Design and Calibration of the Jaguar XK Adaptive Cruise Control - - PowerPoint PPT Presentation

Design and Calibration of the Jaguar XK Adaptive Cruise Control System

Tim Jagger MathWorks 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

20 40 60 80 100 120 140

• 26
• 24
• 22
• 20
• 18
• 16
• 14
• 12
• 10
• 8
• 6
• 4
• 2

2 Range m Range Rate m/s COMPARISON OF XK v S-TYPE ACC APPROACH TO LEAD VEHICLE TRAVELLING AT 50mph XK Headway 1 90mph XK Headway 1 100mph S-TYPE Headway 1 90mph S-TYPE Headway 1 100mph S-TYPE shows smooth continuous reduction

• f range rate with range

XK shows discontinuous reduction

• f 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

20 40 60 80 100 120 20 25 30 35 40 45 Time s ACC Host Vehicle Speed m/s X150 ACC-QA Simulink Model Validation Test - SDV1143 Simulation - 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

20 40 60 80 100 120

• 1.5
• 1
• 0.5

0.5 1 1.5

Range m Range Rate Error m/s

Residuals approach 1 Residuals approach 2 Residuals 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

20 40 60 80 100 120 140

• 15
• 10
• 5

5

Range m Range Rate m/s

20 40 60 80 100 120 140

• 20
• 15
• 10
• 5

5

Range m Range Rate m/s

20 40 60 80 100 120 140

• 25
• 20
• 15
• 10
• 5

5

Range m Range Rate m/s

20 40 60 80 100 120 140

• 30
• 25
• 20
• 15
• 10
• 5

5

Range m Range Rate m/s

Test - 90mph Simulation - 90mph Test - 112mph Simulation - 112mph Test - 100mph Simulation - 100mph Test - 80mph Simulation - 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 a

moderate rate

• Filtering of ACC Speed demand introduced significant lag

Page 19

QUEUE ASSIST

10 20 30 40 50 60 70 80 5 10 15 20 25 Time s Speed m/s Jaguar XK QA Simulation. Acceleration from 5mph to 30mph. Headway 1 0.1g. Baseline Calibration Lead Car Speed Headway 1 0.1g. Baseline Calibration Follow Speed Headway 1 0.1g. Baseline Calibration Vehicle Speed 10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 Time s Range 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

10

• 60
• 30

Phase (deg)

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

• 4
• 3
• 2
• 1

Magnitude (dB)

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

10

• 35
• 30
• 25
• 20
• 15
• 10
• 5

Phase (deg)

System: follow_speed_filt_new_02 Frequency (Hz): 0.979 Phase (deg): -29.9

• 5
• 4
• 3
• 2
• 1

Magnitude (dB)

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 80 10 20 30 40 50 60 70 Time s Range m Jaguar XK QA Simulation. Acceleration from 5mph to 30mph Baseline Calibration filter cut-off @ 0.15Hz Filter cut-off @ 1Hz 10 20 30 40 50 60 70 5 10 15 20 25 Time s Speed 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 Speed Headway 1 0.1g CADS Cal. R44. Follow Speed Filter -3dB @ 1Hz Follow Speed Headway 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