CASE STUDY II TRACKED VEHICLES - University of …arc.engin.umich.edu/events/archive/annual/conf97/case2.pdf · AUTOMOTIVE RESEARCH CENTER Case Study II Tracked Vehicles Objective

AUTOMOTIVE RESEARCH CENTERCase Study II Tracked Vehicles

CASE STUDY II

TRACKEDVEHICLES


Objective

The ability to rapidly predict track vibration, powertrain performance, and vehicle dynamics using component models and integrated models


Technical Goals

• Develop models of individual subsystems to promote high-fidelity simulation

• Integrate the component models to create a broad and flexible simulation environment

• Provide an efficient tool for the assessment of designs for tracked vehicles


Motivation


M1 Abrams Tank

• Main Battle Tank

• Weight 70 tons

• Engine 1500 hp gas turbine

• Maximum speed 42 mph

• Acceleration (0 to 20 mph) 7.2 seconds

Source: www.gdls.com


Outline

VEHICLE MODELS

• Track Models • Experimental Validation • DADS Vehicle Models

POWERTRAIN MODELS

• Engine • Driveline

INTEGRATED MODELS

• Integration • Results • Challenges

TM

Presenter:

Presenter:

Presenter:

Noel Perkins

Dennis Assanis

Christophe Pierre


Acknowledgments

•TACOM -- John Weller -- Mike Saxon -- Ken Ciarelli -- Randy Siers -- Ernie Schwarz -- Milad Mekari

•General Dynamics -- Jim Ajlouny and

co-workers

•The University of Michigan -- Zheng-Dong Ma -- Craig Scholar -- Matt Castanier -- Ian Darnell -- Zoran Filipi -- Guoqing Zhang -- Xiaoliu Liu

•The University of Wisconsin


Outline

VEHICLE MODELS


POWERTRAIN MODELS


INTEGRATED MODELS


TM

Presenter:

Presenter:

Presenter:

Noel Perkins

Dennis Assanis

Christophe Pierre


VEHICLE MODELS

DriveSprocket

IdlerWheel

SupportRoller

TrackAdjusting

LinkTorsion

Bar RoadWheel

RoadArm

Track TurretHull


Dominant Excitation Sources

PITCH-SPROCKET CONTACT

POWERTRAIN

TERRAIN


Dominant Deformation Modes

AAAA

AAAAAA

AAAAAA

AA

AA

AA

IN-PLANE RESPONSETRANSVERSE

LONGITUDINAL


Track Models

QUASI-STATIC MULTI-BODY CHAIN

A A A A A A A A A A A

A A

HYBRID DISCRETE-CONTINUOUS ELEMENT


Research Progress

Tension

Time

Tension

Time

Time

Time

Normal Force

Transverse Deflection

IN PROGRESS

LON

GIT

UD

INA

L

LO

NG

ITU

DIN

AL-

Continuous Element Implementation of

TRA

NS

VE

RS

E

Experimental

Model Validation Whole Vehicle Model

CO

UP

LED


Experimental Validation


Vertical Accelerometer

0 20 40 60 80 100 120 140Frequency (Hz)

7.2 Hz

AccelerationMagnitude


Coupled Longitudinal and Transverse Track Element Model

New Features

• Coupled Longitudinal-Transverse Motions

• Initial Sag

• Translation Speed

• Track-Sprocket Contact

LongitudinalTransverse


DADS VEHICLE MODELS

• Efficient prediction of dynamic track vibration, tension, and vehicle acceleration

• Model of tension-adjusting link, rotation of road wheels

• New DADS element for modeling chain/sprocket

TM

TM


Animation

Simulation of

Vehicle Model


Dynamic Track Tension

14 14.1 14.2 14.3 14.4 14.5

Time (seconds)

170,000 lb

60,000 lb

at Idler

at Support Roller


Acceleration In Hull

0 2 4 6 8 10 12 14 16 18 20

-600

-400

-200

0

200

400

600

800

1000

1200

1400

1600

1800

Time (seconds)

