge, UK, 1969.

The philosophy from the Texas A&M University’s former Institute for Innovation and Design in Engineering (IIDE) was used in a design methodology based on abstraction critical parameter identification, and questioning to train neophyte engineers in CENIDET Mexico, allowing them to get the basic skills necessary to get quick innovative solutions; at the same time having experience in solving real engineering problems related to true needs which otherwise do not have because of lack to exposure to industrial problems. It was shown also that the methodology can be used not only at industry but in every day needs, which after the process could be adopted by industry.

[KB1] Karuppoor, S. S., Burger C. P. and Chona R., “A Way of Doing Engineering Design,” Proceedings of the 2001 ASEE Annual Conference, Albuquerque, NM, 2001. http://www.asee.org/acPapers/01128_2001.PDF. [LS1] Leong, A. and Smith, R. P., “An Observational Study of Design Team Process: A Comparison of Student and Professional Engineers,” Proceedings of the 1997 ASME design Engineering Technical Conference, Sacramento, CA, 1997. [PB1] Pahl, G. and Beitz, W., Engineering Design: A Systematic Approach, Springer Verlag, Berlin, 1996. [S1] Suh, N. P., The Principles of Design, Oxford University Press, New York., 1990.

7- References

[U1] Ullman, D. G., The Mechanical Design Process, McGraw-Hill, New York., 2002.

[B1] Burger C. P., “Excellence in Product Development through Innovative Engineering Design,” Engineering Productivity & Valve Technology, Valve Manufacturers Association of America, Washington, DC, pp. 1-14, 1995.

[UE1]Ulrich, K. T. and Eppinger, S. D., Product Design and Development, McGraw-Hill, New York,1995.

[F1] French, M. J., Conceptual Design for Engineers, The Design Council, London,1985.

P95 VC InCo2006

-10-

Copyright Virtual Concept