Harrer / Pfeffer Steering Handbook

1. Auflage 2017
ISBN: 978-3-319-05449-0
Verlag: Springer International Publishing
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 569 Seiten, eBook

This edited volume presents basic principles as well as advanced concepts of the computational modeling of steering systems. Moreover, the book includes the components and functionalities of modern steering system, which are presented comprehensively and in a practical way. The book is written by more than 15 leading experts from the automotive industry and its components suppliers. The target audience primarily comprises practicing engineers, developers, researchers as well as graduate students who want to specialize in this field.

Zielgruppe

Professional/practitioner

Autoren/Hrsg.

Harrer, Manfred

Pfeffer, Peter

Inhaltsverzeichnis

1;Preface;5
2;Contents;7
3;Abbreviations and Symbols;9
4;Advertisements;14
5;1 Introduction and History;17
5.1;1.1ƒDefinition and Delimitation;19
5.2;1.2ƒTask and Significance of the Steering System;19
5.2.1;1.2.1 Basic Types;20
5.2.2;1.2.2 Designs;21
5.3;1.3ƒHistory of Lateral Dynamics;22
5.4;1.4ƒThe History of Vehicle Steering Systems;27
5.4.1;1.4.1 Turntable Steering;27
5.4.2;1.4.2 The Ackermann Steering;28
5.4.3;1.4.3 The Steering of the First Motor Vehicles;28
5.4.4;1.4.4 Mechanical Steering Gears;32
5.4.5;1.4.5 Power Steering Drives;33
5.5;References;40
6;2 Basic Principles of the Steering Process;42
6.1;2.1ƒSteering: Lateral Control of Vehicles;42
6.2;2.2ƒCornering;44
6.2.1;2.2.1 Slow Cornering;44
6.2.2;2.2.2 Fast Cornering;44
6.3;2.3ƒLateral Properties of the Tire;46
6.3.1;2.3.1 Vertical Force Transmission: Influence on the Length of the Contact Patch;46
6.3.2;2.3.2 Lateral Force of the Tire, Pneumatic Trail and Self-Aligning Torque;48
6.3.2.1;2.3.2.1 Range of Minor Lateral Accelerations (Linear Tire Properties);48
6.3.2.2;2.3.2.2 Range of Higher Lateral Acceleration (Non-linear Tire Characteristics);52
6.3.2.3;2.3.2.3 Influence of the Camber Angle;54
6.3.3;2.3.3 Transient Behaviour of Tire Lateral Forces;55
6.3.4;2.3.4 Summary of Tire Properties;55
6.4;2.4ƒSteering Wheel Torque;56
6.4.1;2.4.1 Calculation of Steering Wheel Torques;57
6.4.2;2.4.2 Steering Reinforcement;59
6.4.3;2.4.3 Steering Assistance Torque;61
6.5;2.5ƒFour-Wheel Steering;63
6.6;2.6ƒActive Suspension Steering;64
6.7;References;66
7;3 Steering Requirements: Overview;67
7.1;3.1ƒFunction and Steering Feel;67
7.2;3.2ƒPackage;68
7.3;3.3ƒWeight;70
7.4;3.4ƒCosts;71
7.5;3.5ƒQuality;71
7.6;3.6ƒEnergy and Environment;72
7.7;3.7ƒAcoustics and Vibrations;72
7.8;3.8ƒSystem Safety;73
7.9;3.9ƒLegal Requirements;74
7.10;References;75
8;4 Steering Kinematics;76
8.1;4.1 Introduction;76
8.2;4.2 Characteristics of the Steering Geometry;76
8.3;4.3 Characteristics of the Wheel Position;83
8.3.1;4.3.1 Steering Ratio;92
8.4;4.4 Steering Linkage;93
8.5;References;103
9;5 Basics of Lateral Vehicle Dynamics;104
9.1;5.1 Vehicle Modelling: Linear Single Track Model;104
9.1.1;5.1.1 Dynamic Equations;105
9.1.2;5.1.2 Steering Angle: Steering Wheel Angle—Power-Assisted Steering;109
