Novel Platform for the Development of Refrigerator Operating Software Using Virtualization, Automation, and Remote Control

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1

A DISSERTATION FOR

THE DEGREE OF DOCTOR OF PHILOSOPHY

Novel Platform for the Development of

Refrigerator Operating Software Using

Virtualization, Automation, and

Remote Control

냉장고 운영 소프트웨어 개발을 위한

가상화, 자동화, 원격제어 기반의 플랫폼 구축

February, 2014

Department of Agricultural Biotechnology

Seoul National University

Sang Oh Kim

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Novel Platform for the Development of Refrigerator Operating Software Using Virtualization, Automation, and Remote Control

냉장고 운영 소프트웨어 개발을 위한 가상화, 자동화, 원격제어 기반의 플랫폼 구축 지도교수 최 영 진 이 논문을 박사학위논문으로 제출함 2012 년 10 월 서울대학교 대학원 농생명공학부 김 상 오 김상오의 박사학위논문을 인준함 2013 년 1 월 위 원 장 장 판 식 (인) 부위원장 최 영 진 (인) 위 원 강 동 현 (인) 위 원 김 용 노 (인) 위 원 고 상 훈 (인)

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3

Novel Platform for the Development of Refrigerator

Operating Software Using Virtualization, Automation,

and Remote Control

By

Sang Oh Kim

Department of Agricultural Biotechnology

Seoul National University

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i

Abstract

Food is material mainly consisting of protein, carbohydrate, and fat used

in the body of an organism to sustain processes essential for growth,

recovery and life support and to furnish energy. In general, food is obtained

through collecting plants or animals, hunting, farming and livestock breeding.

Various methods have been developed and implemented to preserve food for

a long period of time. The most common way to preserve food almost in the

raw is to use a refrigerator or a freezer.

Currently, most freezers are operated after installing hardware and then

software. And, in the current development process, it is very difficult to

verify software before hardware is completely developed. In order to solve

this problem, this study is to seek and establish an environment where

software can be developed and verified by reflecting both values of the

virtual environment simulation and the freezer emulation.

One of the requirements of a competitive and favored freezer wanted by

customers is low electric power consumption. Some countries restrict the

amount of energy consumed and prevent the sales of the home appliance

with energy consumption exceeding the standards. In order to optimize the

electric power consumption, many tests should be conducted by changing

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ii

and human resources and time can be wasted during the process. To solve

this problem, software which is developed in the virtual environment will be

ported into an actual freezer, and the optimized parameter will be found

through an automatic experiment solution.

Even though the refrigerator was developed though the perfect processes

stated above, and all the required tests were executed under the strict test

condition, unexpected errors can appear when it is used by consumers in the

real environment. In an effort to analyze these errors, data from the initial

products is collected for a certain period of time. However, it is hard to

respond to problems in real time with a method of collecting data only after

problems are found. Therefore, data will be analyzed in real time, and errors

will be responded through the remote monitoring method. Also, this big data

will be reflected in the better user experience (UX) of the next- generation

refrigerator.

Studies on new methods to develop a refrigerator and a freezer were

executed well, and in the future, this technique will be applied to diverse

home appliances and will provide the better to the customers.

Key Words: Refrigerator, Freezer, Simulation, Emulation, Virtualization,

Optimization, Automation, Electric Power Consumption, Remote Control,

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iii Student number: 2000-30735

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iv

I I I . R e s u l t s a n d D i s c u s s i o n . . . 1 3 5 3 . 1 . C o m p l e t e d p r o g r a m . . . 1 3 5 3 . 2 . E x p e r i m e n t a l a n a l y s i s . . . 1 3 7 3.2.1. P artial Lea st Squares...13 7 3 .2 .2 . M ul t i p l e R e gr e s s i o n Ana l ys i s . . . .. .. . .. . .. . .. . .. .. . .. .. . .. . .. .. . .. .. . .. 1 50 3.2.3. Two-level Full Factorial Designs...157

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I V. C o n c l u s i o n . . . 1 7 7 V. R e f e r e n c e s . . . 1 7 9

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viii

CHAPTER 3

The Remote Monitoring System Construction in Order to Verify the Field

Test of the Developed Refrigerator and Acquire the Big Data Used for the

Improvement of User Experience (UX)

A b s t r a c t . . . 1 8 8

I. Introduction...189

1.1. Review...189

I I . M a t er i a l s a n d M eth o d s . .. . .. .. .. . .. .. .. .. . .. .. .. . .. . .. .. . .. .. .. .. . .. .. .. . .. .. .. . .. .. 1 9 2 2.1. Hardware design...192

2.2. Server, clients and networks...197

2.3. Software development...200

2.3.1. The software for operating the FSF...200

2.3.2. Client data acquisition software...202

2 . 3 . 3 . We b S e r v i c e . . . 2 0 5 I I I . R e s u l t s a n d d i s c u s s i o n . . . 2 0 7 3.1. Operation condition...207

3.2. The use pattern analysis...209

I V. C o n c l u s i o n . . . 2 1 6 V. R e f e r e n c e s . . . 2 1 8

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ix Appendices A p p e n d i x A . S i m u l a t i o n s o u r c e w i t h V i s u a l C + + . . . 2 2 1 [ V i r t u a l F r e e z e r D l g . h ] . . . 2 2 1 [ V i r t u a l F r e e z e r D l g . c p p ] . . . 2 2 6 A p p e n d i x B . E m u l a t i o n s o u r c e w i t h C + + . . . 2 5 6 [ m o a c o n . c p p ( w i t h s i m u l a t o r ) ] . . . 2 5 8 [ E m u l a t o r . c p p ] . . . 2 6 4 Korean Abstract 초 록 . . . .. . . . .. . . .. . . . ... . . .. . . . .. . . . .. . . .. . . . .. . . . .. . . .. . . . .. . . . .. . . . .. . . .. . 28 2

