Control Moment Gyroscope Gimbal Motor Torque

In summary, the author discusses the concept of torque in relation to the CMG project and its application to a static table. They explain that while the CMG applies a constant torque to the table, the gimbal motor torque must be zero because there is no angular acceleration. However, this does not mean that there is no torque being applied to the table, as it is transferred through conservation of angular momentum. This is why torque amplification occurs, as small torques induce gimbal rates and create larger torques through conservation of angular momentum.
  • #1
Viroos
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Hi !
My name is Max and I'm a Mechanical Engineer.
I'm working on Control Moment Gyroscope project, but because for a long time I didn't deal with theory, I'm stuck at some very basic dynamics problem.
In this article
http://www. spacecraft research.com/files/BrownPeck_JGCD2009
the author writes that the total CMG torque is
[itex]{\tau _{cmg}} = \dot \phi \hat g \times {h_r}[/itex] (eq. 8)
and the gimbal motor torque is
[itex]{\tau _g} = {I_{cmg}}\ddot \phi + {I_{cmg}}{\mathop \omega \limits^B ^{B/N}} \cdot \hat g + ({\omega ^{B/N}} \times {h_r}) \cdot \hat g[/itex] (eq. 9)
But what happens practically if I mount the CMG at the top of a static table at my room, connect both motors (flywheel and gimbal) to power and wait for some steady state ?
In the first equation we get some constant torque that CMG applies to the table, because [itex]\dot \phi [/itex] is some constant value, but on the other side, the gimbal motor torque, [itex]{\tau _g}[/itex] has to be zero, because there is no angular acceleration: [itex]\ddot \phi = 0
[/itex], and the table is static, that is, [itex]{\mathop \omega \limits^B ^{B/N}} = 0[/itex] and [itex]{\mathop \omega \limits^{B/N}} = 0[/itex]. That is, we need torque only to accelerate the gimbal.
My question is how the CMG can to apply torque to the controlled body (table, satellite etc), actually without torque at a gimbal motor ?
Many thanks in advance,
Max
 
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  • #2
Its torque is applied through conservation of angular momentum.

Let h_1 equal the angular momentum stored in the flywheel of the CMG. As the CMG rotates there is a new momentum, h_2 of the same magnitude but a different direction.

The vector difference in h_2 and h_1 represents the integral of a torque applied to the CMG, therefore an equal and oposite torque had to have been transferred to the test stand, satellite, etc.

That's why "torque amplification" exists. Small torques induce gimbal rates, which in turn create huge torques in the form of conservation of angular momentum.
 
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1. What is a Control Moment Gyroscope Gimbal Motor Torque?

A Control Moment Gyroscope Gimbal Motor Torque is a type of motor that is used in spacecraft or satellites to control their orientation and movement in space. It helps to stabilize the spacecraft and maintain its desired position and direction.

2. How does a Control Moment Gyroscope Gimbal Motor Torque work?

A Control Moment Gyroscope Gimbal Motor Torque works by using gyroscopic principles. It consists of a spinning wheel or disk that is mounted on a set of gimbals. As the wheel spins, it creates a torque that can be used to control the orientation of the spacecraft. By changing the direction and speed of the spinning wheel, the torque can be adjusted to maintain the desired position and direction.

3. What are the advantages of using a Control Moment Gyroscope Gimbal Motor Torque?

There are several advantages of using a Control Moment Gyroscope Gimbal Motor Torque. Firstly, it is a highly efficient system that requires minimal power to operate. It also has a fast response time, making it ideal for quickly adjusting the spacecraft's orientation. Additionally, it is a reliable system that is not affected by external forces or disturbances in space.

4. What are the potential applications of a Control Moment Gyroscope Gimbal Motor Torque?

A Control Moment Gyroscope Gimbal Motor Torque has various applications in space technology. It is commonly used in spacecraft and satellites for attitude control and stabilization. It can also be used in space telescopes to maintain a steady aim at a specific target. In addition, it has potential applications in robotics and navigation systems.

5. How is the performance of a Control Moment Gyroscope Gimbal Motor Torque measured?

The performance of a Control Moment Gyroscope Gimbal Motor Torque is typically measured by its ability to maintain a desired orientation and direction. This can be evaluated by measuring the accuracy, speed, and stability of the motor's torque. Other factors such as power consumption and efficiency can also be used to assess its performance.

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