Steering Handbook (eBook)

Preface 5
Contents 7
Abbreviations and Symbols 9
Advertisements 14
1 Introduction and History 17
1.1ƒDefinition and Delimitation 19
1.2ƒTask and Significance of the Steering System 19
1.2.1 Basic Types 20
1.2.2 Designs 21
1.3ƒHistory of Lateral Dynamics 22
1.4ƒThe History of Vehicle Steering Systems 27
1.4.1 Turntable Steering 27
1.4.2 The Ackermann Steering 28
1.4.3 The Steering of the First Motor Vehicles 28
1.4.4 Mechanical Steering Gears 32
1.4.5 Power Steering Drives 33
References 40
2 Basic Principles of the Steering Process 42
2.1ƒSteering: Lateral Control of Vehicles 42
2.2ƒCornering 44
2.2.1 Slow Cornering 44
2.2.2 Fast Cornering 44
2.3ƒLateral Properties of the Tire 46
2.3.1 Vertical Force Transmission: Influence on the Length of the Contact Patch 46
2.3.2 Lateral Force of the Tire, Pneumatic Trail and Self-Aligning Torque 48
2.3.2.1 Range of Minor Lateral Accelerations (Linear Tire Properties) 48
2.3.2.2 Range of Higher Lateral Acceleration (Non-linear Tire Characteristics) 52
2.3.2.3 Influence of the Camber Angle 54
2.3.3 Transient Behaviour of Tire Lateral Forces 55
2.3.4 Summary of Tire Properties 55
2.4ƒSteering Wheel Torque 56
2.4.1 Calculation of Steering Wheel Torques 57
2.4.2 Steering Reinforcement 59
2.4.3 Steering Assistance Torque 61
2.5ƒFour-Wheel Steering 63
2.6ƒActive Suspension Steering 64
References 66
3 Steering Requirements: Overview 67
3.1ƒFunction and Steering Feel 67
3.2ƒPackage 68
3.3ƒWeight 70
3.4ƒCosts 71
3.5ƒQuality 71
3.6ƒEnergy and Environment 72
3.7ƒAcoustics and Vibrations 72
3.8ƒSystem Safety 73
3.9ƒLegal Requirements 74
References 75
4 Steering Kinematics 76
4.1 Introduction 76
4.2 Characteristics of the Steering Geometry 76
4.3 Characteristics of the Wheel Position 83
4.3.1 Steering Ratio 92
4.4 Steering Linkage 93
References 103
5 Basics of Lateral Vehicle Dynamics 104
5.1 Vehicle Modelling: Linear Single Track Model 104
5.1.1 Dynamic Equations 105
5.1.2 Steering Angle: Steering Wheel Angle—Power-Assisted Steering 109
5.1.3 Steady-State Circular Driving 111
5.1.4 Understeer and Oversteer 113
5.1.5 Transient Response: Response Time of a Steering Wheel Step Input 115
5.1.6 Yaw Gain 116
5.1.7 Steering Models 117
5.1.8 Steering Model with Power-Assist and Friction Effects 119
5.1.9 Discussion of the Influence of the Vehicle and Steering Parameters on the Driving and Steering Performance 119
5.2 Basic Dynamic Steering Design 122
5.2.1 Steering Axis Design: Steady State Self-aligning Torque 122
5.2.2 Determination of the Stability Factor 126
5.2.3 Steady State Yaw Gain and Steering Sensibility 126
5.2.4 Steering-wheel Torque/Lateral Acceleration Gradient (Steady State) 128
5.2.5 Frequency Response Wheel Torque/steering wheel angle 128
5.2.6 Free Control Stability 129
5.2.7 Natural Frequency and Damping of the Steering 129
5.2.8 Minimising the Self Steering due to Uneven Braking Forces at the Front Axle 130
5.2.9 Stable Steering Braking System 130
5.2.10 Influence of Aerodynamics on Driveability 131
5.2.11 Front-wheel Drive Vehicles 131
References 131
6 Acoustics and Vibrations 134
6.1ƒInterfering and Operating Noise 135
6.1.1 Sound Sources of Steering Systems 135
6.1.2 Electric Steering Systems 137
6.1.3 Hydraulic Steering Systems 137
6.2ƒStability 141
6.2.1 Hydraulic Steering Clattering 141
6.2.2 Steering Rattle 142
6.2.3 Steering Wheel Nibble 144
