Pedal car design plan - temporary English branch ⟳zo.fi/sorc
Temporary?
Out of necessity caused by the current state of machine translation tools available on the web, this is a redundant English language wiki.
The way to go is to join the branches by converting the Finnish language Pedal car design plan wiki into an interlingual machine translating wiki, which could be viewed and edited in any language through machine translation.
(Google have been prompted to fix the issue, and Wikimedia foundation is supposed to have been working on the issue for quite a while.)
English?
While popular, the English language is a mess that works as a history lesson and either fits in a museum or needs major repair.
The common alternative, Chinese, is simpler and more generative, but impractically uses as its everyday writing tool a complex artwork simplified beyond recognition with no apparent connection to spoken sounds.
A good language would be a capable knowledge representation tool learnable to people and machines.
Intuitive synesthetic gellish Esperanto, or something like that.
Branch?
In knowledge building, forking to branches in the wrong places is bad, because having many separate, independent versions of the same thing impairs information flow in a network of developers and users. Just look at all the recurring bugs in all Linux distributions.
The variety and incompatibility of languages leads to forking, as people think most fluently in their own language, and don’t much seem to work in other languages. Just look at Wikipedia in different languages; spotty coverage, bifurcation and sprawl.
Contents
Popoauto / city commuter, convertible, medium wide, medium high, short
Popoauto open standard platform
PopoAUTO PEDAL CAR
the smallest sensible car for real world traffic
multicategory drive-by-wire pedal-electric series-hybrid semi-autonomous door-to-door car
Electric pedal car - neat, practical, safe, cheap.
Save the world while consuming conspicuously. Exercise from A to B in safety and comfort.
Suomeksi / in Finnish: jpg png svg
Packet switched passenger transportation carrier pod
What new types of public transport could there be? - Packet switched passenger transportation.
Why a pedal-electric car?
Compared to an electric bicycle...
Safer and more comfortable
Enclosing shell protects you from weather, dust, noise and impacts.
Lockable top keeps your luggage safe.
Easier to drive
Doesn’t fall over like a bike.
Goes straight despite heavy load or side-wind gusts.
More fun to drive
A four wheeler reacts to steering motions immediately and produces lateral G-forces.
Goes farther
Bigger battery lasts longer.
Carries more
It has a rear seat and a trunk.
Compared to a microcar... (EU L6e)
Quieter
Less noise pollution.
On bikeways
Comfortably separate from full-size traffic, which is heavy and noisy.
Needs no driving license
Children can drive.
Those who have lost their license can drive.
Keeps you in shape
Requires pedalling to move and large hand movements to steer.
Goes mostly on battery power, requiring only a light effort.
Popoauto / City commuter
convertible, medium wide, medium high, short
This Popoauto body shell was designed in 2012 before the first team disintegrated due to typical Finnish adverse conditions. It was a quick and dirty job just for this illustration for marketing towards customers and investors.
Taxi driver / traffic researcher / entrepreneur Harri K. Hiltunen sketched the overall shape.
Designer Kimmo Hellström used Modo 3D-modeling software (under hand-waving committee rule).
Design goals:
maximize
practicality
interior space
mechanical simplicity
minimize
size
length 2.0m (seems too short: the rear seat space is obviously very cramped)
width 1.0m (0.4m wider than a bicycle, but feels narrow because lane positioning is
more accurate with a naturally stable vehicle)
height 1.2m (the driver can see through parked cars)
wheelbase 1.3m (caused the full-size door-roof-hatch to hit the rear wheel arch when
opened, so the step went a bit too high)
We successfully modeled most of the front suspension and steering with its linkages and controls so that it’s ergonomic, can’t hit the driver’s knees while pedalling, is Ackermann-accurate, and performs anti-dive when braking.
Industrial designer Pasi Turpeinen used Solidworks industrial 3D-modeling software.
Thoughts about body structures after the model above
Quora: How do I choose electric tricycle characteristics?
According to very limited discussions with some potential customers on a Finnish recumbent bike/trike/quad/velomobile forum, a large group of customers seem to want maximal top speed by pedalling, so aerodynamics is prioritized over interior space and usability. Maybe they don’t live in a city, which have other problems than high speed drag.
Current velomobiles do straight line speed well, but otherwise they are impractical and/or dangerous. Flevobike Orca pictured right ->
Begorett (pictured below) is sensibly working towards a fast, safe four-wheeler. It might use the same platform as Popoauto.
Podride is planning to sell kits and/or finished pedal cars as soon as they can.
Minivan
Another group of customers want a passenger seat, some others want space for luggage, so a spacious long wheelbase hatchback/wagon/mpv/van model with a foldable rear seat might be the next thing to draft and explore. Quickly estimated measurements, minimum: wheelbase 1.7m, length 2.5m, width 0.87m, height 1.2m.
4WD forest crawler might be a good idea because of electric quietness and forest floor friendly lightness
(Pihsiang makes a heavy 4WD crawler. Top speed 14 km/h)
(Zoomability unfaired 4WD crawler goes 20 km/h)
Long wheelbase multi purpose vehicle
Just like in the shortest Popoauto above, the door-roof-hatch would slide and pivot backwards with the top part of the windscreen as part of the hatch, and the rear window could be opened to reduce drag.
The door-roof-hatch would be easier to fit in this body style: no rear overhang when open (unlike in the short body), and lower step.
The rear view mirrors would be integrated to the rear facing vertical surfaces of the front wheel arches.
Food for thought
Nicely shaped short hatchback/wagon/mpv Colibri looks like Citroën C4
Volkswagen 1-litre concept for autobahns Nissan Land Glider tilting 4-wheeler
Honda MC-β
Commuter Cars Tango - so simple, so expensive.
Other possible body styles in the Finnish Pedal car design plan.
Research on micro cars
Multidisciplinary development of an electric vehicle typology for the city
Popoauto open standard platform
Crowd designed humane open-source standard modular system for mass production at any scale.
Humane by design
“Humane won’t “just happen”. Humane is never a default.
Humane only comes out of very deliberate and conscientious design work.
If you do the incremental thing and just ride the current wave of technology and let technology lead you wherever it leads you, it’s going to lead you into a tighter and tighter cage.“
Bret Victor - The Humane Representation of Thought
-> Humane tech
-> http://www.oshwa.org/sharing-best-practices/
-> ESMT Case Study: Team Wikispeed: Developing hardware the software way
Interfaces
Qualities
Logical & intuitive
makes sense for anyone in any situation, learnable, memorable, feels natural, ...
Sparse & parsimonious
not too many variants, easy to tell apart, feels obvious, ...
interval factor examples:
0.7, 1, 1.414, 2, 3, 4, 6, 8, 11
0.6, 1, 1.732, 3, 5, 9
0.5, 1, 2.0, 4, 8, 16, 32
0.5, 1, ~2, 5, 10, 20, 50
0.3, 1, ~3, 10, 30, 100
0.1, 1, 10, 100, 1000, 10000
Tolerant
Works under poor conditions and incompetence.
Smaller size key fits and works somewhat.
Manufacturable
Can be manufactured, maintained and repaired with many different methods on the planet.
Low-tech-enabled
Cheap parts
-> Design for manufacturability
Cheap to assemble parts into end product
What can be conducted in a connector
Key shape
type identification for inserters
text…...icon…...colour code…...shape…...machine identifiable
ease of alignment (or no alignment needed)
off size fit
misfits with damage…...sort of fits…...fits…...only by force......doesn’t fit
prevention of accidental release
ease of release
water seal reliability when dirty
contact reliability after prolonged exposure to elements
Force
Linear
pull...push x, y, z 3 directions
Torque
clockwise...counterclockwise a, b, c 3 axes
Electricity
wired
DC (prefer 5V for USB, <50V for human safety)
PWM (avoid radio pollution)
AC sine (constant, prefer automatic synchronization to grid, default according to location)
AC sine (motor power/control)
wireless
...standards here... (avoid radio pollution)
Radio frequency
communication / non-contact tyre puncture welding
Light
communication / illumination / circadian rhythm synchronization/advancement/retardation / heating / disinfection / skin care / plant growth
Matter
Gas
Air
compressed air (pressure: air spring / tyre / cooling/heating / ventilation)
vacuum (pressure: working / cooling / ventilation)
Liquid
(prefer: antifreeze, non-toxic considering leaks)
hydraulic fluid (oil / glycol and/or water / alcohol and water / other)
coolant (glycol and/or water / other)
glue/foam to seal tyre punctures
purified water for drinks (hot / cold) (/condensed humidity) (+just-add-water-powders)
Powder / grains
grit for ice
plastics for printing repair parts, tools, keys, ...
