Model the effects of a time change in mass, such as that due to the fueling and loading of a vehicle. The Variable Mass block accounts for the time-varying inertia force that resists translational acceleration in driveline systems or components.
A physical signal port enables you to specify the mass value as a function of time. A minimum mass parameter ensures the variable mass is always positive and cannot fall below zero. The new block appears under a new library named Inertias & Loads.
Model the effects of a time change in inertia, such as that due to the buildup of mud in a tire. The Variable Inertia block accounts for the time-varying inertia torque that resists rotational acceleration in driveline systems or components.
A physical signal port enables you to specify the inertia value as a function of time. A minimum inertia parameter ensures the variable inertia is always positive and cannot fall below zero. The new block appears under a new library named Inertias & Loads.
Model the effects of a load whose rotational inertia varies instantaneously with the rotation angle. Examples include the wobbling of a spinning axle and shaking of an off-center rotating machine. You can specify the load inertia in terms of its rotation path or as an angle-inertia lookup table. The Unbalanced Load block appears under a new library named Inertias & Loads.
Model the effects of a changing road-tire friction coefficient, for example, due to an encounter with an ice patch or water puddle. The following Tire blocks now provide variable-friction variants:
To switch between tire variants, right-click the Tire block and, under Simscape > Block choices, select the desired tire model. When using variable-friction tire variants, avoid sudden changes to the friction coefficients, as these can cause numerical issues in the model.
Specify the inertias of internal gears in compound gear blocks, for example, to account for inertia torques during rapid changes in rotation direction or speed. You can specify the inertia of internal gears explicitly in a new dialog box tab named Inertia. The following blocks provide the new tab:
Each block provides an inertia parameter for at least one internal gear node. Planetary Gear and Compound Planetary Gear blocks contain one such node while Differential and Ravigneaux Gear blocks contain two. You can ignore internal gear inertias by setting their values to zero.
Model vehicles with different numbers of wheels in their front and rear axles. Examples include three-wheeled forklifts with two wheels in the front axle and one wheel in the rear axle. The Vehicle Body block now enables you to enter the numbers of wheels in the two axles separately as a two-element vector. The first element corresponds to the front axle and the second element to the rear axle. Entering a scalar instead of a two-element vector causes the two wheel numbers to be the same.
Gear blocks now include thermal variants, alternative block implementations that account for heat generation due to meshing, changes in gear efficiency due to temperature fluctuations, and the impact of a gear's thermal mass on those temperature fluctuations.
You can switch between gear variants in the block's context-sensitive menu. You do this by right-clicking the gear block and selecting Simscape > Block choices > Show thermal port to model thermal effects, or Simscape > Block Choices > No thermal port to ignore those thermal effects.
A new Transmissions library provides prebuilt transmission templates—subsystem models built on SimDriveline and Simscape blocks that represent various transmission types.
Use the templates to quickly model 4- to 9- speed transmissions, including CR-CR, Ravigneaux, and Lepelletier systems. Each template contains a clutch schedule that determines which clutches must engage and disengage in order to reach a certain gear.
The Dog Clutch block now includes a variant that accepts the linkage position directly as a physical signal input instead of through a translational conserving port. The new variant provides a convenient means of specifying the shift linkage position when the position signal arises from a control system.
You can switch between variants in the block's context-sensitive menu. You do this by right-clicking the block and selecting Simscape > Block choices > Physical signal position input to use a physical signal port or Simscape > Block choices > Mechanical port shift linkage to use a translational conserving port.
A new featured example shows how to model the dynamics of a four-wheel drive testbed.
The Disk Friction Clutch block includes a new parameter, Directionality. This parameter enables you to model bidirectional and unidirectional clutches. Bidirectional clutches can slip in the positive and negative directions while unidirectional clutches can slip only in the positive direction. The slip direction is positive if the follower shaft spins faster than the base shaft and negative if it spins slower.
Model a high-ratio speed-reduction mechanism based on the eccentric motion of a cycloidal disk in mesh with a ring gear. The Cycloidal Drive block includes efficiency losses in normal and reverse operation modes. This block is in the Gears library.
Model a high-ratio speed-reduction mechanism based on the elastic deformation of a flexible pinion in mesh with a ring gear. The Harmonic Drive block includes efficiency losses due to meshing between teeth and viscous friction at the ball bearings. This block is in the Gears library.
