ISEP

30-05-2012

Powering the Future with Zero Emission and Human Powered Vehicles

 –

Engineering a specification for a Zero Emissions Single-seater Vehicle

Manuel Vilaça | Pedro Pinto

Conteúdo Summary Summary ....................... ............................................ ................................. ................................. ................................. ................................ ............................. ......... 4 History History ........................ ............................................. ................................. ................................. ................................. ................................ ................................ ............ 4 Premises Premises of Work.......................................... Work...................................................... ................................. ................................. ........................... ............... 7 Report............... Report........................... ................................. ................................. ................................ ................................ ................................. ............................... .......... 8 Design................ Design............................ ................................. ................................. ................................. ................................. ................................ ......................... ..... 8 Tadpole Tadpole Trike Variatio Variations ns ........................ ............................................ ................................ ................................. ................................ ........... 9 Suspensi Suspension on ........................ ............................................. ................................. ................................. ................................. ............................... ................... 11 Basic Basic Trike Frame Frame Design Design ........................ ............................................. ................................. ................................. .............................. ......... 12 Weight Weight Distribu Distribution.... tion................ ........................ ................................. ................................. ................................. ................................. .............. 12 Center Center of Gravity........ Gravity.................... ................................. ................................. ................................. ................................. ........................ ............ 12 Wheelbase. Wheelbase............. ........................ ................................ ................................. ................................. ................................ ............................. ................. 13 Wheel Track ......................... ............................................. ................................ ................................. ................................. .......................... .............. 14 Frame Design Design ....................... ............................................ ................................. ................................. ................................. ......................... ............. 15 Steering Steering Geometry........ Geometry.................... ................................. ................................. ................................ ................................. ...................... ......... 16 Trike Steering Steering Geometry Geometry ........................ ............................................ ................................ ................................. ................................. ............ 16 Caster Caster Angle....................... Angle........................................... ................................ ................................. ................................. ............................ ................ 16 Camber............ Camber........................ ................................. ................................. ................................. ................................. ................................. ....................... 17 Toe-In......................................... Toe-In..................................................... ................................ ................................ ................................. ............................. ........ 17  Ackerman Steering Steering Compensation Compensation ....................... ........... ..................... ......... ...................... .......... ...................... .......... ...... 17 Kingpin Inclination (Center Point Steering)................... ............... ............ ............... ........................ ............... ... 0 Kingpin Kingpin to W heel heel Axle Orientation Orientation ......................... ............................................. ................................ .......................... .............. 19 Steering Mechanisms and Linkage Systems ....................... ........... ..................... ......... ...................... .......... ................. ..... 20 Under Under Seat Steering Steering-USS.............. -USS.......................... ................................. ................................. ................................ ......................... ..... 20 Steering Linkage Systems and How They Work........... Work ....................... ..................... ......... ...................... ............ .......... 20 Single Single Tie Rod and Drag Link System ........................ ............................................. ................................. .................... ........ 20 Dual Drag Link Link System System ....................... ............................................ ................................. ................................ ................................ ............ 21

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Crossed Crossed Dual Drag Drag Link...................... Link........................................... ................................. ................................. ................................ ........... 22 Wheel Wheel Size Size ....................... ............................................ ................................. ................................ ................................ ................................. ....................... 23 Brake Brake Systems Systems ......................... ............................................. ................................ ................................. ................................. .......................... .............. 24 Plug-in Plug-in design design for battery battery charging charging........... ....................... ................................ ................................. ............................... .................. 26 Battery Battery ....................... ............................................ ................................. ................................. ................................. ................................ ........................ .... 26 Hub Motor...................... Motor.......................................... ................................ ................................. ................................. ................................. ....................... .. 0 Regenera Regenerative tive Braking................. Braking............................. ................................. ................................. ................................. ................................ ........... 27 Human Human Drive-Tra Drive-Train...................... in........................................... ................................. ................................. ................................. ...................... .......... 28 Calculat Calculations ions............ ........................ ................................. ................................. ................................. ................................. ................................. ....................... 29 Costs.................. Costs.............................. ................................ ................................ ................................. ................................. ................................. ........................ ... 31 Drawings Drawings ....................... ............................................ ................................. ................................. ................................. ................................ ........................ .... 32 Conclusi Conclusion.................... on......................................... ................................. ................................ ................................ ................................. ............................. ........ 34

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Image 1 – 1896 Recumbent............. Recumbent......................... ................................. ................................. ................................ ................................ ............ 0 Image 2 – 1933 Recumbent............. Recumbent......................... ................................. ................................. ................................ ................................ ............ 0 Image 3 - ....................... ............................................ ................................. ................................. ................................. ................................ ............................. ......... 0 Image 4.................... 4........................................ ................................ ................................. ................................. ................................. ................................. ............... ... 6 Image 5.................... 5........................................ ................................ ................................. ................................. ................................. ................................. ............... ... 0 Image 6 – Ride on country countryside side ....................... ............................................ ................................. ................................. ............................. ........ 0 Imag Image e 7 - Sidewinder Procruiser ........................ ............................................. ................................. ................................ ............................. ......... 0 Image 8 - Bergwerk Bergwerk Bikes Bikes GMBH ........................ ............................................. ................................. ................................. ........................ ... 0 Image 9 – Front suspensi suspension on Cad detail............... detail........................... ................................ ................................ .......................... .............. 0 Image 10 – Front Front Suspensi Suspension on detail.......... detail...................... ................................. ................................. ................................. ....................... .. 0 Image 11 11 – Rear Dampe Damperr ....................... ............................................ ................................. ................................. ................................. ................ .... 0 Image 12 – Center of Gravity Gravity ........................ ............................................ ................................ ................................. ................................ ........... 0 Image 13 – Medium/S Medium/Short hort wheelba wheelbase...................... se........................................... ................................. ................................ .................... 0 Image 14 – Long Wheelbase Wheelbase ........................ ............................................ ................................ ................................. ................................ ........... 0 Image 15 – Aluminum Aluminum Tube Tube used for chassis chassis ....................... ............................................ ................................. ................. ..... 15 Image 16 –Crucifo –Cruciform rm Frame ........................ ............................................. ................................. ................................. ................................ ........... 0 Image 17 - Caster Caster ........................ ............................................. ................................. ................................ ................................ ............................ ................ 0 Image 18 - Camber.................. Camber.............................. ................................. ................................. ................................. ........................................ ................... 0 Image 19 – Toe In........................ In............................................. ................................. ................................ ................................ ............................ ................ 0 Image 20 – Kingpin Kingpin Inclination Inclination............ ........................ ................................. ................................. ................................ ............................. ......... 0 Image 21 - Single Tie Rod and Drag Link Link System..................... System.......................................... ................................. ............... ... 0 Image 22 - Dual Dual Drag Drag Link Link System System ....................... ............................................ ................................. ................................ ....................... ... 0 Image 23- Crossed Crossed Duel Drag Link Link ....................... ............................................ ................................. ................................ ...................... 22 Image 24 – Low resistan resistance ce tires ........................ ............................................. ................................. ................................ .......................... ...... 0 Image 25 – Hydraulic Hydraulic Brake System System ........................ ............................................ ................................ ................................. ..................... 0 Image 26 – Brake Leaver................ Leaver............................ ................................. ................................. ................................ ................................ .............. 0 Image 27 – Brake Calipers Calipers and pad......................................... pad..................................................... ................................. ......................... .... 0 Image 28 – Disc Brake................. Brake............................. ................................. ................................. ................................ ................................ ................ .... 0 Image 29 - LiFePO4 LiFePO4 Battery ........................ ............................................. ................................. ................................. ................................ ........... 0 Image 30 – Hub Motor ....................... ........................................... ................................. ................................. ................................ ...................... .......... 0 Image 31 - Controle Controlerr ....................... ............................................ ................................. ................................ ................................ ......................... ............. 0 Image 32 – Mechani Mechanical cal Drive Train............. Train......................... ................................. ................................. ................................ ...................... 0

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Summary

This report tell us the beginning of a project that creates a recumbent tricycle with an electric motor with an assist of a battery that can help the domestic civil person do their  day-by-day work without without sacrificing the planet planet and bother the traffic, and so creating a new genre of tricycles with better autonomy and comfort for us all. Thus this project is named ZEV (Zero Emission Vehicle).

History We tend to think of recumbent bikes as a "new" type of bike, but as Solomon observed "there is no new thing under the sun." The recumbent has been around, in one form or  another, since before the turn of the 20th century. These pictures show that many features of "modern" recumbent design have been around quite a while too!  A recumbent bicycle is a bicycle that places the rider in a laid-back reclining position. Most recumbent riders choose this type of design

Image Ima ge 1 – 1896 1896 Recumb Recumbent ent

for ergonomic reasons; the rider's weight is distributed comfortably over a larger area, supported by back and buttocks. On a traditional upright bicycle, the body weight rests entirely on a small portion of the sitting bones, the feet, and the hands. Most recumbent models models also have have an aerodynamic aerodynamic advantage; advantage; the reclined, legslegsforward position of the rider’s body presents a smaller frontal profile. A recumbent holds the world speed record for a bicycle, and they were banned from racing under  the UCI in 1934[1], and now race under the banner of the Human Powered Vehicle  Association (HPVA). (HPVA). Recumbents are available in a wide range of configurations, including: long to short wheelbase; large, small, or a mix of wheel sizes; over seat, under seat, or no-hands steering; and rear wheel or front wheel drive. A variant with three wheels is a recumbent tricycle.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

In 1933 Francis Faure, a Frenchman, rode a recumbent 28 miles (45 km) in an hour, a new record. In 1934 the UCI (Union Cyclist International) outlawed recumbent bicycles, and has not relented to this day. In 1938 Francois

Faure

rode

the

recumbent

streamliner "velocar" 50.5 km/hour, another  new record. Francesco Moser surpassed this mark on a wedgie. Moser rode 51.1 km/hour, but not till 1984, 46 years later!

Image Ima ge 2 – 1933 1933 Recum Recumben bentt

Windshield for cyclists with the aid of which Berthet has beaten some indoor records.

There is a wedgie in that fairing. Berthet saw the advantage of aerodynamics long before he raced recumbents. The UCI wouldn't allow either.

These are modern racing recumbents recumbents with fairings. They They are all record holders. holders. They show that aerodynamics is still the name of the game for top speeds.

 A well-known well-known trike manufacturer, ICE, has made their first newborn in 1986. The original Trice had three 20" wheels, 1988 saw the introduction of 16" on the front, easier leg length adjustment and many other refinements

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Nowadays even though we have only a few manufacturers, we have some versatility in types of models.

