Group L

MEng Group Project Interim Report CDIO Worldwide Challenge

Group L 11/22/2013

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Table of Contents 1. Introduction .................................................................................................................................... 2

2. Group Dynamics .............................................................................................................................. 2

3. Project Planning .............................................................................................................................. 3

3.1. Electronic Resources ............................................................................................................... 4

3.2. Risk Assessment and Management ........................................................................................ 4

3.3. Project Reviews ....................................................................................................................... 5

4. Market Research ............................................................................................................................. 5

4.1. Existing Products ..................................................................................................................... 5

4.2. Patents .................................................................................................................................... 9

4.3. Components .......................................................................................................................... 10

4.3.1. Braking .......................................................................................................................... 10

4.3.2. Power ............................................................................................................................ 11

4.3.3. Drivetrain ...................................................................................................................... 11

4.3.4. Steering ......................................................................................................................... 12

4.3.5. Chassis ........................................................................................................................... 12

4.4. Future Technology ................................................................................................................ 13

5. Concept Selection ......................................................................................................................... 14

6. Project Progression ....................................................................................................................... 16

7. Conclusion ..................................................................................................................................... 16

8. References .................................................................................................................................... 17

9. Appendix 1 .................................................................................................................................... 18

10. Appendix 2 .................................................................................................................................. 0

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1. Introduction This document covers the details regarding the 5th year Masters Project, related to the CDIO

Worldwide Challenge. This project was to design a single person mode of transport to cut down

commuter traffic within urban environments. This project involves a great deal of interpersonal and

time management skills to enable the group to develop a high level of professionalism. Another key

focus of this project was time and money management. With this is mind, this report was written to

define the initial phase of work and main planning of the project.

2. Group Dynamics Initially the whole group attended project management seminars with Brian Dickson where Belbin’s

Self Perception Inventory (SPI) was introduced. SPI scores people on how they display behaviour

traits commonly displayed in team roles. Each group member carried out the SPI questionnaire and

was categorised into the following SPI groups:

Group Member Primary Group Secondary Group

Cameron Monitor Evaluator Team Worker

Heather Completer Finisher Team Worker

Amy Company Worker Shaper

Peter Company Worker Plant

Rafael Team Worker Company Worker

Catriona Team Worker Shaper

The results of the SPI questionnaire showed that the team did not have a “natural” Chairman, Plant

or Resource Investigator. The group had a strong bias towards Team and Company Workers which

indicated that the group should function proficiently if there is some initial clear direction. The team

also had a Monitor Evaluator which would provide a critical evaluation of group work. A Completer

Finisher was also present within the group and this should ensure an awareness of deadlines and

objectives was always maintained. The group would also have to display the characteristics of their

secondary SPI group. Within the Secondary SPI groups were two shapers which would help provide

direction and leadership. The presence of a Plant also gave a balance that with imaginative thinking.

The results of the SPI showed that the group did not have the “ideal” balance of behaviour traits.

However there was also some scepticism over the results of the SPI since some primary and

secondary group traits seemed to contradict each other. As a group it was felt that with SPI

questionnaire did not necessarily completely define the behaviour traits that were present. The

group therefore established a project plan (detailed in Section 3) that included the necessary

reflection and self-evaluation to ensure a positive and productive group dynamic.

At the very beginning of the project the group operated without a group leader as the SPI

questionnaire didn’t indicate a person with the Chairman behaviour traits. Initially this did not cause

any issues, however it was felt after the contract was drawn up that a group leader was needed. The

group became easily side tracked and non-productive once the focus of completing the contract was

gone. Initial research lacked the necessary focus and direction, therefore at the end of week 5 the

group felt it was necessary to appoint a leader. Amy nominated herself since she felt comfortable

with taking on the responsibility and naturally fell into this role. It was also felt since Amy’s

Secondary SPI group was a Shaper that she would be suited to this role. The group leader role was

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defined as someone who would chair meetings, make important decisions if the team could not

agree, delegate the work load and sort any issues the group had. At this point another two roles

were defined and assigned to ensure the work load was split fairly amongst the group. Catriona was

appointed as an organiser with her directly responsible for booking discussion rooms, reminding the

team of goals and deadlines and updating the group log book. Heather was appointed as our head of

communications with her directly responsible for liaising between the group and the client and any

internal communications. It was clear that the group leader, organiser and communicator would all

work closely together to ensure the smooth running of the team. At this point it was also decided

that the defined group roles would be rotated at the end of week 9 with Cameron becoming group

leader, Peter becoming organiser and Rafael becoming head of communications. At the start of

semester 2 a decision will be made on who performed best within these roles based on the

productivity of the group.

During the writing of the contract it was decided that a review of the teams strengths and attributes

had to be carried out. This decision was made since it was felt that the team needed to be aware of

everyone’s capabilities when dividing the work load. The review revealed that the team had the

following strengths.