...expand here…
Modularity
-> Modularity
Extensibility
Prepare for nesting; reserve slots inside connectors for future connectors (specifications: best guess).
Granularity
Plan for fine grain, then integrate (leave connectors out when unneeded).
While designing connectors, design good and cheap bridging structures to skip connectors to combine parts (prepare to integrate).
Defining the modules = Connector placement
...expand here...
-> http://myvolts.com/blog/creating-a-modular-power-supply/
Pedal car interfaces needing standard connectors
[location, demands, definition, specification]
Help needed: What already exists, and how could it be improved?
tyre to: wheel flanges, compressed air, puncture patcher
wheel to: hub(forces, aux energy for lights/indicators and tyre pressurization, tyre pressure signal)
hub to: motor(axle torque), aux energy(for lights/indicators, pumps, etc.)
hub to: brake surface(torque, heat)
brake pad to: brake caliper(linear forces: friction axis bidirectional, signal axis pressure)
brake caliper to: kingpin/support arm (linear force, brake signal)
motor to: kingpin/support arm
(undamped mass accelerations, torque, control signals+energy, aux energy, coolant in+out)
kingpin/support arm to: spring, damper(opt tuned mass damper), chassis mounts(low pass filtered)
kingpin to: support arm(rotation 100...170deg(opt virtual with ball joints), smooth friction curve)
kingpin to: steering tie rod(low pass filtered, smooth friction curves, avoid interaction with bounce)
spring to: chassis(opt ground clearance adjust motor)
damper to: chassis(low pass filtered)
motor mount connector to: motor controller, aux energy supply
brake signal to: ABS/ESC controller
ABS/ESC controller to: brake actuator
motor controller to: vehicle dynamics modeling and sensing
motor controller to: fuse to: battery case to: battery, charger
...expand here...
Ride quality
Ride quality (noise, vibration, harshness) is very important for a good impression when potential customers test-drive a new type of vehicle. It is also difficult to achieve in a light vehicle.
Some people write that enclosed velomobiles / microcars are noisy, uncomfortable, etc., because they compare them to regular cars.
I believe, by good design, we can make a pedal car / velomobile as comfortable as a regular car.
Noise cancelling is an option (more commonly used in telephones and headphones).
Active suspension is costly but has benefits such as ride level height constancy, adjustable ground clearance, tilting in curves, straightening in slopes, stair climbing, pothole jumping, energy harvesting.
Chassis
A common subframe central box platform with longitudinal arms in the style of BMW C evolution electric scooter’s battery box frame and rear suspension (pictured below) might be a good idea, because it minimizes vibration being conducted to the light plastic body, and hence would be the quietest structure.
Battery slab is the equivalent four-wheeler central box shape minimizing center of gravity height.
Picture: belt-drive from remote motor instead of hub motor minimizes unsprung weight. Sensible engineering or costly overkill?
Breaks front-rear symmetry
Makes it impossible to use rear suspension parts for front suspension.
It would be nice if the same (hopefully cheaper) suspension arms could be used front and back for front/rear/four-wheel drive/steering - this structure is for rear only.
Tesla Model S battery slab chassis / car platform.
Notice the transverse support right where the driver’s knees are in pedal cars.
It is possible to make the previous support U-shaped:
Lotus Elan
You might also lift the transverse support higher to clear the legs.
Suspension
Whichever type the suspension is, make sure this applies to it:
In addition to the above, contact patch longitudinal travel should work to counter diving/nodding when braking or accelerating. To create anti-dive force, make contact patch move forwards when the nose goes down, and rear vice versa (how much: perpendicular to force vector from centre of gravity).
Information on the topic:
-> Wikipedia: Vehicle suspension
-> http://www.autospeed.com/cms/article.html?&A=112914
-> http://www.autozine.org/technical_school/suspension/Index.html
-> http://www.rqriley.com/suspensn.htm
-> http://www.carbibles.com/suspension_bible.html
-> http://www.susprog.com/susptype.htm
The usual car suspension is not the best here
Space constraints
Nothing will fit under the footwell, because the driver’s rotating heels almost scrape the floor, and the floor is the lowest point under the car.
There is space right in front of and behind the footwell, and inside wheel wells.
Struts and vertical shock absorbers?
To be quiet, MacPherson struts require a supporting structure separate from the footwell walls. If strut top end connects to where there is no good rigid structure, it would produce rumble by conducting road vibration interior facing walls.