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x

LIST OF TABLES

Table 1-1. Common properties of air at atmospheric pressure ...28

Table 1-2. The converted PLC functions to be used in Visual C++...54

Table 1-3. The experiment result of actual and virtual temperature...54

Table 3-1. The data flow table of the developed overall system ...199

Table 3-2. The defined communication protocol between the remote FSF server and the client ...201

Table 3-3. The comparison of the use time between a refrigerator and a freezer compartment...213

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LIST OF FIGURES

Figure 1-1. Ideal embedded system development process...13

Figure 1-2. The comparison chart of the development process between the traditional method (a; left) and the new VPSDP method (b; right)...17

Figure 1-3. The difference of between the planned development process and the actual d e ve l o p me nt p r o c e s s . . . 1 9 Figure 1-4. The various energy flows inside the freezer...22

Figure 1-5. The specific heat capacity curve of the air in relation to the temperature...29

Figure 1-5. The actuators installed on the experimental freezer system...33

Figure 1-6. The sensors installed on the experimental freezer system ...35

Figure 1-7. The measuring instruments connected with the experimental freezer system to acquire data...37

Figure 1-8. Overall experimental freezer system...39

Figure 1-9. The concept diagram of the VPSDP (Virtual Product Software Development Process)...41

Figure 1-10. The feedback relation between the environment simulator and the freezer emulator... 44

Figure 1-11. The basic algorithm flow chart of the freezer program ... 45

Figure 1-12. The architectural view of the simulator system and the emulator system ... 47

Figure 1-13. The modified functions provided by the manufacturer to operate in MFC...49

Figure 1-14. The simulator program GUI...52

Figure 1-15. The virtual socket concept for communication between the simulator system and the emulator system; the detail drawings in the perspective of the emulator...64

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Figure 1-16. The virtual socket concept for communication between the simulator system and the emulator system; the detail drawings in the perspective of the

simulator ...66

Figure 1-17. The sent and received protocol format of the virtual communication ...68

Figure 1-18. The dimensions of the actual freezer system...70

Figure 1-19. The picture of the completed experimental freezer system...73

Figure 1-20. The completed simulation program and the operational state ...75

Figure 1-21. The numerical analysis results shown in the console display...76

Figure 1-22. The freezer temperature chart measured by the numerical analysis and the real temperature...84

Figure 1-23. The experiment result analysis of actual and virtual temperature...86

Figure 2-1. Experiment system block diagram detailed in the target Programmable Logic Controller...114

Figure 2-2. The complete refrigeration cycle with the four basic components: compressor, condenser, evaporator, and expansion device. And the temperature control chart...117

Figure 2-3. Experiment system block diagram detailed in the intelligent and automatic experiment proceeding software ...119

Figure 2-4. The detailed program algorithm flowchart in the intelligent and automatic experiment proceeding software ...122

Figure 2-5. The initial GUI design of the intelligent and automatic experiment program ...124

Fi gur e 2-6. T he grap hi c al tes t res ul ts o f t he i nitial proposed e xperi me nt algorithm ...127 Figure 2-7. The test progression using the initial proposed experiment algorithm in relation

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xiii

to time ...128

Figure 2-8. The modified advanced stabilization method to reduce the stabilization time in the experiment algorithm ...129

Figure 2-9. The advanced measurement method to reduce the measurement time in the experiment algorithm ...131

Figure 2-10. The graphical result of the final automatic and intelligent experiment proceeding software algorithm ...132

Figure 2-11. The automatic and intelligent experiment proceeding software developed using LabVIEW ...136

Figure 2-12. Partial Least Squares standard coefficient plot...140

Figure 2-13. Partial Least Squares distance plot...142

Figure 2-14. Partial Least Squares residual versus leverage...143

Figure 2-15. Partial Least Squares loading plot...145

Figure 2-16. Partial Least Squares model selection plot...147

Figure 2-17. Partial Least Squares response plot...149

Figure 2-18. Residual plots for the electric power consumption calculated with all factors...153

Figure 2-19. Residual plots for the electric power consumption calculated with selected factors ...156

Figure 2-20. Normal plot of the standardized effects...161

Figure 2-21. Pareto chart of the standardized effects...163

Figure 2-22. Residual plots for the electric power consumption ...165

Figure 2-23. Main effects plot for the electric power consumption ...167

Figure 2-24. Interaction plot for the electric power consumption ...169

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xiv

Figure 2-26. Response Optimization Result #1; Notch: -23.6364, Differential: 1.0, Compressor_Delay: 423.0303, Fan_Speed: 3000.0, Fan_Delay: 1.2121 (when the target of the electric power consumption is 1,000,000 Whr) ...174 Figure 2-27. Response Optimization Result #2; Notch: -28.1336, Differential: 1.0, Compressor_Delay: 420.0, Fan_Speed: 22128.0257, Fan_Delay: 0.0 (when the target of electric power consumption is 1,000,000 Whr) ...175 Figure 2-28. Response Optimization Result #3; Notch: -27.6340, Differential: 3.7607, Compressor_Delay: 720.0, Fan_Speed: 23000.0, Fan_Delay: 120.0 (when the target of electric power consumption is 1,000,000Whr) ...176 Figure 3-1. The hardware structure and the input-output port of the FSF system ...193 Figure 3-2. The overall connectivity of the experiment network system ...196 Figure 3-3. The flow chart of the data exchange between the FSF and the client software ...204 Figure 3-4. The web service is supported...206 Figure 3-5. The client software gathers the remote condition data and the image data ...208 Figure 3-6. The chart drawn by the received data and the use pattern between (a) and (b). ...210 Figure 3-7. The diverse analysis charts about the use time ...212

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1

Chapter 1 The Freezer Program Emulation Method in the

Virtual Simulation Environment Using the

Virtual Product Software Development Process

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2

Abstract

The freezer is essential for freezing and preserving food for a long period

of time and maintaining the quality of the raw food to the maximum level at

room temperature. The general process to develop a freezer and other home

appliances with software was to develop hardware first and then develop

software for hardware. However, this was accompanied with a problem that

enough time was not given to test the software quality in case the hardware

development was delayed.