Group Member Strengths

Rafael Solidworks, matlab

Heather Technical drawings, ansys, weebly

Cameron Matlab , programming

Amy Solidworks, Abaqus, technical drawings

Catriona MS project, technical drawing

Peter Creo, technical/practical work

This review helped the team establish everyone’s capabilities. Although to date this information has

not been greatly needed it is felt that during the next stage of the project this information will be

valuable. During this review the team also felt that it was necessary to have weekly project reviews

as mentioned in Section 3.3. At these project reviews any problems an individual was having could

be discussed and then help offered by the best person within the group. Overall at this stage in the

project the group is working well and there is a strong motivation and commitment from everyone

to meet everything that was initially outlined in the contract.

3. Project Planning In order to adequately plan the project and keep track of the group’s progress a number of useful

tools were used. As mentioned in the statement of purpose the scope of the project was subject to

change. Microsoft Project was used to produce two Gantt Charts, as shown in Appendix 1, and tasks

were allocated for both eventualities. Two charts were produced due to the gateway review that

would take place at the beginning of semester 2. The Gantt charts were essentially the same until

this gateway review, whereby the charts then focussed on the respective tasks associated with the

build and the CAD respectively. A flow chart, as shown in Appendix 2, was also produced to record

the major milestones and gateways in the project. The document tracker, mentioned in section 3.1

was also useful in planning tasks to be completed by certain members and ensuring that this took

place.

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3.1. Electronic Resources Electronic Resources are an area of key importance for this project, to allow smooth working and

communication between group members. Google Drive has been essential in allowing the group to

easily upload, share and modify documents. A Facebook page was also set up to allow

communication about meetings, tasks to be done and group dynamics. The group has a document

tracker which includes a task list for each week. This ensures all group members can easily check

what tasks have been assigned to whom and when the task has to be completed by. This document

also contains the names of all documents related to each task that can be used for easy referencing.

A group logbook was also kept as a hard copy for all information collated. In the log book minutes of

meetings were kept, the ‘to do’ lists for each week and the administrative information such as who

had booked discussion rooms and times of meetings. Doodle Poll was used to organise meetings

with group members and Professor Boyle. This website allows users to ‘vote’ on meeting times that

suit them, allowing the meeting organiser to easily see when all the users are free to meet. This

saves numerous emails and trying to organise matching timetables

As per the guidelines for the 5th Year Group Project, the group has been assigned £100 per person,

totalling £600. Part of this has been spent on materials for building an initial prototype, this includes

balsa wood, glue, motors, wheels and other electronics accessories required. Materials for an initial

prototype were ordered early to minimise risk to continuation of project. It is planned that should

the build go ahead the remainder of the money will be spent on this, and should the build not go

ahead, more money will be invested in better more suitable materials to devise more small scale

prototypes.

3.2. Risk Assessment and Management Throughout the project risks were managed by making sure that a close note was taken of any issues

that could affect the project and implementing solutions to reduce these risks.

The first major risk would be the fact that the meeting to discuss the CDIO worldwide challenge

details had not yet taken place. This was taken into account within the statement of purpose and the

group decided that careful attention had to be given to ensure that everyone was aware that the

scope of the project may change. A stage gate was inserted into the flowchart to account for this

decision. As it stands the CDIO worldwide challenge details still haven’t been decided upon, so the

group has taken the executive decision, in collaboration with the client to adhere to the basic scope

of the project initially outlined. Any extra details added after the meeting of CDIO will be assessed

and the vehicle will be adapted if it is reasonable to do so.

Another major risk faced by the group is the loss of work due to either poor file management or a

group member being ill/away. In order to account for this the Google drive was set up to manage

this risk along with the document tracker to track all changes to any files or folders. This ensured

that at any one time the state of files could be assessed. All group members were encouraged to use

the drive to upload files when complete and during document production use another form of cloud

storage or some sort of external back up.

From the 13th of December until the middle of January the group will be undertaking exams. It was

agreed that during this time period no official group meetings would take place. When each

individual has completed his or her exams, group work will continue. This is to ensure that the

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project doesn’t infringe on exam revision and indeed that exam revision does not lead to poor

quality group work.

If the group decides to continue down the prototype route and build a large-scale prototype instead

of producing a CAD model then a number of risks will have to be managed. Should this route be

chosen materials will be decided upon and ordered as soon as possible. This should minimise the lag

time from ordering to delivery. At this point workspace and tools to build the prototype must also be

sourced to ensure that as much time as possible is available for building the prototype.

If the group decides to model the prototype using SolidWorks then a potential risk could be the lack

of SolidWorks knowledge within the group. In order to combat this, a training course was organised

with Yevgen Gorash to educate the group to the same level in SolidWorks. Another potential risk

with modelling in SolidWorks is the issue that the software is only available on University computers.

This could be troublesome should the weather be particularly bad over winter, as it has been in the

past few years. This could prevent group members from travelling to university and therefore delay

the modelling. To manage his risk, Yevgen Gorash has been able to direct the group to be able to

install SolidWorks on home computers or laptops using a VPN to the university network.

Should any unidentified risks arise they will be dealt with appropriately and in the best way possible

to ensure the smooth running of the project.

