car templates 1

7/22/2019 Car Templates 1

1/72

Working with Templates


2/72

Adams/Car

134

Template BasicsYour template-based product's library includes a variety of templates. Templates define the topology,

major role, and default parameters for subsystems. This tab includes template information that is specific

to your product.

For general template information, as well as information about the other files that make up model

architecture, see Building Models.

Conventions in Template Descriptions

For each template description, we provide the following:

Overview - A brief description of the template.

TemplateName - The file name containing the template.

Major Role - The major role of the template.

Application - The types of analyses in which you can use the template.

Description - A complete description of the template and its use. Limitations - Limitations of the template design that you should be aware of.

FilesReferenced - The property or MNF files that the template uses to define such entities as

bushings, springs, and flexible bodies.

Topology - How the different entities of the template connect and how forces or torques are

transferred from one entity to another.

Parameter Variables - The parameter variables that store key information in the template. For

example, in templates, parameter variables often store angles for a suspension or the orientationof axes.

Communicators - Communicators used in the template.

Notes - Miscellaneous information about the template.

When we refer to communicator and parameter names, we often use the notation [lr] to indicate that there

is both a left and right communicator or parameter of the specified name.

About Designing Templates

Adams/Car templates are parameterized models in which you define the topology of vehicle components.

Building a template means defining parts, how they connect to each other, and how the template

communicates information to other templates and the test rig.

At the template level, it is not crucial that you correctly define the parts, assign force characteristics, and

assign mass properties, because you can modify these values at the subsystem level. It is very important,

however, to correctly define part connectivity and exchange of information, because you cannot modify

them at the subsystem level.


3/72

135Working with Templates

When building templates, keep in mind the assembly process. That is, make sure that your templates can

communicate to each other and can communicate to the test rigs you specify. In Adams/Car,

communicators define how models communicate.

Template Updates

The 2005 Driving Machine employs vehicle controllers developed by MSC.Software, commonly known

as Machine Control, which replaces DriverLite functionality, and Adams/SmartDriver. You must update

Adams/Car 2003 powertrain and body templates to make the compatible with the enhanced Driving

Machine in MD Adams/Car.

To better control speed and path, the 2005 Driving Machine needs additional information about the

vehicle. In particular, the speed controller uses a feed-forward function to ensure quick and accurate

response. However, this requires information about the available engine brake torque, engine drive

torque, brake torque, and aerodynamic drag. You supply this information by creating new output

communicators in your templates powertrain and body/aerodynamic templates. In addition, you must

also enter vehicle parameter data, such as overall steering ratio that is stored in the assembly file.

Powertrain Template Update

You should update powertrain templates by creating new output communicators to match the following

input communicators in the testrig used by the Driving Machine:

testrig.cis_max_engine_driving_torque

testrig.cis_max_engine_braking_torque

testrig.cis_engine_speed

testrig.cis_engine_map

Maximum engine driving and braking torques

For closed-loop machine control, the maximum engine driving and braking torques must be

communicated to the Driving Machine. The machine control uses these values in its feed forward

computations when determining the needed throttle and brake inputs to achieve a target longitudinal

acceleration. The Driving Machine expects powertrain templates to provide these torques as Solver

Variables. The torques should depend on the engine speed. You must add two output communicators toyour powertrain template and the corresponding entities that are output. The entities are data element

solver variables that compute the maximum driving and maximum braking torques the powertrain

subsystem produces at the current engine speed. Note that without this information machine control of

the vehicle speed and/or longitudinal acceleration will be unreliable.

In the powertrain.tpl and .powertrain_lt.tpl template files distributed in the shared car database, there are

Adams/Solver VARIABLEs with functions computing the maximum powertrain torque (fully open

throttle) and maximum powertrain brake torque (closed throttle):

AKISPL(MAX(0,VARVAL(engine_speed)/ucf_angle_to_radians),1,gss_engine_torque)


4/72

Adams/Car

136

AKISPL(MAX(0,VARVAL(engine_speed)/ucf_angle_to_radians),0,gss_engine_torque)

These functions interpolate the 3D engine map spline at the current engine speed for at full throttle (maxengine driving torque) and closed (0) throttle position (max engine braking torque).

The output communicators you create to output these Adams/Solver VARIABLE are:

Name: engine_driving_torque

Matching Name: engine_maximum_driving_torque

Entity Type: solver_variable

Minor Role: inherit

Entity: engine_driving_torque

Name: engine_braking_torque

Matching Name: engine_maximum_braking_torque


Minor Role: inherit

Entity: engine_braking_torque

Engine Map

If your powertrain contains an engine map spline (torque vs. engine speed and throttle position), you can

output the spline to the Driving Machine via an output communicator to achieve better control of speed

and longitudinal acceleration. However, the engine map is optional. Define the engine_map output

communicator as:

Name: engine_map

Matching Name: engine_map

Entity Type: spline

Minor Role: inherit

Entity: gss_engine_torque

In the templates powertrain.tpl and powertrain_lt.tpl distributed in the shared car database, the

engine_map output communicators reference the gss_engine_torque spline entity. In your own templates,

choose the appropriate spline.

The engine speed is a solver variable outputting the engine speed in radians/s.

Engine speed

In the case of a closed-loop controller on the vehicle forward velocity, you must define an output

communicator in your powertrain template, as follows:

Name: engine_speed

Matching Name: engine_speed


5/72



Minor Role: inherit

Entity: engine_speed

The solver variable, engine_speed, represents the engine rotational velocity expressed in angular/time

units [rad/second]. In the powertrain template distributed in the shared car database , engine_speed is

defined as MAX(0,DIF(._powertrain.engine_omega)).

The __mdi_sdi_testrig references the output communicator you define and SmartDriver uses that

communicator in the smart_driver_controller_inputs_array. The SmartDriver controller input array

references various entities used to sense certain vehicle states. Adding the engine_speed communicatorenables the longitudinal controller so you can perform a constant-speed maneuver or any other type of

closed-loop machine control.

Aero Drag Force

If your vehicle model includes aerodynamic forces, then the drag force affects the longitudinal dynamics

of the vehicle. The feed-forward speed controller can account for the drag force when predicting the

throttle position needed to follow velocity or acceleration profile, if you create an output communicator

that passes the aerodynamic drag force to the __mdi_sdi_testrig. If your vehicle model does not include

aerodynamic forces, then you do not need to create an output communicator for the drag force.

The chassis template delivered in the shared car database, for example, has an aerodynamic force

modeled using a GFORCE. The GFORCEs drag (longitudinal) force component is measured in a solver

VARIABLE named aero_drag_force with this function expression:

GFORCE(aero_forces,0,4,aero_drag_reference_marker)

Then, the aerodynamic drag is output to the __mdi_sdi_testrig using output communicator of type solvervariable:

Name: aero_drag_force

Matching Name: aero_drag_force


Minor Role: inherit

Entity: aero_drag_force

Other Vehicle Parameters

Some sets of quantities that are used by the Adams/SmartDriver lateral and longitudinal controllers

cannot be easily inferred from the vehicle model. These quantities are defined in the test rig as parameter

variables and are easily accessible. To modify vehicle parameters, display the Set Full-Vehicle

Parameters dialog. From the Simulate menu, point to Full Vehicle Analysis, and then select Set Full-

Vehicle Parameters.

In the resulting dialog box, you can set the following ratios that affect the lateral dynamics of the vehicle,

providing Adams/SmartDriver information about the characteristics of the steering system. Bad values


6/72

Adams/Car

138

almost certainly guarantee solver failure in closed-loop events or, if successful, the vehicle will most

certainly be off course.

Steering Ratio - Dimensionless ratio between the steering wheel angle and the road wheelangle. You can obtain this value by running a steering analysis on the front suspension and

steering assembly.

Steering Rack Ratio - Ratio (angle/length) between the steering hand wheel and the rack

displacement expressed in S.I. units. This parameter influences the response of the controller

only when driving by force/displacement.

The following parameters help Adams/SmartDriver in predicting and calculating the brake signal:

Max. Front/Rear Brake Torque - Maximum torque, expressed in model units, representing the

torque generated for each front/rear brake in condition of maximum brake demand, also

expressed in model units.

Brake Bias - Front to rear dimensionless ratio. It can be computed as max_front_brake_torque /

(max_front_brake_torque + max_rear_brake_torque).