9.1.3;5.1.3 Steady-State Circular Driving;111
9.1.4;5.1.4 Understeer and Oversteer;113
9.1.5;5.1.5 Transient Response: Response Time of a Steering Wheel Step Input;115
9.1.6;5.1.6 Yaw Gain;116
9.1.7;5.1.7 Steering Models;117
9.1.8;5.1.8 Steering Model with Power-Assist and Friction Effects;119
9.1.9;5.1.9 Discussion of the Influence of the Vehicle and Steering Parameters on the Driving and Steering Performance;119
9.2;5.2 Basic Dynamic Steering Design;122
9.2.1;5.2.1 Steering Axis Design: Steady State Self-aligning Torque;122
9.2.2;5.2.2 Determination of the Stability Factor;126
9.2.3;5.2.3 Steady State Yaw Gain and Steering Sensibility;126
9.2.4;5.2.4 Steering-wheel Torque/Lateral Acceleration Gradient (Steady State);128
9.2.5;5.2.5 Frequency Response Wheel Torque/steering wheel angle;128
9.2.6;5.2.6 Free Control Stability;129
9.2.7;5.2.7 Natural Frequency and Damping of the Steering;129
9.2.8;5.2.8 Minimising the Self Steering due to Uneven Braking Forces at the Front Axle;130
9.2.9;5.2.9 Stable Steering Braking System;130
9.2.10;5.2.10 Influence of Aerodynamics on Driveability;131
9.2.11;5.2.11 Front-wheel Drive Vehicles;131
9.3;References;131
10;6 Acoustics and Vibrations;134
10.1;6.1ƒInterfering and Operating Noise;135
10.1.1;6.1.1 Sound Sources of Steering Systems;135
10.1.2;6.1.2 Electric Steering Systems;137
10.1.3;6.1.3 Hydraulic Steering Systems;137
10.2;6.2ƒStability;141
10.2.1;6.2.1 Hydraulic Steering Clattering;141
10.2.2;6.2.2 Steering Rattle;142
10.2.3;6.2.3 Steering Wheel Nibble;144
10.3;6.3ƒStructure-Borne Sound Transmission in Hoses and Cables;146
10.3.1;6.3.1 Superposition of Structure-Borne Sound Waves;147
10.3.2;6.3.2 Acoustically Acting Material Parameters;147
10.3.3;6.3.3 Reduction of the Noise Transmission by Bending;149
10.4;6.4ƒSteering Column and Wheel—Design of Vibrations;150
10.4.1;6.4.1 Design Strategy;150
10.4.2;6.4.2 Target Eigen Frequencies of Components and Car;152
10.4.3;6.4.3 Calculation Models and Load Cases;154
10.4.4;6.4.4 Parameter Studies;156
10.4.5;6.4.5 Steering Wheel Absorbers;157
10.5;6.5ƒConclusion;160
10.6;References;160
11;7 Steering-Feel, Interaction Between Driver and Car;161
11.1;7.1ƒSteering Behaviour and Steering-Feel;162
11.2;7.2ƒSteering-Feel;164
11.2.1;7.2.1 Guidance Behaviour;165
11.2.2;7.2.2 Response Behaviour;165
11.2.3;7.2.3 Requirements of Ideal Steering Behaviour and Steering-Feel;166
11.3;7.3ƒEvaluation Methods for the Steering-Feel: Objectification;167
11.4;7.4ƒSubjective Evaluation of the Steering-Feel;168
11.5;7.5ƒObjective Evaluation of the Steering Behaviour;173
11.5.1;7.5.1 Measuring Equipment;173
11.5.2;7.5.2 Driving Maneuvers;174
11.5.3;7.5.3 Automated Data Processing;176
11.5.4;7.5.4 Objective Parameters;176
11.6;7.6ƒCorrelation and Regression Analysis;177
11.7;7.7ƒTarget Ranges for Ideal Steering Characteristics;178
11.8;References;179
12;8 Layout of Steering Systems;181
12.1;8.1 Basic Design of a Steering System;181
12.1.1;8.1.1 Rack Force;181
12.1.2;8.1.2 Steering Wheel Torque;183
12.1.3;8.1.3 Steering Dynamics;184
12.1.4;8.1.4 Steering Power;185
12.1.5;8.1.5 Steering Friction;185