•

The conventional two frontier  

Image 3 -

•

A two-seater  

Imag Im age e4

•

The long-wheel fo for lo long ra range journeys

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Imag Im age e5 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Premises of Work 

Primarily we researched in the market the different recumbent bikes out there, to see the people choices and what would be the perfect choice for our project. The two-front wheeler is the model most used, due to its better accuracy in driving and better  placement of motor in one wheel. the opposite model, two-rear wheeler seemed more complicate to accomplish and did not gave us much confidence in a better result.

We've drawn some sketches in the early stages of our Pre-IP presentation to make sure how we would the bike to be like. Then we researched the different variations of  this kind of model to see which fit our purposes. The typical bigger rear wheel it’s the most significant choice, because it gives more comfort, stability and supports better the hub motor, thus approaching the requisites of t he ZEV project.

What concerned us the most was the suspension because it had to be fitted in the drivetrain to be simple and effective. It reduced our suspensions choices but it was doable so we went through with it. A small spring but stiff enough to absorb the most aggressive bumps in the road. Later on, in Bradford, it was showed a suspensionless trike, which amazed us because we though suspension was essential. It was told to us that for city driving the suspensionless trike was comfort enough, if we put in there some bigger profile tires to make the suspension's job.

The chassis was predetermined that a single tube with length variation was flawless because its, once again, simple, nice and can fit to any weight of anyone in general purposes. The only parts that go outbound the chassis tube are the suspension and the drive train. Everything else is attached to the single tube chassis. Of course to achieve that it has to be machined to a curve state to accommodate all the parts in the bike: seat, drivetrain, suspensions and battery.

When we went home after discussing this journey with our teacher he gave us the opportunity to continue the work, and possibly make our own recumbent trike. We hope to achieve that in a way that we can put into work everything we've learned in the IP and it’s going to be biased from the bike in Bradford Uni. Maybe we can work together  to

help

each

other

and

achieve

our

purpose:

build

a

HPV

with

ZE.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Report  Design Before elaborating on the design overview, it is appropriate to offer some reasons why we prefer the two wheels front, commonly referred to as the 'Tadpole' configuration. The most common common tricycle tricycle design design is the the single single wheel wheel in front, front, two-wheel two-wheel at back back configuration referred to as the 'Delta' configuration.

 Although a well-designed well-designed Delta trike has many merits such as reduced cost, and complexity, itit does not have have the handling handling characteristics characteristics of a Tadpole design. design. In layman terms, a Tadpole trike front-end exhibits less acceleration (less G forces) than the rear end when turning. This allows the trike to negotiate corners at great speed and stability.

On the other hand, a Delta trike exhibits the opposite condition; where the vehicle’s front-end exhibits a higher degree of momentary acceleration in comparison to the rear. This condition results in over-steering and can compromise the handling performance of the vehic vehicle le..

Image 6 – Ride Ride on on country countryside side

 Although the overall handling characteristics are dependent dependent on the actual design of the vehicle, the Tadpole design comes out as the winner as for handling. handling.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

 As for stopping, again the Tadpole has the t he major advantage. During braking, a vehicle weight displacement and force goes forward. This is why on all vehicles the major  braking is performed on the front wheel(s). On a delta, only a single wheel exists. As result, stopping with two front wheels is more effective than a single wheel.

 A tadpole configuration uses the same steering geometry design principles principles as an automobile.

Geometry considerations such as Caster, Camber, and Toe-End exist for this trike design just as they do on an automobile. In contrast, a Delta design uses geometry similar to that of a bicycle. Tadpole Trike Variations

 Although a small niche market, recumbent tadpole trikes come in a plethora of  configurations. In In this section we will show a short list of features features and technologies technologies that describe describe the some some types of of tadpole tadpole trikes. trikes.

One gimmick that pops up periodically is a rear steering HPV. The rear steering concept has been applied applied to both Tadpole and and Delta trike configurations configurations without without any staying success.  Although the virtues of rear wheel steering include include a simplisti simplistic c design, design, lighter lighter weight, weight, a smaller smaller turnin turning g radius, radius, and and an exhil exhilarati arating ng and fun riding experience. However, the fact that the trike drives like a forklift forklift makes makes it a losing losing propo propositio sition n every every

Image 7 - Sidewinder Procruiser

time.

Lean Steering Image Ima ge 8 - Ber Bergwe gwerk rk Bi Bikes kes GMB GMBH H

 A lean steering trike is a three wheeled vehicle that steers by virtue of leaning the rider's body into the desired direction of the turn. Although several variations exist,

the

most

notable

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

implementation is where the seat moves in relation to the frame causing the vehicle wheels to turn or alter the the wheel geometry. geometry. A stationary horn horn or tiller is fixed to the frame (this can also be a U-bar) allowing allowing the rider to lean the seat left or right (the seat is linked to a steering mechanism), hence hence steering the vehicle. Since Since the rider leans leans into the direction direction of the turn, turn, the center of gravity gravity is optimized optimized producing producing a trike with with excellent low speed handling. handling. The concept is similar similar to steering a bicycle bicycle with one obvious exception: exception: the leaning is linear to the steering and not by the G forces applied. applied.

Consequently, Consequently, the steering in this implementation implementation is not optimized for higher higher speeds. Lately, there have been other implementations implementations of the lean steer trike that allow the front wheels to lean into the direction of the turn. Not only does this enhance the handling characteristics of the trike, it also relieves the wheels from side-loading allowing larger  diameter wheels. As with most emerging technology this concept is relatively new, requiring future improvements improvements to make it practical. practical. The main premise of a trike is to provide a stable stable platform that does not require require balancing. balancing. Although lean lean steering has the potential of optimized handling handling at lower lower speeds, speeds, it does require require equilibrium equilibrium to master.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Suspension  A recumbent trike uses smaller wheels than a standard bike. The problem with smaller  wheels is that they provide provide a harsher ride than larger diameter diameter wheels.