Wishbones or links?
Double wishbones and multi-links (including quadralink) are wide right where the driver's feet are, but if you somehow can make them fit, good, because they can be excellent if designed and developed well.
Anti-roll
Independent suspensions need an anti-roll bar (sometimes just one per car).
To get rid of separate springs, consider using the Chevrolet Corvette suspension transverse composite leaf spring / anti-roll bar combo.
Central box/slab platform
Rigid structural central battery box under the driver's seat, to which everything attaches to, even the dampers, like in the Citroën 2CV, pictured right (imagine the engine away) ->.
Suspension (option: modular, front/rear symmetrical)
Trailing/leading arms
Longitudinal arms (semi trailing rear / semi leading front) with anti-sway-bars (a twist beam with a twist) suspension front and back.
Preferably hinged with rubber bushings (likely cheapest, quietest, most reliable), but if the rubber solution fails, maybe with ball joints (used in cars) (steel ball+plastic cup+grease+rubber boot) or even dry sliding rotary bearing bushings (Used in bike suspensions. The cheapest ones have quality problems: squeaking, friction increase over time.)
Front
With longitudinal arms (or twist-beam) in the front, steering king pin inclination (KPI) and mechanical trail magnitude increase along with nose dive. Not sure if it affects the steering feel (2CV drivers should know?). If this becomes a problem, copy the pantograph structure from some motorbike rear suspensions.
BMW R1200GS
Rear
If using front suspension arms trailing in the back, it makes 4-wheel steering easy to implement, actively and/or passively from wheel lateral (sideways) force.
(Active manual 4-wheel steering could be implemented by a 2-axis steering handlebar: the axis pointing at the front axle controls front steering, while the other axis pointing at the rear axle controls rear steering.)
Like in the front suspension, spring and damper would point towards the central box, not upwards.
Twist beam?
If using twist beam, preferably make it with passive rear steering implemented by large diameter transversely flexing rubber bushings rotated slightly outwards around the vertical axis, pictured below.
http://www.zf.com/ap/content/en/inc/press_fragments/press_detail_21855722.jsp
Not sure if camber change over suspension travel is possible with twist beam. In theory, yes, with a “twist beam with a twist”, where the beam converts torsional forces to bending to S-shape. It might consist of directed fibres and elastomers.
Springs and dampers
Usually a coil spring fits around the linear damper, but if space necessitates, apply a compact torsion bar spring.
(Maybe there are rotational dampers (with clutch plates and damping fluid?) to go with torsion bars? Audi has prototyped active electric torsional dampers/noise cancelling actuators/energy harvesters.)
(Maybe we should consider other suspensions too: pneumatic bag or piston / hydro-pneumatic / solid rubber / hydrolastic / composite flexing arm)
Composite flexing leaf double wishbone suspension on a foam board frame by ECOmove.
Powertrain
Series hybrid powertrain overview
Fully electric powertrain
servo generator driven by pedals → battery & motor controller → servo motors driving wheels
Simplified
no transmission, no chain and enclosure, no differential, no drive shafts
Drivability
CVT
Emulate an automatic continuously variable transmission (CVT).
Like on a NuVinci load adjuster, pictured, pedalling force goal (torque limit) is adjustable, and a cadence goal (rpm limit) can be added (if rpm is measured).
Fixed gear
In slow speeds pedal position directly controls vehicle position forward and reverse, just like in a toy pedal car.
Human efficiency improvement NuVinci load adjuster
Muscle exhausting power peaks are never needed.
Power pedalling backwards during braking uses different muscles.
If there are any brake levers, power pedaling is possible when stopped even while drive selector is set on [Drive], [Drive forward and braking], [Drive rectified forward].
When on [Park] or [Neutral], power pedaling is possible in either direction.
Reverse pedalling controls regenerative braking (KERS)
With residual speed, reverse pedalling controls kinetic energy recovery force.
When brakes are being activated, drive motors first recover kinetic energy (just like electric cars and hybrids).
Vehicle stability control (VSC)
A tablet computer will serve as the central controller and display of the pedal car.
It has part of the sensors and all of the processing power needed to implement VSC.