3.3. Project Reviews Throughout the project, weekly reviews took place at the group meetings. The work completed the

previous week was discussed, and also the outcomes for that group meeting and the tasks for the

next week were assigned. At each meeting the Gantt chart was consulted to ensure that the project

was at the suitable stage. Every 2 weeks a meeting with Professor Boyle was organised to update

him on the group’s progress. These meetings were also vital for the group to gain information on the

progress of the CDIO committee, which was vital in deciding how the project should progress.

Professor Boyle was in contact with the CDIO committee for the UK and internationally and was our

only point of contact with regards to the challenge details.

4. Market Research

4.1. Existing Products In recent years governments have been under greater pressure to reduce carbon emissions due to

implementation of Kyoto targets. With the use of cars as a mode of transport becoming more

efficient in recent years, the amount of people choosing to drive to their workplace has increased.

This has led to people choosing to do their daily commute alone rather than car sharing and

increasing congestion within cities. This leads to a rise in stress levels during the average commute

and affects the air quality within city environments. As a result of this, it is more important than ever

to move away from the conventional use of cars and towards more environmentally modes of city

transport.

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Transport in its current form is reliant on a singular fuel source with 95% of transportation currently

fuelled by petroleum an issue of stability of resource becomes predominant [1]. Being solely

dependent on a source of energy which is imported is politically unstable for a country, highlighting

the need for a more self-sufficient method of fuelling transportation.

A significant disadvantage of using cars is the associated costs. In addition to the initial cost of

purchasing the car comes the cost of; insurance, road tax, fuel, general maintenance and inner city

parking. In terms of energy costs, the amount of embodied energy required to manufacture a car is

more than the average energy that the car will use in the first 10 years of use.

The most common form of environmentally friendly, personal transport is the bicycle. As one of the

most efficient modes of transport burning approximately only 50 calories a mile, it uses gearing

systems powered by the rider’s legs to propel the bicycle at speeds comfortably [2]. The advantages

and disadvantages of this mode of transport can be found in Table 1.

Advantages Disadvantages

Running purely on human power they are approximately 3 times more efficient than walking whilst travelling up to 3 or 4 times as fast on the same output.

No weather proofing – the user must wear waterproof/heat resistant clothing depending on conditions

User friendly Unstable at lower speeds and require rider input to remain upright

Cheap to buy and maintain – no need for fuel or taxes

Average users can only manage 10-20 miles on average before becoming fatigued

Huge global infrastructure for use and maintenance has been created

No safety equipment included saving user from injury from collisions

Take up very little space per unit Table 1- Investigation into advantages and disadvantages of bikes

Many people may feel that exerting energy on their daily commute may inconvenience their work

day, this has led to the development of power assisted bicycles. Power assist bicycles work by adding

a motor to either the wheel of a bicycle or the drivetrain of the bicycle. They consist of either a

throttle to power these alone or via a sensor unit, which adds to the power input the user. The

advantages and disadvantages of this mode of transport can be found in Table 2.

Advantages Disadvantages

Remove 100% user input to allow less effort for weaker, older, or less capable riders

Substantially heavier than a regular bicycle – often 10-20 kilos more

Can be repaired similarly to regular bicycles sharing several components

Expensive ranging from £1000-4000 plus more costly maintenance and running

Charge lasts around 15 miles, after which it becomes a very heavy regular pedal cycle

Motor input speeds limited to 15.5mph mean they are still substantially slower than average road users

Table 2 - Investigation into advantages and disadvantages of E-bikes

Scooters and skateboards also have many positive characteristics that are suited to a single person

mode of transport. Scooters and skateboards are both highly manoeuvrable and so can be used in

congested areas with ease. The micro-scooters developed in the late 1990s were highly portable

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because of their folding mechanism. This meant that they could be used to speed up a person’s

commute and then easily stored once they arrived at work. Scooters however are not widely used as

a mode of transport. Skateboards are also highly portable but they are even more unpopular. The

reasons for this may be that a skateboard needs a certain level of skill and practice in order to use it.

Skateboarding also has a fairly negative public perception and is often seen as a nuisance around

town and city centres. Skateboards and scooters have existed for a significant amount of time and

they have not been fully utilised as a mode of transport.

As a result of the disadvantages associated with the carbon neutral methods of transport discussed,

there have been many proposals made by different companies of a small electric city vehicle

designed for just one person. This gives city dwellers the option of an easily operated and cheap to

run electric vehicle, which, in many instances, avoids the traffic and emissions associated with

current city travel.

The Segway is a single person mode of transport that was developed by inventor Dean Karmen. The

Segway operates on the principle of the user balancing on a platform supported by two wheels, and

holding onto the steering column. The Segway is powered by a battery and electric motor, which

gives the Segway good energy efficiency. The user operates the Segway by leaning forwards and

backwards to move the device, which has a number of motors and gyroscopes to keep the platform

stable when in use. The advantages and disadvantages of the Segway can be found in Table 3.

Advantages Disadvantages

Range of 26 miles

Cannot be used in the UK in public spaces- neither bike nor ‘car’

‘Eco’ friendly No protection from bad weather

Quick, manoeuvrable Can be dangerous if inexperienced user

Good for golf players, comes with a number of accessories

If battery is dead, no secondary power source (i.e no human powered option)

Expensive - £5000

Unpopular with certain people due to aesthetics

Requires charging

Draws excess attention compared to bike

Dangerous for use in pedestrianised areas Table 3 - Investigation into advantages and disadvantages of Segway

The main downside of the Segway is the legality of using it on public highways. In the UK the Segway

is banned from pavements because it is not classed as an invalid carriage. Segways are not allowed

on cycle paths because they lack pedals and they are not allowed on highways due to the lack of an

mot and road tax and also the maximum speed at which the product can travel. Another point that

was highlighted through market research was the expense of the Segway. At around £5000, the

Segway is an expensive mode of transport when a small family car could be purchased for this

amount. It can be seen that there are a number of disadvantages to the Segway than there are

advantages. This has ultimately led to the Segway not becoming a worldwide product, the Segway is

however popular in some cities as a method for tourists to tour the city quickly.

The Sinclair C5 was developed in the 80’s as an innovative combination of human and electric power

sources. The vehicle concept was innovative for its time however it did not able to live up to

expectations. The Sinclair C5 had some significant similarities to the car such as increased stability

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and aerodynamics, whilst reducing the associated problems. The advantages and disadvantages of

this vehicle can be found in Table 4.

Advantages Disadvantages

Stability Low height invisible to bigger vehicles

Spacious Lack of reverse gear

Environmentally friendly No weather protection

Aerodynamic Poor battery life

Table 4- Investigation into advantages and disadvantages of Sinclair C5

A major disadvantage of the Sinclair C5 was its lack of safety equipment, with no rear-view mirrors

and indicator lights it was seen to be missing basic safety features. Even though safety had been one

of the top priorities during the project, issues such as this, and its low height made it dangerous to

drive in urban traffic.

In 2010, Sinclair Vehicles launched the Sinclair X1, which is the successor of the Sinclair C5. Major

improvements included; redesigning the handlebar to be more similar to a bicycle handle bar,

addition of a waterproof acrylic dome and the ability to adjust both brakes and handlebars to

provide the driver with a more comfortable ride.

Other concepts have included designing new products based on the success of the bike. The flykly

and Copenhagen wheel are new concepts that involve the use of a replacement wheel for a bike.

The wheel includes an electric motor and internal 3-speed gear hub which replaces the rear wheel

on the users original bike. The electric motor assists the user and therefore less human effort is

needed to move the bike.

One such proposal is that of the Honda 3R-C [3]. This futuristic 3-wheeled motorcycle type vehicle,

shown in Figure 1, is completely electrically

powered, making it ideal for customers who want to

charge it at home and use it to commute. A glass

canopy covers the single seat when not in use, and

offers the vehicle protection from weather. When is

use, the canopy then can fold up and provide a

windscreen for the driver, making the commute

more comfortable as there is protection from the

wind and rain. Although this vehicle causes reduced

city emissions, its 3-wheeled nature makes it quite

wide and therefore unable to avoid city traffic. As

there is no additional power source, range anxiety

could be an issue.

In an effort to maximise the sustainability of their vehicle, designers Kenneth Cobonpue and

Albrecht Birkner have created Phoenix; a three-wheeled car made mainly from bamboo [4]. Inspired

by structures and forms found in nature, the outer bamboo shell is light, cheap and quick to weave.

It is designed to biodegrade in tandem with the life of the car, and can be easily repaired or replaced

if damaged. It is powered by two electric motors, one on each rear wheel. As with the Honda 3R-C,

the electrically powered motors lend themselves well to home charging, this is often cheaper than

Figure 1 - Honda 3R-C [3]

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using petrol. The car itself however is no smaller than an average car, and therefore would be unable

to avoid traffic and require a driveway for parking. Range anxiety could also be an issue if parked in a

location where there are no charging points.

Designed in the shape of an egg, the Hyundai E4U is an example of a more compact electric vehicle

[5]. In a similar way to the Segway, users stand on a platform when driving the vehicle. A door in the

egg shaped exterior allows the driver access and

the top of the egg, which when parked shelters

the seat, can be detached and used as a stylish

helmet and windscreen. It is steered by a sphere,

instead of wheels, which enables it to quickly turn

in any direction. The vehicle itself is fairly

lightweight at 80kg – although still too heavy to be

lifted and carried easily – and it has a top speed of

18mph. Physically much smaller and slower than a

car, it is much more suited to being used on

narrow paths than on a road. Its small size makes

it able to be parked and stored very easily, as well

as being able to dodge city traffic. The vehicle

relies on a battery, which must be plugged in to be

charged, so range anxiety is again an issue.

