Variable Inertia
Variable inertia.
blockType: Engee1DMechanical.Elements.Rotational.VariableInertia
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Path in the library: |
Description
Block Variable Inertia simulates variable inertia. This unit can be used to simulate the deployment of solar panels of a spacecraft. The instantaneous inertia value is sent to the input port at each time step during the entire simulation. To minimize solver errors, avoid discontinuities and sudden changes in the input signal.
When the inertia of a component changes, the torque acting on that component also changes.:
where
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— torque;
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— variable inertia;
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— angular velocity.
If the input inertia value is lower than the minimum inertia value specified in the Minimum inertia parameter, then the block performs its calculations for the minimum inertia. The torque of the inertia force is calculated as:
where — minimal inertia.
Angular momentum is conserved with variable inertia. In the absence of an external torque, a decrease in the moment of inertia leads to a proportional increase in angular velocity. The angular momentum remains constant until an external torque causes it to change.
Variables
Use the Initial Targets parameter group to set the priority and initial target values for the block parameter variables before modeling. For more information, see Configuring physical blocks using target values.
Ports
Conserving
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Flange
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port connecting the unit to the network
`rotational mechanics
Details
A mechanical rotational port that connects a block to a physical network.
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Input
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I
—
variable inertia, kg/m2
scalar
Details
The input port that receives the value of the variable inertia.
| Data types |
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| Complex numbers support |
No |
Parameters
Parameters
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Minimum inertia —
minimum inertia
kg*m^2 | g*m^2 | kg*cm^2 | g*cm^2 | lbm*in^2 | lbm*ft^2 | slug*in^2 | slug*ft^2
Details
The minimum value that the inertia variable can take during simulation.
If the input inertia value is lower than the minimum inertia value, it is set equal to the minimum inertia value.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |