a good use for a mechanical gyro !!
Hi danielsmusic are you still wanting a `gyro` as in gyro sensing where the direction of `down` is? Well for some time now i have been working on a project of my own (off and on for a couple of years now
Mechanical gyros are still used along side electronic versions in planes, they all have there pro`s and con`s, mechanical ones are also used in space ....just brows the web those of you who don`t believe...i have played around with the gyros for helicopters, accelerometers from sparkrite, but all these are far too inaccurate to be used. Bearing in mind that whatever is used it has to be small enough to be made and installed into an r/c model! So that rules out all the laser ring gyros etc, that are far too big and cost as much as a car.
So looking at a few details,
semiconductor gyros drift and not very accurate at slow speed,
accelerometers are inaccurate at high speed and are affected by acceleration movement (as in vibrations, gravity, swinging).
mechanical gyro`s are affected (appear to be) by the the rotation of the earth ie. turn once in 24 hours!
An r/c model in my situation is only going to be airborne for a short time, and is not going to fly far enough that the curvature of the earth is going to upset things so a mechanical gyro suites my needs.
It just so happens that there has been made a gyro small enough for r/c models and i don`t mean the old mechanical helicopter gyros as these are totally different and no way can be altered to fit the job.
The mechanical gyro was made for the silverlite x-ufo r/c model as one is shown here on youtube YouTube - X-ufo indoor flight the round bubble at the centre houses the gyro.
Now, the problem is, that this gyro got itself a bad name because people were trying to fly there model at all angles, but the gyro will only rotate to something like 30 degrees before it binds up causing the gyro to get knocked off it`s alignment causing a crash, so what modelers did was put in or hack electronic versions, this was fine for them because the stability was constantly adjusted with the controls so any drift was never seen. But in my case i will not have any input from myself and i need the gyro to know where down is by it`self.
So i bought a couple of these mechanical gyros to have a play with and asses, here is one, half way down the web page just under the pic of the x-ufo model. **broken link removed** It is about 30mm across the round base it is mounted on, and weighs about 13grams which includes an electronics board attached to the underneath.
Now in my situation i will not be wanting to `bank` to one side or fly as a plane so the 30 degrees is not an issue with me. so what i did was to hack the hall sensors which are used to tell the angle of movement to my own needs (too much at this point to describe) and input the data to a pic micro controller which then uses the data.
I did also look at using a combined electronic gyro/accelerometer but i got stumbled at using the `kalman filter` equations. and even then i am unsure if it would be as responsive as a mechanical version and fit my needs.
I might add that if you wanted to get more than 30 degrees of movement, that you could hack this gyro to get more movement but the hall sensors would NOT be able to get that much movement so i thought that the next thing would be to replace the hall sensors with a `2 axis accelerometer ` fixed as it were to the motor of the gyro (as it were...vibration, i know!) which would gather acceleration data and not rotation data, then use another 2 axis accelerometer on the model frame which takes rotation and acceleration data. Then using a micro controller take the `acceleration only` date from the combined `acceleration and rotation` data which would leave you the rotation data!...job done.
If i have not made myself clear no doubt your`l post!
Hi danielsmusic are you still wanting a `gyro` as in gyro sensing where the direction of `down` is? Well for some time now i have been working on a project of my own (off and on for a couple of years now
Mechanical gyros are still used along side electronic versions in planes, they all have there pro`s and con`s, mechanical ones are also used in space ....just brows the web those of you who don`t believe...i have played around with the gyros for helicopters, accelerometers from sparkrite, but all these are far too inaccurate to be used. Bearing in mind that whatever is used it has to be small enough to be made and installed into an r/c model! So that rules out all the laser ring gyros etc, that are far too big and cost as much as a car.
So looking at a few details,
semiconductor gyros drift and not very accurate at slow speed,
accelerometers are inaccurate at high speed and are affected by acceleration movement (as in vibrations, gravity, swinging).
mechanical gyro`s are affected (appear to be) by the the rotation of the earth ie. turn once in 24 hours!
An r/c model in my situation is only going to be airborne for a short time, and is not going to fly far enough that the curvature of the earth is going to upset things so a mechanical gyro suites my needs.
It just so happens that there has been made a gyro small enough for r/c models and i don`t mean the old mechanical helicopter gyros as these are totally different and no way can be altered to fit the job.
The mechanical gyro was made for the silverlite x-ufo r/c model as one is shown here on youtube YouTube - X-ufo indoor flight the round bubble at the centre houses the gyro.
Now, the problem is, that this gyro got itself a bad name because people were trying to fly there model at all angles, but the gyro will only rotate to something like 30 degrees before it binds up causing the gyro to get knocked off it`s alignment causing a crash, so what modelers did was put in or hack electronic versions, this was fine for them because the stability was constantly adjusted with the controls so any drift was never seen. But in my case i will not have any input from myself and i need the gyro to know where down is by it`self.
So i bought a couple of these mechanical gyros to have a play with and asses, here is one, half way down the web page just under the pic of the x-ufo model. **broken link removed** It is about 30mm across the round base it is mounted on, and weighs about 13grams which includes an electronics board attached to the underneath.
Now in my situation i will not be wanting to `bank` to one side or fly as a plane so the 30 degrees is not an issue with me. so what i did was to hack the hall sensors which are used to tell the angle of movement to my own needs (too much at this point to describe) and input the data to a pic micro controller which then uses the data.
I did also look at using a combined electronic gyro/accelerometer but i got stumbled at using the `kalman filter` equations. and even then i am unsure if it would be as responsive as a mechanical version and fit my needs.
I might add that if you wanted to get more than 30 degrees of movement, that you could hack this gyro to get more movement but the hall sensors would NOT be able to get that much movement so i thought that the next thing would be to replace the hall sensors with a `2 axis accelerometer ` fixed as it were to the motor of the gyro (as it were...vibration, i know!) which would gather acceleration data and not rotation data, then use another 2 axis accelerometer on the model frame which takes rotation and acceleration data. Then using a micro controller take the `acceleration only` date from the combined `acceleration and rotation` data which would leave you the rotation data!...job done.
If i have not made myself clear no doubt your`l post!