Control moment gyroscope design - question

In summary, the conversation revolves around the idea of using a control moment gyroscope (CMG) to stabilize a single track vehicle, such as a motorcycle. The CMG involves spinning pink discs in opposite directions and using a pendulum to rotate them. The purpose of this mechanism is to potentially replace a complex control system with a simple mechanical linkage. However, there are concerns about its effectiveness and limitations, including the need for different gyro action for different vehicle loads and the potential difficulty in turning. The conversation also references examples of similar systems being used in vehicles, both for hobby and commercial purposes.
  • #1
stencilman
8
1
Hi all,

Like a lot of folk on here I am interested in the idea of a CMG used to stabalise a single track vehicle.<< Link to CMG info added by Mentor >>
https://en.wikipedia.org/wiki/Control_moment_gyroscope

I have designed this;

2015-08-09 18_59_41-SolidWorks Premium 2013 x64 Edition - [gyro stabaliser].png


the pink discs spin in opposite directions and the pendulum rotates them.

My question is could this replace a complex control system? or am i making it to simple?

(i tried to simulate it in SW but have not got the premium license)

keen to hear your thoughts

tom
 
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  • #2
I don't understand. The pendulums swing in opposite directions. Is this intentional?
 
  • #3
it is just one pendulum joined with a pin. (i could have made that clearer)
 
  • #4
Though your intent is not clear, I don't think it's going to operate as you wish. If the assembly tilts 5 degrees what happens? In which direction do things move?
 
  • #5
2015-08-14 22_21_53-SolidWorks Premium 2013 x64 Edition - [gyro stabaliser _].png
2015-08-14 22_22_32-SolidWorks Premium 2013 x64 Edition - [gyro stabaliser _].png


my intention is that the frame should be rigidly bolted into a motorcycle frame.

when the motorcycle stops the pendulum provides a negative feedback system tilting the counter rotating gyroscopes so that the rider never has to put his feet down.
 
  • #6
OK, so the axis at the bottom of the box is inline with the long axis of the motorcycle, right?

Then, with the way the gyros are gimbaled, you're counting on the procession of the of the gyros to move the pendulums. I'm not sure how the angular velocity could effect pendulum displacement.
 
  • #7
I think you see what I am trying to do.

the pendulum is acted on by gravity and g force and it dictates the gyros position.

"I'm not sure how the angular velocity could effect pendulum displacement." - if by this your saying the gyros may try to move the pendulum (equal and opposite) then I am not sure either.

on this Wikipedia page a similar system is discussed under principles of operation;

https://en.wikipedia.org/wiki/Gyro_monorail

what i am trying to find out is can a simple mechanical linkage/mechanism replace what lit motors are doing with software/complexity.The above links and below seemed to without software.
300px-Cornering.png
 
  • #8
It's interesting what you are trying to do. The modern approach is to use some electronics feedback to obtain stability.

Consider the limits. When the gyros are spinning at zero angular velocity, the pendulums don't move at all. In some classical limit of high angular velocity of the gyros, the pendulums will move to their limits.

Somewhere in between, a full dress Harley might slowly tip over waiting for the light to turn green.
Then you've got to correct for the lean coming out of the red light. It won't do If you have to
change lanes to do it. I think you just have to try it to see how how it handles. It might suck in the turns. So go for it, and see how it handles. It could be really stiff; impossible to turn. Put a prototype on a bicycle so your friends can laugh at you.
 
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  • #9
i think i understand what your saying; - your concerned the gyros won't always return to center.

on the wikipedia page i referenced there is the figure of 5% of total vehicle mass required for gyros. we had the same idea, first i will check it on SW at work then if it seems workable i will make up a little prototype, say a pair of 200mm diameter 10mm thick steel discs (2.5kg each) at say 5000 or 9000rpm. (depends on which motors i buy) and bolt it to the back of my bicycle (in a sturdy box!)

would you say its better to mount them lower or higher?
 
  • #10
stencilman said:
My question is could this replace a complex control system?
A differently loaded vehicle will need different gyro action for the same lean angle. How would pendulums, affected only by the lean angle, account for this? And since the gyros have to be powered anyway, what is the point in removing the powered control system?
 
  • #11
I think the pendulum will provide a negative system
 
  • #12
A japanese gentleman makes these for a hobby;




notice how they seem to lean like a bike into the corners.
 
  • #15
what is mobility of this mechanism?
 

FAQ: Control moment gyroscope design - question

1. What is a control moment gyroscope (CMG) and how does it work?

A control moment gyroscope is a device used for attitude control and stabilization in spacecraft and satellites. It consists of a spinning rotor that can be controlled to produce torque and alter the orientation of the spacecraft. The gyroscopic effect of the spinning rotor creates a torque that can be controlled through the use of gimbals.

2. What factors are considered when designing a control moment gyroscope?

Some key factors that are considered when designing a control moment gyroscope include the desired torque output, the angular momentum of the rotor, the mass and size constraints, and the power and control requirements. Other factors such as material selection, bearing design, and thermal management also play a role in the design process.

3. How does the size and weight of a control moment gyroscope affect its performance?

The size and weight of a control moment gyroscope can significantly impact its performance. Generally, a larger and heavier gyroscope will have a higher torque output and better stability, but it may also require more power and be more difficult to control. On the other hand, a smaller and lighter gyroscope may have lower torque output and stability, but it can be more agile and easier to control.

4. What are some common challenges in control moment gyroscope design?

Some common challenges in control moment gyroscope design include achieving precise control over the rotor's orientation, minimizing energy losses due to friction and bearing resistance, and ensuring structural integrity and thermal stability. Additionally, designing a gyroscope that can withstand the harsh conditions of space, such as extreme temperatures and radiation, can also be a challenge.

5. How are control moment gyroscopes tested and validated for use in spacecraft?

Control moment gyroscopes undergo extensive testing and validation before they are used in spacecraft. This includes various environmental tests such as thermal cycling, vibration testing, and vacuum testing to ensure the gyroscope can withstand the conditions of space. They are also subjected to functional tests to verify their torque output and control capabilities. Additionally, computer simulations and modeling are used to predict the performance of the gyroscope in various scenarios.

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