The Hong Kong Polytechnic University

MU IPD06 Robotic Insect

IC 349 2011/12

 

 

 

 

Lam Ho Lok (10123953D)

Liu Junying (09826637D)

Ma Siyuan (09807870D)

Pan Tsz Yan (10570526D)

Sun Iat Hou (10024286D)

Wong Ka Kit (10340252D)

Wu Mei (10103264D)

IPD Group 06


 


Content

 

Introduction 3

Project Background 3

Project Objectives 4

Target User 4

Place to Use 4

Achievement 5

Constraints 6

Conceptual Design 7

Schedule 8

Research 9

Design Evaluation 11

Final Design 17

Exploded View of Final Design 19

Bill of Materials 20

Budget 22

Manufacturing 23

Schedule 24

Manufacturing Process 25

Division of Labor 30

Communication 30

Final Design 33

Wings 33

The Second Layer 35

Base 35

Aperture 37

Shading Area 38

Gearbox 39

PCB 42

Light Sensor 42

Servo Motor 42

LED Bulb 43

Program 43

Solar panel 44

Sucker 44

Reflection 45

Conclusion 48

Stage of Evolution 48

Self-Evaluation 48

Result 49

Future Development 50

Conclusion 51

Individual Reflection 52

Lam Ho Lok 52

Liu Junying 55

Ma Siyuan 58

Pan Tsz Yan 61

Sun Iat Hou 64

Wong Ka Kit 67

Wu Mei 70

Acknowledgement 74

 

Introduction

 

Project Background

 

In the beginning, we were assigned to design and fabricate a remote controlled robotic insect driven by DC or servo motors. Simultaneously, our group got an opportunity that our client wants an architectural device for the green building. Based on these two conditions, our group decided to combine the robotic insect and façade as the concept of the product.

Fig. 1-1 Shows the original product we were assigned to make

 

“Green building” is becoming a large area which develops incredibly in worldwide. In response to the tremendous amount of electricity usage in lighting and air conditioning to maintain cool temperature in most commercial buildings, we proposed this robotic insect can have some kind of adaptive and environmental friendly function like facade, which means through designed motions of different components; the amount of light entering the buildings can be controlled.

 

Before the project, all the group members had finished the IC 348 training. We learnt how to manufacture and assemble a basic robotic insect during the training. Therefore, we got the experience of making robotic insect, which is conducive to the project.

Fig. 1-2

Shows the robotic insect we have done in the IC 348 training

 

Project Objective

The objective of the project is:

To design a modular robotic insect with a function that can control the level of incoming sunlight and as a decorative feature.

 

Our group decided to make a modular design rather than a large façade design, because it is more flexible for the users and easy for maintain and repair. For the manufacturing, moreover, the components can be easy to manufacture and cost saving when it is mass production.

 

The mechanism of our product is used for shading the sunlight. By the movement of the mechanism, the robotic insect can control the level of incoming sunlight.

 

Target User

Our target users are the kids in kindergarten. They are normally 2and half to six year-old. For these target users, there are two design considerations we need to mainly notice:

 

Firstly, it is the safety of the product. For the kids, they have low sense of danger and they are relatively easy to get hurt. Therefore, the product should be safe for the user, for example avoid any sharp edges, and avoid any toxic materials and substance in the product.

 

Secondly, attractive appearance can catch the kids’ eyes that can easy bring their interest in our product.

 

Place to Use

As a shading device, the product would be installed in the inner side of the kindergarten window. Therefore, the product should include a component/ some components for mounting the window.

Fig. 1-3

The product would be used in kindergarten

Achievement

We hope that our product can achieve the above things:

 

1. Environmental Achievement

In previous part, we have mention that our product is an architectural device for green buildings. To coordinate with this concept, create a green product is what we want to achieve. We hope that our product can help to lower the carbon emission.

 

Firstly, our product would use of solar energy which means it can lower the power consumptions. The product would be mounted on the window, so we can install some solar panel on the product. We make use of the energy for the movement of the product. At the same time, it would also store the energy for other purpose, for example providing energy for the lighting device.

 

Secondly, our product can control the level of incoming sunlight. We hope that the user can use the sunlight to instead of the artificial light which means the product can help to reduce the use of artificial light.

 

2. Educational Achievement

Our product would be used in the kindergarten. We hope that through the adorable product, kids can observe the change of sunlight pattern. That can encourage children to explore the nature outside the classroom, with the result that to make children appreciate the nature.

Fig. 1-4 Educate children is one of the purposes of the product

 

 

 

 

 

 

Constraints

There are some constraints and limitations for the project.

 

Firstly, the cost limit is only HK$2000. We need to think about how to spend the money. We should list out the expected budget on different categories, including raw materials, standard parts and manufacturing process.

 

Secondly, we only have 6 weeks for the manufacturing stage. Therefore, we need to have an effective schedule, especially assembly the product will take longer time, we need to have enough time for that. Division of labor is also important for time saving. We divide the manufacturing work according to different characteristic of the members that can achieve an effective cooperation.

 

Thirdly, selection of the manufacturing process is limited to the existing available facilities in the Industrial Centre. For example, we have already finished the program writing of CNC machine, but the machine was out of order, so we cannot use it during the manufacturing process.

Fig. 1-5

Our team mate have already finished the programme writing for the CNC machine

 

 

Fourthly, we hope that our product is environmental friendly. Therefore, the product should not only green in the usage stage, but also green throughout the whole product life cycle. We need to concern the material waste and power consumption during the design stage and manufacturing stage.

 

 

 

 

 

Conceptual Design

Schedule

The following are steps to design schedule :

1) Estimate the duration of each process

- The estimation is mainly base on difficulty on production as well as the number of parts. For example, there are lots of parts is produced by machining and machining is very time consuming, therefore, it has the longest duration.

2) Set priority for each process

- Some processes should be arranged in sequence. For example , assembly must start after all the production processes.

 

The whole project period is 13 weeks. The design stage takes 7 weeks and manufacture stage takes 6 weeks.

 

On design stage, we have met with supervisor, done research in first three weeks. Concept design start in week 2 and takes two weeks, then detailed design end in week 5. After, we have done the CAD and virtual prototype, quick simulation and in the last week of the design stage we prepared report.

