**3.3 Functional analysis**

*Form follows functions* approach was used at this stage. That is, functions establishment should be independent of geometrical state to broaden the solution space [4]. A function is a task that transforms input to output in the system [13]. Therefore, functional modelling is a framework that relates functions in a flow, processes, and the operations to a system.


#### **Table 4.**

*Thought aid process applied for becoming the flow.*

designed to detect imbalance through a centre pivot, then motion is generated by this effect. To avoid shock on the system, a damper is used to guide and regulate; as other components rotate towards the desired position [12]. From this process four

main sub-functions can be summarised as follows;

**Design requirements Description**

by an operator.

*Quality Control - Intelligent Manufacturing, Robust Design and Charts*

tourism)

*Identified design requirement for dual axis solar tracker.*

Low energy consumption

Operational in Array setup (On-Grid)

Optimum Power output

Optimum Payback

Environmentally Friendly

Aesthetically appealing

period

**Table 3.**

**Figure 3.**

**98**

*ZomeWorks passive solar tracker [12].*

Low tracking error A highly efficient tracking is the one that can position towards the sun with relatively high accuracy, for an improved energy output.

Fully automated A machine with little human interface of daily operation, but with ease of use

birds through generation of toxic waste materials

For an economically feasible product, the tracking device should consume as

The tracker should be used on national electrical grid-connected PV system.

The solar tracking device should generate enough power either equal or slightly lower than the theoretical expectation, for economical and functional viability.

For an economically viable system there is a need that it has a lower payback period as the profit will be realised in the early period lifetime of the machine.

Solar energy aids in reducing pollution emission. Therefore, the device should not harm its surroundings e.g. ecological system, water sources, wildlife and

Growth in the use of renewable energy technology has led to an increasing interest in many people to comprehend the technology. Therefore, the solar tracking should be aesthetically attractive to attract tourists (i.e. technological

little energy as possible or use a mechanism which saves energy.

Using *"to become the flow"* heuristic approach, the transparent box model was developed to identify the *"function chains"* (i.e. related tasks often performed by a single physical component). **Table 4** shows a thought aid process (e.g. the retrieval questions) used in the "*becoming the flow"* approach. "*Becoming the flow"* approach is based on the flow of energy, signal and material in a system. The first step engaged in this process was to identify the inputs, outputs and following their interactions in the solar tracking system. Inputs in this study are defined as fundamental *"causes"* that ensure that the overall function of the system is performed. Output is the *"effect"* produced in the system i.e. these include; desired and undesired effects. Some of the inputs remain unchanged, while others change (i.e. they are consumed) in a process carried out by a system. These inputs were traced until they exit the system as outputs. To identify inputs and outputs the following guideline were used, a consideration of the requirements (i.e. functional aspect of system), environmental conditions and designer's understanding of the problem.

Transparent box model of a solar tracking device is shown in **Figure 4**. In this model, energy, material, and signal are traced from input to their relative output state. The model was used to identify function chains to achieve relevant tasks. In the stated figure the (SS.) stands for support structure, (tor.) is torque, (sys.) is system, (Ener.) is energy, (mech.) is mechanical, (elec.) is electrical, (Pow.) is power, (Enviro.) is environmental, (Pos.) is position and (Prot.) is protection [14].

#### **3.4 Generation of design alternatives**

A morphological Chart was deployed to perform this transitional process, i.e. to present design alternatives generated in this research. Firstly, the function chains identified with the aid of transparent box model were listed in the column of morphological chart (grid). Then possible alternatives (i.e. these are physical components available in market) to perform the tasks of the function chains were identified. Through brainstorming, the grid of the morphological chart was filled by noting (with text) ideated alternatives alongside their relevant function chains (i.e. on the row of the function chain). For example, two alternatives; electronic

anemometry (Alt 1) and airflow sensor (Alt 2) were brainstormed for the function

Possible combinations <sup>¼</sup> <sup>Y</sup><sup>n</sup>

¼ 5 � 2 � 3 � 4 � 4 � 2 � 5 � 4 � 4 � 2 � 3 � 2 ¼ 4, 147, 200

i¼1

O (1)

chain; wind sensor (**Table 5**) [15].

*Morphological chart present design alternative [15].*

**Function chain (Func.)**

Sun position sensor (Sun Pos.)

Power source (elec.)

Power source (mech.)

Control unit (CU.)

Actuator (Act.)

User's interface (UI.)

Support structure (SS.)

Energy recycling system (ER.)

Feedback sensor (FS.)

Wind sensor (WS.)

Rain sensor (RS.)

Cloud sensor (CS.)