These parameters are saved to the assembly file, as well as to the test rig in session.

Creating Topology for Your Templates

Topology in Adams/Car consists of creating elements, such as hardpoints, parts, attachments, and

parameters that define subsystems, as explained next:

Creating hardpoints - You first create hardpoints. Hardpoints are the Adams/Car elements that

define all key locations in your model. They are the most elementary building blocks that you

can use to parameterize locations and orientations for higher-level entities. Hardpoint locationsdefine most parts and attachments. Hardpoints are only defined by their coordinate locations.

Creating parts - Once youve defined hardpoints, you create parts and define them using the

hardpoints that you created. In this tutorial, you create two types of parts: general parts, such as

control arm and wheel carrier, and mount parts.

Creating attachments - Finally, you create the attachments, such as joints and bushings, and

parameters which tell Adams/Car how the parts react in relation to one another. You can define

attachments for the compliant and kinematic analysis modes. The compliant mode usesbushings, while the kinematic mode uses joints.

Before you begin to build a template, you must decide what elements are most appropriate for your

model. You must also decide which geometries seem most applicable to each part or whether you want

any geometry at all. Once youve decided, you create a template and create the basic topology for it.


7/72


Working with Communicators

You use communicators to exchange of information between subsystems, templates, and the test rig inyour assembly.

This topic includes information for Adams/Car communicators. For general information on

communicators, see the Build tab.

Learn more about working with communicators in Adams/Car:

Communicators in the Suspension Test Rig

Communicators in the SDI Test Rig

Matching Communicators with Test Rigs


The following tables describe the input and output communicators in the suspension test rig

(.__MDI_SUSPENSION_TESTRIG). In the tables, the notation:

[lr] indicates that there is both a left and right communicator of the specified name, as in

ci[lr]_camber_angle.

s indicates a single communicator, as in cis_steering_rack_joint.


The communicator:Belongs to the

class:

Fromminorrole: Receives:

ci[lr]_camber_angle parameter_real any Camber angle value from the suspension

subsystem. Sets the correct orientation of

the test rig wheels.

ci[lr]_diff_tripot location any Location of the differential.

ci[lr]_toe_angle parameter_real any Toe angle value from the suspension

subsystem. Sets the correct orientation ofthe test rig wheels.

ci[lr]_suspension_mount mount any Part to which the test rig wheels can attach.

ci[lr]_suspension_upright mount any Upright part from suspension subsystem.

ci[lr]_jack_frame mount any Not matched (fixed to ground).

ci[lr]_wheel_center location any Location of the wheel center from the

suspension subsystem. Test rig wheelsattach to the suspension at that location.


8/72

Adams/Car

140

Output Communicators in Suspension Test Rig

Communicators in the SDI Test Rig

The following tables describe the input and output communicators in the SDI test rig

(.__MDI_SDI_TESTRIG). In the tables, the notation [lr] indicates that there is both a left and rightcommunicator of the specified name.

Input Communicators in SDI Test Rig

cis_driveline_active parameter_integer any Integer value stored in the suspension

template/subsystem that indicates the

activity of the drivetrain.

cis_powertrain_to_body mount any Part to which differential outputs are

constrained.

cis_leaf_adjustment_steps parameter_integer any Integer value stored in the leaf spring

template (currently not available).cis_steering_rack_joint joint_for_motion any Steering-rack translational joint from the

steering subsystem.

cis_steering_wheel_joint joint_for_motion any Steering-wheel revolute joint from the

steering subsystem.

cis_suspension_parameters_ARRAY array any Array used in the suspension characteristic

calculations; comes from the suspension

subsystems.


class:


The communicator:Belongs tothe class:

Fromminorrole: Outputs:

cos_leaf_adjustment_multiplier array any Leaf Spring toolkit. It is currently not supported inthe standard product.

cos_characteristics_input_ARRAY array any Suspension, vehicle, and test-rig parameters array

IDs used by suspension characteristics

calculations routines.

co[l,r]_tripot_to_differential mount any Outputs the ge[lr]_diff_output parts.

cos_tire_forces_array_left array any Outputs array of Adams IDs used by the

conceptual suspension module.

cos_tire_forces_array_right array any Outputs array of Adams IDs used by the

conceptual suspension module.


9/72



class:

From

minorrole: Receives:

cis_body_subsystem mount inherit Output from the body subsystem. It indicates

the part that represents the body.

cis_chassis_path_reference marker any Marker from the body subsystem. It is used to

measure path, roll, and sideslip error in a

constant radius cornering maneuver.

cis_driver_reference marker any Marker from the body subsystem. It is used inAdams/Driver simulations.

cis_engine_rpm solver_variable any Adams/Solver variable for engine revolute

speed, in rotations per minute, from the

powertrain subsystem.

cis_engine_speed solver_variable any Adams/Solver variable for engine revolute

speed, in radians per second, from the

powertrain subsystem.cis_measure_for_distance marker any Marker used to measure the distance traveled

in the forward direction of the vehicle, from

the body subsystem.

cis_diff_ratio parameter_real any Real parameter variable for final drive ratio,

from the powertrain subsystem.

cis_steering_rack_joint joint_for_motion front Steering-rack translational joint from the

steering subsystem.cis_steering_wheel_joint joint_for_motion front Steering-wheel revolute joint from the

steering subsystem.

cis_max_brake_value parameter_real any Output from brake subsystem (maximum

brake signal value).

cis_max_engine_speed parameter_real any Output from powertrain subsystem (maximum

engine rpm value).

cis_max_gears parameter_intege

r

any Output from powertrain (maximum number of

allowed gears).

cis_max_rack_displacement parameter_real any Output displacement limits from steering

subsystem. Used by the Standard Driver

Interface.

cis_max_rack_force parameter_real any Output force limits from steering subsystem.

Used by the Standard Driver Interface.

cis_max_steering_angle parameter_real any Output angle limits from steering subsystem.

Used by the Standard Driver Interface.


10/72

Adams/Car

142

Output Communicators in SDI Test Rig

cis_max_steering_torque parameter_real any Output from steering subsystem.

cis_max_throttle parameter_real any Output from powertrain (maximum value of

throttle signal).

cis_min_engine_speed parameter_real any Output from powertrain subsystem (minimum

engine rpm value, used for shifting strategy).

cis_rotation_diff diff any Output from powertrain (it is a differential

equation used to measure crankshaftacceleration; its integral is used for engine

rpm).

cis_transmission_spline spline any Spline for transmission gears (output from

powertrain: reduction ratios for every gear).

cis_transmission_input_omega solver_variable any The transmission input engine variable from

the powertrain template.

cis_clutch_diff diff any Clutch slip differential equation from thepowertrain template.

cis_clutch_displacement_ic solver_variable any The clutch initial displacement (engine

crankshaft torque at static equilibrium) from

the powertrain template.

ci[lr]_front_suspension_mount mount front The hub parts (wheel carriers) from

suspension templates (front and rear)

ci[lr]_rear_suspension_mount mount rear The hub parts (wheel carriers) fromsuspension templates (front and rear)


class:



class:

Fromminorrole: Outputs:

cos_brake_demand solver_variable any Brake demand to the brake subsystem.

cos_clutch_demand solver_variable any Clutch demand to the powertrain subsystem.

cos_desired_velocity solver_variable any Desired velocity Adams/Solver variable. Other

subsystems can reference it.

cos_initial_engine_rpm parameter_real any Initial engine RPM real variable to the powertrain

subsystem.cos_throttle_demand solver_variable any Throttle demand to the powertrain subsystem.


11/72


Matching Communicators with Test Rigs

When you create a template, you must meet the following conditions to ensure that an analysis will work

with your new template:

The template must be compatible with other templates and with the test rigs, for example, the.__MDI_SUSPENSION_TESTRIG. The template must also contain the proper output

communicators.

If the template is a suspension template (for example, its major role is suspension), the template

must contain a suspension parameters array. The suspension parameters array identifies to the

suspension analysis how the steer axis should be calculated and whether the suspension is

independent or dependent.

For example, for a suspension template to be compatible with the suspension test rig, the suspensiontemplate must contain either the mount or the upright output communicators. In the following table, the

notation [lr] indicates that there is both a left and right communicator of the specified name.