 

Fig. 2-1 Shows the grant chart of the design stage

 

 

 

 

 

Research

After we set the objective of the project, we did some research to find out some relative information, including morphology of different insects, some existing product and interesting products.

 

The morphology of different insects

Firstly, we have studied on the morphology of different insects, including spider, butterfly, firefly, beetle and dragonfly. We have studied their shape, movement and structure of their body.

Fig 2-2 – 2-5 We have studied different insects

 

We also found a building which used the idea of insect on the architectural field. The building is from Spain, the idea of its front gate is from the structure of an insect head, and the monolithic structure simulates the structure of the wings of the insects, which can stay strong at the same time use this kind of structure can save material and let the building be aseismic with good transmission ability of light.

 

After doing the research, we have drawn some sketches of the insects and the relate inspiration of robots. Then we found that the shape of the beetles and butterflies’ wings can be used of reference as the shape of the facade.

 

Existing robotic insect

There are various types of robotic insect products with different kind of functions on the market. They are widely used on many fields, such as military, astrology and aerography, for example this little robot has suction cups built into its feet, allowing it to climb up, down, around, and upside down smooth surfaces like windows and mirrors.

 

Fig 2-6 – 2-7

We try to find out mechanism of different existing products

 

The buildings with adjustable facade

Recent Building facades are expected to provide interior comfort, a feeling of openness. In addition, green facades are able to save energy, while delivering comfort by optimizing the interior environment, and cutting consumption.

In the development process towards a facade design integrated with the building, it is essential to consider how the shading and insulation performance of the openings impacts energy saving and comfort.

 

Fig. 2-8 -2-9 Show the interesting facade design that can control the level of incoming sunlight

 

We have also found some many interesting structure of window and façade:

Fig. 2-10 The façade plays with light and shades with 3D elements that can individually rotate 360 degrees to create unique, interactive patterns.

 

 

 

               

 

 

 

 

 

 

Interesting ideas

 

Fig. 2-11 Solar Panel: This item is called “Piksol,”

It is made to both collect solar energy and create arbitrary patterns and images on a building’s façade.

 

Fig. 2-12 – 2-13 Lighting Device: The lovely dogs are the book stands.

These adorable book stands that light up when the dog’s tail cord is pulled could just as fashionably fit a child’s playroom as a designer’s atelier.

 

 

Fig. 2-14 – 2-15

Aperture: The aperture is an important element in most optical designs.

Its most obvious feature is that it limits the amount of light that can reach the image. This can be either unavoidable, as in a telescope where one wants to collect as much light as possible; or deliberate, to prevent saturation of a detector or overexposure of film.

 

Design Evaluation

 

Selection of insect

1.      Firefly

Fireflies produce a "cold light", with no infrared or ultraviolet frequencies. This chemically produced light from the lower abdomen may be yellow, green, or pale-red, with wavelengths from 510 to 670 nanometers.

Fig. 2-16 – 2-17 Show the appearance of firefly and they are lighting at night

 

2.      Butterfly

Butterflies have large, often brightly colored wings, and conspicuous, fluttering flight.

Butterflies are characterized by their scale-covered wings. The coloration of butterfly wings is created by minute scales. These scales are pigmented with melanin that give them blacks and browns, but blues, greens, reds and iridescence are usually created not by pigments but the microstructure of the scales.

Fig. 2-18 – 2-20 Show the appearances of different butterfly

 

 

 

 

 

 

 

 

 

 

3.      Dragonfly

A dragonfly is a double-winged insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense. It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body.


Fig. 2-21 – 2-22 show the sketch of dragonfly and the real one

 

4.      Beetle

The reason for the name is that most beetles have two pairs of wings, the front pair, the "elytra", being hardened and thickened into a sheath-like, or shell-like, protection for the rear pair, and for the rear part of the beetle's body.

   

Fig. 2-23 Shows that the outlook of beetle when opening its wings

Fig. 2-24 – 2.25 Show different sketches of beetle

 

5.      Spider

Spiders are arthropods that have eight legs. Their abdomens bear appendages that have been modified into spinnerets that extrude silk from silk glands within their abdomen. Most spiders that hunt actively, rather than relying on webs, have dense tufts of fine hairs between the paired claws at the tips of their legs. These tufts enable spiders with scopulae to walk up vertical glass and upside down on ceilings.

Fig. 2-26 Shows the Spider has eight legs

Some design drawings:

Fig. 2-27 This design is a robotic spider that can climb up the wall.

 

Fig. 2-28 This design is a robotic butterfly that can fly.

 

Fig. 2-29 This design is a robotic beetle that also can climb up the wall or window.

 

 

Weighting table for insect selection

Criteria (Weight)

Firefly

Butterfly

Dragonfly

Beetle

Spider

Appearance (35%)

8

10

5

8

3

Movement (40%)

6

7

5

9

8

Shape (10%)

7

5

6

8

5

Structure (15%)

10

5

6

8

7

Total (100%)

7.4

7.55

5.25

8.4

5.8

*Score: 1-10

Fig. 2-30 Shows the weighting table of selecting insect

 

As beetle got the highest mark among the other insects, it was used in our final design.

 

 

 

Selection of functions

 

1.      Lighting

The robotic insect can provide light in dark area. Moreover, we can choose different colors and intensities of light to enhance the atmosphere of the place.

Fig. 2-31 Shows a lighting device

 

2.      Sunlight shading

We can employ some parts of the robotic insect to shade the sunlight in order to adjust light getting into the room. Thus, it can reduce the power consumption that natural sunlight is used instead of switching on the light in day time.

Fig. 2-32 Shows the facade can shading the specific angle of the sunlight

 

3.      Climbing

Through climbing, the robotic insect can help construction workers to reduce dangerous works at heights. The robotic insect can climb up the outer wall of the building and painting the wall or install parts outside buildings.

Fig. 2-33 We have through about if the robot can climbing like a human

 

4.      Diving

Just like climbing, if the robotic insect can dive into the deep sea, it will help the human to do the dangerous works in sea. For example, the robotic insect can sink into sea to search for resources or survivors etc.

Fig. 2-34 There are some existing product can dive into deep sea

 

5.      Flying

If the robotic insect can fly, it can help us to transport things between two places. Also, it can help people to take out things at the height place.