6.3ƒStructure-Borne Sound Transmission in Hoses and Cables 146
6.3.1 Superposition of Structure-Borne Sound Waves 147
6.3.2 Acoustically Acting Material Parameters 147
6.3.3 Reduction of the Noise Transmission by Bending 149
6.4ƒSteering Column and Wheel—Design of Vibrations 150
6.4.1 Design Strategy 150
6.4.2 Target Eigen Frequencies of Components and Car 152
6.4.3 Calculation Models and Load Cases 154
6.4.4 Parameter Studies 156
6.4.5 Steering Wheel Absorbers 157
6.5ƒConclusion 160
References 160
7 Steering-Feel, Interaction Between Driver and Car 161
7.1ƒSteering Behaviour and Steering-Feel 162
7.2ƒSteering-Feel 164
7.2.1 Guidance Behaviour 165
7.2.2 Response Behaviour 165
7.2.3 Requirements of Ideal Steering Behaviour and Steering-Feel 166
7.3ƒEvaluation Methods for the Steering-Feel: Objectification 167
7.4ƒSubjective Evaluation of the Steering-Feel 168
7.5ƒObjective Evaluation of the Steering Behaviour 173
7.5.1 Measuring Equipment 173
7.5.2 Driving Maneuvers 174
7.5.3 Automated Data Processing 176
7.5.4 Objective Parameters 176
7.6ƒCorrelation and Regression Analysis 177
7.7ƒTarget Ranges for Ideal Steering Characteristics 178
References 179
8 Layout of Steering Systems 181
8.1 Basic Design of a Steering System 181
8.1.1 Rack Force 181
8.1.2 Steering Wheel Torque 183
8.1.3 Steering Dynamics 184
8.1.4 Steering Power 185
8.1.5 Steering Friction 185
8.1.5.1 Negative Features of Steering Friction 186
8.1.5.2 Positive Features of Steering Friction 186
8.2 Response Characteristics of Steering Systems 188
8.2.1 Steering Response (Guidance Response) 189
8.2.2 Steering Feedback Response (Response behavior) 190
8.2.2.1 Steering Feedback Response of Hydraulic Power Steering Systems 190
8.2.2.2 Non-Linear Enhancement for the Description of Hydraulic Power Steering Systems Feedback 194
8.2.2.3 Feedback Reponse of Electric Power Steering Systems Feedback 197
References 201
9 Steering Wheel 202
9.1ƒIntroduction 202
9.2ƒSubassemblies 202
9.2.1 Basic Structure 204
9.2.2 Rim and Corpus 206
9.2.3 Horn 207
9.2.4 AirBag and Crash 208
9.2.4.1 AirBag Cover 209
9.2.4.2 AirBag 209
9.2.4.3 Gas Generator 210
9.2.5 Multi Function 211
9.2.6 Foam, Leather and Decorations 214
9.3ƒRequirements for Components and Assembly 215
9.4ƒTesting and Protection 216
9.4.1 Airbag 217
9.4.1.1 General and Crash Requirements 217
9.4.1.2 Environmental Simulation 217
9.4.2 Steering Wheel 219
9.4.2.1 Operational Safety 219
9.4.2.2 ECE-R12 221
9.4.2.3 Environmental Simulation, Varnish Test, Electroplating Test 222
9.4.3 Controls/EE 223
9.5ƒModularisation, Trends of Development, the Future 223
10 Steering Column and Intermediate Steering Shaft 225
10.1ƒIntroduction 225
10.2ƒSubassemblies 227
10.2.1 Upper Steering Shaft 227
10.2.2 Manually Adjustable Steering Column 228
10.2.3 Electrically Adjustable Steering Column 229
10.2.4 Intermediate Steering Shafts 230
10.2.4.1 Gimbal Error and Centre Point 231
10.2.5 Parts of the Subassemblies 233
10.2.5.1 Adjustable Units 233
Manual Locking 234
Electric Drive Unit 235
10.2.5.2 Upper Steering Shaft Including Jacket Tube 236
10.2.5.3 Crash Elements 238
10.2.5.4 Joints 240
Universal Joints 241
Centred Double Joint 242
10.2.5.5 Length Compensation of the Intermediate Steering Shaft 242
10.2.5.6 Dampers 244
10.3ƒTesting Steering Column and Intermediate Steering Shaft 245
10.3.1 Transmission Capability 246
10.3.1.1 Static Strength 246
10.3.1.2 Dynamic Strength 247
10.3.2 Stiffness 247