Hence, the virtual external environment will be constructed, and the effect

same as developing the software on the actual hardware will be realized

through both of the emulated freezer system and the simulated external

environment. In order to simulate the heat transfer of the virtual environment,

the freezer will be calculated through the numerical analysis, and the

temperature change of this virtual environment will be controlled by the

output state of the emulated freezer software.

The software developed in this way was ported into a freezer which was

actually developed and was controlled equally with the result from operating

the virtual machine.

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3 Virtual Machine, Virtualization, Porting.

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4

I. Introduction

1.1. Review

The previous definition of a Virtual Machine could be described as a

'Completely isolated guest operating system installation within a normal host

operating system" [1]. However, current definition of a virtual machine

includes both the software emulation and the hardware virtualization.

Popek and Goldberg defined the basis of the virtual machine as "an

efficient, isolated duplicate of a real machine". Today, it includes virtual

machines taking no direct correspondence to any real hardware [2, 3].

Virtual machine is divided into system virtual machine based on system

and processor virtual machine based on processor [4]. The system virtual

machine has the concept of installing the virtual machine software on the

main Operating System (OS) and then installing other OS in the top of the

installed virtual machine. VirtualBox (Oracle, CA, USA), VMware (VMware,

CA, USA) and Parallels (Parallels, WA, USA) are considered as typical

system virtual machine products. Using system virtual machines, several

types of OS can be operated at the same time and variety of software

development platforms can be supported. However, system virtual machines

induce processing speed degradation, because hardware resources can be not

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5 machine software.

The process virtual machine is also called application virtual machine

because of the concept of operating only the application area in a software

structure [5]. Typical process virtual machines are platform independent

languages such as Java (Oracle, CA, USA), C# language (Microsoft, WA,

USA) and etc. When source code is compiled, an intermediate binary code

instead of an execution binary code is generated, and the run-time machine

executes the program with real-time interpretation. This virtual machine can

be driven without source code changes on any operating system that supports

run time machine. An intermediate binary code has also the shortcomings

that it is slower compared to an executable-compiled file operated on a

specific OS, but such virtual machines are widely adopted because of the

greatest advantage of them being platform independent.

In all kinds of virtual machines, the word 'emulation' is frequently used.

Emulation supports a real environment of any actual system through

virtualization. An emulator is an imitation of the behavior of a computer or

other electronic systems through the help of another computer or a system [6,

7].

Even if an executable file is not in the actual hardware, an emulator in the

virtual hardware system can provide the same action as the actual

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developing smartphone applications, emulation is a commonly used

technique in platforms such as Android, iOS and Windows Mobile, and

called the software Development Kit (SDK) s.

The virtual development follows the usual procedure in which a program

is firstly developed in the virtual hardware environment and then is operated

and debugged in the actual hardware environment. Initially, the developed

software in the virtual hardware environment can be tested without the actual

hardware, and then the tested software is debugged when the completed

actual hardware is produced. Both the virtual development environment and

the cross-compiling technique which enables the program to operate on other

OS applications are applied among various devices.

Simulator is a machine that conducts simulation in a virtual environment.

Simulation can be defined as a process or behavior which imitates an actual

machine [9, 10]. To conduct simulation, a behavior model imitating the

actual system must be developed. The model represents both major

characteristics and the behaviors of the physical and abstract system. In this

study, the temperature changes of the freezer according to the difference in

the volume and the physical properties of the surrounding environments are

represented through numerical analysis.

Historically, the conduct of simulation has been developed independently

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the cybernetics research using simulation have become more systematic

through the growth of computer industries and improvement of program

techniques.

Physical simulation means that real objects are transferred to physical

objects. The physical objects are often selected because it is smaller and

cheaper than real objects. The interactive simulation is a special kind of

physical simulation. Instead, a person must be used as an operator to do the

simulation. Simulators such as flight simulators or driving simulators mainly

belong to physical simulation. Through physical simulation, a human is

trained in the virtual environment that simulates actual environment, and

when he is sent in the actual environment, he will be able to adapt to the

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1.2. Environmental virtualization

A numerical analysis study of the heat transfer is also necessary to

virtualize the external environment of the freezer. These tasks are managed

using a computer called the Computational Fluid Dynamics (CFD) [11, 12].

Technicians such as Leonardo da Vinci who is known as a great artist made

the initial attempts on testing fluid dynamics and the flow of the natural

world in detail. He recognized the shape and structure of the fluid, and

precisely represented it with accurate diagrams, and has observed natural

phenomena in the world of substances. He contributed in the fluid dynamics

such as the surface of the water, the movement of water, waves, swirl, ebb,

free jet, the interference of the waves, and also has dealt with many other

phenomenons observed in the recent world. His related works are expressed

in part of nine different publications [13].

These achievements by Da Vinci are inherited by Sir Isaac Newton in the

second half of the 17th century. Through his basic Newtonian theories,

Newton tried to predict and measure the fluid flow phenomena.

In 18th and 19th centuries, researchers have attempted to mathematically

describe the movement of the fluid. By Daniel Bernoulli (1700-1782), a

famous Bernoulli equation was introduced. Leonhard Euler (1707-1783)

introduced the Euler equations describing the law of conservation of mass

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9 also proposed the velocity potential theory.