12.1.5.1;8.1.5.1 Negative Features of Steering Friction;186
12.1.5.2;8.1.5.2 Positive Features of Steering Friction;186
12.2;8.2 Response Characteristics of Steering Systems;188
12.2.1;8.2.1 Steering Response (Guidance Response);189
12.2.2;8.2.2 Steering Feedback Response (Response behavior);190
12.2.2.1;8.2.2.1 Steering Feedback Response of Hydraulic Power Steering Systems;190
12.2.2.2;8.2.2.2 Non-Linear Enhancement for the Description of Hydraulic Power Steering Systems Feedback;194
12.2.2.3;8.2.2.3 Feedback Reponse of Electric Power Steering Systems Feedback;197
12.3;References;201
13;9 Steering Wheel;202
13.1;9.1ƒIntroduction;202
13.2;9.2ƒSubassemblies;202
13.2.1;9.2.1 Basic Structure;204
13.2.2;9.2.2 Rim and Corpus;206
13.2.3;9.2.3 Horn;207
13.2.4;9.2.4 AirBag and Crash;208
13.2.4.1;9.2.4.1 AirBag Cover;209
13.2.4.2;9.2.4.2 AirBag;209
13.2.4.3;9.2.4.3 Gas Generator;210
13.2.5;9.2.5 Multi Function;211
13.2.6;9.2.6 Foam, Leather and Decorations;214
13.3;9.3ƒRequirements for Components and Assembly;215
13.4;9.4ƒTesting and Protection;216
13.4.1;9.4.1 Airbag;217
13.4.1.1;9.4.1.1 General and Crash Requirements;217
13.4.1.2;9.4.1.2 Environmental Simulation;217
13.4.2;9.4.2 Steering Wheel;219
13.4.2.1;9.4.2.1 Operational Safety;219
13.4.2.2;9.4.2.2 ECE-R12;221
13.4.2.3;9.4.2.3 Environmental Simulation, Varnish Test, Electroplating Test;222
13.4.3;9.4.3 Controls/EE;223
13.5;9.5ƒModularisation, Trends of Development, the Future;223
14;10 Steering Column and Intermediate Steering Shaft;225
14.1;10.1ƒIntroduction;225
14.2;10.2ƒSubassemblies;227
14.2.1;10.2.1 Upper Steering Shaft;227
14.2.2;10.2.2 Manually Adjustable Steering Column;228
14.2.3;10.2.3 Electrically Adjustable Steering Column;229
14.2.4;10.2.4 Intermediate Steering Shafts;230
14.2.4.1;10.2.4.1 Gimbal Error and Centre Point;231
14.2.5;10.2.5 Parts of the Subassemblies;233
14.2.5.1;10.2.5.1 Adjustable Units;233
14.2.5.1.1;Manual Locking;234
14.2.5.1.2;Electric Drive Unit;235
14.2.5.2;10.2.5.2 Upper Steering Shaft Including Jacket Tube;236
14.2.5.3;10.2.5.3 Crash Elements;238
14.2.5.4;10.2.5.4 Joints;240
14.2.5.4.1;Universal Joints;241
14.2.5.4.2;Centred Double Joint;242
14.2.5.5;10.2.5.5 Length Compensation of the Intermediate Steering Shaft;242
14.2.5.6;10.2.5.6 Dampers;244
14.3;10.3ƒTesting Steering Column and Intermediate Steering Shaft;245
14.3.1;10.3.1 Transmission Capability;246
14.3.1.1;10.3.1.1 Static Strength;246
14.3.1.2;10.3.1.2 Dynamic Strength;247
14.3.2;10.3.2 Stiffness;247
14.3.3;10.3.3 Durability Tests for Adjustable Units of Steering Columns;248
14.3.4;10.3.4 Dynamics;249
14.3.4.1;10.3.4.1 Requirements of the Steering Column;249
14.3.4.2;10.3.4.2 Analytic Identification/Measurement of the Dynamics;250
14.3.4.3;10.3.4.3 Parameters of Influence;251
14.3.5;10.3.5 Crash Characteristics;252
14.3.5.1;10.3.5.1 Steering Spindle;252
14.3.5.2;10.3.5.2 Steering Column;254
14.3.6;10.3.6 Displacement Forces to Adjust the Steering Column;255
14.3.7;10.3.7 Temperature;256
14.3.8;10.3.8 Corrosion;257
14.4;10.4ƒThe Future;258
15;11 Mechanical and Hydraulic Gears;259
15.1;11.1ƒDefinition of Rack-and-Pinion Gears;259
15.2;11.2ƒApplicability/Pros and Cons;261
15.3;11.3ƒKinematic Differentiating Features of Gears;262
15.3.1;11.3.1 Position of the Gear in Relation to the Front Axle;262
15.3.2;11.3.2 On-board Gear Interfaces;263
15.3.3;11.3.3 Adjustment of the Gear Case;264
15.3.4;11.3.4 Tie Rod Interfaces;264
15.3.5;11.3.5 Kind of Gear Ratio;265
15.4;11.4ƒDesign and Main Components of a Mechanical Rack-and-Pinion Gear;265
15.4.1;11.4.1 Gear Case;267
15.4.1.1;11.4.1.1 One-Piece Gear Case;267
15.4.1.2;11.4.1.2 Two-Piece Gear Case in Composite Design;267
15.4.2;11.4.2 Steering Pinion;268
15.4.2.1;11.4.2.1 Pinion Bearing;268
15.4.2.2;11.4.2.2 Implementation of the Pinion Dovetailing;270
15.4.3;11.4.3 Rack and Rack Guide;270
15.4.3.1;11.4.3.1 Rack Guide;270
15.4.3.2;11.4.3.2 Rack Yoke;272
15.4.3.2.1;Construction of the rack yoke;272
15.4.3.2.2;Rack yoke tuning;274
15.4.3.3;11.4.3.3 Rack Bushing;274
15.5;11.5ƒDovetailing and Gear Ratio;275
15.5.1;11.5.1 Constant Gear Ratio;275
15.5.2;11.5.2 Variable Gear Ratio;275
15.5.2.1;11.5.2.1 History of the Development;277
15.5.3;11.5.3 Applications;277
15.5.3.1;11.5.3.1 Applications for the Steering System;277
15.5.3.1.1;Mechanical gear—diminished torque;278
15.5.3.1.2;Power-assisted gear—reduced power consumption;278
15.5.3.2;11.5.3.2 Driver Application;279
15.5.3.2.1;Ergonomics;279
15.5.3.2.2;Vehicle dynamics;280
15.5.3.3;11.5.3.3 Special Applications;280
15.5.3.3.1;Combined applications;281
15.5.4;11.5.4 Technical Limits;283
15.5.4.1;11.5.4.1 Size of the Rack Gain;283
15.5.4.2;11.5.4.2 Contact Lines;284
15.5.4.3;11.5.4.3 Stability and Noise (NVH);285
15.5.5;11.5.5 Manufacturing Processes;287
15.5.5.1;11.5.5.1 Rotary Swaging;287
15.5.5.2;11.5.5.2 Semi-hot Forging;288
15.5.5.3;11.5.5.3 Pipe Reshaping;289
15.6;11.6ƒRequirements of a Mechanical Rack Gear;290
15.6.1;11.6.1 Functional Requirements of Gears;290
15.6.1.1;11.6.1.1 Rack Yoke Clearance;291
15.6.1.2;11.6.1.2 Steering Pinion Torque;291
15.6.1.3;11.6.1.3 Rack Displacement Force;292
15.6.1.4;11.6.1.4 Efficiency;293
15.6.1.5;11.6.1.5 Noise (NVH) Requirements;294
15.6.2;11.6.2 Strength Requirements of the Gear;294
15.6.2.1;11.6.2.1 Static Strength;295
15.6.2.1.1;Fracture Torque Test;295
15.6.2.1.2;Charpy Impact Test;295
15.6.2.2;11.6.2.2 Dynamic Strength and Wear Test;295
15.6.2.2.1;Parking Test;295
15.6.2.2.2;Wear Test;296
15.6.3;11.6.3 Environmental Requirements of the Gear;296
15.6.3.1;11.6.3.1 Salt Spray Test;296
15.6.3.2;11.6.3.2 Dirt Water Test;296
15.7;11.7ƒDesign Verifications and Product Validation of a Rack-and-Pinion Gear;297
15.7.1;11.7.1 Concept Verification;297
15.7.2;11.7.2 Design Verification;297
15.7.3;11.7.3 Product Validation;297
15.7.4;11.7.4 Accompanying Test;298
15.8;11.8ƒHydraulic Steering Systems;298
15.8.1;11.8.1 Objectives;298
15.8.1.1;11.8.1.1 Reducing the Steering Forces;298
15.8.1.2;11.8.1.2 Reducing the Steering Ratio;299
15.8.1.3;11.8.1.3 More damping of the steering system;299
15.8.1.4;11.8.1.4 More Freedom in the Design of the Chassis;300
15.8.2;11.8.2 Necessary Changes in the Vehicle Opposed to Manual Steering;300