Fig. 2-35 Shows the robot which can fly

 

Weighting table for function selection

Criteria  (Weight)

Lighting

Sunlight

Shading

Climbing

Diving

Flying

Feasibility (30%)

9

8

4

2

1

Creativity (20%)

5

7

9

9

8

Environmental friendly (30%)

2

3

2

3

2

Necessity (20%)

5

6

3

3

2

Total (100%)

5.3

5.9

4.2

3.9

2.9

Score: 1-10

Fig. 2-36 Shows the weighting table of selecting functions

 

Since light and sunlight shading get the highest marks in the table, we decided to use both function in our design.

Final design

Base on the result of the weighting tables, beetle is used to be the appearance of the robotic insect.

 

Moreover, there are three main design features. They are wings with patterns, aperture and LED lighting device.

Fig. 2-37 Shows the CAD drawings after we finished the conceptual design

 

 

Quick Simulation

Fig. 2-38 Shows the paper Model of Wing Layers

 

The overall effect of the three-layer wings of the robotic insect was simulated by a paper-made model to test combination of different patterns and shapes. Positioning of mechanism was also explored using this model.

 

 

 

 

 

 

 

Fig. 2-39 Shows different patterns of wing layer

 

Different patterns of the wing layers were made and then tested using papers. Some combinations of particular patterns could generate beautiful and interesting effect

 

Fig 2-40 Shows the testing of the lighting system applied on our product

To enhance the lighting system, we found through tests that the transparent plastic board lighted by LEDs from the side could convey very good lighting effect with a shining contour around the boundary. Particular patterns can be carved or sand-blasted on the board to achieve similar effect.

 

 

Fig. 2-41 shows the CAD drawing of light Controlling Component (Aperture)

The Light Controlling Component is used to control the amount of incoming light by changing the size of the center hole, which is similar to a scale-up aperture of lenses. The 3D visual model of this component was constructed by our group with Solidworks. The mechanism of the aperture is good in the simulation operations.

 

 

Exploded View of Final Design

Fig. 3-1 Shows the exploded view of the final product

 

 

Fig. 3-2 Shows the detail of the aperture

 

Bill of Materials

 

 

 

 

 

 

 

 

 

 

Budget

 

The total budget of our project is 2000HKD, and we finally spend 1921HKD, which was just within the budget.

Subjects

Planning Costs (HK$)

Actual budgets  (HK$)

Differences (HK$)

Procurement of raw materials

(e.g. Acrylic, Aluminum)

600

417

183

Procurement of standard parts

(e.g. Screws, Spacers)

400

404

-4

Manufacturing Process

(e.g. PCM, Laser cut)

1000

1100

-100

Total

2000

1921

79

 

More than half of the money we have spend was in the manufacturing process, because operating the instrument of IC is expensive, such as PCM and Laser cutting.

 

Fig. 5-1 Shows the difference between the planning costs and actual budgets

 

 

Manufacturing

 

After the design stage, engineer drawing were made for the manufacturing stage. It is very important to state the quantity, dimension, tolerance, material and other requirements for engineer parts clearly in these drawing. Also, engineer drawing is an effective way for designers to communicate with manufacturers. By using solidworks, engineer drawing can be exported easily.

 

All of the non-standard parts were made inside the Industrial Centre during manufacturing period. Our group also tried to reduce the number of non-standard parts, because it can minimize the cost and time consumption.

Selection of manufacturing process is also essential, the process selected should able to meet the requirement of different parts. Tolerance and geometry of parts are the main consideration.

 

The following are the processes involved in our project.

1) Laser Cut

2) Machining

3) Wire Cut

4) PCM

5) Surface finishing

All these processes are explored one by one in the following part

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Schedule

 

On manufacturing stage, we spend first three weeks to manufacture the components of our product by using the facilities in IC including laser cut, machining, wire cut and PCM. Then assembly, testing and design revision and rework were done on week 4 to week 6. On the last week, we prepared the presentation.

Fig. 6-1 Shows the grant chart of the manufacturing stage

 

Some of the tasks, which have little influence on each other, are processed at same time, and some of the tasks must have a sequencing, such as we must manufacture all the gears by wire cutting and then we can assembly the gear box, such tasks are laid in sequence.

 

 

 

 

 

 

 

 

 

 

 

 

 

Laser Cut

It is a computer-assisted technology which works by directing the output of high-power laser to cut material.

 

There are many advantages by using laser cut.

1) Easy to use

Fig. 7-1 Shows the machine is doing laser cutting

- Solidwork 3D modeling have already been made in the design stage. Exporting a dxf file was the only work that our group need to do. After input the file into computer, the components can be cut automatically. Therefore, it is very easy to use and does not require any skills.

2) High efficiency

- The output of laser cut is very fast . A part can be cut within a minute.

3) Edge with high quality finish

-The components produced do not need secondary operation for smoothing the edge because it has high quality finish.

 

It seems that this technique is very perfect, nonetheless, it has its' own disadvantage.

1) High cost

-it cost $120 per hour. It is very expensive compare with other manufacturing processes. The high cost is mainly due to the high power consumption.

2) Vary tolerance

-As the cutting of material by using laser will affect by refraction. Therefore, the parts will not have high tolerance by using laser cut. Therefore, laser cutting should not be used to produce some precise components.

 

Upper wing

Lower wing

Base

Aperture

Outer/inner ring

Connecter

Gear box base

Transparent wing

Fig. 7-2 Shows the components made by laser cutting

 

Machining

Machining is a different process which is used to cut a piece of material into desired shape. We used milling, drilling and turning (lathing) process in our project. Machining is the process which we use to produce a lot of party.

Fig. 7-3 Shows our team mates using the machines for doing machining

 

Advantage:

1) High flexibility

-Machining has high flexibility to produce components.

2) Zero cost

-These processes do not have any cost in IC. It is a great benefit for us because our group have limited budget.

 

Disadvantage:

1) Time consuming

- It is very time consuming. A complex part may use more than two hours to produce. All the parts need to be manufactured carefully and slowly. Because it is very easy to over cut the material.