**Table 5.**

**101**

Micro controller

Hydraulic cylinder

Keypad and LCD screen

Electronic Anemometry (EA)

Weighing precipitation gauge (WPG)

Cable mount Parallel

Spring system Piezoelectric

Optical sensor Ceilometer

**Alternatives (Alt.)**

*DOI: http://dx.doi.org/10.5772/intechopen.93951*

Photo sensors Real-time

Mini PV panel Grid

clock (RTC)

electricity

Personal computer (PC)

Pneumatic cylinder

Safety switch and LED flashlight

kinematics device (PKD)

system

Airflow sensors

Optical rain gauge

Solar engines Spring system Gravity engines

**Alt 1 Alt 2 Alt 3 Alt 4 Alt 5**

*Improving Product Quality through Functional Analysis Approach: Case of Dual Axis Solar…*

Programmable Logic controller (PLC)

Motor and gearbox

Rotating platform (RP)

Inclinometer Accelerometer Magnetometer Gyroscope

Spring return fluid power actuators

Water Sensors

Camera Global

positioning system device (GPS)

Field Programmable Gate Array (FPGA)

Stepper motor

Energy recovery wheel (ERW)

Polar mount Counterbalance

mount (CBM)

RTC+ photo sensor (Hybrid)

**Figure 4.** *Transparent box model of a dual axis solar tracking [14].*


*Improving Product Quality through Functional Analysis Approach: Case of Dual Axis Solar… DOI: http://dx.doi.org/10.5772/intechopen.93951*

#### **Table 5.**

Using *"to become the flow"* heuristic approach, the transparent box model was developed to identify the *"function chains"* (i.e. related tasks often performed by a single physical component). **Table 4** shows a thought aid process (e.g. the retrieval questions) used in the "*becoming the flow"* approach. "*Becoming the flow"* approach is based on the flow of energy, signal and material in a system. The first step engaged in this process was to identify the inputs, outputs and following their interactions in the solar tracking system. Inputs in this study are defined as fundamental *"causes"* that ensure that the overall function of the system is performed. Output is the *"effect"* produced in the system i.e. these include; desired and undesired effects. Some of the inputs remain unchanged, while others change (i.e. they are consumed) in a process carried out by a system. These inputs were traced until they exit the system as outputs. To identify inputs and outputs the following guideline were used, a consideration of the requirements (i.e. functional aspect of system), envi-

Transparent box model of a solar tracking device is shown in **Figure 4**. In this model, energy, material, and signal are traced from input to their relative output state. The model was used to identify function chains to achieve relevant tasks. In the stated figure the (SS.) stands for support structure, (tor.) is torque, (sys.) is system, (Ener.) is energy, (mech.) is mechanical, (elec.) is electrical, (Pow.) is power, (Enviro.) is environmental, (Pos.) is position and (Prot.) is protection [14].

A morphological Chart was deployed to perform this transitional process, i.e. to present design alternatives generated in this research. Firstly, the function chains identified with the aid of transparent box model were listed in the column of morphological chart (grid). Then possible alternatives (i.e. these are physical components available in market) to perform the tasks of the function chains were identified. Through brainstorming, the grid of the morphological chart was filled by noting (with text) ideated alternatives alongside their relevant function chains (i.e.

on the row of the function chain). For example, two alternatives; electronic

ronmental conditions and designer's understanding of the problem.

*Quality Control - Intelligent Manufacturing, Robust Design and Charts*

**3.4 Generation of design alternatives**

**Figure 4.**

**100**

*Transparent box model of a dual axis solar tracking [14].*

*Morphological chart present design alternative [15].*

anemometry (Alt 1) and airflow sensor (Alt 2) were brainstormed for the function chain; wind sensor (**Table 5**) [15].

$$\text{Possible combinations} = \prod\_{i=1}^{n} \text{O} \tag{1}$$

$$= 5 \times 2 \times 3 \times 4 \times 4 \times 2 \times 5 \times 4 \times 4 \times 2 \times 3 \times 2$$

$$= 4,147,200$$

The evaluation measures formulated at the planning stage of the design process were then deployed to judge the alternatives. As a way of guiding selection of best alternatives, that will be used to develop a concept. Some of the evaluation measures, which are normally used for evaluation of concepts, are defined below:

**Func. Criteria Alt 1 Alt 2 Alt 3 Alt 4 Alt 5**

*Improving Product Quality through Functional Analysis Approach: Case of Dual Axis Solar…*

Serviceability 4 5 1 3 4 Availability 5 4 1 3 4 Interfacing 4 5 1 3 5

**Point scored 16 16 7 10 17 Rank 2 2 4 3 1**

> Pneumatic cylinder

3 4 35

5 5 34

High response 3 4 2 5 Controllability 4 4 2 4 Interfacing 4 5 2 3

**Points scored 19 22 12 21 Rank 2 1 3 2**

Interfacing 5 3 2 3 Accuracy and Precision 3 5 4 4 Availability 5 4 3 5 Serviceability 5 4 2 2 Adaptability to control 4 5 5 5 **Point scored 22 21 16 19 Rank 1 2 4 3**

CU. Microcontroller PLC FPGA PC

Photo sensor RTC Camera GPS Hybrid

3 2 4 14

engines

Motor and gearbox

stepper motor

Sun Pos.