15.8.3;11.8.3 Necessary Changes in the Gear Opposed to Manual Steering;300
15.8.4;11.8.4 Specific Features of Hydraulic Gears for On-board Use;301
15.9;11.9ƒConstructions and Components of Hydraulic Gears;301
15.9.1;11.9.1 Configurations;302
15.9.1.1;11.9.1.1 End Tap;302
15.9.1.2;11.9.1.2 Central Tap;303
15.9.1.3;11.9.1.3 Parallel Auxiliary Cylinder;304
15.9.2;11.9.2 Cylinder;305
15.9.2.1;11.9.2.1 Rack in the Cylinder Area;306
15.9.2.2;11.9.2.2 Pistons with Piston Ring;307
15.9.2.3;11.9.2.3 Rack Gaskets and Sealing System of the Cylinder;308
15.9.2.3.1;Configuration of a rack seal;309
15.9.2.3.2;Interface at the external diameter;309
15.9.2.3.3;Interface in the inner diameter;310
15.9.2.3.4;Integration of the seal in the gear;311
15.9.2.4;11.9.2.4 Cylinder Pipe with Connections;311
15.9.3;11.9.3 Rotary Disk Valve with Input Shaft and Steering Pinion;313
15.9.3.1;11.9.3.1 Steering Pinion;314
15.9.3.2;11.9.3.2 Torsion Bar and Overload Fuse;314
15.9.3.3;11.9.3.3 Sleeve with Valve Rings;315
15.9.3.4;11.9.3.4 Input Shaft;316
15.9.3.5;11.9.3.5 Configuration Forms;317
15.9.4;11.9.4 Other Parts of a Hydraulic Gear;318
15.9.4.1;11.9.4.1 Transfer Pipelines;318
15.9.4.2;11.9.4.2 Bellow Vent Pipe;318
15.9.5;11.9.5 Typical Characteristics of Hydraulic Gears;319
15.10;11.10ƒFunctionality of the Steering Hydraulics;319
15.10.1;11.10.1 Steering Valve: Principle of the Cutback;319
15.10.2;11.10.2 External Influence on the Valve Indicator;324
15.10.3;11.10.3 Effects of Steering Movements: Volumetric Flow Splitting;326
15.10.4;11.10.4 Valve Noises: Hiss;327
15.10.5;11.10.5 Internal Leakage;328
15.10.6;11.10.6 Modelling (Position Control Circuit);330
15.10.7;11.10.7 Damping: Instabilities;330
15.11;11.11ƒAdditional Hydraulic Systems;331
15.11.1;11.11.1 Centring;331
15.11.2;11.11.2 Speed Dependence;333
15.11.3;11.11.3 Damping Valves;336
15.11.4;11.11.4 Steering Valves with Damping Qualities;337
15.11.5;11.11.5 Pressure Limitation in the Rack-and-Pinion End Position;339
15.12;11.12ƒBall-Circulation Gears with Nuts/Utility Vehicle Steering Systems;341
15.12.1;11.12.1 Fields of Application;341
15.12.2;11.12.2 Configuration of Ball-Recirculating Gears with Nut;342
15.12.3;11.12.3 Comparison Between Ball-Recirculating Gear with Nut and Rack-and-Pinion Steering;343
15.12.4;11.12.4 Technical Data and Parameters;344
15.12.5;11.12.5 Additional Systems;344
15.12.6;11.12.6 Dual-Circuit Steering;345
15.13;11.13ƒRequirements for a Hydraulic Gear;346
15.13.1;11.13.1 Functional Requirements;346
15.13.2;11.13.2 Strength Requirements;347
15.13.2.1;11.13.2.1 Static Strength: Burst Pressure Test;347
15.13.2.2;11.13.2.2 Dynamic Strength: Pressure Pulsation;347
15.13.3;11.13.3 Environmental Requirements: Cold Start Test;347
15.14;References;347
16;12 Tie Rods;348
16.1;12.1ƒIntroduction;348
16.2;12.2ƒBasic Variants;349
16.2.1;12.2.1 Tie Rods for Ball-and-Nut Steering;349
16.2.2;12.2.2 Tie Rods for Rack-and-Pinion Steering;349
16.3;12.3ƒTie Rod Joints;351
16.3.1;12.3.1 Inner Joint (Axial Joint);351
16.3.1.1;12.3.1.1 Ventilation Function of the Inner Joint;352
16.3.2;12.3.2 Outer Joint (Radial Joint);353