 

Brush

Shaft

Spacer

Fig. 7-4 Shows the components made by machining

 

 

 

 

 

Wire Cut

It is a manufacturing process in which a desired shape is produced by electrical discharges. The main advantage of wire cut is that it can produce irregular shape with high tolerance. Therefore, most of the gears inside the gear box are manufactured by wire cut. It works like laser cut, we can import a CAD fie into the machine and produce it automatically. The only thing we need to do is to clamp the material firmly inside the machine.

However, the disadvantages are the high cost and long duration. The main cost comes from the wire usage. It takes a lot of time to produce one part 

Fig. 7-5 Shows our team mate writing the programme for wire cutting

Fig. 7-6 Shows the operation of the wire cutting machine

Fig. 7-7 Shows the gears made by wire cutting

PCM(Photochemical machine)

It is the process to fabricate a sheet metal by using etchants and photo resist to remove away selected area. The thickness of sheet metal is between 0.25~1mm. 

 

Fig. 7-8 Mr. Lee teach us the knowledge of using PCM

 

Fig. 7-9 -7-10 shows the operation of using PCM

 

Advantages of PCM:

1) High tolerance

-The tolerance is high, so that it is suitable to fabricate a D-lock which require very high accuracy to interference with the D-shaft.

2) High quality surface finishing

The product is a fancy sheet metal with special pattern. It does not require any secondary operation.

 

Disadvantage of PCM:

1) Time consumption

There are a lot of processes to use PCM to produce a part. Firstly, a photographic film is printed inside a dark room.

2) High cost

In our project, totally two stainless steel wing with A3 size were made. The total cost of these two wings is $1000, which is a little bit out of our expectation.

 

We use PCM to produce two stainless steels wing with light weight.

Fig. 7-11 shows the wing made by PCM

 

 

Surface finishing

Surface finishing includes a lot of processes to change the appearance/surface of component. For our project, we have used blasting, e-coating, painting. The aim of our project is to make our product lovelier as our customer is those children in kindergarten.

 

Fig. 7-12 – 14 shows our team mates doing blasting, e-coating and painting

 

 

 

 

Division of Labor

The division of labor is based on the abilities of our group member. When conduct certain task, we need to have an effective cooperation. Therefore team work could be an important role on the manufacture stage.

Fig. 7-15 Shows the table of division of labor

 

For example, to manufacture a shaft, we need to using lathe machine, drilling and tapping the screw thread. Therefore we let three people do the tasks separately, which will be more effective.

Moreover, team work can be particularly important when we meet problem.

 

Communication

As a group project of seven members, communication among group could be very significant.

 

The communicate method we have used including:

Project status report

Team meetings

Google Docs

Facebook

 

 

 

 

 

 

Project status report

Every week, we have a project status report to report the status of project and the work we have done in the week.

 

The report mainly focus on the work, budget, risks and issues of the project. It helps us have a clear understanding of the project status. Besides, by reading the report, group members can get known of the works of others. Also, it helps us have a better arrangement of the future works.

 

Team meetings

Every morning we have a brief meeting among our group before we do the work of ourselves, in the meeting we decided the detail work of every group members should do in the day.

 

Also, we have a group meeting on the end of everyday before we go home to conclude the works of the day, problems and difficulties will be mention on the meeting.

Fig. 7-16 – 7-17 show that we are doing team meeting

 

 

 

 

 

 

 

 

 

 

 

 

Google docs

We use google docs to share and edit the Office files of the project, such as words and ppt.

Fig. 7-18 shows the webpage of Google docs

 

Facebook Group

Facebook is been used to communicate among groups when we are separate, we use it to arrange time and contact supervisor. Also, we share photo and files by using Facebook.

Fig. 7-19 shows the webpage of our Facebook group

 

Final Design

We totally designed and manufactured two generations of the product. The final design improved the structure and functions based on the first generation design.

 

The final design mainly consists of three layers, the wings, a transparent board and the base. The aperture, gear box and suckers are installed on the base. On the upper edge of the transparent board, there is a LED lighting device. The three layers are connected by shafts, and only the wings can move.

Fig. 8-1 - 8-2 Show the bottom view and side view of the product

 

 

Wings

The first layer is the wings with many circular patterns. Actually, each of the wings consists of two layers, and it makes the wings appear more tridimensional. The red part is the protruding layer, and it is pasted on the black layer.

 

In the original design, the black layer is similar to the red one, and it is just bigger than the red layer. Therefore, the red part of the wing actually has two layers, and they are connected by screws. Since the wings are made of acrylic, the two-layer combination wings are too heavy, and the motor cannot drive them. The wings are improved in our final design. We cut the central part of the black layer which can be covered by red layer, and remain some superposition area to paste them together. Thus the red part of the wing is only the red layer. What’s more, we paste them together instead of using screws so that the wings can be lighter.

 

 

 

 

 

 

 

Fig. 8-3 the reverse side of the two generations of wings

The left one is the original one which has full black layer. The right one is the improved one. It reduces nearly 50% of weight than the original one. Thus the motor can drive the improved wings.

For the final product, we also design the alternative wings which are made by PCM. The thickness of the aluminum sheet is only 0.2mm. Therefore, the wings can be lighter if we use aluminum sheet as the material.

 

Fig. 8- 4 shows the aluminum wing.

The edges of it lean outward to make the wings more tridimensional. The motor can drive the aluminum wings easier since it is much lighter than the acrylic one. We can also electroplate the wings so that the wings can get colorful and attract the children.

 

 

 

 

 

 

 

 

 

 

 

 

The second layer

The second layer is a transparent plastic board with blasting pattern. The LED lighting device is installed on the upper edge of it. When the environment is dark, the LEDs can provide lighting and highlight the blasting pattern on the layer.

 

LEDs are used as indicator lamps in many devices and are increasingly used for lighting. LEDs have lower electrical power and not fragile so that they are proper for children use. For our final product, we use a LED banding instead of bulbs to save energy and space. What’s more, the LEDs are colorful and children will like it.

 

Figure8- 5 shows the second layer with the LEDs.

 

Children can be relaxed when they see it in the evening. The blue light can make children calm down and have a good mood.

 

There are two guide grooves on the second layer. They are used to guide the wings so that the wings can move smoothly. Moreover, we use sand blasting to make the pattern on it.