The first compact, compact, foldable bikes solved this problem problem by using using a compressed rubber  rubber  elastomer as a shock absorber. Thanks Thanks to the ever evolving evolving technologies technologies of the mountain bike, we now have shock absorbers that rival those in automobiles.

 A well designed suspension system can offer a featherbed ride regardless of the conditions of  the road. Up until recently, recently, most implementations implementations have been limited to rear suspension, as it was extremely easy to implement, and it doesn’t pose any restrictions to handling handling or steering geometry. With easy-to-route chain management systems, and the cranks cranks being being so far forward forward from from the the swing

arm,

it's

obvious

to

see

that

rear 

suspension can be easily adapted to a tadpole conf config igu ured red compromise.

recu recumb mben entt

tri trike ke

with ith

lit littl tle e Image 9 – Front Front suspension suspension Cad detail detail

Image 10 – Front Front Suspens Suspension ion detail detail Powering the Future With Zero Emission Em ission and Human Powe Powered red Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

However,

the

virtue

of

a

rear 

suspension system is refutable, as the rear wheel delivers less than 1/3 of the total shock felt by the rider. Secondly, the

swing

arm

designs

currently

employed on these trikes are all more susceptible to side-loading forces than conventional triangulated rear ends.

Front suspension is more effective in

Image Ima ge 11 – Rear Rear Dam Damper  per 

reducing shock than rear suspension.  After all, 60% of all the shock is produced produced by the front wheels. wheels.

Considering that we chose rear and front independent suspension for comfort and dynamic behavior. The front suspension will be Double Arm which allows each wheel to move in a wider range but still not having too much influence in the Steering Geometry which is very complex. In the rear we will have a simpler spring damper  suspension since this doesn’t need to support so much shock as previously stated before.

Basic Trike Frame Design Weight Distribution The weight distribution is the ratio of the horizontal weight displaced between the forward and aft wheels. It dictates how a trike handles handles and how stable stable it will be. The more weight on on the forward wheels, wheels, the better the cornering cornering and less over-steer. However, too much much weight on the front wheel causes causes the rear wheel wheel to be too light. This can lead lead to rear wheel wheel washwash-out out during during hard hard cornering cornering or or cause the the trike trike to endendover during during braking. Too much weight on on the rear of the trike causes it to capsize capsize even during mild handling handling as the single wheel has has the majority of weight. A trike with 70/30weight distribution is optimum. Center of Gravity If weight distribution is the ratio of horizontal weight, than Center of Gravity is the ratio of top to bottom vertical vertical weight. weight. Center of gravity is as crucial crucial as weight distribution distribution for 

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

optimum trike handling characteristics. characteristics. However, However, unlike weight weight distribution, the center  of gravity has no handling or stability compromises when its ratio is lowered.

If all the weight is placed well below the axle, axle, the trike is going to have have excellent excellent handling regardless regardless of weight weight distribution. Obviously, Obviously, a low slung vehicle does does have sev severa eral

disa disad dvanta antage ges s

visibil bility, ty,

safety fety,,

incl inclu uding ding

co comfor fort

an and

practicality. For practical reasons most road worthy trikes trikes wil willl have have most most of the weig weight ht above axles.

Image Ima ge 12 – Cen Center ter of Gra Gravity vity

Wheelbase In regards to a recumbent trike, trike, the length of the wheelbase wheelbase influences influences the steering, steering, stability, weight distribution distribution and overall comfort. The wheelbase wheelbase is the length between between the rear wheel wheel axle and front wheel(s) wheel(s) axle.

Short Wheelbas Wheelbase e (under 1m) Pros:   

Creates a tighter turning radius Faster and sportier handling Smaller, more compact frame (stiffer and lighter)

Cons:  

Rider’s position has more effect on overall weight distribution Reclining of seat position is limited due to rear wheel clearance

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Image Imag e 13 – Medium/ Medium/Sh Short ort Project code: 2011-1-GR1-ERA10-06828 wheelbase Manuel Vilaça Vilaça – Pedro Pedro Pinto

(overr 1m) 1m) Long Wheelbase (ove Pros:  

Rider’s position has less effect on weight distribution than SWB Seat has more clearance for reclining, even with a larger diameter rear wheel

Cons:  

Longer frame lends to higher weight and flexing Larger turn radius

Image Imag e 14 – Long Whee Wheelba lbase se

So what is a happy happy medium? If we took a wheelbase wheelbase consensus consensus of all the production production trikes trikes on the market, market, they they would would average average betwe between en 96.5cm 96.5cm to 103cm. 103cm. This This variatio variation n takes into account account wheel sizes that can vary vary from 20 inch to 700c. 700c.