The SimDriveline™ Couplings & Drives library provides one new block, Universal Joint. This block represents a rotational coupling that connects two driveline shafts at an arbitrary angle.
The SimDriveline Gears library provides one new block, Double-Pinion Planetary Gear. This block represents a planetary gear train containing two meshed planet gear sets between its sun and ring gears.
A new featured example models the dynamics of a helicopter transmission system.
The Couplings & Drives library contains a new sublibrary, Springs & Dampers. The sublibrary contains eight blocks.
|Nonlinear Translational Spring||Translational spring with nonlinear force-displacement curve|
|Nonlinear Translational Damper||Translational damper with nonlinear force-velocity curve|
|Nonlinear Rotational Spring||Rotational spring with nonlinear torque-displacement curve|
|Nonlinear Rotational Damper||Rotational damper with nonlinear torque-velocity curve|
|Variable Translational Spring||Translational spring with variable spring stiffness|
|Variable Translational Damper||Translational damper with variable damping coefficient|
|Variable Rotational Spring||Rotational spring with variable spring stiffness|
|Variable Rotational Damper||Viscous rotational damper with variable damping coefficient|
The Couplings & Drives library contains one new block.
|Shock Absorber||Linear spring-damper with friction and hard stops|
The Gears library contains one new block.
|Simple Gear with Variable Efficiency||Simple gear with externally specified meshing efficiency|
The Generic Engine block contains new options:
Specify and sense engine fuel consumption
Specify an idle speed controller to prevent engine stall at low engine speeds
SimDriveline adds one block to the Tires & Vehicles Library:
|Rolling Resistance||Resistance force due to road-wheel contact|
The Tire (Friction Parameterized) and Tire (Magic Formula) blocks introduce an optional set of rolling resistance parameters. Represent tire rolling resistance with a constant resistance coefficient or with a pressure and velocity dependent model that meets the SAE J2452 standard.
A new example demonstrates a five-speed transmission model. The model contains five forward gears and one reverse gear driven by an engine. Proportional control systems govern a set of double-sided synchronizers that engage each gear with an output shaft.
Stepping Mechanism with Detents
Models a stepping mechanism, including using Translational Detent blocks.
Power Window System
Models a power window system, including using the new Rope Drum and Belt Pulley blocks.
Sheet Metal Feeder
Models the feeding mechanism of a sheet metal cutter, including the use of the Loaded Contact Translational Friction block.
The "Vehicle with Four-Wheel Drive" example (sdl_4wd_dynamics) now uses Simulink® subsystem variants to allow testing with several different tire models.
SimDriveline Version 2 Transitional library blocks that accept Simulink inputs now have an Input Handling tab. You can choose between no filtering, first-order filtering, and second-order filtering with a time constant that you specify. For more information, see Input Handling Options in Version 2 Transitional Library Blocks.
Some Transitional library blocks have multiple Simulink input ports. Changing the settings under the Input Handling tab affects all Simulink input ports equally.
Simulink-PS Converter blocks provide input handling options in Transitional library blocks. The SimDriveline software uses these Simscape™ blocks in the architecture of the Transitional library blocks. These blocks exist behind a mask. For more information, see Input Filtering Usability Enhancements and Simulink-PS Converter in the Simscape documentation.
Note: In the Version 2 Transitional library, the Motion Actuator block does not require an acceleration input. The input port is still present to provide a consistent block interface, but it no longer uses an acceleration signal. For more information, see version 2 transitional library.
When using an explicit Simulink solver in a SimDriveline Version 2 model, you must specify a sufficient number of input derivatives in the Input Handling tab. Failure to do so results in an error.
These blocks have been added in Version 2.1.
If you log data in a SimDriveline model using the Simscape data logging feature, some internal node and subcomponent names will change when you log data from an unchanged model using SimDriveline 2.1, as compared with Version 2.0.
These changes enhance your understanding of the internal structure of SimDriveline models, as reflected in the data logging object.
If you have written a script that depends on the specific names of nodes and subcomponents in SimDriveline data logging objects, you need to update your script so that it conforms with the new naming scheme.
The reference chapter on working with legacy Version 1 models and libraries has been expanded with a new section on how to rebuild Version 1 models in Version 2 without automatic conversion. See Manual Reconstruction of Version 1 Models in Version 2 in Relationship of Version 1 and Version 2.