 

Base

The base is the important part of our final design. It carries many components such as the gear box and the aperture.

Fig. 8-6 shows the base carries the aperture with different situations.

 

Moreover, the base has the same circular patterns as the wings.

The combination of the wings and base

 

When the wings are moving, the circular pattern of wings can produce different effect with the pattern of base. It is the main way for our product to shade the light. The movement of wings is according to the light situation. The wings can open and close slowly along with the luminosity of sunlight.

 

Fig.8- 7 shows the movement of the wings

 

When the environment has the brightest situation, the wings are opened and the circular pattern of wings and base are not aligned so that the wings can shade the sunlight. For the darkest situation, the wings are closed and the circular patterns of the two layers are aligned so that most of sunlight can go through

 

Between the brightest and the darkest situation, the wings can move slowly along with the luminosity of sunlight. What’s more, the shadow of the patterns can present different shapes due to the movement of wings. The observing of sunlight pattern changing makes children appreciate the nature and encourage them to explore the nature outside.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Aperture

Mechanism of aperture

- The design of aperture use up a lot of time. Our group refer to many mechanisms of aperture in website. Mainly, there are two types of aperture.

The first one is mechanical aperture

(http://www.youtube.com/watch?v=fVwYMNgfjX4&feature=related)

 

The second one is camera aperture (http://www.youtube.com/watch?v=WHPrGHBgsaA)

(http://www.youtube.com/watch?v=jAWElOSiMoM&feature=related)

 

Lastly, the first type of aperture is chosen. It is a four-bar linkage in which the five leaves can work independently. For the second type, the leaves will contact each other. If one of it is trapped , it will affect other leaves.

When we rotate the outer ring in anti-clockwise direction, the end of the bar then follow to move. At the same, the bar will follow the guide pattern to move upward. Thus, the leaves will also follow the motion of the bar move upward, and so the aperture is opened

 

In the middle of the base, there is an aperture installed on it. The aperture can control the shading area of sunlight.

Fig. 8- 8 there are five blades in the aperture

These black blades can shade the sunlight when they are closed. There are two loops to control the movement of the blades. The bigger loop is installed on the base. When the motor drives the smaller loop, the blades will open and close along with the rotating of smaller loop.

Fig. 8-9 Shows the back view of the base

As we can see in figure 9, there are five guide grooves on the base, so that the blades can open and close smoothly. In the original design, the guide grooves are on the aperture base, which is a plastic board installed between the bigger loop and base. The function of aperture base is just guiding the blades. Therefore, in our final design, we put the guide grooves on the base to reduce the number of components.

 

The aperture can open and close based on the light situation. When the environment tends to dark, the blades of aperture will open slowly and let the sunlight pass in. When the light outside is too strong, the blades will close to shade the sunlight.

 

Shading area

In order to measure the capability of our product shading the sunlight, we use Solidworks to simulate the brightest and darkest situation. Then we get the difference of shading area between the two situations.

Fig. 8-10 shows the calculation of the shading area

 

As we can see in figure 10, the blue area represents the shading area, and the total calculation area is 77000mm². For the brightest situation, the wings are opened and the aperture is closed. Thus the shading area is 53000mm², which is 70% of the total area. For the darkest situation, the wings are closed and the aperture is opened. Thus the shading area is 35000mm², which is 45% of the total area. The difference of shading area between the two situations is 25%.

 

Gearbox

We try to use a simple gear system to control the movement of two upper wings and the aperture

 

Gearbox contains:

-          gearboxes’ layers *2

-          gearbox supporting shafts *4

-          31 teeth gear *2

-          15 teeth gear *1

-          34 teeth gear *1

-          Spacers *4

-          Brushings *4

-          Gear shafts *2

Fig. 8-11 shows the first generation of the gearbox

 

Also, the gearbox is a modular design, so it can be replaced or repaired easily.

 

However, we found that some problems presented in the first generation of gearbox, such as, friction between gears, too large for the gearbox and so on.

 

 

 

 

 

 

 

 

Thus, a second generation of gearbox is manufactured to eliminate those problems.

The new gearbox includes:

-          gearboxes’ layers *2

-          gearbox supporting shafts *4

-          31-teeth gear *2

-          15-teeth gear *2

-          34-teeth gear *1

-          25-teeth gear *1

-          Spacers *4

-          Brushings *4

-          Gear shafts *2

-          Gear shaft for iris *1

Fig. 8-12 -8-14 show the second generation gearbox design 

 

The two main differences between the new and old gearbox is the servo motor is installed outside the gearbox and one servo motor is used in the second generation of gearbox instead of two. Thus, size of the gear box can be greatly reduced. Also, the size of insect can be diminished.

 

 

 

 

 

 

Moreover, we use wire cut to make metal gears instead of using laser cut to make plastic gears. Therefore, the dimension of gears is more precise and the friction between gears becomes smaller.

 

There are two main motions in our robotic insect. They are both linear relationship to the light sensor value.

 

For the movement of the wings, each wing is going to rotate about 55-60 degree when the light intensity is the highest. Base on the gears used (a 15-teeth gear to rotate a 31- teeth gear), the gear ratio is about 1:2. Then, we need to set the rotate angle of the servo motor be 120 degree in order to rotate the greatest angle of the wings.

 

For the movement of the aperture, we need to rotate the aperture about 40 degree in order open the full hole of the aperture.

 

Given that a 34-teeth gear rotate a 15-teeth gear, then a 25-teeth gear held with the 15-teeth gear rotate the inner part of aperture (173-teeth gear) to operate aperture.

 

Calculation

The gear ratio of inner part of the aperture to 25-teeth gear

= 173/25

= 7:1

 

Thus, 25-teeth gear is required to rotate to open the full hole of aperture

= 40 x 7

= 280 degree

 

The gear ratio of the 15-teeth gear to 34-teeth gear

= 15/34

= 1:2.3

 

So, servo motor is needed to rotate

= 336 x 1/2.3

= 122 degree is similar to 120 degree

 

There one servo motor can be used to control the movement of wings and aperture.

