Design and Calibration of the Jaguar XK - MathWorks and Calibration of the Jaguar XK Adaptive Cruise Control System Tim Jagger MathWorks International Automotive Conference 2006 Page

Design and Calibration of the Jaguar XK Adaptive Cruise Control System

Tim JaggerMathWorks International Automotive Conference 2006

Page 3

JAGUAR XK

Page 4

ADAPTIVE CRUISE CONTROL(ACC) MODEL BASED CALIBRATION

• Adaptive Cruise Control – The Driver’s Perspective

• The Adaptive Cruise Control System – Control Aspects

• Jaguar XK Adaptive Cruise Control System

• Jaguar XK Adaptive Cruise Control Virtual Vehicle Model

• Model Correlation

• Jaguar XK Adaptive Cruise Control Calibration Development

• Queue Assist Development

Page 5

ADAPTIVE CRUISE CONTROL THE DRIVER’S PERSPECTIVE• Driver Comfort Feature

• Allows Host Vehicle to follow a target vehicle

• Automatically Resumes to set speed in absence of target vehicle

• Driver selects headway

• Available Headways

– 1.0s, 1.4s, 1.8s, 2.2s

• Driver Selects Cruise Speed

– Min. 20mph, Max. 112mph

Page 6

ADAPTIVE CRUISE CONTROL CONTROL APSECTS

Page 7

JAGUAR XK ADAPTIVE CRUISE CONTROL

• New Adaptive Cruise Control Algorithms for XK

• New Features

– Queue Assist Algorithms

– Lead Vehicle Acceleration Algorithm (LVA)

• Initial Functional Testing – April 2005

• Initial Calibration Testing – May 2005

• Unexpected Results ….

Page 8

APPROACH XK v S-TYPE

0 20 40 60 80 100 120 140-26

-24

-22

-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

0

2

Range m

Ran

ge R

ate

m/s

COMPARISON OF XK v S-TYPE ACC APPROACH TO LEAD VEHICLE TRAVELLING AT 50mph

XK Headway 1 90mphXK Headway 1 100mphS-TYPE Headway 1 90mphS-TYPE Headway 1 100mph

S-TYPE shows smooth continuous reduction of range rate with range

XK shows discontinuous reduction of range rate with range

Page 9

TEST & DEVELOPMENT

• Results from 1st ACC Test Session

– Harsh Early Brake Intervention

– LVA Algorithm gave unpredictable results

– Generally unrefined ACC Performance

• Expectation was that XK ACC would only need small scale refining

– Developed from ACC3

Page 10

TEST & DEVELOPMENT

• In reality major development was required

• Second test period was for validation NOT development

• Tight timescales & challenging vehicle allocation

Page 11

ADAPTIVE CRUISE CONTROL VIRTUAL VEHICLE MODEL

Page 12

MODEL CORRELATION

0 20 40 60 80 100 12020

25

30

35

40

45

Time s

AC

C H

ost V

ehic

le S

peed

m/s

X150 ACC-QA Simulink Model Validation

Test - SDV1143Simulation - CADS-X150-CP39-SDB4-trj04h.mdl

Approach 1

Approach 2

Auto-Resume to Set Speed

Cruising at Set Speed

Approach 3

Following Target Vehicle

Page 13

MODEL CORRELATION

0 20 40 60 80 100 120-1.5

-1

-0.5

0

0.5

1

1.5

Range m

Ran

ge R

ate

Erro

r m/s

Residuals approach 1Residuals approach 2Residuals approach 3

X150 ACC-QA Simulink Model Validation

Test Vehicle - X150 SDV1143 Simulation - CADS-X150-CP39-SDB4-trj04h.mdl

Page 14

CALIBRATION DEVELOPMENT

• Test Results indicated seven parameters influenced ACC refinement

– Lead Vehicle Acceleration Algorithm (LVA)