Wheel Track 

The wheel track is the width between the two front wheels. The wider the wheel track the less susceptible the vehicle is to capsizing during cornering. However, if too wide, the vehicle becomes impractical on most bike lanes. An 82 cm wheel track offers excellent handling and is practical for all bike roads too. Several manufacturers have released compact trikes that have reduced wheel tracks under 74 cm. The overall widths of these trikes allow them to pass through a standard 82 cm doorway. Other  trikes have a negative camber that allows a wider wheel track but the overall width is compact enough to fit through a door way.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

 Another consideration consideration for wheel track width is the front wheel diameter, as the turn radius is dependent dependent on the lock to lock lock travel of the steering system. system. Larger diameter  wheel will interfere with the rider’s legs while turning, thus limiting the lock to lock travel of the steering and ultimately dictating the turning radius. This also applies to basic ergonomics; as the wheel track decreases, so does the space and comfort in the trike. Frame Design The last element in basic trike technology is the frame design. There are several issues here that affect efficiency and and handling. handling. The most important issues issues of the frame are weight and rigidity. Along with rigidity comes stability, as any frame or wheel flex is always undesirable especially at high speed. Beyond these basic requirements are other elements that should be equally noted. Reliability, cost, ergonomic and convenience are but a few requirements that we must consider. However, these considerations go beyond the scope of performance.

Image 15 – Aluminum Aluminum Tube Tube used used for chassi chassis s

For excellent performance and reliability a 3-dimensional space frame is an excellent choice. These types of frames all have triangulated chain stays that use the seat as part of the structural frame. The result is a frame that has reduced flexing which enhances stability and reliability. Even better is a frame that also includes web-gusset to reinforce the bottom bracket boom and cross-members. This type of frame reduces the effects of pedal steering caused by uneven cadence and boom flex.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Although Although stiffer, stiffer, these 3-D frames frames are are not necessa necessarily rily lighter lighter since since they requi require re more more frame frame components and have several weld weld joints.

The lightest and least expensive trike designs use a standard cruciform frame that does not include seat stay support or an integrated integrated seat. Although the least rigid and reliable, these trike trike are also the easiest easiest to design and build. build.

Image Ima ge 16 –Cr –Cruci ucifor form m Fra Frame me

Steering Geometry The quality of the steering steering system and steering geometry geometry also dictates the performance performance of the trike. In the next chapter we will discuss this topic.

Trike Steering Geometry  A recumbent trike is only as good as the steering, as it behaves similar to an automobile. As similar to an auto, the steering steering system is inherently inherently complicated, as more than a single geometry is used to define it. In this section, I'll I'll discuss the fine art of steering geometry. Caster Angle The first geometry is the caster angle. This This

angl angle e

is is

the the

kin kingpin gpin

plan plane e

relations relationship hip to the the wheel wheel contactin contacting g the road (contact patch). As the drawing illustrate illustrates, s, the kingpin kingpin points points down down in front of the tire's contact patch. Since the steering system rotates on the Kingpin plane, plane,

the

relati relations onshi hip p

betwe between en

the

contact contact patch and and the kingpi kingpin n forces the the

Imag Im age e 17 - Cast Caster  er 

wheels to point inward as weight is Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

placed on the wheels. Increase the kingpin angle, angle, and and more force is applied to bring the wheel inward. The resulting resulting effect forces the steering system system to return back back to a neutral (or straight) straight) position. Normal caster values for recumbents are 12°. As a footnote, a standard automobil automobile e uses a 4-5° caster caster and and a race car car or go-cart go-cart gets much much steeper. steeper. Camber The next geometry is the camber  angle of the front wheels. If the wheels wheels are at exact right right angles angles to the ground (90 degrees) or the distance betw betwee een n the the top top of both both whe wheel els s equa equals ls the the dis dista tanc nce e betw betwee een n the the Imag Im age e 18 - Camb Camber  er 

bottom of both wheels, the camber is

said to be neutral. If the distance distance between between the top of both wheels wheels is shorter than the bottom, the camber camber is said to be negative. negative. And, if the distance between the the top of both both wheels is is longer than than the bottom, bottom, the camber camber is said to be positive. positive. Normally, a negative or neutral camber is desirable. Toe-In The Toe relationship is somewhat similar to Camber, but at at a 90°from 90°from the the axis axis of the the kingpin kingpin (longitud (longitudinal inal axis). Positive Toe or Toe-In refers to the front wheels pointing inward inward towards each other at the forward forward end and away away from each each other other at the rear. This inward inward relationship is relatively very small. With most vehicles a ‘Toe-In’ relationship relationship is a desirable desirable trait in that it provides greater greater straight straight line stability stability at the cost of efficiency and and sluggishness sluggishness on cornering cornering response. In practice, a recumbent trike requires little if any ToeIn. A Toe-In of of no more than than 0.1" is sufficient. sufficient.

Imag Im age e 19 – Toe Toe In

 Ackerman Steering Steering Compensation Compensation

The Ackerman steering compensation provides a way for a vehicle to turn without the front wheels scrubbing. scrubbing. In layman's layman's terms, this means that when the vehicle vehicle is steered in either direction, the inside inside wheel shall always always turn sharper than the outside wheel. wheel.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Let's look at this with an example: example: A “X” trike can turn around a 4.5m circle. This means that the outer tire is pointing pointing at a particular particular angle that follows follows the 4.5m circle. However, However, the inside wheel, which tracks 82cm closer closer to the inside, must turn at a sharper angle angle so that it can follow a 62cm circle. Obviously, if both wheels turned at the exact angle, they would scrub when the vehicle turns. turns. Not only would would this wear wear out the tires, itit would also cause the vehicle to drastically slow-down slow-down when turning. There is some consideration concerning Ackerman that must be understood. First, perfect Ackerman does does not mean always always yield yield the best performance. performance. Secondly, Secondly, the accuracy of the Ackerman compensation compensation is dependent dependent on the type of steering system system used on the trike design.