In an effort to harness locally available power while driving “Blue Car”, conceived by “le Groupe

Bolloré”, is equipped with solar panels integrated into its roof and bonnet [6]. Its design is similar to

any other electrically powered car, and is therefore most suitable for use on roads. This means that

it isn’t able to avoid city traffic, although it doesn’t produce any pollutants. Having solar panels

integrated into the fabric of the car gives it an advantage over other electrical vehicles that are

unable to charge except when near a charging point. Being able to park and leave the car to charge

in any location where there is sunlight means that range anxiety is much less of an issue. It also

means that the car is likely to be more popular in locations closer to the border where it will be more

able to take advantage of the increased sunlight hours.

4.2. Patents Initial research into existing patents was carried out to gain an initial understanding of the products

available. The decision to incorporate a renewable or human powered technology led to a search for

innovative existing patents.

An interesting patent, involved multiple air ducts on the underside of the carriage, which would

force the air into small turbine generators, generating energy [7]. This energy was then collected and

stored within a battery powering the car. Another patent for powering of a vehicle through an

environmentally friendly source, is a component which converts the axel shaft rotational energy to

electric energy, powering a battery whilst the vehicle is in motion [8]. Incorporating the

methodology of human powered element a patent for a device which generated power through

pedalling was investigated [9]. Within this device, current is generated from a DC generator by a

pedalling force and is supplied through a DC/DC converter to electric apparatus.

Figure 2 - Hyundai E4U [5]

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A patent found for the steering mechanism was the gravity driven lean to steer mechanism [10].This

design was invented for mainly recreational or racing purposes. The user would sit on the seat, push

off with their hands and steer through leaning to the desired direction of turning.

Further research was carried out into vehicles which were practical and portable. A patent was

found for a collapsible vehicle which can be easily transported [11].This patent shows a vehicle with

a collapsible body which folds into the size of an average suitcase. The vehicle comprises of two

parts which nest inside one another when folded.

4.3. Components

4.3.1. Braking

When choosing the style of brakes to be used, there are several significant factors: the weight of the

brakes, the braking power they provide and their resistance to wear and tear to name but a few.

Rim brakes – often called V brakes - can be either hydraulically or mechanically operated. They are

mounted round about the outer rim of the wheel and, in the mechanically operated case; a cable is

used to pull two rubber pads into contact with the wheel rim. The friction between these pads and

the wheel rim is what causes the wheel to slow. When the brakes are hydraulically operated, they

function in the same way, but are operated by fluid pumped into a compartment within the brake

system causing the pads to press against the wheel. These brakes have a negative effect on the rim

of the wheel and extensive use will eventually cause the rim to wear away and the wheel to fail.

Furthermore, as they are located on the outer rim of the wheel, they are affected heavily by dirt and

moisture that readily collects on this part of the wheel. This can greatly reduce their reliability and

effectiveness.

Disc brakes are a popular alternative to rim brakes, and can also be either mechanically or

hydraulically operated. Disc brakes work by applying pressure to a small metal disc that turns with

the wheel and is mounted in parallel on the axel. As there is no danger that this braking system will

cause wear to the wheel, they are able to brake much harder than rim brakes. Moreover, as they are

located towards the centre of the wheel, they are less likely to come into contact with dirt and

moisture from the road. Often holes are drilled into the braking disc to give an escape route for any

dirt that collects and heat dissipation. However, they are slightly more expensive than their rim

brake counterparts.

Commonly used on the rear wheel of motor vehicles, drum brakes are an internal braking system

that is completely protected from dirt and moisture. A drum is connected in to the axis of the wheel

which spins with the wheel itself. A pair of shoes inside the drum press against the internal surface,

and the friction causes the rotation of the wheel to slow. This type of braking is cheap to

manufacture but consists of many moving parts which can be difficult to access and repair if broken.

The addition of an entire drum means the brakes are less affected by corrosion and dirt build-up, but

this also adds a lot of weight to the wheel. This makes the whole system much less portable

compared to other braking systems.

It is possible to use the braking system to capture some of the energy that would otherwise be lost

as friction. Regenerative brakes function by turning the motor into a generator to slow the car. This

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type of braking is often used in combination with regular friction brakes, just in case it fails. By

harnessing energy from braking, the electric batteries of cars can last longer than they would

normally, therefore increasing their range. It also adds to the car’s image of being “green”. This type

of braking relies on a vehicle having a battery and electric engine, so therefore is not compatible

with those that are purely human powered. It is also a much more expensive and technologically

intensive braking system, meaning that often it cannot be simply repaired.

4.3.2. Power

Human Powered

Powering a vehicle purely by having the user propel the vehicle is a very environmentally concept

due to no emissions from an engine or the disposal of a battery. The most common example of this,

as mentioned in section 4.1, is the human powered bicycle, whereby the user turns a crank using

pedals. This method of transport has seen several evolutions, including the development of electric

bikes in recent years.

Battery/Electric

Using batteries and electric motors as a form of propulsion is a method used by a number of concept

cars as mentioned in Section 4.1. The electric motor is more environmentally friendly than using a

combustion engine but the question still remains on the viability of producing lithium ion batteries.

A new technology being revised is the use of super capacitors, which are faster charging, with a high

number of cycles however the technology is in early stages and has less power storage than

conventional lithium ion batteries.

