Driveline Environment

Represent driveline environment

Library

Solver & Inertias

Description

Each driveline represented by a connected SimDriveline™ block diagram requires global environment information for simulation. The Driveline Environment block specifies this global information and connects the solver that your model needs before you can begin simulation.

Each topologically distinct driveline block diagram requires exactly one Driveline Environment block to be connected to it.

Clutch Modes and Mode Iteration

The Driveline Environment block also controls how the Controllable Friction Clutches of your model lock and unlock during simulation. Once a clutch locks and switches from kinetic to static friction or unlocks and switches from static to kinetic friction, it can unlock only under certain conditions that are tested by mode iteration.

  • With mode iteration turned on, the simulation suspends its time steps and enters an algebraic loop to check the conditions for locking or unlocking until it reaches global consistency across the model. This is the default.

  • With mode iteration turned off, the simulation checks for locking and unlocking while continuing in time. Turning off mode iteration improves your simulation performance, but might degrade its accuracy.

Mode Iteration and Code Generation

In the default mode, clutch mode changes simulate with mode iteration turned on. However, in the generated code versions of SimDriveline models, mode iteration is turned off automatically. Clutch locking and unlocking are determined over multiple time steps.

Specifying Clutch Velocity Tolerances in a Driveline

A Driveline Environment block can control the velocity tolerance settings for all the clutches in the driveline connected to it. It specifies these settings by default if you do not specify overriding settings in individual clutches.

Apart from overriding individual clutch settings, the velocity tolerance settings act on the entire driveline differently depending on the type of solver you choose.

  • If you choose a variable-step solver, you can require non-overriding clutches either to

    • Compute the velocity tolerance value automatically from solver settings (the default configuration of the Driveline Environment block).

    • Use the velocity tolerance value you enter here.

  • If you choose a fixed-step solver, you must specify a velocity tolerance value. In those clutches without overriding individual values, the driveline always uses the velocity tolerance value you enter here.

Dialog Box and Parameters

Disable mode iteration for clutch locking

Controls the mode iteration for locking and unlocking of Controllable Friction Clutches in your driveline model. Select the check box to disable mode iteration. The default is unselected.

Default clutch velocity tolerance

For clutches without individual override settings, the default velocity tolerance value, in radians/second (rad/s). This value must be strictly positive. The default value is 1e-3.

This setting is valid if

  • You use a variable-step solver and unselect the Use automatic default clutch velocity tolerance for variable-step solvers check box.

  • You use a fixed-step solver, regardless of the Use automatic default clutch velocity tolerance for variable-step solvers check box setting.

Use automatic default clutch velocity tolerance for variable-step solvers

Requires clutches in the connected driveline without individual overrides to compute a velocity tolerance based on solver settings. Valid only if you use a variable-step solver. The default is selected.

 Restricted Parameters

Was this topic helpful?