16.4;12.4ƒToe Adjustment;354
16.5;12.5ƒRequirements and Design;354
16.5.1;12.5.1 Design Regulations for Tie Rods;354
16.5.2;12.5.2 Design of the Tie Rod with Regard to Component Strength;354
16.5.3;12.5.3 Design of the Joint Bearing;357
16.5.4;12.5.4 Design of the Outer Joint Sealing;358
16.5.4.1;12.5.4.1 Requirements of the Joint Sealing;359
16.6;12.6ƒDamping/Decoupling;360
16.7;12.7ƒInterfaces to the wheel carrier;360
16.8;12.8ƒLightweight Design;361
16.9;12.9ƒThe Future;362
16.9.1;12.9.1 Overload Behaviour;362
16.9.2;12.9.2 Sensor Joint;364
16.10;References;364
17;13 Hydraulic Power Supply;366
17.1;13.1ƒServo Pumps;366
17.1.1;13.1.1 Introduction;366
17.1.2;13.1.2 Vane-Type Pump;366
17.1.2.1;13.1.2.1 Vane-Type Pumps with Bypass Valve for Energy Conservation;369
17.1.2.2;13.1.2.2 Variable Pump;370
17.1.3;13.1.3 Radial Piston Pump;373
17.1.4;13.1.4 Tandem Pump;374
17.2;13.2ƒOil Supply and Oils;374
17.2.1;13.2.1 Oil Tank;374
17.2.1.1;13.2.1.1 Types;375
17.2.1.2;13.2.1.2 Filling and Ventilation;375
17.2.1.3;13.2.1.3 Filtration;377
17.2.1.4;13.2.1.4 Separation Efficiency;377
17.2.1.5;13.2.1.5 System Purity;378
17.2.1.6;13.2.1.6 Design Under Lateral Acceleration;379
17.2.2;13.2.2 Steering Hoses and Tubes;379
17.2.2.1;13.2.2.1 High-Pressure Duct Including Screw Connection (Hose Types and Construction);380
17.2.2.2;13.2.2.2 Screw Connections Of High-Pressure Lines and Stretch tubes;381
17.2.2.3;13.2.2.3 Suction and Return Conduits;383
17.2.2.4;13.2.2.4 Acoustic Tuning/Noise Measures;383
17.2.3;13.2.3 Cooling/Cooling Fronds/Cooler;384
17.2.4;13.2.4 System Limits;384
17.2.5;13.2.5 Servo Oils;385
17.2.5.1;13.2.5.1 Other Specifications;388
18;14 Electrically Powered Hydraulic Steering;389
18.1;14.1ƒIntroduction;389
18.1.1;14.1.1 Configuration and Functional Principle;389
18.1.2;14.1.2 Steering System Classification;391
18.1.3;14.1.3 Application Examples;392
18.2;14.2ƒSystem Descriptions;392
18.2.1;14.2.1 System Overview;393
18.2.2;14.2.2 System Layout;394
18.2.2.1;14.2.2.1 Steady State Layout;395
18.2.2.2;14.2.2.2 Dynamic Layout Criteria;396
18.2.3;14.2.3 Energy Consumption;397
18.2.3.1;14.2.3.1 Efficiency;397
18.2.3.2;14.2.3.2 Power Input and Energy Consumption;397
18.3;14.3ƒComponents;399
18.3.1;14.3.1 Motor Pump Unit;400
18.3.1.1;14.3.1.1 Main Requirements and Interfaces;400
18.3.1.2;14.3.1.2 Electric Power Pack;400
18.3.1.3;14.3.1.3 Pump and Valves;403
18.3.2;14.3.2 Hydraulic Pipe System;405
18.3.2.1;14.3.2.1 Main Requirements;405
18.3.2.2;14.3.2.2 Configuration and Damping Principles;406
18.3.2.3;14.3.2.3 Determination of the Damping Behaviour;406
18.3.2.4;14.3.2.4 Hydraulic Resistance;407
18.3.3;14.3.3 Other Components;408
18.3.3.1;14.3.3.1 Sensors;408
18.3.3.2;14.3.3.2 Fluids;408
18.3.3.3;14.3.3.3 Tanks and Brackets;409
18.4;References;409
19;15 Electric Power Steering Systems;410
19.1;15.1ƒIntroduction;410
19.1.1;15.1.1 Analogies of EPS and HPS;412
19.2;15.2ƒDesigns of EPS Systems;413
19.2.1;15.2.1 EPSc: Column;413
19.2.2;15.2.2 EPSp: Pinion;415
19.2.3;15.2.3 EPSdp: Dual Pinion;415
19.2.4;15.2.4 EPSapa: Axle Parallel;416