Wind

The concept of using wind to power a vehicle has been utilised in land buggies, whereby a sail is

used to propel the buggy. This is commonly used on beaches and is an unviable method for used in

cities due to the size constraints and the effect of buildings on wind speed and direction. The system

also relies on a sufficient wind speed to propel the buggy, without this the buggy is powerless. A

wind turbine could also be another way of harnessing the wind. Using the wind turbine whilst the

vehicle was in motion propelled by another power source would negate any savings made due to

drag, therefore the wind turbine would have to be implemented whilst the car was stationary,

perhaps to charge the battery.

Solar Panels

Solar panels have been used with great success on boats, with large surface areas on the roof

covered with solar panels. Ford have also implemented a system whereby solar panels in the

headlights store energy to then power the headlights at night. Solar Panels could be easily fitted to

the roof of a vehicle in order to store energy form the sun, this could then be used to recharge a

battery, which would provide power to an electric motor. Every year the World Solar Challenge takes

place whereby single person vehicles are raced across Australia, using only solar power.

4.3.3. Drivetrain

The drivetrain of the vehicle allows the power to be translated from the motor to the wheels. This

consists of an axle setup and a connecting belt or rod from the axle to the motor crankshaft.

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Axle configurations are simple, consisting of one or two wheels mounted on the same rotational

axis. A single wheel is the simplest method with the axle being mounted at either side of the wheel.

This stops any unwanted movement of the wheel under the driving forces. To mount two wheels on

an axle is somewhat more complex. As a vehicle turns the inside and outside wheels move at

different speeds due to the outer wheel traveling much further therefore a differential is needed.

Having two wheels at the rear provides stability as well as an improvement in power transfer.

However this requires the addition of a differential complicating the design.

There are 3 main methods to transfer the power from the motor to an axle – the cog-chain, the cog-

belt and the driveshaft. They tend to be made from steel plates held at intervals by a joining pin in

the middle. These pins mesh into teeth on a cog, which convert rotational motion of the cog into

linear motion of the chain pins, pulling the plates.

A cog-belt setup remains very similar to a chain-cog. The cog profile changes when using a belt drive

to a more rectangular profile designed to let the larger teeth of the belt to mesh. This belt can be

designed to resist strain under high loads as well as having a high tensile strength to avoid failure.

The flexibility of the belt is similar to that of the chain, and has the advantage of not requiring a

lubricant. The durability of the drive-belt is impressive with resistance to UV in hot weather, as well

as a wipe clean surface for use under inclement weather conditions.

A driveshaft is found in almost all road vehicles, providing a steel or composite shaft that can be

subjected to very high torsional loads. This can translate into a very high torque transferred to the

wheels. Although the driveshaft can take a very high torque, it must be reinforced and hence adds a

large mass to the vehicle. Added to this, for the driveshaft to be angled it must use a CV or Universal

joint. Once again this added mass is inappropriate for use in such a small vehicle.

4.3.4. Steering

The existing mechanism used to steer a conventional car is referred to as the rack and pinion

method. This mechanism converts the rotational motion of the steering wheel into linear motion,

which is then utilised in turning the wheels in the desired direction. A similar method of steering is

recirculating ball steering, which is mainly used on trucks and other heavy vehicles [12]. The

rotational motion of the steering wheel is input into a recirculating ball steering gear, inside which a

worm gear rotates. This worm gear is fixed so that when it spins, it moves the block transmitting

motion through the gear to an arm, connected to the steering rack. This motion causes the wheels

to turn.

As mentioned in Section 4.2, another method of steering was to lean and steer. This was thought to

be a good mechanism as it enables the user to accurately control their direction without a

complicated gearing system. The lean and steer idea was similar to the mechanism in the Segway

concept discussed in Section 4.1, although not electrically controlled.

4.3.5. Chassis

Inspiration for chassis types was taken from a number of sources, such as recumbent bikes and

trikes. Also the vehicles mentioned in section 4.1 and other standing type vehicles such as the

Segway and the eliptigo. The chassis type and design would rely heavily on the other choices made

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with regards to wheels, brakes and steering mechanisms. Also the power supply chosen would have

a big impact on the chassis type and design, especially if it was to have a human input. The materials

used to make the chassis would depend on cost constraints and also the strength and weight

required.

4.4. Future Technology In the initial brief from CDIO it stated that the single person vehicle that is designed should be

“developed for a future lifestyle context of an energy self-sufficient household”. This was

instrumental in influencing the power considerations mentioned in section 4.3.2. The power

concepts focused on a self-sufficient mode of propulsion; the use of electricity was considered

though. Currently there are a number of electric vehicles on the market but these all need to be

charged using electricity from the grid. Renewable energy currently only makes up 10% of the power

generated in the UK [13]. This means that using energy from the grid still means relying on energy

derived from fossil fuels. Currently there is a lot of research into how to power “homes of the

future”. Integrating renewables into the grid and micro generation are all being considered. There

are already totally self-sufficient homes in existence that generate all the electricity they use [14].

However, these homes are normally just managing to be self-sufficient and therefore it is essential

that the single person vehicle designed does not heavily rely on electricity.