French researcher Claude Louis Marie Henry Navier (1785-1836) and

Irishman George Gabriel Stokes (1819-1903) introduced the movement of

viscous with Euler equations, which is established as the Navier-Stokes

equations. This theory established almost 200 years ago now forms the

foundation of the modern CFD industry [15]. It includes the expression of

the preservation of mass, momentum, pressure, and the turbulent surface.

This equation is difficult to find answers to, but after digital computers were

introduced in the 1970, the problem of the actual fluid was able to be solved

by them.

In the 19th century, researchers such as Jean Le Rond d'Alemert,

Simeon-Denis Poisson, Joseph Louis Lagrange, Jean Louis Marie Poiseuille, John

William Rayleigh, M. Maurice Couette, Osborne Reynolds, and Pierre

Simon de Laplace have all made contributions in expressing the fluid

dynamics.

In the early 20th century, Fluid flow has been performed to establish the

theory of the boundary layer and the turbulent layer. Ludwig Prandtl

(1875-1953) have proposed the boundary layer theory, which establishes the

concept of mixing length, compression flow, Prandtl number, and many more

things which we take for granted today. Theodore von Karman (1881-1963)

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Geoffrey Ingram Taylor (1886-1975) proposed the statistical theory of

turbulence and the Taylor micro-scale. Andrey Nikolaevich Kolmogorov

(1903-1987) introduced the concept of the universal energy spectrum and the

Kolmogorov scale of turbulence. George Keith Batchelor (1920-2000)

contributed to the theory of homogeneous turbulence.

The beginning of CFD was initiated by Britain's Lewis Fry Richardson

(1881-1953), who developed the first numerical weather prediction system.

Calculating the fastest numerical solution to the flow passing of a cylinder

was performed by Thom has in the UK, 1933.

In 1953, Kawaguti of Japan calculated the cylindrical fluid flow by using

mechanical desk calculator, working 20 hours per week for 18 months.

In 1960, many numerical calculations such as Particle-In-Cell (PIC),

Marker-and-Cell (MAC), Vorticity-Stream function methods, Arbitrary

Lagrangian-Eulerian (ALE) methods and the ubiquitous k-e turbulence

model that are still being used in the CFD in NASA's theory division located

in Los Alamos in the United States have been established.

In 1970, At Imperial College London, k-equations’ SIMPLE algorithm and

TEACH code were developed by researchers lead by D. Brian Spalding

(Spalding & Launder, 1972). They continued to develop the updraft, and

combustion models such as 'Eddy breakup' and 'presumed PDF' were

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In 1980, ‘Numerical Heat Transfer and Fluid Flow’ written by professor

Suhas V. Patankar was published. This book is the most influential book in

the CFD, and has created thousands of CFD codes. In the early 1980s,

commercial CFD codes were introduced into the open market by Patankar’s

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1.3. The objective of this study

Designing a firmware system includes both hardware and software design.

Often also mechanics design is needed. The diagram shown in Figure 1-1 is

the best ideal firmware development model [16]. In many cases the final

hardware cannot be defined until very late in a project. This means that most

of the time the software development is done on different hardware than the

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13 Figure 1-1. Ideal embedded system development process.

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14

In the field of home appliances using MICOM installed with the firmware

software, there has been much progress on utilizing simulation and

simulators. However, in the current situation, the emulator device for

developing the software of the microcomputer mounted in home appliances

are configured separately from surrounding environment. This study will

develop both the simulated system of external environment and the emulated

freezer control software, and their data are synchronized with each other and

through this research, more advanced research paradigms will be created.

Among software developers of home appliances, the main issue is always

related to the need for researching the parallel development process shown in

Figure 1-x. In the development process, the last schedule is assigned to the

software developer, and by many software errors and software problem,

much delay is induced due to lack of the software test time. However, the

proceeding process of the hardware developers is the bigger issue rather than

the willingness of the software developers. Software is difficult to develop

without the hardware, and if hardware eventually is provided without enough

time, the software verification tasks cannot be satisfied, which will cause the

porting to eventually contain errors.

If the ideal development process is applied, the developed software can be

verified, debugged and completed at the hardware completion time because

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Therefore, this helps in shortening the mass production considerably.

The objective of this research is to develop the system program in the

virtual environment to simulate a real-world environment that reflects the

flow of these technologies. A virtual environment reflecting the actual

surroundings is built for the sake of this study, and there is a need to emulate

the virtual freezer system. The former virtual environment is called a

simulator, and the latter virtual freezer system is called emulator. Such a

development process is named as Virtual Product Software Development

Process (VPSDP).

If more systematic approaches of VPSDP methodology are possible, the

property of the common resemblance is founded, and the software function

library can be made, and it will have a positive value to the entire software

development system.

Actually, the development process in the electronic business is shown in

Figure 1-2 (a). However, if the embodied VPSDP techniques through this

study are used, a lot of time can be saved as shown in Figure 1-2 (b). This

development environment is used by implementing the most advanced

mobile development environment.

However, generally the equipment used in the food industry such as

refrigerators and freezers must follow the (a) process of the development.

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means that until the final hardware development is completed, the software

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(a) Common Method (b) VPSDP

Figure 1-2. The comparison chart of the development process between

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As shown in the Figure 1-3, the actual schedule compared to the initial

plan is always delayed from a few months to a few years. The schedule delay

that accounts for the biggest portion of delay is software error. Even if the

freezer system has 100% integrity, the integrity can also become 0% because

of one error in the operation of the software loaded in the system.

Therefore, the importance of the software in the system is heavily

emphasized, but the time to test the software on the hardware is not given in

the development locus.

When pre-production is finished, hardware system is revealed, and

software test is enabled. The responsibility of the delayed schedule of this

problem is given to the software developer, which implies much stress on

them. To solve these problems, this research resolves the production

schedule delays and improves software quality.