SimDriveline 2.0 is a new version of an existing product in the Physical Modeling family that models and simulates drivetrain systems. The new version is fully integrated with Simscape software and supports physical connections, physical signals, data logging, local solvers, and other Simscape features. At the same time, this new version extends the Simscape library with additional rotational and translational mechanical components.
With SimDriveline software, you can model bodies rotating around and translating along multiple axes, connect them with gears, and create powertrains with clutches, transmissions, and other dynamic elements and subsystems. SimDriveline software also lets you actuate and measure torques, forces, and motion. You can model, simulate, analyze, and control the motion of complex drivetrains.
SimDriveline 2.0 also includes:
Components that couple rotational and translational motion.
Gears with optional friction loss.
Clutches using Coulomb friction that lock and unlock.
Improved algorithms for simulation of redundant dynamic constraints.
A translator function to convert Version 1 models and user-defined libraries to be compatible with the new Version 2 product library.
SimDriveline software is an extension of the Simscape product and requires these products:
For an introduction to Simscape blocks, modeling, and simulation, consult the Simscape Getting Started Guide.
For learn more about the Simscape features that improve how you model and simulate driveline systems, see these sections of the Simscape User's Guide:
To learn how to define Simscape based blocks programmatically, see the Simscape Language Guide.
Efficiency and other frictional losses in Version 2 gears.
These loss features are now built into the gear blocks. MathWorks recommends that you select adaptive zero-crossing in the Configuration Parameters menu of models that include gears with efficiency loss.
Data logging without sensors.
Version 2 supports the Simscape data logging capability.
Simscape fixed-step local solver now supported.
You can use a separate local, fixed-step solver on physical networks in Version 2 models.
Redundant dynamic constraints now solved without errors.
In Version 2 models, when ideal clutches lock and carry the same load, the load is now distributed between the clutches without generating simulation errors.
Certain mechanical rotational components in the Version 1 library now provided by the Simscape Foundation library, in its mechanical and utilities sublibraries.
Direct connection to other Simscape components.
You can directly connect Version 2 blocks to other components based on Simscape software, without an interface component, as long as you respect the Simscape rules concerning physical ports and connections. SimDriveline driveline ports and connection lines are now mechanical conserving rotational or translational ports and physical connection lines.
Motion initial conditions set in Version 2 Inertia and Mass blocks.
In Version 1, you set initial conditions in a separate block.
Simulink variable-step solvers for variable-step simulation.
Version 2 is compatible with all Simulink solvers. For
variable-step simulation, MathWorks recommends that you select
your model Configuration Parameters menu.
Version 2 generated code simulation is slower than with Version 1.
Tunable parameters are not supported with the SimDriveline 2 libraries.
Changing block parameter values for simulating with generated code requires changing those parameter values in the block dialog boxes and regenerating the code from the model. A workaround is:
Create your own versions of the blocks using the Simscape language.
Make the parameters that you want to tune into signal inputs by defining the input values as Simulink Constant blocks.
Convert these Simulink constant signals into physical signals with Simulink-PS Converter blocks.
Tune the Constant block values during the simulation.
Block diagrams built from Version 1 and block diagrams built from Version 2 can coexist in the same model or library. You can indirectly connect Version 1 block diagrams and Version 2 block diagrams using Version 1 Rotational Coupling interface blocks. You cannot connect them directly.
You can continue to create and use Version 1 models and libraries, separately from Version 2 models and libraries.
Optionally, you can convert models and user-defined libraries
from Version 1 to Version 2 with a model conversion utility, accessed
sdl_update function. This utility creates
new models and user-defined libraries with Version 1 components replaced
by new versions using a transitional library that is based on the SimDriveline 2
and Simscape libraries.
The Version 1 library and documentation are included with Version 2.
To open the Version 1 library, at the command line, enter
To view a list of the Version 1 example models, do one of the following:
In the Help browser, on the Version 1 SimDriveline product roadmap page, click the product examples link.
At the command line, enter
If you use the command line, the examples list appears at the command line. If you click a linked individual example model name, information about that model appears at the command line.
|Release||Features or Changes with Compatibility Considerations|
|R2012a||Input Filtering Usability Enhancements in SimDriveline Version 2 Transitional Library Blocks|
|R2011b||Changes to Data Logging Object Naming|
|R2011a||Working with Version 1 Models and Libraries|