Inertia
Perfect rotational inertia.
Description
The Inertia block represents ideal rotational inertia, which is described by the following equation:
Where:
-
- torque.
-
- moment of inertia.
-
- angular velocity.
-
- time.
By default, the block has one mechanical port that stores rotation. The positive direction of the block is from its port to the reference point. This means that torque is positive if it results in acceleration in the positive direction.
In some applications, it is common to display inertial elements in series with other elements in the block diagram. To support this use case, the Number of graphical ports parameter allows a second port to be displayed on the opposite side of the block icon.
The two-port option is purely graphical: both ports have the same angular velocity, so the block functions the same whether it has one or two ports. The block icon changes depending on the value of the Number of graphical ports parameter.
| Number of graphical ports | Block icon |
|---|---|
1 |
|
2 |
|
Ports
I is the port that connects the unit to the network
`rotational mechanics
A mechanical rotational port that connects the block to the physical network.
J is the second graphics port
`rotational mechanics
A second rotation-preserving mechanical port that allows inertial elements to be connected in series with other elements in the block diagram. This port is hardwired to the I port, so the difference between the one-port and two-port representation of the block is purely graphical.
Dependencies
To enable this port, set the Number of graphical ports parameter to 2.
Parameters
Inertia, kg*m² - moment of inertia
`0.01 kg*m² (by default)
The value of the moment of inertia, which is constant during the simulation.
Number of graphical ports - number of graphical ports
1 (by default) | 2
Number of graphical ports:
-
1- The unit has one port that connects it to the mechanical rotary system. If the unit has one port, connect it to the connection line between the other two units. -
2- selecting this option opens a second port that allows the unit to be daisy-chained to other units in the chain. The two ports are hardwired and have the same angular velocity, so the unit functions exactly as if it had one port.