> Reliable in cloudy weather

*DOI: http://dx.doi.org/10.5772/intechopen.93951*

Act. Hydraulic

Minimal energy consumption

Compatible to support structure

*Evaluation of design alternatives for solar tracking [15].*

**Table 6.**

**103**

Electric. Mini PV panel Grid

Serviceability 5 4 Availability 5 5 Reliability 4 3 **Points scored 14 12 Rank 1 2** Mech. Solar engines spring system gravity

> Serviceability 5 5 4 Availability 4 5 2 Reliability 5 2 2 **Points scored 14 12 8 Rank 1 2 3**

> > cylinder


Evaluation of alternatives was then carried after a five-point Likert scale was established. Then each alternative was scored against the evaluation measure in a relevant manner (i.e. according to the knowledge and discretion of the designer). Points scored by each alternative were aggregated, and the alternative scoring high points were ranked as first choice (refer to **Tables 6** and **7**) [15].

Lastly, a concept was developed from aggregating the best-selected alternatives. This resulted in the final design which was modelled using a SolidWorks® platform (**Figure 5** shows the developed concept).

#### **3.5 Complexity analysis**

The analysis was carried out by comparing the existing systems' design complexity with the developed concept. In the comparison, the approach used in reference [11] was adopted. This approach uses modules and interactions between the modules to compare design products. A typical Keating's model is given in **Figure 6** whereby the number of components/modules (M), and number of interactions (I), in the design are counted and the inherent complexity computed using (Eq. (2)).

$$\mathbf{C} = \mathbf{M}^2 + \mathbf{I}^2 \tag{2}$$

**Table 8** shows a complexity metrics of systems developed in the period, 1997-2017. The average complexity of these systems was found to be 221.43 in this research.

**Figure 7** shows a diagrammatic embodiment design of the designed system. Plotting the complexity index of the developed concept against the complexity values of the existing systems give **Figure 8**. The trend illustrated the graph shows a relatively constant increasing pattern at the beginning of the study period up to the year 2005-2007. Generally the system designed is more complex when compared with developed between 1997 and 2004. While from 2005 to 2011 the existing


*Improving Product Quality through Functional Analysis Approach: Case of Dual Axis Solar… DOI: http://dx.doi.org/10.5772/intechopen.93951*

#### **Table 6.**

The evaluation measures formulated at the planning stage of the design process were then deployed to judge the alternatives. As a way of guiding selection of best alternatives, that will be used to develop a concept. Some of the evaluation measures, which are normally used for evaluation of concepts, are defined below:

• Serviceability/maintainability: This attribute describes the timeliness, relative cost and availability of skilled personnel in the local areas to carry out

• Reliability: the ability to maintain an expected functional behaviour at all times

• Interfacing/compatibility: the ability of the component to be useable with different configurations and strategies to achieve the desired function.

• Scalability: can a component be easily down or up sized for a specified

• Cost: the price value of a single component will affect the total cost of device

• Availability: ease of access of a component locally or less difficulties in sourcing it.

Lastly, a concept was developed from aggregating the best-selected alternatives. This resulted in the final design which was modelled using a SolidWorks® platform

The analysis was carried out by comparing the existing systems' design complexity with the developed concept. In the comparison, the approach used in reference [11] was adopted. This approach uses modules and interactions between the modules to compare design products. A typical Keating's model is given in **Figure 6** whereby the number of components/modules (M), and number of interactions (I), in the design are counted and the inherent complexity computed using (Eq. (2)).

*<sup>C</sup>* <sup>¼</sup> *<sup>M</sup>*<sup>2</sup> <sup>þ</sup> *<sup>I</sup>*

**Figure 7** shows a diagrammatic embodiment design of the designed system. Plotting the complexity index of the developed concept against the complexity values of the existing systems give **Figure 8**. The trend illustrated the graph shows a relatively constant increasing pattern at the beginning of the study period up to the year 2005-2007. Generally the system designed is more complex when compared with developed between 1997 and 2004. While from 2005 to 2011 the existing

**Table 8** shows a complexity metrics of systems developed in the period, 1997-2017. The average complexity of these systems was found to be 221.43 in this

<sup>2</sup> (2)

Evaluation of alternatives was then carried after a five-point Likert scale was established. Then each alternative was scored against the evaluation measure in a relevant manner (i.e. according to the knowledge and discretion of the designer). Points scored by each alternative were aggregated, and the alternative scoring high

points were ranked as first choice (refer to **Tables 6** and **7**) [15].

replacement and/or repair of components.