10.3.3 Durability Tests for Adjustable Units of Steering Columns 248
10.3.4 Dynamics 249
10.3.4.1 Requirements of the Steering Column 249
10.3.4.2 Analytic Identification/Measurement of the Dynamics 250
10.3.4.3 Parameters of Influence 251
10.3.5 Crash Characteristics 252
10.3.5.1 Steering Spindle 252
10.3.5.2 Steering Column 254
10.3.6 Displacement Forces to Adjust the Steering Column 255
10.3.7 Temperature 256
10.3.8 Corrosion 257
10.4ƒThe Future 258
11 Mechanical and Hydraulic Gears 259
11.1ƒDefinition of Rack-and-Pinion Gears 259
11.2ƒApplicability/Pros and Cons 261
11.3ƒKinematic Differentiating Features of Gears 262
11.3.1 Position of the Gear in Relation to the Front Axle 262
11.3.2 On-board Gear Interfaces 263
11.3.3 Adjustment of the Gear Case 264
11.3.4 Tie Rod Interfaces 264
11.3.5 Kind of Gear Ratio 265
11.4ƒDesign and Main Components of a Mechanical Rack-and-Pinion Gear 265
11.4.1 Gear Case 267
11.4.1.1 One-Piece Gear Case 267
11.4.1.2 Two-Piece Gear Case in Composite Design 267
11.4.2 Steering Pinion 268
11.4.2.1 Pinion Bearing 268
11.4.2.2 Implementation of the Pinion Dovetailing 270
11.4.3 Rack and Rack Guide 270
11.4.3.1 Rack Guide 270
11.4.3.2 Rack Yoke 272
Construction of the rack yoke 272
Rack yoke tuning 274
11.4.3.3 Rack Bushing 274
11.5ƒDovetailing and Gear Ratio 275
11.5.1 Constant Gear Ratio 275
11.5.2 Variable Gear Ratio 275
11.5.2.1 History of the Development 277
11.5.3 Applications 277
11.5.3.1 Applications for the Steering System 277
Mechanical gear—diminished torque 278
Power-assisted gear—reduced power consumption 278
11.5.3.2 Driver Application 279
Ergonomics 279
Vehicle dynamics 280
11.5.3.3 Special Applications 280
Combined applications 281
11.5.4 Technical Limits 283
11.5.4.1 Size of the Rack Gain 283
11.5.4.2 Contact Lines 284
11.5.4.3 Stability and Noise (NVH) 285
11.5.5 Manufacturing Processes 287
11.5.5.1 Rotary Swaging 287
11.5.5.2 Semi-hot Forging 288
11.5.5.3 Pipe Reshaping 289
11.6ƒRequirements of a Mechanical Rack Gear 290
11.6.1 Functional Requirements of Gears 290
11.6.1.1 Rack Yoke Clearance 291
11.6.1.2 Steering Pinion Torque 291
11.6.1.3 Rack Displacement Force 292
11.6.1.4 Efficiency 293
11.6.1.5 Noise (NVH) Requirements 294
11.6.2 Strength Requirements of the Gear 294
11.6.2.1 Static Strength 295
Fracture Torque Test 295
Charpy Impact Test 295
11.6.2.2 Dynamic Strength and Wear Test 295
Parking Test 295
Wear Test 296
11.6.3 Environmental Requirements of the Gear 296
11.6.3.1 Salt Spray Test 296
11.6.3.2 Dirt Water Test 296
11.7ƒDesign Verifications and Product Validation of a Rack-and-Pinion Gear 297
11.7.1 Concept Verification 297
11.7.2 Design Verification 297
11.7.3 Product Validation 297
11.7.4 Accompanying Test 298
11.8ƒHydraulic Steering Systems 298
11.8.1 Objectives 298
11.8.1.1 Reducing the Steering Forces 298
11.8.1.2 Reducing the Steering Ratio 299
11.8.1.3 More damping of the steering system 299
11.8.1.4 More Freedom in the Design of the Chassis 300
11.8.2 Necessary Changes in the Vehicle Opposed to Manual Steering 300
11.8.3 Necessary Changes in the Gear Opposed to Manual Steering 300
11.8.4 Specific Features of Hydraulic Gears for On-board Use 301
11.9ƒConstructions and Components of Hydraulic Gears 301
11.9.1 Configurations 302
11.9.1.1 End Tap 302
11.9.1.2 Central Tap 303
11.9.1.3 Parallel Auxiliary Cylinder 304
11.9.2 Cylinder 305
11.9.2.1 Rack in the Cylinder Area 306