In other areas of the world there is an alternative to integrating green technology into an already

existing city. In both Abu Dhabi and South Korea there are projects into building so-called “future

cities”. In Abu Dhabi there is a city being built called Masdar, which will be a sustainable, zero-

carbon, car free city [15]. The initial plan for the city was to have a personal rapid transfer (PRT)

system to enable ease of movement around the city [16]. PRT systems are electrically powered small

automated vehicles that operate on a network of guide ways. There are currently many examples of

PRT systems being used worldwide but on a fairly small scale. At Heathrow airport there is currently

a PRT system consisting of 21 vehicles connecting Terminal 5 to its business passenger car park.

Heathrow airport states that customers wait an average of 12s for a personal vehicle to take them

the 2.4mile route [17]. In Masdar the PRT project was initially trialled but in October 2010 it was

announced that the trial would not be expanded. This was due to the expense of building the

necessary infrastructure needed for a PRT system to work. Masdar is now looking into electric cars

and other clean-energy vehicles for public transport. In South Korea there is a city called Songdo that

has also been built with the concept of providing an accessible and reliable public transport network

[18]. In Songdo there is a focus on providing suitable pathways and bike lanes to encourage the use

of walking and cycling. Projects like this demonstrate that there is not yet one convenient answer to

personal transportation around the city environment.

As previously mentioned in section 4.1 there are many laws within the UK that place a great number

of restrictions on any possible single person city transportation vehicle designs. In order for any

possible design to be legal within the UK they must either meet the laws regarding bikes and E-bikes

[19] or the Highways Act of 1835 [20]. Globally there are many different laws and as mentioned this

has been one of the main hindrances of previous single person vehicles such as the Segway and the

Sinclair C5.

Overall it was felt that designing for an already existing city environment would place an extensive

amount of restrictions on any design. Designing for a future city that doesn’t actually exist means

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that there are no complications with trying to abide by the different laws in countries around the

world. Designing for a future city also allows for a greater amount of freedom and innovation and

this freedom appealed to the group.

If the single person city vehicle was going to be designed for a future city it was felt that it must also

include some form of “smart technology”. In recent years there has been an immense growth in

smart technology due to the increasing prominence of smart phones in everyday life. There are

already smart phone apps that can be used for navigation, weather forecasting, monitoring speed

and monitoring the number of calories burned. Google have also been developing a “driverless car”

that relies on lasers to generate a 3D map of the environment surrounding the car [21]. Many car

manufacturers are also researching autonomous vehicles. Although there are currently no fully

autonomous cars on the market there are many cars that have built in autonomous features such as

adaptive cruise control, lane assist and parking assist [22]. Therefore it would be possible to build in

autonomous safety features into designs for a single person city transporter. Overall since the brief

stated that the vehicle was to be for a “future lifestyle” the inclusion of smart technology was

thought to be essential in any potential designs.

5. Concept Selection To generate conceptual vehicle designs, the project was first broken down into several component

parts, as detailed in section 4.3 Component. Several concepts were generated for each part, and

Pugh’s Total Design Method was used to select the most suitable design for the brakes, drive type

and power supply. Figure 3 and 4 is an example of concept drawings. This required the use of a

Controlled Convergence Matrix (CCM) to assess each of the component designs against each other.

From this an optimal design could be inferred for each component. Knowing this, several different

concept designs were generated.

With the major components of the vehicle split into 5 categories as shown in section 4.3, each of the

methods were compared against each other to find the strongest and most viable option.

With the braking system there was very little deviation from the datum choice, which made it

difficult to narrow down an ideal choice. After discussion it was decided the weighting of each

category was not equal and meant that we had to make a group decision in the end opting for

hydraulic disc brakes similar to those found in high end mountain bikes or motorbikes.

As stated in the project plan, the power supply of the vehicle had to be low energy and economical.

From comparisons in the CCM, solar power was clearly an advantage. Initially, our final concept

featured a mixture of a PV array, powering a battery, along with a pedalling system similar to that of

a bicycle that could also be used to propel the vehicle. In theory this idea seemed to make sense, as

it could be purely human powered on a flat section of path to save battery power. Also, initially the

element of human power was included due to the UK laws on vehicles in cycle paths. When it came

to fruition however this system was far more complicated than had been anticipated and it was soon

realised that a new plan must be made to avoid it being too similar to the common bicycle or

recumbent bike. The group decided to design this product without taking into account laws for a

specific city, allowing a more innovative design with use of future technologies. Ultimately it was

decided upon a solar only power source. This would charge the battery as long as there was a source

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of lighting. In the evening or times of little use, the vehicle could also be hooked up to a domestic

supply to charge the battery.

For drivetrain it was decided that a single rear wheel would be the prime option to avoid the need

for a differential. It would also allow a smaller footprint for the vehicle and allow a more streamlined

shape. The single rear wheel axle would be connected to the motor by a drive-belt. A belt is durable

enough to withstand various weather conditions, which allow it to be a ‘fit and forget’ item,

something that cannot be said for a chain.