– ACC brake gain

– Brake demand slew rate

– Time to collision gain

– Residual Distance

– Coast Deceleration Estimate

– Headway Control Maps

Page 15

CALIBRATION DEVELOPMENT

• Test Matrix of 8 possible ACC configurations

• 4 days per configuration to test on vehicle = 32 days vehicle testing

• Complete test matrix was evaluated by simulation in 10 days

ACC Vehicle Simulation was vital for calibration development

Page 16

SIMULATION PREDICTIONS V TEST RESULTS

0 20 40 60 80 100 120 140-15

-10

-5

0

5

Range m

Ran

ge R

ate

m/s

0 20 40 60 80 100 120 140-20

-15

-10

-5

0

5

Range m

Ran

ge R

ate

m/s

0 20 40 60 80 100 120 140-25

-20

-15

-10

-5

0

5

Range m

Ran

ge R

ate

m/s

0 20 40 60 80 100 120 140-30-25-20-15-10-505

Range m

Ran

ge R

ate

m/s

Test - 90mphSimulation - 90mph

Test - 112mphSimulation - 112mph

Test - 100mphSimulation - 100mph

Test - 80mphSimulation - 80mph

Headway 1 Approach Results. Test v Simulation Predictions

Page 17

COMPARISON OF SIMULATION PREDICTIONS WITH PRODUCTION CALIBRATIONS

• Two calibrations changed from simulation to production

• Changes based on subjective driver assessment

Page 18

QUEUE ASSIST

• Extension of ACC operating range to 0mph

• Headway opened significantly at low speeds

• QA host vehicle unable to track target vehicle accelerating at amoderate rate

• Filtering of ACC Speed demand introduced significant lag

Page 19

QUEUE ASSIST

10 20 30 40 50 60 70 800

5

10

15

20

25

Time s

Spee

d m

/s

Jaguar XK QA Simulation. Acceleration from 5mph to 30mph.

Headway 1 0.1g. Baseline Calibration Lead Car SpeedHeadway 1 0.1g. Baseline Calibration Follow SpeedHeadway 1 0.1g. Baseline Calibration Vehicle Speed

10 20 30 40 50 60 70 800

10

20

30

40

50

60

70

Time s

Ran

ge m

Jaguar XK QA Simulation. Acceleration from 5mph to 30mph.

Headway 1 0.1g. Baseline Calibration

Page 20

FILTER CUT-OFF FREQUENCY

10-2 10-1 100

-60

-30

0

Pha

se (d

eg) System: follow_speed_filt_current

Frequency (Hz): 0.15 Phase (deg): -42

-4

-3

-2

-1

0

Mag

nitu

de (d

B)

System: follow_speed_filt_current Frequency (Hz): 0.151 Magnitude (dB): -3

FREQUENCY RESPONSE OF THE FOLLOW SPEED FILTER R44 CALIBRATION.

FREQUENCY Hz 10-1 100-35

-30

-25

-20

-15

-10

-5

0

Pha

se (d

eg)

System: follow_speed_filt_new_02 Frequency (Hz): 0.979

Phase (deg): -29.9

-5

-4

-3

-2

-1

0

Mag

nitu

de (d

B)

System: follow_speed_filt_new_02 Frequency (Hz): 0.979

Magnitude (dB): -3

FREQUENCY RESPONSE OF FOLLOW SPEED FILTER - DESIGN 02.

Frequency Hz

•Use frequency response toolbox to re-calculate filter constant

Page 21

EFFECT OF NEW FILTER CONSTANT

10 20 30 40 50 60 70 800

10

20

30

40

50

60

70

Time s

Ran

ge m

Jaguar XK QA Simulation. Acceleration from 5mph to 30mph

Baseline Calibration filter cut-off @ 0.15HzFilter cut-off @ 1Hz

10 20 30 40 50 60 700

5

10

15

20

25

Time s

Spee

d m

/s

X150 QA Simulation. Headway 1. Acceleration from 5mph to 30mph. Follow Speed Filter -3db @ 1Hz

Headway 1 0.1g CADS Cal. R44. Follow Speed Filter -3dB @ 1Hz Lead Car SpeedHeadway 1 0.1g CADS Cal. R44. Follow Speed Filter -3dB @ 1Hz Follow SpeedHeadway 1 0.1g CADS Cal. R44. Follow Speed Filter -3dB @ 1Hz Vehicle Speed

Page 22

JAGUAR XK MODEL BASED DESIGN AND CALIBRATION

SUMMARY

• Jaguar XK ACC system modelled in simulink

• ACC Model shows good correlation with test results

• Model was used to develop Jaguar XK ACC Calibrations

• Development time per calibration loop reduced from 30 days to 10 days

(Typically 3 - 4 calibration loops on a vehicle program)

• Vehicle test time now used for validation - not experimentation