Output Communicators in Suspension Templates

The co[lr]_suspension_mount output communicators publish the parts to which the test rig wheelsshould mount. As you create these communicators, ensure that you set their minor role to inherit. By

setting the minor role to inherit, the communicator takes its minor role from the minor role of the

subsystems that use your suspension template.

cos_transmission_demand solver_variable any Transmission (gear) demand to the powertrain

subsystem.

cos_sse_diff1 diff any Differential equation computed during quasi-

static prephase, used to control the vehicle

longitudinal dynamics.

cos_std_tire_ref location any X,Y,Z location of standard tire reference marker

(positioned appropriately at the correct height,including 2% of road penetration).

The communicator:

Belongs to the

class:

Fromminor

role: Outputs:

The communicator: Belongs to the class: From minor role: Receives:

co[lr]_suspension_mount mount inherit suspension_mount

co[lr]_suspension_upright mount inherit suspension_upright

co[lr]_wheel_center location inherit wheel_center

co[lr]_toe_angle parameter_real inherit toe_angle

co[lr]_camber_angle parameter_real inherit camber_angle

Ad /C144


12/72

Adams/Car

144

The co[lr]_wheel_center output communicators publish the location of the wheel centers to the test rig

so the test rig can locate itself relative to the suspension. As you create these types of communicators,

make sure that you also leave their minor role set to inherit.

The toe and camber communicators (co[lr]_toe_angle and co[lr]_camber_angle) publish, to the test rig,

the toe and camber angles set in the suspension so the test rig can orient the wheels correctly.

145


13/72


Templates

Conceptual Steering System

Overview

Using conceptual templates, Adams/Car allows you to study system-level vehicle dynamics without

having to create detailed multibody suspension models.

Figure 1 Conceptual Steering System

Template name

_concept_steering

Major role

Steering

Application

Suspension and full-vehicle analyses with the conceptual suspension system template.

Adams/Car146


14/72

Adams/Car

146

Description

The conceptual steering system is a very simple model of steering that communicates the steering-wheel

revolute joint to the conceptual suspension system. The conceptual suspension system uses the rotationof the joint i and j markers as a measure of the steering input.

Topology

The conceptual steering system template consists of a steering wheel and column rotating through a

revolute joint. The revolute joint connects the rigid bodies to a mount part.

CommunicatorsMount parts provide the connectivity from the template to the body subsystems. Output communicators

publish steering limits for displacement, angle, and force, and torque information.

The following table lists the communicators in the template.

Conceptual Suspension System

Overview

Using conceptual templates, Adams/Car allows you to study system-level vehicle dynamics without

having to create detailed multibody suspension models. You can use the conceptual suspension system

to define the wheel movements with respect to the body using a collection of characteristic curves or

dependencies.

The communicator: Belongs to the class: Has the role:

cos_max_steering_angle parameter_real inherit

cos_max_steering_torque parameter_real inherit

cos_steering_wheel_joint joint_for_motion inherit

cis_steering_column_to_ body mount inherit

147


15/72


Figure 2 Conceptual Suspension System

Template name

_concept_suspension

Major role

Suspension

Application

Suspension or full-vehicle analyses. You can mix and match conceptual suspensions in a full-vehicle

assembly with multibody suspension models.

Default files referenced

References the file dwb_front.scf, stored in the suspension_curves.tbl directory in the Adams/Car shared

database. The suspension characteristic file defines kinematic relations or dependencies between

suspension characteristic angles, suspension track, and base and the vertical wheel and steer travel.

Topology

The topology of the template is very simple, and you do not need to modify it in the Template Builder.

Adams/Car148


16/72

Three curve-to-curve constraints drive each wheel carrier along a predefined trajectory. A user-written

curve subroutine calculates the trajectory depending on the inputs to the system, such as the forces and

torques coming from the tire subsystem and the amount of wheel and steer travel.

A conceptual suspension will have four degrees of freedom. A conceptual vehicle, therefore, will have

14 degrees of freedom. The following table lists the model topology for the left side of the template. The

right side entities are connected in a similar way.

Parameters

The toe and camber parameter values define the wheel spin axis, and the unsprung mass parameter

variable defines the wheel carrier part mass. Finally, 68 hidden variables define the dependency flagsarray, with each of parameters setting the status (active or inactive) of a dependency.

Communicators

Mount parts provide connectivity from the template to the body subsystems and differential. Input

communicators receive information about the tire forces, the steer axis, and the steering-wheel joint.

Output communicators publish toe, camber, steer axis, and wheel center location information.


The joint: Connects the part: To the part:

left_ptcv_O (point-to-curve) wheel_carrier_left mts_body

left_ptcv_X (point-to-curve) dummy_left_X mts_body

jolrev_spindle_upright hub_left wheel_carrier_left

joltra_tripot_to_differential gel_tripot mtl_tripot_to_differential

jolcon_drive_sft_int_jt gel_tripot gel_drive_shaft

jolcon_drive_sft_otr gel_drive_shaft hub_left

jolinp_dummy_wheelplane_y dummy_left_X wheel_carrier_left

jolinp_dummy_wheelplane_z dummy_left_X wheel_carrier_left

jolori_dummy_wheelplane_ori dummy_left_X wheel_carrier_left

josfix_subframe_to_body ges_subframe mts_body


ci[lr]_ARB_pickup location inherit

ci[lr]_tripot_to_differential mount inherit

cis_body mount inheritcis_characteristics_input_ARRAY array inherit

cis_steering_wheel_joint joint_for_motion inherit

149


17/72


Disc-Brake System

Overview

The disc-brake system template represents a device that applies resistance to the motion of a vehicle.

cis_tire_forces_array_left array inherit

cis_tire_forces_array_right array inherit

co[lr]_camber_angle parameter_real inherit

co[lr]_suspension_mount mount inherit

co[lr]_suspension_upright mount inherit

co[lr]_toe_angle parameter_real inherit

co[lr]_tripot_to_differential location inherit

co[lr]_wheel_center location inherit

cos_driveline_active parameter_integer inherit

cos_engine_to_subframe mount inherit

cos_suspension_parameters_ARRAY array inherit


Notes: Spring and damper entities in the conceptual suspension template consist of a special user-

defined element. A user-written subroutine computes the forces. The subroutine takes into

account the nonlinear spring/damper characteristics and the stabilizer bar forces

You must use the conceptual suspension system template with the Conceptual Steering

System.

Adams/Car150


18/72

Figure 3 Disc-Brake System

Template name

_brake_system_4Wdisk

Major role

Brake.

Application

Full-vehicle analysis to simulate the effect of braking on the dynamics of the vehicle.

DescriptionThe disc-brake system template represents a simple model of a brake system. It applies a rotational torque

between the caliper and the rotor.

Files referenced

None.

Topology

The caliper part is mounted to the suspension upright, while the rotor is mounted to the wheel. A

rotational SFORCE is applied between the two parts.

151W ki ith T l t


19/72


Parameters

The toe and camber values that the suspension subsystem publishes define the spin axis orientation. In

addition, the braking torque is expressed as a function of a number of parameters.

The following table lists the parameters in the template.

Limitations

The disc-brake template is a simple model of a brake system. It does not model the complex interaction

between the rotor and caliper.

Communicators

Mount parts provide the connectivity between the template and suspension subsystems. Inputcommunicators receive information about the toe and camber suspension orientation and the wheel-

center location. Input to the brake system is brake demand.


The parameter: Takes the value: Its units are:

front_brake_bias Real No units

front_brake_mu Real No units

front_effective_piston_radius Real mm

front_piston_area Real mm2

front_rotor_hub_wheel_offset Real mm

front_rotor_hub_width Real mm

front_rotor_width Real mm

max_brake_value Real No units

rear_brake_mu Real No units

rear_effective_piston_radius Real mm

rear_piston_area Real mm2

rear_rotor_hub_wheel_offset Real mm

rear_rotor_hub_width Real mm

rear_rotor_width Real mm

Adams/Car152


20/72


ci[lr]_front_camber_angle parameter_real front

ci[lr]_front_rotor_to_wheel mount front

ci[lr]_front_toe_angle parameter_real front

ci[lr]_front_wheel_center location front

ci[lr]_front_suspension_ upright mount front

ci[lr]_rear_rotor_ro_wheel mount rear

ci[lr]_rear_suspension_ upright mount rear

ci[lr]_rear_toe_angle parameter_real rear

ci[lr]_rear_camber_angle parameter_real rear

ci[lr]_rear_wheel_center location rear

cis_brake_demand solver_variable any

cos_max_brake_value parameter_real inherit

Notes: The torque on the rotor depends on a number of parameters. The front right torque function

is:

T = 2 x PistonArea x BrakeLinePressure x x EffectivePistonRadius x STEP

where:

BrakeLinePressure is calculated as follows:BrakeLinePressure = BrakeBias * BrakeDemand * 0.1

where:

BrakeBias defines the front and rear proportioning of the brake line pressure.

