Simulation of reaction wheels in a spacecraft

[tttttt]

How to identify a model of spacecraft actually works before launching.waht type of simulation software is used to do. Actually I am doing a model by using reaction wheels and I want to show the simulation of how it actually makes the whole body to change its attitude so I need a good software to do it

 

[DaveC426913]

What are you testing? Aerodynamics? Propulsion? Avionics? Fuel-Payload ratio?
There is no such thing as Microsoft "Does this Spaceship Design get us to Mars?"

 

[tttttt]

What are you testing? Aerodynamics? Propulsion? Avionics? Fuel-Payload ratio?
There is no such thing as Microsoft "Does this Spaceship Design get us to Mars?"

Aerodynamics ...actually I am trying to create a new model to place the reaction wheel and I want to check whether my idea works or not..so is there any way

 

[DaveC426913]

Aerodynamics ...actually I am trying to create a new model to place the reaction wheel and I want to check whether my idea works or not..so is there any way

Well that's not aerodynamics.
What aspect(s) of the reaction wheel are you trying to test?

 

[berkeman]

Welcome to PF.

waht type of simulation software is used to do.

I did a Google search on Mechanical Dynamics Simulation Software and got lots of good hits. At the high end (of price and complexity and capability) are packages like Ansys Motion and Simcenter:

https://www.google.com/search?client=firefox-b-1-d&q=mechanical+dynamics+simulation+software

But unless you have many $10k to spend on the software and training classes, and a year or more to learn it, you may need to do something simpler like generate detailed 3D Free Body Diagram (FBD) models and use Excel to do simple time-step simulations...

 

[FactChecker]

MATLAB by MathWorks is a popular (but expensive) set of software for analysis of that type. There are packages (for an additional price) for a lot of engineering design specialties.
It might not be so expensive for students.

 

[tttttt]

Well that's not aerodynamics.
What aspect(s) of the reaction wheel are you trying is a model where inside a sphere

Usually a spacecraft needs three or more reaction wheel if I am not wrong so here I am introducing a spherical hallow ball inside which I place the reaction wheel and by rotating this sphere I will get the reaction wheel to act in 3 axis so this reduces the use of other two wheels and helps to control the attitude ....this is just my idea and I want to check if this works

 

[tttttt]

Welcome to PF.


I did a Google search on Mechanical Dynamics Simulation Software and got lots of good hits. At the high end (of price and complexity and capability) are packages like Ansys Motion and Simcenter:

https://www.google.com/search?client=firefox-b-1-d&q=mechanical+dynamics+simulation+software

But unless you have many $10k to spend on the software and training classes, and a year or more to learn it, you may need to do something simpler like generate detailed 3D Free Body Diagram (FBD) models and use Excel to do simple time-step simulations...

Can I know how to do the excel calculation and simulations

 

[tttttt]

Any alternative for matlab

MATLAB by MathWorks is a popular (but expensive) set of software for analysis of that type. There are packages (for an additional price) for a lot of engineering design specialties.
It might not be so expensive for students.

 

[DaveC426913]

Usually a spacecraft needs three or more reaction wheel if I am not wrong so here I am introducing a spherical hallow ball inside which I place the reaction wheel and by rotating this sphere I will get the reaction wheel to act in 3 axis so this reduces the use of other two wheels and helps to control the attitude ....this is just my idea and I want to check if this works

Sounds like it can only act on one of three axes at a time. It has to rotate between active axes, does it not?

 

[berkeman]

I am introducing a spherical hallow ball inside which I place the reaction wheel and by rotating this sphere I will get the reaction wheel to act in 3 axis so this reduces the use of other two wheels and helps to control the attitude

How do you manage to rotate the sphere in any of 3 axes? That would take 3 separate spinning wheels in contact with the sphere, no?

Can I know how to do the excel calculation and simulations

You put your time in the first column, with the simulation time incrementing by $\delta t$ for each row. Then you put the variable you want to simulate in the 2nd column, using an equation that depends on the time t in the first column and the value of the simulated value in the row above.

So to calculate the position based on acceleration and velocity, you would have 4 columns:

time      acceleration           velocity       position
-----     -------------          --------       ---------
.000           1.0                 v(0)            x(0)
.001           1.0                 v(1)            x(1)
.002           1.0                 v(2)            x(2)
.003
<etc.>

I show a constant acceleration of 1.0 in the example above. You would use the standard kinematic equations to calculate v(t) and x(t) given the value of a(t) and the previous values of v(t-1) and x(t-1).

