Rotational Inertia

Ideal mechanical rotational inertia

Libraries:
Powertrain Blockset / Drivetrain / Couplings
Vehicle Dynamics Blockset / Powertrain / Drivetrain / Couplings

Description

The Rotational Inertia block implements an ideal mechanical rotational inertia.

Power Accounting

For the power accounting, the block implements these equations.

Bus Signal			Description	Variable	Equations
`PwrInfo`	`PwrTrnsfrd` — Power transferred between blocks Positive signals indicate flow into block Negative signals indicate flow out of block	`PwrR`	Mechanical power from base shaft	P_TR	$P_{T R} = T_{R} ω$
		`PwrC`	Mechanical power from follower shaft	P_TC	$P_{T C} = T_{C} ω$
	`PwrNotTrnsfrd` — Power crossing the block boundary, but not transferred Positive signals indicate an input Negative signals indicate a loss	`PwrDampLoss`	Power loss due to damping	P_d	$P_{d} = - b {\| ω \|}^{2}$
	`PwrStored` — Stored energy rate of change Positive signals indicate an increase Negative signals indicate a decrease	`PwrStoredShft`	Rate change of stored internal torsional energy	P_s	$P_{s} = ω \dot{ω} J$

The equations use these variables.

T_R	Input torque
T_C	Output torque
ω	Driveshaft angular velocity
J	Rotational inertia
b	Rotational viscous damping
P_d	Power loss due to damping
P_s	Rate change of stored internal torsional energy

Ports

Input

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RTrq — Input torque
`scalar`

Applied input driveshaft torque, T_R, in N·m.

Dependencies

To enable this port, for Port Configuration, select Simulink.

CTrq — Output torque
`scalar`

Load driveshaft torque, T_C, in N·m.

Dependencies

To enable this port, for Port Configuration, select Simulink.

R — Angular velocity and torque
two-way connector port

Angular velocity in rad/s. Torque is in N·m.

Dependencies

To enable this port, for Port Configuration, select Two-way connection.

Inertia — Input
`scalar`

Rotational inertia, in kg·m^2.

Dependencies

To create the Inertia port, select External inertia input.

Output

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Info — Bus signal
bus

Bus signal containing these block calculations.

Signal			Description	Variable	Units
Trq	`R`		Applied input driveshaft torque	T_R	N·m
	`C`		Output driveshaft torque	T_C	N·m
	`Damp`		Damping torque	T_d=bω	N·m
Spd			Angular driveshaft speed	ω	rad/s
PwrInfo	`PwrTrnsfrd`	`PwrR`	Mechanical power from base shaft	P_TR	W
	`PwrTrnsfrd`	`PwrC`	Mechanical power from follower shaft	P_TC	W
	`PwrNotTrnsfrd`	`PwrDampLoss`	Power loss due to damping	P_d	W
	`PwrStored`	`PwrStoredShft`	Rate change of stored internal torsional energy	P_s	W

Dependencies

To enable this port, select Output Info bus.

Spd — Driveshaft speed
`scalar`

Angular driveshaft speed, ω, in rad/s.

Dependencies

To enable this port, for Port Configuration, select Simulink.

C — Angular velocity and torque
two-way connector port

Angular velocity in rad/s. Torque is in N·m.

Dependencies

To enable this port, for Port Configuration, select Two-way connection.

Parameters

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Block Options

Port Configuration — Specify configuration
`Simulink` (default) | `Two-way connection`

Specify the port configuration.

Dependencies

Specifying Simulink creates these ports:

RTrq
CTrq
Spd

Specifying Two-way connection creates these ports:

Output Info bus — Selection
`off` (default) | `on`

Select to create the Info output port.

External inertia input — Input rotational inertia
`off` (default) | `on`

Dependencies

To create the Inertia port, select External inertia input.

Parameters