Note that although the term is constant, in reality, simple hydraulic systems

allow dynamic front and rear proportioning of the brake pressure depending on

a number of factors, including longitudinal slip angle of the tires and dynamic

load transfer.

BrakeDemand is the force on the pedal (N) as it is output from the analysis.

0.1 is a conversion factor that converts into pressure the force applied on the

pedal.

STEP is the function of the rotation of the rotor to wheel and suspension upright

markers. The function prevents backward spinning of the wheels. STEP is a

simple function that measures the WZ rotation of the marker on the rotor with

respect to the marker on the upright and reverses the sign of the applied torque

if the wheel is spinning backward.



21/72


Double-Wishbone Suspension

Overview

A double-wishbone suspension is one of the most common suspension designs. It uses two lateral control

arms to hold the wheel carrier and control its movements.

Figure 4 Double-Wishbone Suspension

Template name

_double_wishbone

Major role

Suspension

Application

Suspension and full-vehicle assemblies

Adams/Car

154


22/72

Description

The double-wishbone template represents the most common design for doublewishbone suspensions.

You can use the template as a front steerable suspension or as a rear non-steerable suspension.You can set subsystems based on this template to kinematic or compliant mode. In kinematic mode,

Adams/Car replaces the bushings that connect the control arms to the body mount part with a

corresponding purely kinematic constraint. Adams/Car also does this for the top mount and lower strut

mount.

You can deactivate the subframe part, as well as the halfshafts. A spring acts between the upper mount

part and the lower strut. A bumpstop acts between the upper and lower strut parts.

Files referenced

Bushings, springs, dampers, and bumpstops property files

Topology

The lower wishbone connects to a subframe or to the mount if you've deactivated the subframe. The

upper wishbone connects to the body mount part. A spherical joint constrains the upright part to the upper

and lower arms.

A spherical joint also connects the tie rods to the uprights. Tie rods attach to mount parts through convel

joints. Convel joints also connect the tripots to the drive shafts. A static rotation control actuator locks

the rotational degree of freedom of the hub during quasi-static analyses.


jklrev_lca gel_lower_control_arm ges_subframe

jolsph_lca_balljoint gel_upright gel_lower_control_arm

jolsph_tierod_outer gel_tierod gel_upright

jolcon_tierod_inner gel_tierod mtl_tierod_to_steering

josfix_subframe_rigid ges_subframe mts_subframe_to_body

jklhoo_top_mount_kinematic gel_upper_strut mtl_strut_to_body

jolsph_uca_balljoint gel_upper_control_arm gel_upright

jolcyl_lwr_upr_strut gel_lower_strut gel_upper_strut

jklrev_uca gel_upper_control_arm mtl_uca_to_body

jklhoo_lwr_strut_kinematic gel_lower_strut gel_lower_control_arm



jolcon_drive_sft_otr gel_drive_shaft gel_spindle



23/72

g p

Parameters

Toe and camber variables define wheel spin axis, spindle part, and spindle geometry. The following table

lists the parameters in the template.

Communicators

Mount parts provide connectivity from the template to body subsystems and the differential. Output

communicators publish toe, camber, steer axis, and wheel-center location information to the appropriatesubsystems and the test rig. The following table lists the input and output communicators.


phs_driveline_active Integer No units

phs_kinematic_flag Integer No units

pvs_subframe_active Integer No units

pv[lr]_toe_angle Real Degrees

pv[lr]_camber_angle Real Degrees

pv[lr]_drive_shaft_offset Real mm



ci[lr]_strut_to_body mount inherit

ci[lr]_tierod_to_steering mount inherit


ci[lr]_uca_to_body mount inherit

cis_subframe_to_body mount inherit

co[lr]_arb_bushing_mount mount inherit


co[lr]_droplink_to_ suspension mount inherit







Adams/Car

156


24/72

Flexible LCA Double-Wishbone Suspension

Overview

The flexible LCA double-wishbone suspension template is similar to the standard Double-Wishbone

Suspension. In the flexible template, however, a flexible representation replaces the rigid body lower

control arms.

Figure 5 Flexible LCA Double-Wishbone Suspension

cos_engine_to_subframe mount inherit

cos_rack_housing_to_suspension_subframe mount inherit



Note: The integer parameter variables allow you to activate and deactivate the subframe part and

the driveshafts. The kinematic flag variable toggles between kinematic and compliant

mode.



25/72

Template name

_double_wishbone_flex

Major role

Suspension

Application


Description

Flexible bodies replace the left and right rigid lower control arms.

MNF files referenced

LCA_left_shl.mnf and LCA_right_shl.mnf. In addition, because of the way the node IDs are numbered,

you can swap the default modal neutral files with LCA_left_tra.mnf and LCA_right_tra.mnf.

Topology

In addition to the general topology described for the Double-Wishbone Suspension, this template uses

interface parts to connect the flexible bodies to the rest of the suspension. Node IDs define the location

of interface parts.

Parameters

Refer to the Double-Wishbone Suspension.

Communicators

Refer to the Double-Wishbone Suspension.

ISO Road Course

Overview

The ISO road course template represents a closed circuit with an ISO lane-change section.

Adams/Car

158


26/72

Figure 6 ISO Road Course

Template name

_ISO_road_course

Major role

Environment

Application

With the optional Adams/Driver module

Description

The ISO road course template consists of shell elements and frustums, and represents a closed circuit

with an ISO lane-change section.

Files referenced

Geometry elements (shells) reference shell files stored in the Adams/Car shared database in the

shell_graphics.tbl directory. The shell files are Iso_road_inr.shl, Iso_road_otr.shl, and Iso_road_c.shl.

Topology

All the graphic elements are created on the ground part.



27/72

Parameters

Contains no parametric information.

Communicators

Contains no communicators.

MacPherson Suspension

Overview

The MacPherson suspension design in this template is similar to the SLA geometry, and is probably the

most often used suspension for passenger cars in the world. It uses a telescopic strut incorporating a

damper element. The upper end is fixed to the body and the lower end is located by linkages. The

MacPherson design provides advantages in packaging, and it is generally used for front-wheel-drive

cars.

Note: The corresponding Adams/Driver representation of this course is available as a trace on the

x-y plane and lane width in the driver_roads.tbl directory. The file is called

ISO_road_course.drd. You can use the file to run full-vehicle analyses with Adams/Driver.Including the ISO road course template in your full-vehicle assembly adds a graphical

representation of the circuit.

Adams/Car

160


28/72

Figure 7 MacPherson Suspension

Template name

_macpherson

Major role

Suspension

Application


Description

The MacPherson suspension template represents the most common design for MacPherson suspensions.

You can use the template as a front steerable suspension or as a rear non-steerable suspension.

You can set the subsystems based on this template to kinematic or compliant mode. In kinematic mode,

Adams/Car replaces the bushings with the corresponding kinematic constraints. The bushings connect

the control arm and the damper strut to the body mount parts. You can also activate or deactivatedriveshafts.



29/72

A spring acts between the upper strut part and the lower strut. Bumpstops and reboundstops are also

present.

Files referenced

Bushings, springs, dampers, bumpstops, and reboundstops property files

Topology

The MacPherson suspension template represents a standard design employing a one-piece lower control

arm (also known as A-arm) and a subframe. The upright to which the wheel mounts is located by the

lower control arm, the tie rod, and the strut. The lower control arm regulates the fore-aft and lateralmotions of the upright. The tie rod controls steering rotation of the upright, and the strut controls the

vertical motion of the upright and the side and front view rotations, as well. A static rotation control

actuator locks the rotational degree of freedom of the hub during quasi-static analyses.

The following table lists the topological information of the left side of the MacPherson suspension.

Parameters

Toe and camber variables in the template define the wheel spin axis, spindle part, and spindle geometry.