 

 

PCB

Fig. 8-15 shows the PCB we used in our product

 

The model of PCB is Arduino Duemilanove w/ ATmega328. It is connected to a light sensor, servo motor, LED bulb and battery holder. We input the program though PC into the PCB

 

Light sensor

 Fig. 8-16 shows the light sensor we used in our product

 

We use light sensor to detect the light situation. It is installed on a PCB board and control the movement of motor. When a light sensor detects the change of luminosity, it will send signal to PCB board. Then the PCB board will react accordingly.

The range of light sensor value is 0 – 1023. 0 is the brightest situation while 1023 is the dimmest situation.

 

Servo motor

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Fig. 8-17 shows the servo motor we used in our product

 

It is used to control the movement of the wings and aperture. The limited rotate angle of this servo motor is 120 degree

LED bulb

 Fig. 8-18 shows the LED light we used in our product

 

It is a 5mm light bulb with 5V. It is used to light the middle transparent layer in order to show the lighting effect of the circular patterns.

Battery holder

We use 4 AAA batteries to be the power supply of the robotic insect.

Fig. 8-19 shows the 4 AAA battery box

 

Program

There are two main motions in our robotic insect. They are movement of wings and aperture. They are both linear relationship to the light sensor value.

 

Fig. 8-20 the programme we used for the product

 

 

Solar panel

 

We use solar panel as the source of energy. Solar energy is a huge energy source which is reproducible and clean. The solar panel can be used as a component of a larger photovoltaic system to generate and supply electricity in many applications. Solar panels use light energy from the sun to generate electricity through the photovoltaic effect.

 

Since the battery is not easy to be recycled and the 220V voltage electricity energy is not safe to children, we decide to use solar energy, which is a kind of clean energy as the power.

Fig. 8-21 shows the solar panel

 

 

 

Sucker

There are four suckers on the back of our product. The suckers can suck the glass to install our product on the window.

 

As figure 8-21 shows, the suckers and the base are connected with four shafts. The suckers are fastened on the shaft.

Fig. 8-22 shows the sucker install on the base

 

 

Reflection

1. High tolerance

For technical problems, first of all, we are not familiar with the machines we used in the industry center. We need to take some time to practice in order to minimize the parts’ tolerance. Moreover, sometimes we produced the parts with the incorrect dimension as our design. This led us to waste more time on reworking the parts until the components almost fit our dimension. For example, we had designed to use two D lock shafts in our gear box so that the D lock gear may rotate with the shaft in the interference fit stage. However, due to our unsatisfactory technique on using milling machine, we did only produce the parts with high tolerance. The D-lock shafts had clearance fit with the D-lock gears. This is undesirable for the movement of the wings since the wings will not move together with the gear box as these two parts did not interference with others as design. We need to rework on the shafts that they bind the gear tightly. This had lengthened our manufacturing time.

 

2. High weight for acrylic wings

Then, as we do not have enough experience in product design, when we come to assembly stage, we found that the parts did not have the serve the same function as our estimation. For example, in design stage, we estimated that the servo motor Futaba S3154 will be able to provide enough torque in order to rotate the gears in gear box. Then the beetle wings and aperture can be raised up or open according to the sunlight received. However, after production of all parts and assembly them together, we found that the wings were able to be rotated when the beetle was placed horizontally on the table. But the wings were not able to be opened when we placed the beetle vertically, like our default using condition, which is bound to the window. We then decided to make the wings lighter by empting the overlapping area of the lower wings. This action also lengthened our assembly time as we had to laser cut the acrylic board again. After this action, the wings were able to be moved up, both in horizontal state and vertical state.

 

 

 

 

 

 

 

 

 

3. Tolerance on acrylic board

Besides, the holes inside the acrylic wings did not have the accurate dimension as design. This is because of the refraction of laser cut. The edges obviously have certain inclination that the lower edge is much smaller. The components like shafts and brushes were not able to fit in those acrylic boards. We needed to enlarge the hole by using some files or make the components smaller. This caused some extra human force to rework, which lower our speed towards finished beetles.

 

4. Derailment on aperture

After that, in the assembly stage of the aperture, we found that the aperture had the problem of derailment since there were high friction between the connecting screws and the aperture base. This was totally different from the situation in CAD. The aperture become totally useless as it cannot be opened or closed. To solve this problem, we decided to provide a guiding path for the connecting screws to ensure that all screws are moving along the paths we designed. After production of several aperture bases and testing, we finally come out one workable aperture with smooth movement. These guiding paths undoubtedly served their mechanical function.

 

5. Ignorance of position of screws

Lastly, we found that some screws’ head were in contact with the other parts of insect like the gears, wings and base. This will generate a great friction in gear movement and heighten other parts which may cause misalignment. For example, the gear to push iris was collided with one of the screws used to fix iris. This generated a great friction that the gear is hard to initiate and also the gear was heightened that the gear cannot contact with iris.

 

6. Programming on Arduino platform

Since we only studied very little about programming in control system in IC training, we are not familiar with programming to control the mechanical movement by electric source. We needed to supervise some tutors in industrial center to gain some basic knowledge in programming about arduino platform. After the template program was given, we had to modify the program according to the sunlight data we got, such as setting range and setting linear function on the programming.

 

 

 

 

 

 

7. Limitation of servo

In the testing stage, we found that the servo motor, Futaba S3154, can only rotate about 120 degree. This was totally different from our expectation. We assumed that the servo motor could provide the serving angle from 180 to 270 degree. We had to set the initial angle of the servo motor be 0 when we tested the workability of the motor and the functionality of the beetles, which was very undesirable.

 

Moreover, in the final version of our beetle, we hoped to reduce the thickness of our gear box and tried to reduce the number of servo motor from two to one in order to reduce the material cost and reduce the chance of misalignment within gears due to great thickness of gear box. However, due to the serving angle limit, the gear box for first generation beetle no longer suited the second generation beetle. In second generation, we had to also consider using the motor to control the aperture and also the wings opening system. It was totally different from two independent gear systems in first generation beetle. Therefore, we tried to apply different gears’ ratio like 15 teeth gear to 34 teeth gear, 15 teeth gear to 31 teeth gear in order to control the rotation angle that the wings and aperture can be opened or closed at the same time.

 

8. Wearing of Acrylic gear and Acrylic board

In our testing, we tried to use 3mm acrylic board to cut the desired acrylic gear for demonstration. However, since the acrylic has much lower Young’s modulus than metal, we found that some teeth of gear were broken and the entire gear box is out of service. Then we redesigned the gear system, using the aluminum board to produce gears by wire cutting. These gears were not easy to have teeth broken or suffer from wearing. Thus, these gears were more desirable in our gear box.

 

Similarly, the D-lock position of the middle wings suffered from severe wearing after repeat testing. In view of this, we modified the middle wings and the spacers connecting the lower wing and middle wings that the spacers and the middle wings will be fixed together by screws. The second version of beetle did not have the problem of tolerance.

 

 

 

 

 

 

 

Conclusion

 

Stage of evolution

In the mid of August, the first prototype has already been made and it worked properly. However, we would like to make our product more prefect. Therefore, our group decided to produce the second generation which has been scale down and the gear box was redesigned.

The smaller size is preferred because it use least material. Especially for the wings, A pair of A4 size stainless steel wing produced by PCM is much cheaper.
And the size of gear box is minimized to reduce the misalignment problem.

Fig. 10-1 shows the two generations of our product

 

 

Self-Evaluation

 

Completeness

 We have produced the first prototype in the mid of August. At the end of the project, we have finished the second generation. So, we would give ourselves a 5    for the completeness in our project.

Functionality

During the testing of our insect, it worked properly. It fulfilled all the functional requirements. So, there is also 5    for the functionality.

 

Accuracy

Most of the components were produced within the tolerance. However, some of them were not. But it does not affect the function of our insect. So we would give ourselves a 4    for the Accuracy.

 

Results

 

Overall, this project was successful completed on time. We were satisfied with the outcome of the project. From the testing, evaluation and analysis, we find out to solutions to solve mechanical problems. Our targeted user was kids in kindergarten, so we were very concerned about the safety issues of a robotic insect such as sharp edges, rough surfaces, toxic materials and chemical substances. In addition, an appearance of robotic insect is one of the important factors to affect buyer’s decision

Thus, we have designed it as toys with different sizes and colors.

 

Moreover, the main function of robotic insect was used for controlling the level of incoming sunlight. The wings and aperture were controlled by gear system and act as a switch. There was a light sensor to detect the light intensity, when the light was too strong, and then the wing would open 30 degrees and the aperture would close so the sunlight passed through the window could be reduced. With a number of trials and errors by adjusting several factors such as tolerance, weight of material, friction, and program, we finally redesigned the wings, shafts and spacers to reduce the weight and friction. Meanwhile, we reproduce the gear by adapting different manufacturing processes. For instance, we produced the plastic gears by using laser cutting and the metal gear by using wire cutting. As a result, we found that metal gear was a better design because it could reduce the tolerance and friction.

 

One of the functions of the robotic insect was lighting effect. LED strip lights mounted on the middle layer of the wing. This layer was a transparent plastic with blasting pattern. When switching on the LED strip lights, the pattern on the layer would be reflected so the LED strip lights could create mood light at the dark environment. However, it was not possible to emit more than one color of light.  The limited voltage of the PCB affected the operation of the LED strip lights. It was because the voltage of LED strip lights was too high (12V) and the motor of wings and the motor of aperture had been connected to the PCB already. Therefore, the PCB could not tolerate the voltages of the motors and the LED strip lights at the same time. To find out a solution to fix a power supply problem, we tried to use a single LED to replace the LED strip lights.  The voltage of a single LED was usually 2V so using several single LEDs for lighting can reduce the voltage. The methods below could be used to connect the single LEDs.

 

1.      Connecting single LEDs in series:  If same four LEDs were connected in series, the voltage capacity of the PCB was sufficient to provide power supply because the voltage of each single LED was 2V. One resistor was used to limit the current passing through the LEDs. Otherwise, the LEDs would burn out.

 

2.      Connecting single LEDs in parallel: If same four LEDs were connected in parallel, it was necessary for each LED to have its own resistor. Otherwise, the current was too large and would destroy the LEDs.

                                                                 

Future Development

We hope the product could be applied widely, not just applied in the kindergarten. To become more popular among kids, we would like to advance the design to enhance the kid’s learning interest in mechanic and science. 

We proposed the new ideas of robotic insect as follows:

 

-          Form ( e.g. 3D-Butterfly, Bee, Bird)

-          Pattern ( e.g. Start, Heart, Rainbow, Irregular sharp)

-          Lighting Effect (Light color-LED: e.g. Red, Green, Yellow, Purple / Fluorescence)

-          Sound Effect (Nature sound: e.g. Rainforest, Beach, Rain / Nursery Rhymes)

 

According to the kid’s preferences, we considered the form, the pattern, the lighting effect and the sound effect to design robotic insect.  For example, the form of robotic insect could be designed as butterfly, bee, bird, and so on. To create a 3D visual effect, more layers of the wings could be included and the wings could be redesigned from a 2D format to a 3D format.

  Moreover, we designed different types of patterns of wing layers such as start, heart, and rainbow. It was suggested that the wing layers could be replaced by user. The patterns will be projected on the wall or floor when the sunlight passing
through the hollow patterns. To increase the attractiveness of the product, the wings could be made of fluorescence plastic so they would be luminous in the dark. Furthermore, multiple-colors of the light of LEDs could create special lighting effect.

 

Different sound effects such as nature sounds and nursery rhymes could be adopted. These sound effects could help our body and mind to be relax and happy.   To make the kids feel like living in a natural environment, we could combine the robotic insect with the nature sound.

 

 

Conclusion

  The robotic insect was a modular design and could come in different sizes and colors. It would be installed in the inner side of the kindergarten window. Also, it was easy to use and clean. Different sizes of the robotic insect were designed so it would be suitable to install in different size of windows.  The robotic insect could be used to control the level of incoming sunlight and as a decoration. It was very sensitive to sunlight because there was a light sensor to detect the light intensity. The sunlight intensity depended on the diurnal, seasonal, weather and orientation.

