Wednesday, December 31, 2008

Tire/rim installed!

The outer tire pops easily in place thanks to the spring setup on the upper suspension, the idler wheels also maintain a tight grip on the inner rim while allowing the drive wheel to rotate quite smoothly!

A shot showing the twin suspension viewed from below, here you can see the spring supports. They are glued to the right side of the crescent and attached to the left side via two bolts.

The frame is completed!!! Now all that is left to do is make the battery/rider support and install the electronics!

Upper Twin Suspension

The Zero will also sport two upper idler wheels to hold the whole inner frame in place. Above you can see the assembled setup.

Springs are also added to help counter the tension exerted by the front suspension, this also cushions the vehicle against vibrations while keeping the inner frame (and rider) in place when going through a bumpy road.

Above shows the upper suspension installed, the springs rest on extra supports fixed to the crescent frame.

Front suspension done!

Extra bracing has been added around the suspension arms. Also, aluminum tubing was also threaded through the suspension rods to help strengthen the whole setup.

Sunday, December 28, 2008

Front suspension in the works...

Here are the parts to the front suspension, you can see the idler gear, washers, suspension rod and spring, and finally, the suspension support made from wood and a smaller metal bushing. The top left shows one of the assembled suspension arms.
Suspension fully assembled!

Drive Train Assembled

From left to right: Drive gear (black), clutch ring, spindle and spur gear (yellow).

The whole drive train close-up, the clutch ring and the drive gear are fixed on the shaft, whereas the yellow spur gear and the spindle rotate freely on the drive shaft.

The whole thing now assembled onto the frame. You can see the small pinion gear on the motor and the auxiliary spur gear (black). The only torque applied to the yellow spur gear comes from the motor via the auxiliary gear, which also rotates freely on a fixed shaft and bearings. Because of the centrifugal clutch, the transmission can only be engaged by the spur gear moving forward. So, when the motor is stopped, the drive gear is still rotating, since the clutch ring only allows it to rotate forwards. With the frictional forces present around the drive shaft, this should bring the vehicle to a smooth stop.

Centrifugal Clutch

At the heart of the drive train is the centrifugal clutch. Since monowheels suffer from the effects of "gerbling" under breaking, that is, when sudden deceleration is applied, the inner hub, along with the rider will have a tendency to roll backwards along the inner wheel. The worse case scenario occurs when the entire inner hub simply starts rotating around the inner wheel as the vehicle slows down, which is potentially (very) dangerous!

In an attempt to solve this problem, we've installed a clutch system which consists of an outer "clutch ring" and an inner spindle attached to the main drive gear:

Clutch ring (above) and spindle non-assembled (below):

Part of the spindle is fixed to the drive gear (yellow). Below is the spindle completely assembled:

Close up of the spindle, when the drive gear turns, the grey swing arms (made of strong ABS plastic) will swing outwards due to the centrifugal force applied. In turn, they will catch onto the inner teeth of the clutch ring, engaging the transmission and moving the vehicle forwards. Below you can see the clutch ring, now fully sanded:

Sunday, December 21, 2008

Frame 90% complete

Update: The frame is almost complete, all that is left to do is install the braces that will hold them in place, dill holes for the gear train, and installing the idlers.

The steering is provided by a single servo located at the front. The battery will be placed on a holder which will be then fixed on the servo arm.

Wednesday, October 29, 2008

Updated the CGI model of the Zero with a thinner wheel much more scaled to the real one, here you can see the new location of the motor and the drive gear that will turn the planetary gear teeth located all the around the inner circumference of the wheel. The right gearbox will be used to house the transmission system (We've decided to go with a gear system versus the earlier drive belt design), whereas the left one will be used to contain any electronics and circuits that will not fit outside the housings.

Side view of the wheel, here you can see the mounting platform for the rider's seat. More to come...

Sunday, October 12, 2008

The Loop

The popsicle sticks have been dried and after a week of being clamped in place, the wood grain successfully maintained its curvature. Pics show how the two layers of sticks form the wheel's inner/outer rims and in addition, hot glue sticks were glue to the outer rim to make the "tire". Next step: Sanding of the inner rim to obtain a smooth, horizontal surface for the gear belt to rest on and epoxying the whole wooden surface.

Sunday, October 5, 2008

Starting the Build...

New progress,

Today, the jig for the inner and outer rims were made.

The rims will be made from wooden sticks that were submerged in water for about a week. The softness made them easier to bend. To hold them in place, I used wire fasteners looped inside holes that were made in cardboard.

Friday, September 26, 2008

Finally some pictures to show!

Here you go, made this quickie sketch using Metasequoia, an excellent (and easy to use) 3D-imaging software made by M. Osamu Mizuno.

This is just to give a general idea of what the concept is. You can see the (potential) location of the motor and the drive wheel. Keep in mind that this is just a preliminary sketch... Still have no idea what the final product will look like.

So... what the hell are we doing?

What is a monowheel?

A monowheel, as the name suggests, is an unique type of motocyle with only one wheel. Compared to an ordinary bike, on which the rider sits on a seat above the drive wheels, a monowheel rider is instead seated inside the wheel's inner hub.

Monowheel designs have evolved over the years, from early pedal-powered versions built in as early as the beginning of the 19th century to more advanced and motorized versions during the early 1900's to today! However, as unique as they may be, monowheels have never actually caught on as a serious and accepted method of transportation...

Hopefully... we're about to change all that!

Project Zero, as it is known, is our quest at solving the various issues involved with monowheel designs in the past (these include such things as stability problems, engine configuartions, steering, etc), and hopefully finding a way around them.

The plan, as it stands now, is for the fabrication of two, fully functional, radio-controlled models. They are:

1. The Zero: This will serve as our prototype and testbed model on which wil be carrying out our initial stability, steering, and drive line tests. Presently, the plan is to make this an electrically powered version.

2. The Motion Zero: The results and lessons learned from the prototype tests will be finally incorporated in to the building of a second, more updated and refined version of The Zero. Our goal is to make this model much easier to control, and try to eliminate the major issues encountered with the previous version.

In the end, if all goes well, this project will (hopefully) be entered into the 2009 Bell Science Fair in Montreal.

Wish us luck and see you there!