The following table lists the parameters in the templates.


jklrev_lca gel_lower_control_arm ges_subframe

jolsph_lca_balljoint gel_upright gel_lower_control_arm

jolcyl_strut gel_upright gel_upper_strut

jolsph_tierod_outer gel_tierod gel_upright

jolcon_tierod_inner gel_tierod mtl_tierod_to_steering

jksfix_subframe_rigid ges_subframe mts_subframe_to_body

jklhoo_top_mount_kinematic gel_upper_strut mtl_strut_to_body




jolrev_spindle_upright gel_spindle gel_upright




Adams/Car

162


30/72

Communicators

Mount parts provide the connectivity from the template to the body subsystems and differential. Output

communicators publish toe, camber, steer axis, and wheel-center location information to the appropriate

subsystems and test rig. The following table lists the input and output communicators in the template.






ci[lr]_strut_to_body mount inherit

ci[lr]_tierod_to_steering mount inherit

ci[lr]_tripot_to_differential mount inheritcis_subframe_to_body mount inherit

co[lr]_arb_bushing_mount mount inherit


co[lr]_droplink_to_ suspension mount inherit


co[lr]_suspension_upright mount inheritco[lr]_toe_angle parameter_real inherit




cos_rack_housing_to_ suspension_subframe mount inherit



Note: The integer parameter variables let you activate and deactivate the driveshafts. The

kinematic flag variable toggles between kinematic and compliant mode replacing the joints

with the corresponding elastic elements. For example, Adams/Car replaces the revolute

joints that connect the lower control arms to the subframe with bushings



31/72

Multi-Link Suspension

OverviewThe multi-link suspension represents an independent suspension model for use as a rear suspension.

Figure 8 Multi-Link Suspension

Template name

_multi_link

Major role

Suspension

Application


Description

The multi-link suspension template represents a common rear independent suspension design. It includes

a subframe (represented by the outline graphics) that is connected to the upper arm, to the lateral links,

and to the track rod. The suspension is nonsteerable and intended to be used as a rear suspension only.

Adams/Car

164


32/72

Files referenced

Springs, dampers, and bushings property files

Topology

Spherical joints, which are active in kinematic mode, connect the uprights to links. Bushings connect the

trailing links to the mount parts. Springs and dampers act between the trailing links and the body. A static

rotation control actuator locks the rotational degree of freedom of the hub during quasi-static analyses.

The following table provides a topological map of the template.

Parameters

Toe and camber variables in the template define the wheel spin axis, spindle part, and spindle geometry.

The following table lists the parameters in the templates.


jklsph_hub_tl gel_Upright gel_Trailing_Link

jklhoo_trailing_link_body gel_Trailing_Link mtl_trailing_link_body

jklrev_ula_sbf gel_upper ges_Subframe

joltra_dpr_upr_dpr_lwr gel_Damper_Upper gel_Damper_Lower

jklsph_dpr_lwr_tl gel_Damper_Lower gel_Trailing_Link

jklhoo_dpr_spring_seat_upper gel_Damper_Upper mtl_Spring_Seat_Upper

jksfix_sbf_body ges_Subframe mtl_body_sbf_front

jklsph_hub_ll gel_Upright gel_lateral

jklsph_hub_tr gel_Upright gel_Track_Rod

jklhoo_sbf_ll ges_Subframe gel_lateral

jklhoo_sbf_tr ges_Subframe gel_Track_Rod

jklsph_hub_ula gel_Upright gel_upper




jolrev_spindle_upright gel_spindle gel_Upright




pvs_subframe_active Integer No units



33/72

Communicators


Parallel-Link Steering System

Overview

The parallel-link steering system template is essentially a four-bar mechanism consisting of a pitman

arm, center link, and idler arm.


pv[lr]_camber_angle Real mm



ci[lr]_body_sbf_front mount inherit

ci[lr]_body_sbf_rear mount inherit

ci[lr]_Spring_Seat_Upper mount inherit

ci[lr]_trailing_link_body mount inherit








cos_suspension_ parameters_ARRAY array inherit


Note: The integer parameter variables let you activate and deactivate the subframe part and the

driveshafts. The kinematic flag variable toggles between kinematic and compliant mode.

Adams/Car

166


34/72

Figure 9 Parallel-Link Steering

Template name

_parallel_link_steering

Major role

Steering

Application


DescriptionA recirculating ball steering gear transmits motion from the steering wheel to the pitman arm. The pitman

arm rotates to impart motion to the center link and idler arm. The translation of the center link pulls and

pushes the tie rods to steer the wheels.

Files referenced

Steering assist and torsion bar deflection property file. The default property file is mdi_steer_assis.ste,

stored in the steer_assist.tbl directory of the shared Adams/Car database.



35/72

Topology

The recirculating ball steering gear consists of three major parts:

Ball screw

Rack

Sector

The steering wheel rotates the steering input shaft. A torsion bar attaches the steering input shaft to a ball

screw. The ball screw imparts translational motion to the steering gear through a coupler. The steering

gear, in turns, rotates the sector through a coupler, which is connected directly to the pitman arm shaft.

The following table maps the topology of the template.


joshoo_column_intermediate ges_steering_column ges_intermediate_shaft

joshoo_intermediate_shaftinput ges_intermediate_shaft ges_input_shaft

josrev_steering_wheel ges_steering_wheel ges_column_housing

joscyl_steering_column ges_steering_column ges_column_housing

josfix_column_housing_to_housing_

mount

ges_column_housing mts_steering_column_to_body

jolsph_centerlink_arm ges_center_link gel_arm

jolrev_pitman_arm_steering_gear gel_arm swl_steering_gear_mount

josrev_ball_screw_steering_gear ges_ball_screw swl_steering_gear_mount

josrev_input_shaft_steering_gear ges_input_shaft swl_steering_gear_mount

jostra_rack_steering_gear ges_rack swl_steering_gear_mount

josfix_steering_gear_housing ges_steering_gear_housing swl_steering_gear_mount

josper_centerlink_pitman_arm ges_center_link gel_arm

vfo_steering_assist ges_rack swl_steering_gear_mount

gksred_ball_screw_input_shaft_lock josrev_ball_screw_steering

_gear

josrev_input_shaft_steering_

gear

grsred_steering_wheel_column_lock josrev_steering_wheel joscyl_steering_column

grsred_ball_screw_rack josrev_ball_screw_steering

_gear

jostra_rack_steering_gear

grsred_pitman_arm_rack jolrev_pitman_arm_steerin

g_gear


Adams/Car

168


36/72

Parameters

A parameter variable switches between kinematic and compliant mode, effectively defining the status of

the ball screw input shaft lock reduction gear.

Communicators


Pitman Arm Steering System

Overview

The pitman arm steering system template is a simple steering system derived from a parallel-link design.

It is commonly used in trucks. It consists of a three-bar mechanism: pitman arm, draglink, and tie rod.


ci[lr]_steering_gear_to_body mount inherit

ci[lr]_steering_gear_to_suspension_subframe mount inherit


co[lr]_tierod_to_steering mount front

cos_steering_rack_joint joint_for_motion inherit


Note: The parallel-link steering template contains general spline elements. The general spline

element gss_torsion_bar spline provides torque as a function of the angular deflection of

the input shaft relative to the ball screw. A switch part is also present. It allows you to

explore two different topological solutions. You can rigidly connect the steering gear to the

body or to the suspension_subframe part.



37/72

Figure 10 Pitman Arm Steering System

Template name

_pitman_arm

Major role

Steering

Application


Description

A recirculating ball steering gear transmits motion from the steering wheel to the pitman arm. The pitmanarm rotates to impart motion to the draglink. The draglink pulls and pushes the tie rod and steers the

wheels.

Files referenced

The point torque actuator references the torsion_bar datablock in the mdi_steering.ste property file,

stored in the Adams/Car shared database, under the steer_assists.tbl table or directory.

Topology

The recirculating ball steering gear consists of three major parts:

Adams/Car

170


38/72

Ball screw

Rack

SectorThe steering wheel rotates the steering input shaft. The steering input shaft attaches to the ball screw

through a torsion bar, currently locked by a coupler. The ball screw imparts translational motion to the

rack, through a coupler. The rack, in turns, rotates the sector through a coupler.