Through Chapter 1 of this study, and after building a virtual environment

without hardware, the possibility and feasibility of the software development

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Figure 1-3. The difference of between the planned development process

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II. Materials and Methods

2.1. Model system and equations

The freezer is simulated through the implemented model system. The

thermal conductivity (k) of the freezer heat insulation material, the heat

transfer area, the speed of the fan, the volume, and the convective heat

transfer coefficient (hin, hout) can be changed through the GUI of the

developed simulator program. Whether the virtualization will be successful

of not will be known through being compared with a modified actual system,

FD-170-SF freezer (Unique Daesung Co., Ltd, Gyunggi, South Korea) [18].

The flow of energy from the freezer is designed as shown in the Figure 1-4

From the energy balance, we can calculate the energy of air (Qair) and food

(Qfood) in the freezer by the value of eliminated energy from the evaporator

(Wevaporator) minus the sum of the incoming heat through the insulation

material (Qinsulation) and the food respiration heat (Qrespiration) [19-25].

To solve this problem, the following assumptions are given. Heat transfer

is composed as one-dimensional because of the wall thickness of the freezer

is significantly related. Thermal properties, heat transfer coefficients, and

outdoor temperature are constant. Radiant heat is ignored. During this period,

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barometric pressure is 1 atm. The food and corner space is ignored. Incoming

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α: diffusivity Tn : nodal temperature Δx : nodal space

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Various properties that are used for calculation is obtained by user-defined

manner through the GUI of the program. The incoming flow of heat through

the heat insulation will be solved through explicit finite element method [27].

(1-1)

The number of nodes, M, is determined by the insulation thickness from

the program given by the Equation 1-1, M = L / Δx +1.

In this analysis, because the unknown n-1 nodal temperature will be given,

four formulas are generated. The range of the interior node is from 2 to n-1.

To solve them, the general explicit finite difference relation uses the

following Equation 1-2.

(1-2)

Nodes from 1 to n-1 related to the convection and radiation can be defined

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As the heat transfer is made through convection, an expression derived

through the following Equation 1-3, 1-4 can be created about Node1.

(1-3)

(1-4)

Node 2 to Node n-2are calculated by using the following Equation 1-5,

because the thermal conductivity is made through the interior properties.

(1-5)

Node n-1 is achieved through the process of convection heat transfer to the

final inside wall. Therefore, the final expression can be derived through the

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(1-6)

(1-7)

The mesh Fourier number is obtained through the following Equation 1-8:

(1-8)

The weight of the air can be obtained through the following equation 1-9:

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The final equation in the energy balance Node n section about the air

space of the freezer can be derived through the following Equation 10,

1-11.

(1-10)

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2.2. The characteristics of the air and equations

The following Table 1-1 and Equations 1-12~1-16 are re-made by being

based on all existing references for simulation with computer [27].

Specific heat capacity:

(1-12) Thermal conductivity: (1-13) Density: (1-14) Kinematic viscosity: (1-15) Prantl’s number (1-16)

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29 2.3. Designable food and equations

The model food is generally assumed to be a rectangular parallelepiped

figure. The properties such as width, height, length, protein, fat, carbohydrate,

water, ash, respiration heat, etc., are freely changed by the developed

program through GUI. Through this many different varieties of food can be

simulated. Whether a model food is success or not will be evaluated by the

test package used commonly as refrigeration load tester.

In order to reflect the freezing characteristics of food, the heat transfer

algorithm of food is designed. Governing equation follows the steady-state

heat conduction equation, and it reflects considering surrounding

temperature and the heat exchange rate. Because food has the various

complex physical properties and special characters, the numerical analysis

equation using the test package which simulates food is calculated.

Numerical analysis result is compared with the actual load result using the

test package(TYPE 1250”, -1℃; MADI, ITALY).

The refrigeration load represents the total calories that need to be removed

from the object of any kind until it reaches the desired temperature. In order

to effectively freeze the object, the used freezer must have enough ability to

remove the calories of the refrigeration load.

Refrigeration load can be divided into two groups, refrigeration load of

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calories that need to be removed in order to maintain a constant temperature

storeroom. On the other hand, unsteady state refrigeration load is the

removal rate of the calories to freeze an object stored in a freezer for a

limited time until the desired temperature [12, 28-33].

Calories in food requirements can be obtained through the following

Equation 1-17.

(1-17)

Because food material can be set freely through the program, an

expression can predict the specific heat required. This is predicted through

the following Equation 1-18 [34, 35].

(1-18)

In addition, the ratio of the material must always satisfy 1, as shown in the

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(1-19)

Because fruits and vegetables breathe, the respiration heat must be

included in the refrigeration load. As respiration heat is a function of

temperature, it can be expressed as shown in the following Equation 1-20. If

weight is multiplied with the equation, the respiration calories can be

calculated.

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32 2.4. Experimental system configuration

The experimental verification is progressed through the system shown in

the Figure 1-5. Of the existing product under sale, only the outer part and the

cycle are used, while the control part is separately made and used [36].

A fan to simulate both the direct and indirect cooling freezer by

controlling the mass flow rate is installed in the freezer of the direct cooling

method. The evaporator to exchange heat is installed on all four sides, and

the discharge temperature of the capillary tube can be as low as -50℃.

A FD-170-SF deep-freezer will be used as the target freezer. A small

cabinet for freezing the food is installed to monitor the food temperature

change associated with the freezer temperature change. Also, Programmable

Logic Controller (PLC) is installed to replace the existing control unit.

