X-Ufo SwissGyro Optimization

The X-Ufo is one of the first mass produced remote-control Quadrocopter models. Quadrocopters have minimal inherent stabilisation because the center of mass is not below the rotor level as with a helicopter but mostly on the same level. This facilitates higher agility but makes the model pratcically impossible to steer without a stabilization mechanism.

Original X-UFO
UFO-Doctor with stripped model

Whereas all other multi-rotor models use some kind of electronic ("solid state") gyro modules, the X-Ufo designers decided to construct a fully mechanical gyroscope for stabilisation. It uses a small electric motor to rotate a brass disc, the unit's movement along the nick and roll axis is measured with hall sensors and read in the by the central microcontroller that changes the speed of the respective motors to compensate for an unwanted movement.

Unfortunately the original X-Ufo gyro prooved to be very sensitive to hard landings and has a limited measure range of just 22 degrees. This led a swiss engineer, the 'UFO-Doctor', to construct an improved version, called SwissGyro.

This is where this move starts - it is about the experience of building a SwissGyro from the kit, the flight results, possible optimization - and some philosophy.

Gyro Kit building

The kit consists mainly of a newly constructed gimballing mechanism, made of precision aluminium and PET parts, as well as new hall sensors. The building instructions are made for the technicians in a series production and include a number of quality management and test steps not neccessary for the one-time builder. Some proposed materials and tools are also quite rare - like PET-primer and bearing selection - and can well be omitted or replaced by standard means. Assembling the mechanical parts took around 3 hours, not including the time for the glue to harden.


Working with and soldering the fine 0,06 mm wires prooved to be the main challenge, this was finally solved by a skilled aquaintance and took around 2,5 hours. Now the signal wires were soldered to the electronic board, followed by balancing and oiling of gyro parts and sealing of the contacts.

After in-hand tests showed that the gyro works - changing of motor speeds according to the X-Ufo angle - the first flight was done. Now here the vehicle was swinging back and forth - the sensitivity of the sensors was too high, they have to be bend away from the measuring magnet axis a little bit. After this the X-UFO flew nice - probably the way it way originally intended. Now more "flip over" - a 180 degree turn over in some flight situations - and easily controllable even with banking angles around 45 degrees.

What remains is the little effect of the radio control steering - the "swashplate" controls (nick and roll) act more like switches here and tilt the rotor layer only a few degrees - enough for controlled movement indoors and preferable for beginners, but not enough to steer against even light wind outside or for more agile maneuvers.

Philosophy

The SwissGyro's charme is obviously the swiss watchmaker spirit and thus a sense of technical nostalghia that it brings into a mass produced toy-like product. The mechanical gyro already made up an almost humerous mixture with the otherwise futuristic construction of a Quadrocopter UAV. By focussing much love and attention towards this element - that prooved to be the weakest part in the original - the 'UFO-Doctor' and each one assembling his kit demonstrate a "The path is the goal" attitude that would normally not be associated with a technical construction for a flying vehicle. Then the blinking finish of the gyroscope with it's tiny wires and precision parts exhibit a visual appearance close to a piece of jewelry. This is accompanied by the practical effect of enabling the machine to hover and move more easily in the air which adds up to the overall aesthetical achievement.

Improvement and optimization

The electric motor was taken over from the original gyro here - and brought with it the same cheap construction. After two batteries or around 15 minutes flight it started to produce nasty sounds, sometimes combined with a decrease in speed. Oiling helps a little but never for long. Are there more realiable motors available? → Not known, but according to Ufo-doctor the original motors prooved quite reliable, so exchanging it for the same type should suffice.

Changing the motor

Exchanging the motor unit in the gyroscope is easy because the axis are fixed with screws on both sides. But removing the very thin copper wire from the motor made it break. Instead of re-wiring the motor we just added some other wire to lenghten the original, but even this took two hours of concentrated work - a more flexible wire would really be helpful.


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move/x-ufo.txt · Last modified: 06.03.2010 14:51 (external edit)
 
 
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