The sector is connected directly to the pitman arm shaft. The pitman arm drags the draglink, which is

directly connected to the right wheel, and pulls the tie rod, connected to the left wheel. Spherical joints

connect the draglink and tie rod.




joshoo_intermediate_shaft_i

nput

ges_intermediate_shaft ges_input_shaft

josrev_steering_wheel ges_steering_wheel ges_column_housing

joscyl_steering_column ges_steering_column ges_column_housing

josfix_column_housing_to_h

ousing_mount

ges_column_housing mts_steering_column_to_body

josrev_pitman_arm_steering

_gear

mts_steering_gear_to_suspension

_subframe

ges_idle_arm

jossph_centerlink_arm ges_idle_arm ges_draglink

josrev_input_shaft_steering_

gear

ges_input_shaft mts_steering_gear_to_suspension

_subframe

josrev_ball_screw_steering_

gear

ges_ball_screw mts_steering_gear_to_suspension

_subframe

jostra_rack_steering_gear ges_rack mts_steering_gear_to_suspension

_subframe

jossph_draglink_to_tierod ges_draglink ges_tierod

grsred_steering_wheel_colu

mn_lock

josrev_steering_wheel joscyl_steering_column

gksred_ball_screw_input_sh

aft_lock

josrev_ball_screw_steering_gear josrev_input_shaft_steering_gear

grsred_pitman_arm_rack josrev_pitman_arm_steering_gea

r


grsred_ball_screw_rack josrev_ball_screw_steering_gear jostra_rack_steering_gear



39/72

Parameters

A parameter variable switches between kinematic and compliant mode, effectively defining the status of

the ball screw input shaft lock reduction gear.

Communicators


Powertrain System

Overview

The Adams/Car shared database includes a powertrain template, powertrain.tpl. The template models an

engine, manual transmission, and a limited-slip differential that may be used for a front engine, front-

wheel-drive vehicle, or a rear engine, rear-wheel-drive vehicle.


ci[lr]_steering_gear_to_suspension_subframe mount inheritcis_steering_column_to_ body mount inherit

cos_tierod_to_steering mount front

cos_draglink_to_steering joint_for_motion inherit


Note: The pitman arm steering system template does not interface with any of the Adams/Car

shared database suspension templates because those suspension templates have tie rods. To

correctly assemble the pitman arm steering to a suspension subsystem, you must remove

the tie rods from the suspension. The draglink and the tie rod have to be mounted to the left

and right upright parts.

Adams/Car

172


40/72

Figure 11 Powertrain

Template name

_powertrain

Major role

Powertrain

Application

Full-vehicle assemblies

Description

The powertrain system template represents an engine, clutch, transmission, and differential:

Engine model - Consists of a single part (ges_engine) representing the total mass and inertia of

the engine block, clutch housing, and transmission. A general spline element

(gss_engine_torque) represents the engine's steady-state torque versus engine speed and throttle

position. Before any analysis, gss_engine_torque is updated by reading the engine torque versus

engine speed and throttle from a powertrain property file. For example,

mdids://acar_shared/powertrains.tbl/V8_240HP_400Nm.pwr.



41/72

To allow for larger integration time steps during simulation, the engine crankshaft is not

included as a part in the templates. Instead of a rotating crankshaft part, a differential equation

(engine_omega) integrates the engine crankshaft's rotational acceleration (Adams/Solver

requires one integration time step for each 60 degrees of part rotation). The engine crankshaft'srotational acceleration is the difference between the engine torque and the clutch torque divided

by the engine rotational inertia.

Clutch model - The clutch torque is modulated by the clutch demand, which ranges in value

from zero (0) to one (1):

A clutch demand of zero means that the driver's foot is off the clutch pedal and the clutch is

closed.

A clutch demand of one means that the driver has pushed the clutch pedal completely to the

floor and the clutch is open.

You can set the values of clutch demand, for which the clutch is completely closed or open,

using the parameter variables pvs_clutch_closed and pvs_clutch_open.

The clutch develops torque only when it is at least partially closed and there is some slip

displacement or slip speed between the engine crankshaft and the transmission input shaft.

When the clutch is closed, it acts like a torsional spring-damper, except that the maximum clutch

torque developed is limited by the clutch capacity, which you can modify (pvs_clutch_capacity).

You also set the clutch's torsional stiffness and damping. When the clutch is partially closed, the

clutch stiffness and damping, as well as the clutch capacity (torque), are scaled by the clutch

demand.

The clutch slip speed is the difference between the engine crankshaft and the transmission input

shaft rotational speeds. When the clutch is closed, the clutch slip displacement is the integral of

the clutch slip speed. When the clutch is open, the clutch slip displacement decays to zero with a

time constant given by pvs_clutch_tau. Transmission model - The transmission model is simple: it applies the gear ratio selected by the

gear demand, and has no rotating inertia. The clutch torque is multiplied by the selected gear

ratio and applied to the differential input shaft. The differential input shaft speed is likewise

multiplied by the same ratio to determine the transmission input shaft speed. You can set the

number of gears and the ratio for each gear:

A gear number of zero (0) represents neutral.

A gear number of minus one (-1) represents reverse.

Differential model - The differential model has rotating left and right output shaft parts that

connect to half-shafts in suspension subsystems. The differential input shaft speed is the average

of the left and right output shaft speeds multiplied by the final drive ratio you enter. Likewise,

the transmission output torque is multiplied by the final drive ratio and then split equally

between the two output shafts. A reaction torque is applied about the longitudinal axis to the

ges_engine part.

The differential model includes a limited slip torque that acts between the left and rightdifferential output shafts. The torque depends on the difference between the output shaft speeds.

The limited slip torque-speed characteristic is read from a property file in the differentials.tbl.

Adams/Car

174

Files referenced


42/72

Files referenced

The file, V12_engine_map.pwr, stored in the powertrains.tbl directory, defines the engine map. The

differential references the MDI_viscous.dif property file, stored in the differentials.tbl directory. The

MDI_viscous.dif property file defines the slip torque-speed relationship as a two-dimensional spline.

Topology

The powertrain template contains very simple topological information because it is a functional

representation of the powertrain. The only general rigid parts, besides the engine body, are the diff

outputs and the revolute joints that connect the rigid bodies to the engine body.

Parameters

The following table lists the powertrain system template parameters.

The parameter: Takes the value: Its units are: Description:

phs_kinematic_flag Integer No units When flag = 1, engine is

rigidly mounted to chassis;

when flag = 0, engine ismounted on bushings. Set

from the Adjust menu.

pvs_clutch_capacity Real Torque Maximum torque clutch can

sustain with zero slip speed.

pvs_clutch_close Real No units Value of clutch demand at

which clutch is fully closed.

Value should be less thanpvs_clutch_open and in the

range of 0 and 1.

pvs_clutch_damping Real Torsional_damping Clutch damping torque per

unit of clutch slip speed.

pvs_clutch_open Real No units Value of clutch demand at

which clutch open.

pvs_clutch_stiffness Real Torsional_stiffness Clutch torque developed perunit of clutch slip.

pvs_clutch_tau Real Time Time constant for clutch slip

decay when clutch is open.

pvs_ems_gain Real No units Proportional gain used in

EMS idle speed control

pvs_ems_max_throttle Real No units Value of throttle demand that

corresponds to the maximumcapability of the EMS system



43/72

Communicators

Mount parts provide the connectivity from the template to the body subsystems. Output communicators

publish information, such as engine RPM and transmission spline. The following tables list the input and

output communicators in the powertrain system template.

Input Communicators

pvs_ems_trottle_off Real No units Value of throttle demand at

which EMS system engagesidle speed control

pvs_engine_idle_speed Real RPM Engine idle speed in RPM.

pvs_engine_inertia Real Inertia Engine rotational inertia.

Must be greater than zero.

pvs_engine_rev_limit Real RPM Maximum engine speed in

RPM.

pvs_final_drive Real No units Differential input shaft

(pinion) to ring gear ratio.

pvs_gear_[1-6] Real No units Transmission input shaft to

output shaft ratio for gears 1

through 6.

pvs_graphics_flag Integer No units 1 = include powertrain

graphics; 0 = do not include

powertrain graphics

pvs_max_gears Integer No units Number of gear ratios in the

transmission.

pvs_max_throttle Real No units Value of throttle demand for

which throttle is fully open

(throttle demand = 0 is

throttle closed).