Steering is an essential part of controlling the vehicle, so something that proved intuitive was key.

The idea of tilt steering was novel yet natural for the user, and still in-keeping with the feeling of it

being a bicycle or motorbike. Traditional rack and pinion steering would a stable yet direct method,

which would be simple to design and operate.

For the structure of the vehicle, an I-beam style chassis connecting the axles to the drivetrain and

motor could be used with a fiberglass shell for weather protection, and to mount the solar panels.

Fibreglass was chosen due to its high malleability under construction whilst remaining weather proof

and resilient once formed.

A model was constructed using balsa wood to model the I-beam style chassis as well as utilising a

small motor powered by AA batteries. This was to give a basic idea of the aesthetics and layout of

the vehicle before adding in the aerodynamic shell. The driver of the vehicle sits in a somewhat

recumbent position, which allows a lower centre of gravity adding stability to the vehicle. To the

underside and behind of the driver’s seat, the battery as well as the motor is located to keep it out

of the way of the driver to stop injury through contact with the moving drive-belt. This also gives an

optimum path from the motor to the rear wheel clear of any obstructions for the belt to pass

through.

Figure 3 Example of Concept Drawing

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Figure 4 Example of Concept Drawing

6. Project Progression

One of the main objectives of the project is the development of each member’s group work skills

that are fundamental to develop into a well-rounded engineer. The group has so far worked well

together, as detailed in group dynamics the organiser, communicator and group leader were

assigned and have completed tasks as instructed. Weekly group meetings have been well attended

with all members completing tasks as required and working well together. The document tracker has

been updated and communication has been clear within the group, using emails and the Facebook

page.

As mentioned in the risk section, the details of the CDIO worldwide challenge are crucial in deciding

the form that the project takes. At this point, the final details have not yet been given. The group has

kept on track with the Gantt chart, and as it currently stands we are ahead of schedule. The tasks

scheduled previous to this report were accomplished successfully and currently the group is

completing final decisions about the final prototype. A final prototype should be decided and a small

model completed for week 12.

After this has been completed the next milestone will be the breakdown of the design into

component parts and then a decision will be made as to whether only CAD the concept or whether

building a full size prototype would also be a viable option.

7. Conclusion In Conclusion, the group are working well to achieve the milestones set out within the statement of

purpose. With the strengths and weaknesses of group members determined from an early stage the

group were able to use these to their advantage. Roles distributed within the group ensured the

group were making decisions to stay on the correct path and focused on deadlines. With the initial

phase of work done and initial concepts created, the group have entered the final concept selection

stage. If the group continue to remain with this momentum, the project will provide promising

results whichever path it follows.

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8. References

1. http://www.ipcc.ch/pdf/assessment-report/ar4/wg3/ar4-wg3-chapter5.pdf

2. http://www.livestrong.com/article/135430-calories-burned-biking-one-mile/

3. http://world.honda.com/news/2010/4100224Geneva-Motor-Show/

4. http://www.albrechtbirkner.com/PHOENIX

5. http://green.autoblog.com/2013/04/09/hyundai-unveils-e4u-ev-eggs-seoul-motor-show/

6. http://www.bluecar.fr/fr/pages-accueil/default.aspx

7. Eco-friendly wind power based electric vehicle

W02013094808 - 27TH January 2013

8. Method for internally generating electric energy in electric vehicles

US20130154363 A1 - 19th December 2011

9. Pedalling power generation health machine

WO2003059461 A1- 24TH July 2004

10. Gravity driven lean to steer wheeled vehicle

CA 2406914 A1 – 22ND April 2004

11. Collapsible Vehicle

WO 2011016722 A2 – 10th February 2011

12. http://auto.howstuffworks.com/steering3.htm

13. http://theenergycollective.com/david-k-thorpe/237161/it-s-not-utopian-100-renewable-

electricity-here

14. http://inhabitat.com/sosoljip-is-a-self-sufficient-net-zero-energy-house-in-south-korea/

15. http://masdarcity.ae/en/62/sustainability-and-the-city/transportation/

16. http://en.wikipedia.org/wiki/Masdar_City

17. http://en.wikipedia.org/wiki/Personal_rapid_transit

18. http://www.songdo.com/songdo-international-business-district/the-city/master-

plan/transportation/inner-city-travel.aspx

19. https://www.gov.uk/electric-bike-rules

20. http://www.legislation.gov.uk/ukpga/Will4/5-6/50/section/72

21. http://www.google.co.uk/about/jobs/lifeatgoogle/self-driving-car-test-steve-mahan.html

22. http://en.wikipedia.org/wiki/Autonomous_car

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9. Appendix 1 Gantt chart Build

19

Gantt chart CAD

10. Appendix 2 Flow Chart:

Project Selection

1

Preliminary Investigation

2

Concept Definition

3

Concept Development

4

Computer Training

5

Source Materials

Statement Of Purpose

Interim Report

Research Approval

Time Discussion

1

Build Prototype OR Visual Models

6

Test Prototype OR Run Simulation

7

Create Website

8

Presentation

Final Report

Reflection Meeting

Finished Product