11.9.2.2 Pistons with Piston Ring 307
11.9.2.3 Rack Gaskets and Sealing System of the Cylinder 308
Configuration of a rack seal 309
Interface at the external diameter 309
Interface in the inner diameter 310
Integration of the seal in the gear 311
11.9.2.4 Cylinder Pipe with Connections 311
11.9.3 Rotary Disk Valve with Input Shaft and Steering Pinion 313
11.9.3.1 Steering Pinion 314
11.9.3.2 Torsion Bar and Overload Fuse 314
11.9.3.3 Sleeve with Valve Rings 315
11.9.3.4 Input Shaft 316
11.9.3.5 Configuration Forms 317
11.9.4 Other Parts of a Hydraulic Gear 318
11.9.4.1 Transfer Pipelines 318
11.9.4.2 Bellow Vent Pipe 318
11.9.5 Typical Characteristics of Hydraulic Gears 319
11.10ƒFunctionality of the Steering Hydraulics 319
11.10.1 Steering Valve: Principle of the Cutback 319
11.10.2 External Influence on the Valve Indicator 324
11.10.3 Effects of Steering Movements: Volumetric Flow Splitting 326
11.10.4 Valve Noises: Hiss 327
11.10.5 Internal Leakage 328
11.10.6 Modelling (Position Control Circuit) 330
11.10.7 Damping: Instabilities 330
11.11ƒAdditional Hydraulic Systems 331
11.11.1 Centring 331
11.11.2 Speed Dependence 333
11.11.3 Damping Valves 336
11.11.4 Steering Valves with Damping Qualities 337
11.11.5 Pressure Limitation in the Rack-and-Pinion End Position 339
11.12ƒBall-Circulation Gears with Nuts/Utility Vehicle Steering Systems 341
11.12.1 Fields of Application 341
11.12.2 Configuration of Ball-Recirculating Gears with Nut 342
11.12.3 Comparison Between Ball-Recirculating Gear with Nut and Rack-and-Pinion Steering 343
11.12.4 Technical Data and Parameters 344
11.12.5 Additional Systems 344
11.12.6 Dual-Circuit Steering 345
11.13ƒRequirements for a Hydraulic Gear 346
11.13.1 Functional Requirements 346
11.13.2 Strength Requirements 347
11.13.2.1 Static Strength: Burst Pressure Test 347
11.13.2.2 Dynamic Strength: Pressure Pulsation 347
11.13.3 Environmental Requirements: Cold Start Test 347
References 347
12 Tie Rods 348
12.1ƒIntroduction 348
12.2ƒBasic Variants 349
12.2.1 Tie Rods for Ball-and-Nut Steering 349
12.2.2 Tie Rods for Rack-and-Pinion Steering 349
12.3ƒTie Rod Joints 351
12.3.1 Inner Joint (Axial Joint) 351
12.3.1.1 Ventilation Function of the Inner Joint 352
12.3.2 Outer Joint (Radial Joint) 353
12.4ƒToe Adjustment 354
12.5ƒRequirements and Design 354
12.5.1 Design Regulations for Tie Rods 354
12.5.2 Design of the Tie Rod with Regard to Component Strength 354
12.5.3 Design of the Joint Bearing 357
12.5.4 Design of the Outer Joint Sealing 358
12.5.4.1 Requirements of the Joint Sealing 359
12.6ƒDamping/Decoupling 360
12.7ƒInterfaces to the wheel carrier 360
12.8ƒLightweight Design 361
12.9ƒThe Future 362
12.9.1 Overload Behaviour 362
12.9.2 Sensor Joint 364
References 364
13 Hydraulic Power Supply 366
13.1ƒServo Pumps 366
13.1.1 Introduction 366
13.1.2 Vane-Type Pump 366
13.1.2.1 Vane-Type Pumps with Bypass Valve for Energy Conservation 369
13.1.2.2 Variable Pump 370
13.1.3 Radial Piston Pump 373
13.1.4 Tandem Pump 374
13.2ƒOil Supply and Oils 374
13.2.1 Oil Tank 374
13.2.1.1 Types 375
13.2.1.2 Filling and Ventilation 375
13.2.1.3 Filtration 377
13.2.1.4 Separation Efficiency 377
13.2.1.5 System Purity 378
13.2.1.6 Design Under Lateral Acceleration 379
13.2.2 Steering Hoses and Tubes 379
13.2.2.1 High-Pressure Duct Including Screw Connection (Hose Types and Construction) 380
13.2.2.2 Screw Connections Of High-Pressure Lines and Stretch tubes 381