Note that there are some quantization errors in such a simulation, so it is better to use very fine time steps for the simulation (which increases the number of rows in the spreadsheet, often to a very large number). There are better ways to do such a simulation in terms of calculating the next values, but we can leave those for a later set of posts if you decide to try this.

 

[tttttt]

MATLAB by MathWorks is a popular (but expensive) set of software for analysis of that type. There are packages (for an additional price) for a lot of engineering design specialties.
It might not be so expensive for students.

Sounds like it can only act on one of three axes at a time. It has to rotate between active axes, does it not?

Yes it can act at one axis at a time and to mention it does not only works in 3 axis it can rotate in any degree which is similar to the gimbal mechanism and by this spherical ball I can rotate the wheel to get change its axis as our desired coordinates

 

[tttttt]

How do you manage to rotate the sphere in any of 3 axes? That would take 3 separate spinning wheels in contact with the sphere, no?


You put your time in the first column, with the simulation time incrementing by $\delta t$ for each row. Then you put the variable you want to simulate in the 2nd column, using an equation that depends on the time t in the first column and the value of the simulated value in the row above.

So to calculate the position based on acceleration and velocity, you would have 4 columns:

time      acceleration           velocity       position
-----     -------------          --------       ---------
.000           1.0                 v(0)            x(0)
.001           1.0                 v(1)            x(1)
.002           1.0                 v(2)            x(2)
.003
<etc.>

I show a constant acceleration of 1.0 in the example above. You would use the standard kinematic equations to calculate v(t) and x(t) given the value of a(t) and the previous values of v(t-1) and x(t-1).

Note that there are some quantization errors in such a simulation, so it is better to use very fine time steps for the simulation (which increases the number of rows in the spreadsheet, often to a very large number). There are better ways to do such a simulation in terms of calculating the next values, but we can leave those for a later set of posts if you decide to try this.

Thankyou I will try

 

[tttttt]

How do you manage to rotate the sphere in any of 3 axes? That would take 3 separate spinning wheels in contact with the sphere, no?

Actually I am trying to implement the spherical gear mechanism which was invented as ABENICS..so here the spherical gear is made hollow and I am placing the reaction wheel inside it

 

[berkeman]

Yes it can act at one axis at a time and to mention it does not only works in 3 axis it can rotate in any degree which is similar to the gimbal mechanism and by this spherical ball I can rotate the wheel to get change its axis as our desired coordinates

Instead of simulating this, it may just be easier and quicker to build a small scale model to try it out.

 

[berkeman]

ABENICS

Interesting mechanism!

https://newatlas.com/technology/abenics-versatile-active-ball-joint-gear/

 

[tttttt]

Instead of simulating this, it may just be easier and quicker to build a small scale model to try it out.

yeah i want to give a try but the problem Is I want to submit my project in 2 days I think I can't do that in this short time

How do you manage to rotate the sphere in any of 3 axes? That would take 3 separate spinning wheels in contact with the sphere, no?

Actually I am trying to implement the spherical gear mechanism which was invented as ABENICS..so here the spherical gear is made hollow and I am placing

 

[berkeman]

yeah i want to give a try but the problem Is I want to submit my project in 2 days I think I can't do that in this short time

So this thread is for schoolwork?

 

[tttttt]

Actually I am trying to implement the spherical gear mechanism which was invented as ABENICS..so here the spherical gear is made hollow and I am placing the reaction wheel inside it

So this thread is for schoolwork?

Clg research work

 

[berkeman]

Sorry, what is Clg?

 

[DaveC426913]

Yes it can act at one axis at a time

You miss my point: it can only act in one axis at time. It must move to a different orientation to act on a different axis, and that means a delay.

In fact, there will always be a delay. Consider:

With a 3-motor system, any axis of rotation is immediately available - two motors can act together to produce rotation of any orientation - and can do so with zero delay.

With a 1-motor system, there will always be a delay while the system sets itself to the desired axis.

 

[tttttt]

You miss my point: it can only act in one axis at time. It must move to a different orientation to act on a different axis, and that means a delay.

In fact, there will always be a delay. Consider:

With a 3-motor system, any axis of rotation is immediately available - two motors can act together to produce rotation of any orientation - and can do so with zero delay.

With a 1-motor system, there will always be a delay while the system sets itself to the desired axis.

Okay I understood...i want to get knowledge about this..have you heard about the Apollo 13 gimbal lock ..so in that case they used something similar to a spherical ball rotation to control the vehicle's attitude, so I got an idea to avoid that lock by giving this alternative solution ,there many be other solutions to solve it but I just wanted to give a try to this mechanism

 

[FactChecker]

I want to submit my project in 2 days

2 days certainly rules out my suggestion of learning MATLAB.