19.2.5;15.2.5 EPSrc: Rack Concentric;417
19.3;15.3ƒSubassemblies of the EPS;418
19.3.1;15.3.1 Power-Assisted Gear;418
19.3.1.1;15.3.1.1 Worm Gear;419
19.3.1.2;15.3.1.2 Ball Screw Drive;420
19.3.1.3;15.3.1.3 Toothed Belt Drive;421
19.3.2;15.3.2 Electric Motor;423
19.3.2.1;15.3.2.1 Overview/Comparison/Working Area;423
19.3.2.2;15.3.2.2 DC Motor with Mechanical Commutator (see also Stölting and Kallenbach 2006);426
19.3.2.3;15.3.2.3 Asynchronous Motor;427
19.3.2.4;15.3.2.4 Synchronous Motor;428
19.3.2.5;15.3.2.5 Position and Rev Sensors;430
19.3.3;15.3.3 Torque Sensor;433
19.3.3.1;15.3.3.1 Requirements/Classification;433
19.3.3.2;15.3.3.2 Sensors with Torsion Rod;434
19.3.3.3;15.3.3.3 Torsion-Resistant Sensors;439
19.3.4;15.3.4 ECU;441
19.3.4.1;15.3.4.1 Designs;442
19.3.4.2;15.3.4.2 Signal Electronics;444
19.3.4.3;15.3.4.3 Power Electronics;445
19.4;15.4ƒSystem Design;446
19.4.1;15.4.1 General System Requirements;446
19.4.2;15.4.2 Design Parameters;448
19.4.3;15.4.3 Requirements for the Wiring System;452
19.5;15.5ƒSystem Safety;454
19.5.1;15.5.1 Normative Code;454
19.5.1.1;15.5.1.1 IEC 61508;454
19.5.1.2;15.5.1.2 ISO 26262;454
19.5.2;15.5.2 Safety in EPS Applications;455
19.5.2.1;15.5.2.1 Task of the Safety Concept;455
19.5.2.2;15.5.2.2 EPS Risk Classification;455
19.5.2.3;15.5.2.3 Qualities of the Safe State;457
19.5.2.4;15.5.2.4 Switch-Off Channels;458
19.5.2.5;15.5.2.5 Safety Measures for Subcomponents of the System;459
19.5.2.5.1;Monitoring of External Signals;460
19.5.2.5.2;Monitoring Sensors;460
19.5.2.5.3;Monitoring Plan of the Computer System;461
19.5.2.5.4;Monitoring Power Electronics/Actuator;462
19.5.2.5.5;Safety-Related ECU Block Diagram;462
19.6;15.6ƒSteering Functions and Control;463
19.6.1;15.6.1 Steering Functions;464
19.6.1.1;15.6.1.1 Basic Steering Functions;464
19.6.1.1.1;Power-Assistance;465
19.6.1.1.2;Friction Compensation;467
19.6.1.1.3;Inertia Compensation;467
19.6.1.1.4;Active Damping;468
19.6.1.2;15.6.1.2 Extended Steering Functions;468
19.6.1.2.1;Active Return;468
19.6.1.2.2;Directional Stability Correction;469
19.6.1.3;15.6.1.3 Functions at Vehicle Level;469
19.6.1.3.1;Park Steering Assistant;469
19.6.1.3.2;Driver Warning/Lane Departure Warning;470
19.6.1.3.3;Tracking/Lane Keeping System;470
19.6.1.3.4;Dynamic Steering Torque Recommendation;470
19.6.2;15.6.2 Control Plans for the Steering Feel;471
19.6.2.1;15.6.2.1 Classical Control Plans;471
19.6.2.2;15.6.2.2 Control of the Driver’s Torque;472
19.7;References;473
20;16 Superimposed Steering System;475
20.1;16.1ƒIntroduction;475
20.2;16.2ƒHistory;475
20.3;16.3ƒFunctional Principle;476
20.4;16.4ƒConfigurations;478
20.4.1;16.4.1 General System Configuration;478
20.4.2;16.4.2 Actuators and Actuator Varieties;480
20.4.2.1;16.4.2.1 Audi/ZFLS Dynamic Steering;480
20.4.2.2;16.4.2.2 Active Steering BMW/ZFLS;482
20.4.2.3;16.4.2.3 Lexus/JTEKT VGRS;483
20.4.3;16.4.3 Adaptations in the Steering System;485
20.4.3.1;16.4.3.1 Steering Ratio;485
20.4.3.2;16.4.3.2 Adaptations to Meet NHV Requirements;486
20.4.3.3;16.4.3.3 Adaptations Due to Steering Stabilisation;486
20.4.3.4;16.4.3.4 System Network;486