The communicator: Entity class: From minor role: Matching name:

ci[lr]_diff_tripot location inherit tripot_to_differential

ci[lr]_tire_force force inherit tire_force

cis_clutch_demand solver_variable inherit clutch_demand

cis_engine_to_subframe mount inherit engine_to_subframe

cis_initial_engine_rpm parameter_real any initial_engine_rpm

cis_powertrain_to_body mount inherit powertrain_to_body

The parameter: Takes the value: Its units are: Description:

Adams/Car

176



44/72

Output Communicators

cis_sse_diff1 diff inherit sse_diff1

cis_throttle_demand solver_variable inherit throttle_demandcis_transmission_demand solver_variable inherit transmission_demand

The communicator: Entity class: To minor role: Matching name:

co[lr]_output_torque force inherit output_torque

co[lr]_tripot_to_differential mount inherit tripot_to_differential

cos_clutch_displacement_ic solver_variable inherit clutch_displacement_ic

cos_default_downshift_rpm parameter_real inherit min_engine_speed

cos_default_upshift_rpm parameter_real inherit max-engine_speed

cos_diff_ratio parameter_real inherit diff_ratio

cos_engine_idel_rpm parameter_real inherit engine_idle_rpm

cos_engine_map spline inherit engine_map

cos_engine_max_rpm parameter_real inherit engine_revlimit_rpm

cos_engine_rpm solver_variable inherit engine_rpm

cos_engine_speed parameter_real inherit engine_speed

cos_max_engine_driving_torque solver_variable inherit engine_maximum_driving

_torquecos_max_engine_braking_torqu

e

solver_variable inherit engine_maximum_brakin

g_torque

cos_max_gears parameter_integer inherit max_gears

cos_max_throttle parameter_real inherit max_throttle

cos_powertrain_gse gse inherit powertrain_gse

cos_transmission_input_omega solver_variable inherit transmission_input_omega

cos_transmission_spline spline inherit transmission_spline




45/72

Quad-Link Axle Suspension

Overview

The quad-link axle suspension template is an example of a dependent suspension model. The wheels are

mounted at either end of a rigid beam so the movement of one wheel is transmitted to the opposite wheel

causing them to steer and camber together. Solid beam axle suspensions are commonly used on the front

of heavy trucks, where high-load carrying capacity is required.

Figure 12 Quad-Link Axle Suspension

Template name_quad_link_axle

Note: The engine and clutch portion of the powertrain is implemented as a GSE (general state

equation) element in solver. The gsesub associated with this element is available here.

The solver_variable "analysis_type" indicates whether the analysis is steady-state or

dynamic. When the analysis_type is steady-state the engine torque map and transmission

gear ratios are ignored.

Adams/Car

178

Major role
http://../solver/solver_c_plus.pdfhttp://localhost/var/www/apps/conversion/acar/examples/powertrain/gse977.fhttp://localhost/var/www/apps/conversion/acar/examples/powertrain/gse977.fhttp://../solver/solver_c_plus.pdf


46/72

Suspension

Application


Description

The quad-link axle suspension template represents a common design for solid axles suspensions. You can

use the template as a front steerable suspension or as rear nonsteerable suspension.

You can set subsystems based on this template to kinematic or compliant mode. In kinematic mode,Adams/Car replaces the bushings that connect the lower and upper links to the body mount part with the

corresponding purely kinematic constraints.

Files referenced

Bushing, spring, and damper property files

TopologySpherical joints connect the upper and lower links to the solid axle. The draglink is attached to the bell

crank. The bell crank moves the tie rod, which steers the wheels. Revolute joints connect the uprights to

the solid axle. A joint force actuator locks the hub to the wheel carrier. The following table maps the

topology of the template.


jklhoo_lower_link_frame gel_lower_link mtl_lower_link_frame

jklhoo_upper_link_frame gel_upper_link mtl_lower_link_frame

jklsph_upper_link_axle gel_upper_link ges_axle

jklsph_lower_link_axle gel_lower_link ges_axle

jolrev_knuckle_axle gel_knuckle ges_axle

josrev_bell_crank_axle ges_bell_crank ges_axle

jossph_draglink_pitman_arm ges_draglink mts_draglink_steering

joshoo_draglink_bell_crank ges_draglink ges_bell_crank

jossph_tierod_knuckle ges_tierod gel_knuckle

jolrev_bearing gel_hub gel_knuckle

josinp_tie_rod_bell_crank ges_tierod ges_bell_crank


Parameters


47/72

Parameters

Toe and camber variables define wheel spin axis, spindle part, and spindle geometry. The following table

lists the parameters in the template.

Communicators

Mount parts provide the connectivity from the template to body subsystems and steering. Output

communicators publish toe, camber, steer axis, and wheel center location information to the appropriate

subsystems and the test rig. The following table lists the input and output communicators.

Rack and Pinion Steering System

Overview

The rack and pinion steering system is usually found in passenger cars. The pinion gear translates the

rotary motion of the steering wheel into the linear motion of the rack. The rack moves the tie rods backand forth to steer the vehicle.






ci[lr]_lower_link_frame mount inherit

ci[lr]_spring_upper_to_body mount inherit

ci[lr]_upper_link_frame mount inherit

cis_draglink_steering mount inherit






cos_suspension_ parameters_ARRAY any inherit

Note: The kinematic flag variable toggles between kinematic and compliant mode.

Adams/Car

180


48/72

Figure 13 Rack and Pinion Steering System

Template name

_rack_pinion_steering

Major role

Steering

Application


Description

A series of hooke joints, which connect the three steering column shafts, transmit motion from the

steering wheel to the pinion. A revolute joint connects the lower column shaft to the rack housing. A

bushing (torsion bar) connects the shaft to the pinion. A revolute joint connects the pinion to the rack

housing.

In kinematic mode, a reduction gear is active and connects the steering input shaft revolute joint to the

pinion revolute joint. The underlying Adams/View entity (a coupler) is active only in kinematic mode.

The reduction gear (pinion to rack) converts pinion rotational motion to the rack translational motion. A


translational joint constrains the rack to the rack housing. An additional VFORCE provides the steering


49/72

assist force.

Files referenced

Property file, mdi_steer_assis.ste, stored in the steer_assist.tbl of the shared Adams/Car database. It

defines the steering assist vector force.

Topology


Parameters

A parameter variable switches between kinematic and compliant mode. You can set the activity of the

steering assist vector force through the hidden parameter variable, steering_assist_active. A series of

parameters define the maximum values of angle, rack displacement, rack force, and steering-wheel

torque.

Communicators

The following table lists the input and output communicators.



joshoo_intermediate_shaftinput ges_intermediate_shaft ges_steering_shaft

jostra_rack_to_rackhousing ges_rack ges_rack_housing

josrev_steering_wheel ges_steering_wheel mts_steering_column_to_body

josrev_pinion ges_pinion ges_rack_housing

joscyl_steering_column_to_body ges_steering_column mts_steering_column_to_body

josrev_steering_input_shaft ges_steering_shaft ges_rack_housing

jksfix_rigid_rack_housing_mount ges_rack_housing sws_rack_house_mount

steering_assist_vforce ges_rack ges_rack_housing

gksred_input_shaft_pinion_lock josrev_steering_input_shaft josrev_pinion

grsred_steering_wheel_column_lock josrev_steering_wheel joscyl_steering_column_to_body

grsred_pinion_to_rack josrev_pinion jostra_rack_to_rackhousing

Adams/Car

182


50/72

Rear Driveline System

Overview

The rear driveline system template provides an example model of a driveline for rear-wheel drive (RWD)

vehicles.


cis_rack_housing_to_

suspension_subframe

mount inherit

cis_rack_to_body mount inherit


co[lr]_tierod_to_steering mount front

cos_max_rack_ displacement parameter_real inherit

cos_max_rack_force parameter_real inherit

cos_max_steering_angle parameter_real inherit

cos_max_steering_torque parameter_real inherit

cos_steering_rack_joint joint_for_motion inherit


Note: The rack and pinion steering system template contains general spline elements. Thegss_torsion_bar spline gives the torque as a function of the angular deflection of the input

shaft relative to the pinion.

The template also contains a switch part, which lets you explore two different topological

solutions. You can connect the steering rack housing to the body or to the

suspension_subframe.