Long

itudi

nal A

ccel

erat

ion

At T

ank

C.G

. (in

/sec

**2) Dynamic

Quasi-Static


Torque on First Torsion Bar

0 2 4 6 8 10 12 14 16 18 20

-8e+06

-6e+06

-4e+06

-2e+06

0

2e+06

4e+06

6e+06

Time (seconds)

Tor

que

On

Firs

t Tor

sion

Bar

(lb

-in)

Dynamic

Quasi-Static


Outline

VEHICLE MODELS


POWERTRAIN MODELS


INTEGRATED MODELS


TM

Presenter:

Presenter:

Presenter:

Noel Perkins

Dennis Assanis

Christophe Pierre


POWERTRAIN MODELS

Powertrain


arc

Vehicle System

Diesel EngineSystem

Vehicle &Track

Dynamics

T C

Trns

Tr C

D

DADSTM

V12 Diesel

Driveline

Point Mass or


arc

The Engine Sub-System• Hypothetical V12 Diesel Engine

• 4-Stroke DI Diesel

• 2 Turbochargers

• 2 Intercoolers

• Bore = 6.25 in (15.9 cm)

• Stroke = 6.25 in (15.9 cm)

• CR = 16

• Predicted Power: 1450 HP@2100 rpm

INTER-COOLER

FUELSYSTEM

AirExhaustgas

W.

TC CT

Air Exhaustgas

INTER-COOLER

V12 ENGINE

IM

IM

EM

EM


arc

The Torque Converter

• Developed based on Allison Transmission X1100-1C

• Pump absorption characteristics scaled to match the V-12 diesel.

PumpTorqueEngineSpeed

K Factor=

2

Torque Converter Modeling:

To Engine -Load Torque

Torque ratio vs.Speed ratioLook-up Table

Turbine Torque To Transmission

0.99

0.5

Speed Ratio=0


arc

The Transmission

Gear Ratios

First 3.69:1Second 2.02:1Third 1.38:1Fourth 1.00:1

Clutch Positions (1: Engaged, 0: Disengaged)

Clutch 1 1 1 1 3-4 Shift 1Clutch 2 0 0 2-3 Shift 0 1Clutch 3 0 1-2 Shift 0 1 0Clutch 4 0 1 0 0Clutch 5 1 0 0 0

• 4-speed automatic transmission with planetary gears.

• Model based on Allison Transmission HT-740.

• Transmission logic provides upshifts at 1800 rpm to take advantage of high engine torque.

• Clutch transient during a gear change is completed within one second.


arc

Connecting Sub-System Models

Engine Driveline VehicleDynamics

Sprocket Angular Speeds

Engine Load Torque

Engine Speed & Torque

SprocketDrive

Torques

RigidCrankshaft

FlexibleAxle Shafts

Torque Converter & Transmission Point-Mass

or FullMulti-Body

Dynamics Modelωτ


arc

0

5000

10000

15000

20000

0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0

Sh

aft

To

rqu

e (

Nm

)

TIME (s)

Engine

TorqueConverterOUT

Sprocket

0

500

1000

1500

2000

0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0

Rot

atio

nal S

peed

(R

PM

)

TIME (s)

ENGINE

TorqueConverterOUT

Transmission OUT

Drive Shaft

Powertrain Transients During Vehicle Acceleration

• Tank on the flat surface; vo= 0 mph ; driver demand 80%

SLIP

GEARSHIFTS 1st 2nd 3rd 1st 2nd 3rd


arc

The Effect of Engine Design Change on Powertrain System Response

• Standard Engine vs. the Low Heat Rejection (LHR) EngineBaseline: Tw = 500 K LHR: Tw = 1000 K

600

800

1000

1200

1400

1600

1800

2000

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30 35 40

LHRBaseline

LHR Engine

Baseline

En

gin

e S

pe

ed

(R

PM

)V

eh

icle sp

ee

d (m

/s)

TIME (s)

Engine Speed

TankSpeed


arc

The Effect of Engine Design Change on Powertrain System Response - cont.