 

Three main design features including wings, aperture and lighting device. The wings and aperture were controlled by a gear system. The gear system consisted of gears, motors and other small components. It was used to control the movement of wings and aperture (open or close). We used various manufacturing processes to make wings, aperture, gears, shafts and spacers. The motors, washers, and screws were bought from the store. In the manufacturing process stage, we have learned a lot of from the IC training center. The spacers and shafts were small, so we need to operate the lathe machine carefully and used additional tool to fix the spacers and shafts. The wings and aperture were made of plastics so the thickness of them could be easily reduced. Thus, the movement of wings and aperture would become smoothly by reducing the weight and fiction. However, the dimension of gears was not accurate because of using laser cutting machine. We need to redo the parts or use another manufacturing process such as wire cutting.

 

Moreover, the program was one of the factors to affect the movement of the wings and aperture. We tried to rewrite the program many times and redesigned the wings, spacers and gears in order to make the whole operation smoothly. Lastly, we have completed the design of robotic insect and the robotic insect passed the testing. Therefore, we believe that the robotic insect could be applied in the kindergarten and satisfied the needs of the client.                                                                                                        

 

 

 

 

 

 

 

 

 

Individual Reflection

Lam Ho Lok (10123953D)

Contribution

In IC349, there were totally two stage. One was the design stage in last semester and the manufacturing stage in summer semester. During this period, we have finished a lot of task.

 

In the design stage,we did the brainstorming for the direction of our project firstly. We did research on robotic insert and facet . We have come out many good ideas. After that ,we decided our final direction and firmed up our plan. Lastly, We made a paper prototype.Until this stage we all worked together.

 

However ,when we tried to go to detail , we found that there were too many problems to solve. Therefore, each of our groupmates responded in different area. If any one of us find difficulities, other members helps to finish the task.

 

For me, I was responsible to design gear. I studied gear design consideration and found a software (eMachineShop) which can help to generate a gear CAD file easily  Moverove, i helped wu mei to solve some problems in aperture and give some ideas to my groupmates on different aspect.

 

Before the manufacturing stage, we were notified that one of our groupmates were going to leave us. We redistributed our work.

In the manufacturing stage, the whole project include a lot of manufacturing processes . Each process was distributed to different groupmates accoding to the ability of groupmates. Therefore, we will have a very efficecy cooperation.   

 

For me, I am good at Machining because of frequent practice of meachine in IC348. I have experience on Laser cut too. I had some product need to be made by laser cut when i was promoting a drama. After we finished our first generation, I took part in redesign. Because I find there were some problem in the mechanism of aperture.

One time ,I and Pan Tsz Yan went out to purchase some standard parts.

Lastly, we all worked togerther to assembly the insert.

 

 

Findings

Actually, it was not the first time I meet this kind of product development project. Nonetheless, this is the most difficult project I have taken part in. Most of the project, I acted as a role of leader. And sometimes, I felt uncomfortable to give some major works to my group mates, I would rather do it all by myself. But this time, I found that the project was too big to hold, I really could not pay attention to all aspect in the project. Therefore, this project made some changes in my mind. I should confidence in my group mates. I should share the responsibilities to my group mates. I found that the project flow became more efficient. Because I let my group mates to keep their own idea and all the thing had discussed in detail before they worked.  And lastly, they really did it well . The outcome was so good that it was out of our expectation.

I think it is a high time to change my mind and try to do this again in the next project.

 

Reflection

There is a reflection which I want to give to IC.

Sometimes, when we desired to manufacture some components in IC, the machine was occupied to other student. (Other training or MU project). It disarranged our schedule. Although it is our responsibility to book the machine, the number of machine is still limited to fulfill all the need of students. It is ridiculous for IC to purchase more machines for us to use. Instead of this, I think IC can post a timetable/ booking schedule of the machine for in the entire floor (just like the booking schedule in laser cutting). Therefore, we can adjust our plan in order to avoid wasting time on waiting the machine.

 

Comments

Although it is really a hard work, I really learn a lot and all group mates are very helpful. For me, I love this project very much. It is not a pleasing common. I like this kind of experience learning. Because instead of just setting down and listening for staff to talk about the theory just like a lecture, we can have a chance to practice our own idea. We can try and learn everything we want. It can make me remember these experiences for a long period and not easily forget.

The 8hours 5days training is a little bit harsh. But, I know that it is really a must to have such long time training. Because there is many problems and work

 

Conclusions

Our project was finished with a grateful ending. We benefited a lot from this project

I deeply appreciate our client to give a chance for us to do this WIE project. Patrick and Ivan is really helpful who give us a lot of great advice. Also, I must offer my heartfelt thanks to my group mates who helps me a lot. And I really enjoy the time to stick with all of them. 

 

Lastly, most of the IC staff are helpful and nice. They can help us to solve many problems and they are willing to do so. It gives me a sense of belonging in IC. I want to stay in IC rather than lecture.

 

 

 

 

 

 

 

LIU Junying 09826637D

Introduction

We had finished the design process of our MU project last semester. This summer, we did the manufacturing process based on the drawings we designed before. The manufacturing period lasted six weeks, and the last week was used to prepare the presentation. During the manufacturing stage, we improved our skills of operating the machines and cooperation. We also found that it was difficult to turn the design in drawings to the operational objects. However, we finally overcame all of the difficulties and completed our final design on time.

 

Personal contribution

Our group did the research and designed together during the design stage. According to the different characters of our team members, we divide the manufacturing work in order to achieve an effective cooperation.

 

I mainly did the machining work for our product. As shown in figure 1. I could use the lathe adroitly and accurately to machining the components. For the two generations of our design, I had manufactured dozens of metal components such as shafts, bushes and spacers. I also tapped them if necessary.

 

Moreover, I designed the PCM wings in Solidworks as shown in figure 2. The PCM wings were the alternative of the acrylic wings which was lighter in weight.

 

I also did some laser cutting work and produced some plastic components for fastening the motor and wires. For the final presentation, I made many slides of Powerpoint and helped to take photos of our product.

 

Findings

For the manufacturing stage, I learnt a lot during this period. First of all, I improved my capability of cooperation. I realized that in a group, nobody could do the entire work alone, we should work with others. Everyone has their unique characters, and we should make full use of it. Secondly, I found that it was difficult to turn the drawings to the operational objects. We always found that there were some problems we did not consider before. However, we learnt a lot from these problems, and our capabilities were improved by solving them.