 As mentioned, perfect Ackerman steering compensation compensation does not guaranty the best performance. In some cases it is desirable to reduce the Ackerman during large radius turns as it makes the steering less sensitive and less prone to over-steering. This Anti Ackerman actually prevents prevents over-steering at high speeds. speeds. An Anti-Ackerman is actually a partially compensated Ackerman implementation and allows a small amount of  scrubbing when turning a large radius, but it follows the full compensation during smaller  radius turns. The exaggerated exaggerated result is a vehicle that slows down in the corners, but allows the trike to sustain faster faster speeds speeds without steering instability.

Kingpin Inclination (Center Point Steering) The inclination of the Kingpin allows the steering axis to turn turn precisely precisely on the center center patch patch of tire contacting the pavement (hence the name Center  Point Point Steering) Steering).. This imagi imaginary nary intersecti intersection on is commonly referred to as the Scrub Patch. Because Because the steerin steering g axis rotates rotates directly directly over  over  (and front of) the contacted patch of tire, the steering is less affected by defects in the road, hence reducing reducing 'bump steering' and allowing allowing the full effects of the caster to work. Another byproduct of of kingpin kingpin inclination and Caster Caster allows allows

Image 20 – Kingpi Kingpin n Inclin Inclination ation

the camber camber to change change in relati relationsh onship ip to the wheel wheel steering angle. angle. This This compensation allows the wheels wheels to lean into the corner in which they are turning. Ultimately, Ultimately, this dynamic orientation modifies modifies the wheel geometry geometry

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

resulting in slightly enhanced handling. The kingpin inclination is at a 90- degree plane in relationship relationship to the caster caster angle. Kingpin to Wheel Axle Orientation

The placement of the wheel axle, in relationship to the kingpin, drastically affects the steering. If the wheel axles are placed in front (lead) of the kingpin axles, the 'caster  effect' is is defeated making the steering unpredictable unpredictable and extremely unstable. However, if the wheel wheel axles axles trail too far behind behind the kingpin kingpin,, the steering steering may be be influence influenced d by road shock shock and brake brake steering. Again, this occurrence is referred to as bump bump steering steering and brake pull. Ultimately, Ultimately, the wheel axle and kingpin should should intersect intersect or be be within 0.5 inches trailing.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Steering Mechanisms and Linkage Systems Under Seat Steering-USS The steering steering mechanism mechanism for Under Under Seat Steering Steering is a U-bar U-bar configuration configuration or dual lever  design. The dual lever lever design is best best suited for ultimate comfort, comfort, while the U-bar gives gives the vehicle a sportier and lighter lighter feel. Additionally, the U-bar U-bar system tends to be simpler  and cheaper as as it requires fewer parts for operation. operation. However, However, the expensive, expensive, duallever system offers superior linearity linearity and better flexibility flexibility for adjustment. Pros: 

Intuitive control makes it easier to master 



Provides comfortable support for arms



Gives the rider support during high G turn, precludes the use of lateral seat support.

Cons: 

Increases the Frontal Area making the trike less aerodynamic. aerodynamic.



Places the riders hands dangerously close to the wheels or ground



Requires ample room for U bar clearance that may compromise wheel track or  seat width.

Steering Linkage Systems and How They Work  Single Tie Rod and Drag Link System

This type of steering system was common on early automobiles and eventually found its way to farm tractors. A knuckle-to-knuckle knuckle-to-knuckle Drag Link provides provides continuity continuity between between the wheels, while while the Tie Rod provides linkage to a Bell Bell Crank (Pitman Arm).

The best attribute is that the main linkage consists consists of only two rod-end bearings. bearings. This allows the steering steering to remain relatively relatively tight. Although this system system uses more parts than the other two steering steering systems, itit provides provides superior flexibility for adjustment adjustment and provides adequate Ackerman compensation. compensation.

However However,, the system system weighs weighs slight slightly ly more than than the the other other two systems systems mention mentioned. ed. Misalignment of of the Bell Crank orientation orientation (caused by by the Tie Rod deviating deviating from 90°) Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

causes a slight slight non-linearity throughout the steering steering range. This This is compensated by applying Ackerman Ackerman to the steering knuckle control control rod that links it to the Bellcrank. Bellcrank. This design also offers good Ackerman compensation.

Image Imag e 21 - Si Sing ngle le Tie Tie Rod Rod and Drag Link System

Dual Drag Link System

This system offers lower weight, fewer parts than the Single Idler Arm system and is optimized for Over Seat Steering, Steering, as the Bell Crank is is mounted almost almost at the kingpin plane. plane. The major major advantage advantage to this this system is that that it provides provides near perfec perfectt Ackerman Ackerman compensation. compensation. This design was used on the Volkswagen Volkswagen Bug over 50 years years ago. The Bell Crank orientation orientation and length must remain constant to maintain maintain proper Ackerman. Ackerman.  Adapting a USS steering steering system requires requires a U-bar mounted aft of the king pins.

Imag Im age e 22 - Du Dual al Drag Drag Link System

Unfortunately, the steering linkage becomes increasingly complicated as a second Pitman Arm (Bell Crank) Crank) and Tie Rod are required required (refer to the drawing below). below). The Bell Crank length (from arm pivot pivot to axle) must equal the Steering Knuckle Lever Lever length (measured from the arm pivot to kingpin axle). Deviations to this relationship can diminish the Ackerman compensation. compensation.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Crossed Dual Drag Link  The Crossed Duel Drag Link is optimized for a USS (U-bar system), as the Bell Crank (Pitman arm) is placed behind the steering steering Kingpins. Kingpins.