• Standard Engine vs. the Low Heat Rejection (LHR) Engine

400

500

600

700

800

900

1000

1100

1200

20

40

60

80

100

120

140

0 5 10 15 20 25 30 35 40

Te cTe m

LHR Engine

Baseline

Exh

aust

Tem

pera

ture

(K

)B

oost Pressure (%

)

TIME (s)

Exhaust Temperature

Boost


Outline

VEHICLE MODELS


POWERTRAIN MODELS


INTEGRATED MODELS


TM

Presenter:

Presenter:

Presenter:

Noel Perkins

Dennis Assanis

Christophe Pierre


INTEGRATED MODELS

DriveSprocket

IdlerWheel

SupportRoller

TrackAdjusting

LinkTorsion

Bar RoadWheel

Road

Track TurretHull

Powertrain

Diesel Engine

Arm


Integration

Torque

RPM

POWERTRAIN

Matlab

STRUCTURE

DADS

Drive Sprocket

TM TM


Predictor-Corrector Scheme

• Powertrain and Structure retain their own convergence criteria

• Information exchanged: states at converged time steps

• Powertrain (predictor) always ahead of Structure (corrector)

• Powertrain never leads by more than a set amount of time

time

Powertrain o o o o o o o

Structure x x x x x


INTEGRATED SIMULATION 1

Terrain: Flat

Driver Demand: 100%


0 2 4 6 8 10 12 14 16 180

20

40

60

80

100

120

140

160

180

200

Time (sec)

Spe

ed (

rad/

sec)

Rotational Speed

Integrated Simulation 1: Flat Terrain

Engine

Torque Converter

Transmission

Drive Shaft/

Transient Gear ShiftsEngine/TC

Sprocket

Out

Out


0 2 4 6 8 10 12 14 16 180

2000

4000

6000

8000

10000

12000

14000

16000

18000

Time (sec)

Tor

que

(N−m

)

Shaft Torque


Drive Shaft/

Torque Converter

Engine

Sprocket

Transient Gear ShiftsEngine/TC

Out


0 2 4 6 8 10 12 14 16 18

11500

12000

12500

13000

13500

14000

14500

15000

15500

Trac

k Te

nsio

n A

t Idl

er a

nd S

proc

ket (

lb)

Track Tension


Sprocket

Idler


INTEGRATED SIMULATION 2

0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000

Terrain: Profile 4

Driver Demand: 100%

1 ft.

100 ft.

Profile 4


0 1.4 2.8 4.2 5.6 7 8.4 9.8 11.2 12.6 14

-2

0

2

4

6

8

10

12

14

16

Time (seconds)

Tan

k V

ertic

al D

ispl

acem

ent (

in)

Vertical Displacement

Integrated Simulation 2: Profile 4


0 2 4 6 8 10 12 140

50

100

150

200

250

Time (sec)

Spe

ed (

rad/

sec)

Rotational Speed


Engine

Torque Converter

Transmission

Drive Shaft/

shiftshift

Out

Out

Sprocket


0 2 4 6 8 10 12 140

2000

4000

6000

8000

10000

12000

14000

16000

18000

Time (sec)

Tor

que

(N−

m)

Shaft Torque


Drive Shaft/

Torque Converter

Engine

Sprocket

shift shift

Out


Contributions

• Dynamic track model with longitudinal vibration

• Experimental validation of track element models

• Implementation of new track model in DADS (with enhancements)

• Simulation of engine transient behavior

• Development of integrated powertrain/vehicle models

TM


Future Challenges

• Coupled longitudinal-transverse vibration track model

• Further experimental validation

• Chain-sprocket contact

• Hull flexibility and vibration transmission

• 3-D modeling

• Further use of integrated modeling codes to provide new design capabilities

Documents

CASE STUDY II TRACKED VEHICLES - University of …arc.engin.umich.edu/events/archive/annual/conf97/case2.pdf · AUTOMOTIVE RESEARCH CENTER Case Study II Tracked Vehicles Objective