13.2.2.3 Suction and Return Conduits 383
13.2.2.4 Acoustic Tuning/Noise Measures 383
13.2.3 Cooling/Cooling Fronds/Cooler 384
13.2.4 System Limits 384
13.2.5 Servo Oils 385
13.2.5.1 Other Specifications 388
14 Electrically Powered Hydraulic Steering 389
14.1ƒIntroduction 389
14.1.1 Configuration and Functional Principle 389
14.1.2 Steering System Classification 391
14.1.3 Application Examples 392
14.2ƒSystem Descriptions 392
14.2.1 System Overview 393
14.2.2 System Layout 394
14.2.2.1 Steady State Layout 395
14.2.2.2 Dynamic Layout Criteria 396
14.2.3 Energy Consumption 397
14.2.3.1 Efficiency 397
14.2.3.2 Power Input and Energy Consumption 397
14.3ƒComponents 399
14.3.1 Motor Pump Unit 400
14.3.1.1 Main Requirements and Interfaces 400
14.3.1.2 Electric Power Pack 400
14.3.1.3 Pump and Valves 403
14.3.2 Hydraulic Pipe System 405
14.3.2.1 Main Requirements 405
14.3.2.2 Configuration and Damping Principles 406
14.3.2.3 Determination of the Damping Behaviour 406
14.3.2.4 Hydraulic Resistance 407
14.3.3 Other Components 408
14.3.3.1 Sensors 408
14.3.3.2 Fluids 408
14.3.3.3 Tanks and Brackets 409
References 409
15 Electric Power Steering Systems 410
15.1ƒIntroduction 410
15.1.1 Analogies of EPS and HPS 412
15.2ƒDesigns of EPS Systems 413
15.2.1 EPSc: Column 413
15.2.2 EPSp: Pinion 415
15.2.3 EPSdp: Dual Pinion 415
15.2.4 EPSapa: Axle Parallel 416
15.2.5 EPSrc: Rack Concentric 417
15.3ƒSubassemblies of the EPS 418
15.3.1 Power-Assisted Gear 418
15.3.1.1 Worm Gear 419
15.3.1.2 Ball Screw Drive 420
15.3.1.3 Toothed Belt Drive 421
15.3.2 Electric Motor 423
15.3.2.1 Overview/Comparison/Working Area 423
15.3.2.2 DC Motor with Mechanical Commutator (see also Stölting and Kallenbach 2006) 426
15.3.2.3 Asynchronous Motor 427
15.3.2.4 Synchronous Motor 428
15.3.2.5 Position and Rev Sensors 430
15.3.3 Torque Sensor 433
15.3.3.1 Requirements/Classification 433
15.3.3.2 Sensors with Torsion Rod 434
15.3.3.3 Torsion-Resistant Sensors 439
15.3.4 ECU 441
15.3.4.1 Designs 442
15.3.4.2 Signal Electronics 444
15.3.4.3 Power Electronics 445
15.4ƒSystem Design 446
15.4.1 General System Requirements 446
15.4.2 Design Parameters 448
15.4.3 Requirements for the Wiring System 452
15.5ƒSystem Safety 454
15.5.1 Normative Code 454
15.5.1.1 IEC 61508 454
15.5.1.2 ISO 26262 454
15.5.2 Safety in EPS Applications 455
15.5.2.1 Task of the Safety Concept 455
15.5.2.2 EPS Risk Classification 455
15.5.2.3 Qualities of the Safe State 457
15.5.2.4 Switch-Off Channels 458
15.5.2.5 Safety Measures for Subcomponents of the System 459
Monitoring of External Signals 460
Monitoring Sensors 460
Monitoring Plan of the Computer System 461
Monitoring Power Electronics/Actuator 462
Safety-Related ECU Block Diagram 462
15.6ƒSteering Functions and Control 463
15.6.1 Steering Functions 464
15.6.1.1 Basic Steering Functions 464
Power-Assistance 465
Friction Compensation 467
Inertia Compensation 467
Active Damping 468
15.6.1.2 Extended Steering Functions 468
Active Return 468
Directional Stability Correction 469
15.6.1.3 Functions at Vehicle Level 469
Park Steering Assistant 469
Driver Warning/Lane Departure Warning 470
Tracking/Lane Keeping System 470
Dynamic Steering Torque Recommendation 470
15.6.2 Control Plans for the Steering Feel 471
15.6.2.1 Classical Control Plans 471
15.6.2.2 Control of the Driver’s Torque 472
References 473
16 Superimposed Steering System 475