Image 23- Cros Crossed sed Duel Duel Drag Drag Link

The science of maintaining a linear rod linkage system requires the application of the Right Right Angle Angle Rule. The Right Right Angle Angle Rule Rule requires requires that both rod ends ends maintain maintain a 90° angle to each linked lever arm when when the wheels are in a neutral, forward forward position. Not only does this practice insure that both rods rods maintain maintain a linear arc arc throughout the full range of motion, motion, it also also insures the stability stability of the linkage. As the rod ends ends approach approach an angle close to 0° or or 180° in relationship to either either of the lever arms, the linkage rod loses its ability to hold and control the arm. The Right Angle approach guarantees the steering linkage linkage force is optimized throughout the 90° arc arc of steering steering travel. This This principal is is applied to the Crossed Dual Drag Link steering configuration shown above. To achieve the 90°-angle 90°-angle relationship relationship with the above above example, example, the two drag link rods rods require separate mounts on the Pitman Arm. To prevent tire scrubbing scrubbing during turning, turning, these mounting mounting locations are angled back further on the Pitman Pitman Arm to provide provide the necessary Ackerman compensation.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Wheel Size Tadpole-designed trikes come in a wide variety of wheel size configurations. If the center center of gravity gravity were were not an issue, issue, we would would be bold bold to menti mention on that that wheel wheel size size has little effect on handling (provided the rear wheel stays are sturdy enough). Chiefly, Chiefly, wheel size affects efficiency, efficiency, weight, ergonomics, and quality quality of ride. Smaller wheels in front allow sharper turn radius, as the larger wheels tended interfere with the rider.

Image Imag e 24 – Low Low resistance tires

Since the rear tire is is under less side loading, we think to use use 26-inch wheels that offer  excellent rolling resistance and made the ride significantly smoother than a rear 20-inch BMX wheel wheel.. The chief advantage of a small rear wheel is that it offers better reliability and lighter  weight than a large wheel. wheel. The reliability reliability aspect of a smaller smaller wheel system is that that they tend to take side loading better better than larger wheels. The lighter lighter weight virtue is obvious, obvious, as a smaller wheel wheel is lighter than a larger larger diameter wheel wheel and the wheel wheel stays are smaller, too.

It should be pointed out that both front and rear tire size selections have much different requirements. On the Front wheels, the size is restricted to maintain a smaller tract,

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

tighter turn radius and aerodynamics. aerodynamics. On the Rear wheel, wheel, the size may be restricted to maintain rear rear end stiffness, but but needs to be be large enough enough for adequate adequate gear/inch gear/inch range. The chief advantage advantage of of larger wheels wheels is that they provide provide better Roll-Over  Roll-Over  resistance and offer offer a stable, more comfortable comfortable ride. ride. Additionally, Additionally, a large rear wheel wheel does not not require specia speciall gearing gearing (such as an oversi oversized zed chain chain ring and extra extra chain). chain). However, this case case applies to the rear wheel only. only.

Our is using a 26 inch inch rear wheel, wheel, as it allows an excellent excellent high gear inch inch range, provides a softer ride and has superior “roll over” qualities that give it an overall performance edge over over a 20” rear wheel. wheel. For the front we prefer prefer to use 20 inch as these have average roll-over resistance, adequate leg clearance, and good aerodynamics.

Brake Systems Basically, three types of braking systems can be employed in trikes: Drum, Disc, and Caliper but for our project we will only consider the Disc ones.

The major advantage of a Disc Brake is that they provide provide excell excellent ent and reliable reliable braking braking and are optimized optimized for Tadpole Tadpole trike trike designs. designs. The disc disc brake brake action action is proportio proportional nal and provides provides smooth smooth braki braking ng even even durin during g the the harshest weather conditions. Disc brakes are smaller, stronger, and quieter.

Image 25 – Hyd Image Hydrau raulic lic Brake System

Hydraulic brake systems use a piston at the hand lever called the "master' piston. The piston pushes brake fluid through sealed brake tubing to another set of pistons at the caliper called the "slave" pistons. The slave pistons push the pads to the rotor. Because the hydraulic fluid does not compress or flex, hydraulic systems are considered higher performance than mechanical systems. The amount of force developed by the Master piston depends on the piston’s displacement. The direct force that can be applied by a hydraulic system is enormous.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Our choice is:



Ergonomic shift arc follows natural hand movement with inward shift stroke distance reduced for rapid and precise gear changes.



Brake lever pivots have been positioned to increase power and improve ergonomics when riding on the hoods.

Image Ima ge 26 – Brake Brake Leav Leaver  er 



Oversized 22mm ceramic pistons, with ceramic brake pads optimized for heat heat insulation, lightweight lightweight and stiffness.

Image 27 – B Brake rake Calip Calipers ers and pad



Disc Brake Rotor 170 mm CenterLock



The lock ring mounting system enhances precision and rigidity while improving braking efficiency.



The Center Lock system makes an easy rotor installation possible possible with a spline mount and lock ring.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project Image Ima ge 28 – Disc Disc Brake Bra kecode: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Plug-in design for battery charging Battery



Large

and

safe

LiFePO4

cells inside 10AH. 

Compact in size and light in weight.



BMS manages to each cell for high reliability.