The compressor, the AC fan of the machine room, and the freezer DC fan

shown in Figure 1-8 are controlled by the newly designed controller using

PLC. The compressor and the machine room fan are driven with the on/off

operation through relays. The DC fan is controlled by the variable through

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34

The room temperature and the freezer temperature are measured with the

thermoresistor (PT100Ω) sensor shown in Figure 1-6, while the room

humidity and the freezer humidity is measured with the humidity sensor

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35

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36

A WT120 (Yokogawa, Japan) power meter shown in Figure 1-7 is used to

measure the electric power consumption. In order to acquire operation state

data, a general personal computer is used to connect with controllers and

measurement devices [38].

For communication shown in Figure 1-7, RS-232C serial communication

is used [39]. In order to allow remote measurement, wired signal is

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Figure 1-7. The measuring instruments connected with the experimental

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As shown in the Figure 1-8, actuators, sensors, instrumentation, and

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40 2.5. Virtualization concept

The virtual system for emulating the freezer as shown in Figure 1-9 is

made using the Microsoft Windows environment. The freezer program is

developed and executed directly in the virtual environment, while the

freezing time is predicted using the influence of the virtual food. After

completion of the development process, it will be ported in the actual freezer

system and compared to evaluate how well it is suited to the system.

The simulator program is made by using the model equation. The virtual

temperature of the simulator is quantified in conjunction with the compressor

of the emulator and the fan output. This will in turn be reflected in the

temperature of the emulator.

The emulation program is virtualized in the simulator to logically

controlled using the provided temperature value. Since this emulator is the

virtual program that represents the actual control machine, it must be

programmed using the grammar of the control program. Therefore, the

control program must be written in C language, and the library must also be

virtualized because only the libraries provided by the manufacturer can be

used. The manufacturer's library used in this program is changed by using

the virtualization program rule. The list and description of the converted

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2.6. Algorithm design for the virtual system

Machine like freezers generally use the feedback control method which

controls the output through the input value. This can be classified according

to the control type such as simple on/off control, proportional control, PI

control, PID control, and etc. In our model, the simple on/off control and

PID control are used in conjunction because the composed actuators of the

freezer are a recipro-type compressor and a variable DC-type fan.

Parameters used for configuring a freezer are divided into two types, the

input type and the output type shown in Figure 1-10. Input types are

temperature and humidity, while output types are fan and compressor.

Predicting the temperature change between two types is composed as the

simplified frozen load change algorithm.

All input and output ports are virtualized, and all freezer processor

programs are input/output through the virtualized ports. The basic algorithm

of the freezer firmware program is constituted as follows and Figure 1-11 is

the program flow chart.

[Basic Algorithm] If current sensor temperature is greater than

<setting temperature + differential>, fans and the compressor become ON. If current sensor temperature is less than <setting temperature + differential>, fans and the compressor become OFF

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The virtualization environment software and the freezer processor

software are programmed by using Visual C++ (Microsoft, USA). The

freezer processor software is implemented through redesigning and porting a

c-based manufacturer providing functions used in MOACON PLC (Comfile

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Figure 1-10. The feedback relation between the environment simulator

and the freezer emulator.

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2.7. Overall software architecture

The virtual system shown in Figure 1-12 is divided with the system

emulator part and the freezer program part. When the freezer program is

executed, the system emulator part calculates the effects of freezer outputs

on the system. Using these output influences, the system input values are

changed. To express these area values in detail, it is continuously calculated

using the heat transfer equation presented earlier. Also, the heat transfer

algorithm of the virtual food is included for calculating the temporal frozen

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This virtualization program is designed on the MFC library based on

Windows OS. To constitute the Windows program based on GUI, the

program is produced using Microsoft Visual C++ [43]. The freezer program

area is constituted by C language as the program area operated with PLC,

and this program is operated in the virtual system like as the actual system.

After the development is completed, it is programmed with library supported

in PLC because it must later be ported in the actual freezer system. The

standard functions in MFC and C does not maintain specific functions for

PLC management. To embody the special PLC function in the virtual system,

the PLC library function for the virtual system like as Figure 1-13 will be

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49

Figure 1-13. The modified functions provided by the manufacturer to

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50 2.8. GUI composition

The GUI interface will be constituted like shown in Figure 1-148, and the

program linked with the PLC program will monitor the operation state of the

virtual system. Interfaces are composed with the area of Chart, Indicators,

Communication and Data Storage Settings, and Virtual Environment Settings.

This program can also be used for communication with the actual system.

2.8.1 Chart Area

Chart area draws a graphical representation of the state of load and

temperature over time. These values may be expressed from the result of the

simulation or the actual system. This depends on whether 'Virtual System

Usage' item is checked in the area of 'Communication and Data Storage

Settings'.

Through this area, the cumulative series changes of the system are

understood visually.

2.8.2. Indicators Area

Through the indicators area, status of the current points such as

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2.8.3. Communication and Data Storage Settings Area

If ‘Use Virtual System’ is checked, the freezer program based on the

virtual freezer system and the system simulator is operated. Otherwise, it will

communicate with the actual developed freezer.

2.8.4. Virtual Environment Settings area and The Food Area

This area is the configuration part of the virtual freezer system. By setting

various parameters, the freezer is simulated. The already determined virtual

foods are simulated depending on its size. If the food model is not

determined, it provides a pop-up window so that a user-defined food can be

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(a) Main Program GUI

(b)Model Food Maker Program GUI

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2.9. Program flow to emulate the freezer controller (or PLC)

The following Table 1-2 is the list of new library functions for

cross-compiling between different systems. If this function file does not exist,

compilation in Visual C++ environment cannot be executed properly

cross-compilation cannot be done on C or C++ of other OS.

The freezer program shown in Figure 1-15 is composed of the basic

algorithm described previously. In this section, the program is analyzed in

the logic associated with PLC emulator in more detail. Basically, variables

are initialized and the watchdog is set in the program start point. The

program is looped infinitely by a ‘while(1)’ instruction and whenever the

program reaches the initiation point, the program announces the watchdog

reset to the emulator to notify that the program is operating without problems.