*Quality Control - Intelligent Manufacturing, Robust Design and Charts*

and under specific conditions.

hence its economic feasibility.

(**Figure 5** shows the developed concept).

**3.5 Complexity analysis**

research.

**102**

application.

*Evaluation of design alternatives for solar tracking [15].*


systems are more complex the concept developed in this research study. For period between 2012 and 2017 the system developed and existing system are generally equal in complexity. The pattern was realised because of the advancement which were made to the dual axis tracking such as including weather intelligent features

**Func. Criteria Alt 1 Alt 2 Alt 3 Alt 4 Alt 5**

*Improving Product Quality through Functional Analysis Approach: Case of Dual Axis Solar…*

optical gauge

water sensor

gauge

CS. Optical sensor Ceilometer Interfacing 5 2 Scalability 4 3 Availability 5 1 Cost 5 1 **Points scored 19 7 Rank 1 2**

*Continuation of evaluation of design alternatives [15].*

*General assembly drawing of the solar tracking concept developed.*

Interfacing 1 1 5 Availability 2 3 5 Scalability 2 4 5 Cost 2 1 5 **Point scored 7 9 20 Rank 3 2 1**

RS. Weighing

*DOI: http://dx.doi.org/10.5772/intechopen.93951*

**Table 7.**

**Figure 5.**

**105**

#### *Quality Control - Intelligent Manufacturing, Robust Design and Charts*


*Improving Product Quality through Functional Analysis Approach: Case of Dual Axis Solar… DOI: http://dx.doi.org/10.5772/intechopen.93951*

#### **Table 7.**

**Func. Criteria Alt 1 Alt 2 Alt 3 Alt 4 Alt 5**

SS. Cable mount Polar Parallel mech. CBM RP

Versatile utility 3 4 2 5 1 Assemble-ability 5 3 1 5 3

Robust mechanical 1 4 5 3 5 Points scored 18 17 11 22 12 Rank 2 3 4 1 5

Ease of use 4 1 5 2 Maintainability 5 2 4 1 Availability 4 2 5 1 **Points scored 18 8 19 5 Rank 2 3 1 4**

FS. Accelerometer Inclinometer Magnetometer Gyroscope Interfacing 4 5 1 2 Cost 5 5 1 1 Availability 5 5 2 2 **Points scored 14 15 4 5 Rank 2 1 4 3**

> Airflow sensor

ER. Springs Piezoelectric Spring return fluid

4 3 2 51

5 3 1 42

power actuators

53 5 1

ERW

LED and switch

UI. Keypad and

Accessibility of information

Optimal land coverage

Optimal material consumption

Compatibility to control

WS. Electronic

**104**

anemometry

Interfacing 4 4 Availability 3 5 Scalability 3 4 Cost 4 5 **Points scored 14 18 Rank 2 1**

LCD screen

*Quality Control - Intelligent Manufacturing, Robust Design and Charts*

High alarm rate 4 4 Compatibility 5 4 **Points scored 14 11 Rank 1 2**

5 3

*Continuation of evaluation of design alternatives [15].*

#### **Figure 5.**

*General assembly drawing of the solar tracking concept developed.*

systems are more complex the concept developed in this research study. For period between 2012 and 2017 the system developed and existing system are generally equal in complexity. The pattern was realised because of the advancement which were made to the dual axis tracking such as including weather intelligent features

#### **Figure 6.**

*A block diagram showing module and interaction of system developed by Akbar et al. (2017).*


**4. Conclusion**

**Figure 8.**

**Figure 7.**

*Embodiment diagram of a solar tracking concept developed.*

*DOI: http://dx.doi.org/10.5772/intechopen.93951*

**Acknowledgements**

**107**

nology for technical and financial assistant.

In this chapter a design of a dual axis solar tracker was used to describe a way of enhancing product's quality, during the early stage of product design. A design and complexity analysis undertaken resulted in a less complex solar tracker. The developed concept was evaluated against the existing solar tracking systems. Therefore, carrying out an analysis of complexity on system at an early stage of product design is important in improving the product functionality and simplicity factor. Conse-

*Improving Product Quality through Functional Analysis Approach: Case of Dual Axis Solar…*

I would like to thank Botswana International University of Science and Tech-

quently, this will relatively reduce the product's cost and design effort.

*A comparison of design complexity for the developed concept and existing mechanisms.*

#### **Table 8.**

*Design complexity study of existing solar trackers.*

(wind and rain shield systems). In summary the developed system, firstly, falls within the average complexity of existing systems, and secondly, it is 10% less complex than the existing systems.

*Improving Product Quality through Functional Analysis Approach: Case of Dual Axis Solar… DOI: http://dx.doi.org/10.5772/intechopen.93951*

**Figure 7.**

*Embodiment diagram of a solar tracking concept developed.*

**Figure 8.**

*A comparison of design complexity for the developed concept and existing mechanisms.*