Extra long cycle life life - 5 times life of Lead Lead Acid and 2 times of NiMH

Imag Im age e 29 - Li LiFe FePO PO4 4 Battery

Extremely safe: no explosion, no fire under collision, over charged or short circuit

Hub Motor



Seamless integration



Without gears



Using wasted space in the rim



No maintenance



Weather proof 



Regenerative braking and cruise control



60mm thin hub for common bike frames



Support disc-brake and 10-speed sprocket



Power Rating: 1000W



Voltage: 48V Image Ima ge 30 – Hub Hub Mot Motor  or 

Image Ima ge With 31 - Cont CZero ontrol roler  er ission and Human Powered Powering the Future Em Emission Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Regenerative Braking If we want to achieve maximum efficiency we should think also to apply Regenerative Braking into our Trike. Regenerative Braking uses the energy that normally is dissipated as heat in mechanical brakes. With regeneration we transform the kinetic energy back into chemical energy that recharges the battery. We thought about several ways to do this seamless integration into normal brake system. So we end up with this system that we will explain further in detail. If there is no actuation by the user in the brake leaver the system, the trike in this case will be free rolling (only with air drag and bearings friction). When the user starts to do

some force in the leaver, the displacement will start to actuate the master piston, but instead of applying this force to the mechanical brakes we will first actuate a resistor 

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

that is connected to the electronic controller. The controller will then send a signal to the hub motor so it can start behaving as a generator. No kind of energy is free, so as soon as the hub motor/generator starts convert energy the trike will slow down, or if we going downhill, downhill, we can maintain speed not causing causing the mechanical brakes to fade by excess of heat. When we want full braking power both systems will actuate because the oil will flow to disc pistons and at the same time the hub motor is converting energy. This is a simple principle that allows not only regenerative braking but also increases security because we have 2 different kind of braking systems completely independent.

Human Drive-Train Obviously the first premise of this project was a human power vehicle, so we need the human drive train.  Although the trike can be used entirely electric, if we have a malfunction on the electrical system or we just want to have fun we can use the pedals. We should use at front a 3 gears system that allows three different type of situations, and at back we should use a 8 gear system that offers the user a wider range of  choices and of course ride comfort. All together we have 24 different gears. All the power

will

be

transmitted

from

front

to

back

with

a

chain.

Note: The red arrows represent protected chain guidance from Image Ima ge 32 – Mechani Mechanical cal Drive Drive Train

front to back

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Calculations

We need to do some calculations to make sure the building of this trike is made within a secure margin of success and, of course, in safety.

First of all we need need to know the known known forces in the trike.

With an estimate weight of 1471.5 N (P) and a coefficient of friction (µ) of 0.8 and g = 9.81 m/s^2 we have:

Maximum deceleration: a = µ * g = 0.8 * 9.81 9.81 = 7.84 7.84

Total braking force: F = m*a = 1471.5 N

Maximum braking energy:

E = 0.5 * 150 * 13.88^2

, where v = 13.88 m/s = 50km/h

Braking forces per axle: Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Fr= µc * N = (0.8*1471.5)/2 = 588.4 N

Braking forces per wheel: (Front)

Fr= (588* 0.8)/2 = 235.36 N

(Rear)

Fr= (588* 0.8)=471.72 N

Braking torque: Tbraking = Ftyre*rtyre = 19404 N

Disc forces per wheel: (Front)

Fdisc * 0.085 = 235.36 * 0.33 => Fdisc = 913.751 N

(Rear)

Fdisc * 0.085 = 470* 0.33 => Fdisc = 1827.5 N

Disc dimensions: Ø = 170mm = 0.085 m radius

Actuating forces per wheel:

(Front)

Fdisc = Tbraking * µ/pad => = 1827.5 Tbraking * 0.8/2 = 4568.75 N

(Rear)

913.751 *Tbraking * 0.8/2 = 2284.38 N

Caliper piston diameter:

Tbraking = p * A, with A = (π* D^2)/4

(Front)

45468.75 = 68* 10^5 *A => A = 0.0006782 m^2

(Rear)

913.751 = 68* 10^5 *A => A = 0.000336 m^2

Master cylinder diameter:

D = (4*A/π (4*A/π)^ )^ ½ = 0.0292 0.029251 51m^2 m^2

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Costs

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Drawings

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto

Conclusion First of all we would like to notice the amazing opportunity that European students had to make such a difference in the world. It changed the way we think and want to improve our life as engineers. It's ideas such as these that make the world spin in joy.

The project in a nutshell it had a positive outcome. We've learned all the basics about automotive vehicles, zero emission alternatives and, more precisely, about how to build an HPV in the safest and effective way possible. Every part of the basics was tremendously accurate and essential so that from that we could build a HPV by putting everything together.

Working as a group has taught us how to circle around a problem and also to solve it  just by separating the problem problem by simple parts and solve solve it in a group. Also it reinforced our trust in every one in a group, because without trust, there is no group. Separating them and making international groups is a good way to give a chance on our social skills and put our knowledge together, making our ideas a better job by exposing them to others and listen to their ideas too.

Of course there were some minor issues. The time was our enemy and the project was too long to be accomplished accomplished in just two weeks. The final report report should be made within within the IP time because it would give us the chance to create a final project with the ideas that we started to expose as international groups. Nevertheless we can accomplish anything just by trying to make a difference in this matter. We think we've made a decent job, even though the time was, also, our enemy, as university has his own problems for us. We hope next year our fellow students can create the bike, finally, because that’s what everyone wanted in the first place. I hope we started an idea that can change the world in driving purposes and, essentially, pollution-wise.

Powering the Future With Zero Emission Emission and Human Powered Powered Vehicles – Bradford, UK, 2012 Project code: 2011-1-GR1-ERA10-06828 Manuel Vilaça Vilaça – Pedro Pedro Pinto