Through the use of virtual communication with the virtual simulation

environment, the freezer algorithm is performed to control the values of the

environment, and the final load state is also decided. The load output values

and other reset variables value are processed and fed back to the virtual

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Table 1-2. The converted PLC functions to be used in Visual C++.

(a) System Emulation Functions

void delay(u32 interval)

Parameters

interval: Number of milliseconds to pause Pauses execution for interval milliseconds. void statusLED(u8 onoff)

Parameters

onoff: 0=Off, 1=ON

Turns the status LED on the CPU Module on or off. void wdtOn(u8 timeout)

Parameters

timeout: A number corresponding to a specified timeout (0 ~ 6) Enables the watchdog timer with a specified timeout, timeout. void wdtClear (void)

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(b) Event Emulation Functions

void startTimerEvent (u16 interval)

Parameters

interval: The amount of time between each event in milliseconds (1 ~ 65,535)

Starts a timer that triggers events every interval milliseconds. void timerEvent (void)

This is the function that is called when a timer's event fires. void stopTimerEvent (void)

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(c) MCU Digital Output Emulation Functions

void portInit(u8 portBlockNumber, u8 mode)

Parameters

portBlockNumber: Port Block Number (e.g. 0 for ports 0~7, 1 for ports 10~17, etc...)

mode: 0 or 1 (0=Output, 1=Input)

Initializes a port block's I/O mode as either Input or Output. void portOff (u16 portNumber)

Parameters

portNumber: The port number to turn off

Sets the output state of the given port, portNumber, to off. void portOn (u16 portNumber)

Parameters

portNumber: The port number to turn on

Sets the output state of the given port, portNumber, to on. void portReverse (u16 portNumber)

Parameters

portNumber: The port number to toggle

Toggles the output state of the given port, portNumber. u8 portOutStat (u16 portNumber)

Parameters

portNumber: The port number to read current state.

Returns

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Read the output state of the given port, portNumber. void portOut (u16 portNumber, u8 value)

Parameters

portNumber: Port Number of an individual port (not a port block)

value: 0 or 1 (0=Off, 1=On)

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(d) Temperature Input Module Emulation Functions

int getTemp (u8 tempId, u8 tempCh)

Parameters

tempId: The ID of the Temperature Input Module (0 ~ 9) tempCh: The channel on the Temperature Input Module (1 ~ 2)

Returns

the temperature in °C multiplied by 10. (-1000 ~ 5000)

Gets the temperature read from a PT100 sensor connected to Temperature Input Module tempId on channel tempCh.

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(e) Communication Emulation Functions

void openCom (u8 comCh, u32 comBaud, u8 comMode)

Parameters

comCh: Channel number comBaud: Baud rate

comMode: Communication mode (data bits, parity, and stop bits) Opens the port on channel comCh with the given baud rate, comBaud, and the communication mode, comMode.

short comGets(u8 comch, u8 * dest, u16 length)

Parameters

comCh: Channel number

dest: Pointer to where data that is read should be stored length: The amount of data (in bytes) to read.

Returns

–1 if data is read; 0 if data is not read.

Reads length bytes from the receive buffer on channel comCh, and stores the data in memory at address dest.

void comPuts(u8 comch, u8 * src, u16 length)

Parameters

src: Pointer to data that should be sent

length: The amount of data (in bytes) to send.

Transmits length bytes of data from memory address src out channel comCh.

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u16 comLen (u8 comCh)

Parameters

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(f) LCD Emulation Functions

void clcdI2cInit(u8 clcdAdr)

Parameters

clcdAdr: The I2C slave address of the CLCD module

Initializes the CLCD library to use slave address clcdAdr for all function calls.

void clcdPower(u8 onOff)

Parameters

onOff: 0=Off, 1=On

A 5V power source is supplied by the MOACON to the CLCD display

module.

void clcdCsr(u8 onOff)

Parameters

onOff: 0=Off, 1=On

Shows or hides the cursor on the CLCD module.

void clcdPrint(u8 cx, u8 cy, char *formatString[, arg0, ..., argn])

Parameters

cx: x-position (column) of first character to be printed cy: y-position (row) of first character to be printed

formatString: A character string to be printed that can optionally contain format

specifiers

arg0,...,argn: An optional set of arguments to be used by format specifiers.

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Prints a character string, formatStrng, on the CLCD device at location cx, cy. F

void clcdCls()

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(g) PWM Emulation Functions

void pwm(u8 pwmChannel, u16 pwmDuty, u16 pwmWidth)

Parameters

pwmChannel: PWM channel

pwmDuty: Duration for which the pulse is ON pwmWidth: Pulse period

Sets the duty cycle and period of the pulse width modulator (PWM) on channel pwmChannel.

void pwmOff(u8 pwmChannel)

Parameters

pwmChannel: PWM channel

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Figure 1-15. The virtual socket concept for communication between the

simulator system and the emulator system; the detail drawings in the

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2.10. Program flow to simulate the virtual environment

The virtual environment simulator program calculates the heat transfer

value using the load output value and previous state environment values that

are given by the logic program of emulator like as Figure 1-16. The

numerical analysis results are automatically databased and transferred to the

emulator logic through virtual communication socket. The numerical

analysis at this point relates not only to compartment temperature of the

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Figure 1-16. The virtual socket concept for communication between the

simulator system and the emulator system; the detail drawings in the

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2.11. How to exchange the data of emulator and simulator

In order to hold the state data and the environment data in common

between the emulator program and simulator program, a 50 bytes array data

is configured by assigning each of the variables like as Figure 1-21. The real

freezer actually initiates communication. Therefore it is programmed using

the communication functions and defined as the virtual socket. In order to

make it look like being communicated, they are connected with each other

using virtual communication socket, and data are read and written within in

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Figure 1-17. The sent and received protocol format of the virtual

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III. Results and Discussion

3.1. The simulated experiment system

The numerical values shown in the Figure 1-18 is that of the simulated

freezer. The upper part of the Figure 1-18 is the measured values of the inner

space of the freezer, and lower is the measured values of the evaporator area.