51/72

Figure 14 Rear Driveline System

Template name

_driveline_rwd

Major role

Driveline

Application

Full-vehicle assemblies

Description

The rotational motion of the front propshaft is transmitted to the rear shaft and from there to the diffoutputs. Diff outputs should be connected to the driving wheels.

Files referenced

Bushing property files

Adams/Car

184

Topology

The rear dri eline template consists of a t o piece propshaft a slip oke and a differential For


52/72

The rear driveline template consists of a two-piece propshaft, a slip yoke, and a differential. For

convenience, the template includes the propshaft input part for applying motion or torque. The propshaft

input part attaches to the powertrain through a revolute joint. A bearing supports it at its aft.

The front propshaft attaches to the support bearing through an inline joint primitive that prevents

translation of the front propshaft perpendicular to the propshaft's spin axis.

Hooke joints transmit the motion to the slip yoke part. The slip yoke supports and transmits torque to the

rear propshaft through a translational joint. The differential input shaft receives torque from the rear

propshaft through a hooke joint.

The differential is an open design rather than a limited slip. Four bushings mount it to the body. Settingkinematic mode fixes the differential housing to the body and deactivates the bushings. The following

table maps the topology of the template.

Parameters

The parameter variable final_drive_ratio defines the pinion to ring ratio.


josrev_diff_input ges_diff_input ges_diff_housing

jolrev_diff_output gel_diff_output ges_diff_housingjorrev_diff_output ger_diff_output ges_diff_housing

joshoo_propshaft_at_diff ges_propshaft_rear ges_diff_input

joshoo_propshaft_input_to_ front ges_propshaft_input ges_propshaft_front

joscon_propshaft_front_to_ yoke ges_propshaft_front ges_slip_yoke

jostra_propshaft_rear_to_yoke ges_propshaft_rear ges_slip_yoke

josrev_propshaft_input_to_ trans ges_propshaft_input mts_propshaft_input_to_powertrain

jksfix_diff_housing_to_body ges_diff_housing mts_diff_housing_to_body

josinl_support_bearing_to_propshaft_f

ront

ges_support_bearing ges_propshaft_front

josori_support_bearing_orientation ges_support_bearing mts_propshaft_support_to_body

josinp_support_bearing_ location ges_support_bearing mts_propshaft_support_to_body

jksinl_support_bearing_to_ body ges_support_bearing mts_propshaft_support_to_body

grsdif_differential josrev_diff_input jolrev_diff_output

grsdif_differential josrev_diff_input jorrev_diff_output

grsdif_differential jolrev_diff_output jorrev_diff_output


Limitations


53/72

The rear driveline template uses a number of rotating parts. If the driveline dynamics are not of interest

to you, then it is more efficient to apply direct drive torque to the wheels, because the rotating parts in

the template might slow the numerical integration during the analysis.

Communicators

Output communicators of the type mount publish the left and right differential output shafts to the

suspension templates and subsystems. The following table lists the input and output communicators.

Rigid Chassis

Overview

The rigid chassis template represents the base frame of a vehicle.


ci[lr]_tripot_to_differential location rear

cis_diff_housing_to_body mount inherit

cis_driveline_torque solver_variable inherit

cis_propshaft_input_to_ powertrain mount inherit

cis_propshaft_support_to_ body mount inherit

co[lr]_tripot_to_differential mount rear

Adams/Car

186

Figure 15 Rigid Chassis


54/72

Template name

_rigid_chassis

Major role

body

Application

Suspensions, tires, and steering systems in full-vehicle assemblies

Description

A single rigid body part models the chassis.

Files referenced

Shell elements create the chassis graphic. All the shell files are stored in the Adams/Car shared database,

in the shell_graphics.tbl directory.

Topology

The ges_chassis part is unconstrained.

Parameters

The rigid chassis template defines a series of parameter variables, most of which are used to compute the

aerodynamic forces acting on the body. The following table lists the parameters in the template. For adetailed description of the force function, see Force Function Description.

Force function description

Adams/Car expects air density and area parameter variables to be in model units.

As a result of an air stream interacting with the vehicle, forces and moments are imposed on the vehicle.

Out of the three forces and three moments, only the most relevant ones are modeled in the template. Theaerodynamic general force takes into consideration the drag force (longitudinal force) and torque

(pitching moment and torque along the y-axis of the vehicle, in the SAE coordinate system). In detail:


pvs_aero_drag_active Integer No units

pvs_aero_frontal_area Real Area

pvs_air_density Real Density

pvs_drag_coefficient Real No units


F = 0.5 x AirDensity x DragCoeff x Area x VX(chassis)2

T = F x DZ (RideHeight)


55/72

The pitching moment acts to transfer weight between the front and rear axles. It arises because the drag

does not act at the ground plane. Therefore, it accounts for the elevation of the drag force.

Limitations

The rigid body modeling of the chassis does not account for torsional stiffnesses and other effects. You

could create a more accurate representation of a chassis frame by connecting the multiple rigid bodies

though spring dampers to take into account torsional stiffnesses and using modal flexibility.

Communicators

The rigid chassis template defines a series of mount part communicators. The assembly process matches

them with the corresponding output communicators created in suspensions, steering, and other

subsystems. The following table lists the communicators. Note that the output communicator

tierod_to_steering (rear) allows the tierod_to_steering mount parts in the rear suspension to connect to

the chassis body.


co[lr]_spring_to_body mount inherit

co[lr]_strut_to_body mount inherit

co[lr]_tierod_to_steering mount rear

co[lr]_tv_link mount inherit

co[lr]_uca_to_body mount any

co[lr]_upr_link_fr mount inherit

co[lr]_upr_link_rr mount inherit

cos_aero_drag_force force inherit

cos_body mount inherit

cos_body_subsystem mount inherit

cos_chassis_path_ reference mount inherit

cos_concept_to_body mount inherit

cos_diff_housing_to_body mount rear

cos_driver_reference mount inherit

cos_measure_for_distance mount inherit

cos_powertrain_to_body mount inherit

cos_propshaft_support_to_body mount rear

cos_rack_to_body mount inherit

Adams/Car

188

cos steering column to body mount inherit



56/72

Simple Anti-Roll Bar System

Overview

The simple anti-roll bar system template represents a bar fitted transversely to the suspension. The bar is

made out of steel or a user-defined material. The bar is installed in a vehicle to reduce the roll of the

vehicle body as the vehicle takes a corner. It increases suspension roll rate.

Figure 16 Simple Anti-Roll Bar System

Template name

_antiroll_simple

cos_steering_column_to_ body mount inherit

cos_subframe_to_body mount inherit

cos_aero_force force inherit

Note: The rigid chassis light template (_rigid_chassis_lt) is exactly the same as the rigid chassis

template (_rigid_chassis), but without the shell graphic geometry.


Major role

Antiroll


57/72

Antiroll

Application

Suspension and full-vehicle analyses

Description

The anti-roll bar system template provides a simple model of anti-roll bar (also known as stabilizer bar).

It consists of two bar halves connected by a torsional spring-damper component.

Files referenced

Bushing property files

Topology

A revolute joint connects the two bar halves of the anti-roll bar system. Bushings then attach the bar

halves to the body or to the suspension subframe. Drop links transmit the suspension motion to the bar

ends. The drop links attach to the suspension with spherical joints and to the bar ends with convel joints.

The following table maps the topology of the anti-roll bar system template.

Parameters

A parameter variable (pvs_torsional_stiffness) defines the torsional stiffness of the spring-damper

component. The following table lists the parameter, its value, and units.

Limitations

The anti-roll bar system template represents a simple approximation of a stabilizer bar. For morecomplex solutions, you would need to create a more accurate representation of the bar through the

discretization of rigid bodies, nonlinear rods, or flexible bodies.

The joint: Connects part: To part:

jo[lr]sph_droplink_ upper_bal ge[lr]_droplink mt[lr]_droplink_to_suspension

jo[lr]con_droplink_to_arb ge[lr]_droplink ge[lr]_arb

josrev_arb_rev_joint ger_arb gel_arb

arb_torsion_spring (rotational

spring)

ger_arb gel_arb


pvs_torsional_stiffness Real variable Nmm/Degrees

Adams/Car

190

Communicators

Mount parts provide the connectivity t

car templates 1

Documents