16.1ƒIntroduction 475
16.2ƒHistory 475
16.3ƒFunctional Principle 476
16.4ƒConfigurations 478
16.4.1 General System Configuration 478
16.4.2 Actuators and Actuator Varieties 480
16.4.2.1 Audi/ZFLS Dynamic Steering 480
16.4.2.2 Active Steering BMW/ZFLS 482
16.4.2.3 Lexus/JTEKT VGRS 483
16.4.3 Adaptations in the Steering System 485
16.4.3.1 Steering Ratio 485
16.4.3.2 Adaptations to Meet NHV Requirements 486
16.4.3.3 Adaptations Due to Steering Stabilisation 486
16.4.3.4 System Network 486
16.5ƒFunctions of the Superimposed Steering System 487
16.5.1 VGR 487
16.5.1.1 Low Speed 488
16.5.1.2 Medium Speed 488
16.5.1.3 Stability at High Speed 488
16.5.1.4 Varieties of Characteristic Curves According to the Driver’s Request 490
16.6ƒSteering Stabilisation 490
16.6.1 Steering Stabilisation at Oversteering 491
16.6.2 Steering Stabilisation at Understeering 492
16.6.3 Steering Stabilisation During Braking on Roads with Different Friction Values (?-split) 493
16.7ƒSystem Safety 493
16.8ƒThe Future 497
References 498
17 All-Wheel Steering 499
17.1 Introduction, History, Basics, Objective 499
17.2 Construction Methods 500
17.2.1 Mechanical Systems 500
17.2.2 Hydraulic Systems 504
17.2.3 Electromechanical Systems 506
17.2.4 Central Actuator Versus Single Wheel Actuators 509
17.3 Effects of an All-Wheel Steering on Vehicle Dynamics 510
17.3.1 Kinematic Qualities of an All-Wheel steering 511
17.3.2 Influence of an All-Wheel Steering on the Stationary Vehicle Characteristics 512
17.3.3 Influence of an All-Wheel Steering on the Nonstationary Vehicle Characteristics 513
17.3.4 Combination of a Rear-Wheel Steering with a Superimposed Steering System at the Front Axle 514
References 517
18 Steer by Wire 519
18.1 Introduction 519
18.1.1 State-of-the-Art 519
18.1.2 Pros and Cons 520
18.2 Components 522
18.2.1 Operating Element Quality 523
18.3 Steering Functions 526
18.3.1 Discussion of the Normal Driving Mode 527
18.3.2 Discussion of the Lateral Dynamic Limit Range 527
18.3.3 Compensating Interferences 528
18.3.4 Combined Longitudinal–Lateral Guidance 529
18.4 Safety Concepts 529
18.5 The Future 531
References 531
19 Overview: Driver Assistance System Functions 533
19.1 Overview of Selected Driver Assistance System Functions Concerning Steering 533
19.2 Driving Stability Interventions 534
19.2.1 Function ‘Steering Recommendation’ 534
19.2.1.1 ‘Steering Recommendation’ at Yawing 535
19.2.1.2 ‘Steering Recommendation’ in the µ-split Situation 535
19.2.2 Ergonomics Requirements 536
19.2.3 Safety Requirements 537
19.3 Lane Assist 537
19.3.1 Lane Keeping System: LKS 538
19.3.1.1 Technical Realisation 538
19.3.1.2 Functioning 540
19.3.1.3 In Practise 540
19.3.2 Lane Departure Warning: LDW 541
19.3.3 Selected Systems on the Market 542
19.3.4 The Future of Lane Keeping Support 543
19.4 Parking Assist 544
19.4.1 Parking Assist System Requirements 545
19.4.2 Technical Realisation 546
19.4.3 Selected Systems on the Market 547
19.4.4 The Future of Parking Assists 548
References 549
20 Outlook: The Future of Steering Systems 551
20.1 Autonomous Driving 551
20.2 Steer by Wire 552
20.3 All-Wheel Steering 553
20.4 Integrated Chassis Control 553
20.5 Modules and Modularization of Steering Systems 554
20.6 Future Markets 554
20.7 Changes in Steering Technology 555
20.8 Steering Wheel Developments 556
20.9 Steering Column Developments 556
References 557
Advertisements 558
Index 563