An experiment system shown in the Figure 1-19 is a completed form that

consists of freezer, control system, and measurement system. In the freezer, a

fan and a load simulating a food model is installed. This actual freezer

controller is successfully operated by the previous developed freezer

program in the simulation environment program.

At regular time intervals, the data of the freezer system is gathered by the

measurement system after starting operation. The data collected from the

actual hardware was compared and analyzed with the virtual environment

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(a)The modified freezer circuitry

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(c) The completed PLC controller (Up)

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(e) The completed PLC controller (Right)

(f)An installed fan and model food in the freezer.

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3.2. The developed virtual system program

The developed program as shown in Figure 1-20 has different

characteristics compared with the design specification of the previous

designed program shown in Figure 1-14. However, in the overall context, the

program can be seen as the same. The GUI arrangement is improved for ease

of use in the actual experiment.

Using the theoretically presented virtualization methods and the numerical

analysis, the simulation software and the emulation software is made, and the

simulation assigned by the necessary parameters is carried out. This is the

freezer program made by the VPSDP method. Inside this program, the

program that needs to be ported to the actual freezer hardware is included.

The result shown in Figure 1-21 is the arithmetic progression based on the

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Figure 1-20. The completed simulation program and the operational

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Figure 1-21. The numerical analysis results shown in the console

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In the future, more research will be done, as the data calculated with the

numerical analysis cannot accurately reflect the actual environment as 100%.

Processes that acquire experimental data are also required, and we believe

that through trial and error, more results can be acquired.

The completeness of the program will be strengthened by applying various

controllable parameters and equations. Through this, the program will be

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3.3. Completed model Functions

The equations using the numerical analysis reflected in the program

directly calculates the environment values through the high speed operation

of the computer. Each calculation functions must be written so that it can be

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3.4. Node No.1 Calculation Function

float CVirtualFreezerDlg::FutureFirstNodeMeshTemperature( float h0, float k, float roC, float outTemp, float selfTemp, float nextTemp, float meshSize, float timeInterval) { float fValue = (h0*(outTemp-selfTemp)+k*(nextTemp -selfTemp)/meshSize)*2*timeInterval/(roC*meshSize) + selfTemp; return fValue; }

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3.5. Node from No.2 to No.(n-2) Calculation Function

float CVirtualFreezerDlg::FutureMiddleNodeMeshTemperautre( float prevTemp, float selfTemp, float nextTemp, float tau) {

float fValue = tau*(prevTemp+nextTemp)+(1-2*tau)*selfTemp; return fValue;

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3.6. Node No.(n-1) Calculation Function

float CVirtualFreezerDlg::FutureLastNodeMeshTemperature( float hi, float k, float roC, float prevTemp, float selfTemp, float inTemp, float meshSize, float timeInterval) { float fValue = (hi*(inTemp-selfTemp)+k*(prevTemp- selfTemp)/meshSize)*2*timeInterval/(roC*meshSize) + selfTemp; return fValue; }

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3.7. Node No.n Calculation Function

float CVirtualFreezerDlg::FutureTargetNodeMeshTemperature( float hi, float Ai, float prevTemp, float selfTemp, float m1, float C1, float m2, float C2, float timeInterval, float watt, float rH) { float newTemp = (hi*Ai*(prevTemp-selfTemp)- -watt/1000+rH/1000)*timeInterval/(m1*C1 + m2*C2) + selfTemp; return newTemp; }

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3.8. The numerical data vs. the actual data

The configuration values for the simulation environment are that the notch

temperature is -20 ℃ and the differential temperature is ±3℃. This

emulated software is ported to the PLC of the actual freezer, and the result

data of both environments are compared. As shown in the Figure 1-22, the

chart of both temperatures is not accorded to 100%, but in control aspects, it

can be safely assumed that it is controlled properly.

With various case analysis results shown in Table 1-3 and Figure 1-23, in

the -20℃ temperature zone, simulated the average temperature was

controlled within 90% to 92% regardless of the differential temperature like

as the actual average temperature, and in the -30℃ temperature zone, it was

in accord with 96% to 98% level. In the -40℃ temperature zone, it was

controlled in accord with 98% to 101% level as shown in Table 1-3.

The virtual system was operated properly between the -30℃ and the -40℃

temperature zone if it was assumed that confident level is great than 95%. In

the future, ongoing study will be made to the confident level in the -20℃

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Figure 1-22. The freezer temperature chart measured by the numerical

Novel Platform for the Development of Refrigerator Operating Software Using Virtualization, Automation, and Remote Control

A DISSERTATION FOR

THE DEGREE OF DOCTOR OF PHILOSOPHY

Novel Platform for the Development of

Refrigerator Operating Software Using

Virtualization, Automation, and

Remote Control

냉장고 운영 소프트웨어 개발을 위한

가상화, 자동화, 원격제어 기반의 플랫폼 구축

February, 2014

Department of Agricultural Biotechnology

Seoul National University

Sang Oh Kim

Novel Platform for the Development of Refrigerator

Operating Software Using Virtualization, Automation,

and Remote Control

By

Sang Oh Kim

Department of Agricultural Biotechnology

Seoul National University

Abstract

CONTENTS

LIST OF TABLES

LIST OF FIGURES

Chapter 1

The Freezer Program Emulation Method in the

Virtual Simulation Environment Using the

Virtual Product Software Development Process

Abstract

I. Introduction

II. Materials and Methods

III. Results and Discussion