Articles about human powered series hybrids
→ http://en.wikipedia.org/wiki/Hybrid_vehicle#Two-wheeled_and_cycle-type_vehicles
Andreas Fuchs in Switzerland has researched a series hybrid powertrain on a pedal car:
→ http://extraenergy.org/main.php?language=en&category=&subcateg=&id=55771
→ http://www.datei.de/public/extraenergy/2014_Veranstaltungen/EUROBIKE/DigitalDrives.pdf
→ http://homepage.bluewin.ch/andreasfuchs/
Applications elsewhere
e-bikes:
→ http://www.mandofootloose.com/
General information
→ Quora: How much electricity does a pedal powered generator produce?
Pedal generator
“
A notice to muscle powered generator manufacturers:
As you manufacture a pedal generator, be aware that for it to be usable
for current home and office applications it needs:
battery bank connector
I recommend configurable for different battery type and size
4.2...57 Volts
current limit, Amperes
add-on unit:
solar panel input
add-on units:
USB and/or mains power output
(mains preferably with automatic AC-synchronization for grid)
mini-office: chair, desk, mouse pad, distance to pedals adjustable
for future series-hybrid vehicle applications it additionally needs to be:
servo-type
position encoder output, high resolution
(for vehicle motor control)
power sensor output
(equivalent to force sensor x position change rate)
(for vehicle motor control)
tactile feedback adjustable at high refresh rate (frequency)
(obeys vehicle dynamics modeling and sensing)
cadence goal
torque limit (slip threshold)
Traditional Chinese, Google Translation:
的通知，肌肉驅動的發電機製造商：
當你製造了腳踏發電機，要知道，它是有用的
當前家庭和辦公應用需要：
電池組連接器
我建議配置為不同的電池類型和尺寸
4.2... 57伏特
電流限制，安培
附加設備：
太陽能電池板的輸入
附加設備：
USB和/或主電源輸出
（最好的電源與電網全自動交流同步）
迷你寫字樓：椅子，桌子，鼠標墊，距離可調的踏板
對於未來的串聯混合動力汽車應用中，還需要是：
伺服式
位置編碼器的輸出，高清晰度的
（車用電機控制）
功率傳感器輸出
（相當於力傳感器x位置變化率）
（車用電機控制）
在高刷新率可調觸覺反饋（頻率）
（服從車輛動力學建模與遙感）
抑揚頓挫的目標
轉矩限制（單閾值）
Seat to pedals adjustment
Boom
Usually there is a central longitudinal boom on which the pedals slide, but this is obviously ugly and a problem when climbing in/out. Twike below.
Do pedal generator forces need a longitudinal boom?
As Popoauto will have a generator integrated to the pedals, forces will be less than in those systems with chains, and the adjuster mechanism can be more compact.
Expect about 1kN - 3kN force when the driver pushes with both feet to crack their back against the seat (unless this force is limited by intentional forward flexion of the pedal boom, which might also be used to control brakes).
How about moving the seat, not the pedals?
Maybe it would be wise to fix pedals in place and adjust the seat.
Problem: drivers could legally be children of age 10 years or so (when vehicle speed is limited to 25km/h) with very short legs, so the seat would need to go near the windscreen. If the windscreen is taken farther forward, then fine.
(If the occupants sit side-by-side, and the pedal sets are installed parallel, a passenger with short legs would block driver’s vision. If the passenger’s pedals are further back, then fine.)
Body
Injection molded plastic closed-cell foam between pre-printed thermoformed surface films, maybe with some inserted tensioning bands.
Pressurizable bubbles might be used to stiffen it (tested by Walter Janach).
Could be made quieter by adding a softer layer to the bottom to absorb gravel noises.
Air suspension might be integrated somehow.
...expand here...
Doors-roof-hatch
Mechanism:
virtual axle implemented by hinged support arms
offset linear bearings proximal linear bearings
...expand here...
Cost
Good competitors everywhere. Must be very cheap to manufacture.
The most direct competitors:
Renault Twizy
Two-seat tandem.
€ 7000 + battery lease (eq. total € 12,000), top speed 45 km/h
€ 9000 + battery lease, top speed 80 km/h
Estrima Biró
Two-seat side-by-side.
Top speed 45 km/h
€ 12 000
Imitations of this are made in China.
Ducati Energia Freeduck4
Two-seater, they say, but very narrow for that, width 0.91m (without mirrors)
Top speed 45 km/h
€ 7200
Looks like the customers said “looks don’t matter”.
...expand here...
More competing vehicles here and tiny cars there in the Finnish Pedal car design plan.