20.5;16.5ƒFunctions of the Superimposed Steering System;487
20.5.1;16.5.1 VGR;487
20.5.1.1;16.5.1.1 Low Speed;488
20.5.1.2;16.5.1.2 Medium Speed;488
20.5.1.3;16.5.1.3 Stability at High Speed;488
20.5.1.4;16.5.1.4 Varieties of Characteristic Curves According to the Driver’s Request;490
20.6;16.6ƒSteering Stabilisation;490
20.6.1;16.6.1 Steering Stabilisation at Oversteering;491
20.6.2;16.6.2 Steering Stabilisation at Understeering;492
20.6.3;16.6.3 Steering Stabilisation During Braking on Roads with Different Friction Values (?-split);493
20.7;16.7ƒSystem Safety;493
20.8;16.8ƒThe Future;497
20.9;References;498
21;17 All-Wheel Steering;499
21.1;17.1 Introduction, History, Basics, Objective;499
21.2;17.2 Construction Methods;500
21.2.1;17.2.1 Mechanical Systems;500
21.2.2;17.2.2 Hydraulic Systems;504
21.2.3;17.2.3 Electromechanical Systems;506
21.2.4;17.2.4 Central Actuator Versus Single Wheel Actuators;509
21.3;17.3 Effects of an All-Wheel Steering on Vehicle Dynamics;510
21.3.1;17.3.1 Kinematic Qualities of an All-Wheel steering;511
21.3.2;17.3.2 Influence of an All-Wheel Steering on the Stationary Vehicle Characteristics;512
21.3.3;17.3.3 Influence of an All-Wheel Steering on the Nonstationary Vehicle Characteristics;513
21.3.4;17.3.4 Combination of a Rear-Wheel Steering with a Superimposed Steering System at the Front Axle;514
21.4;References;517
22;18 Steer by Wire;519
22.1;18.1 Introduction;519
22.1.1;18.1.1 State-of-the-Art;519
22.1.2;18.1.2 Pros and Cons;520
22.2;18.2 Components;522
22.2.1;18.2.1 Operating Element Quality;523
22.3;18.3 Steering Functions;526
22.3.1;18.3.1 Discussion of the Normal Driving Mode;527
22.3.2;18.3.2 Discussion of the Lateral Dynamic Limit Range;527
22.3.3;18.3.3 Compensating Interferences;528
22.3.4;18.3.4 Combined Longitudinal–Lateral Guidance;529
22.4;18.4 Safety Concepts;529
22.5;18.5 The Future;531
22.6;References;531
23;19 Overview: Driver Assistance System Functions;533
23.1;19.1 Overview of Selected Driver Assistance System Functions Concerning Steering;533
23.2;19.2 Driving Stability Interventions;534
23.2.1;19.2.1 Function ‘Steering Recommendation’;534
23.2.1.1;19.2.1.1 ‘Steering Recommendation’ at Yawing;535
23.2.1.2;19.2.1.2 ‘Steering Recommendation’ in the µ-split Situation;535
23.2.2;19.2.2 Ergonomics Requirements;536
23.2.3;19.2.3 Safety Requirements;537
23.3;19.3 Lane Assist;537
23.3.1;19.3.1 Lane Keeping System: LKS;538
23.3.1.1;19.3.1.1 Technical Realisation;538
23.3.1.2;19.3.1.2 Functioning;540
23.3.1.3;19.3.1.3 In Practise;540
23.3.2;19.3.2 Lane Departure Warning: LDW;541
23.3.3;19.3.3 Selected Systems on the Market;542
23.3.4;19.3.4 The Future of Lane Keeping Support;543
23.4;19.4 Parking Assist;544
23.4.1;19.4.1 Parking Assist System Requirements;545
23.4.2;19.4.2 Technical Realisation;546
23.4.3;19.4.3 Selected Systems on the Market;547
23.4.4;19.4.4 The Future of Parking Assists;548
23.5;References;549
24;20 Outlook: The Future of Steering Systems;551
24.1;20.1 Autonomous Driving;551
24.2;20.2 Steer by Wire;552
24.3;20.3 All-Wheel Steering;553
24.4;20.4 Integrated Chassis Control;553
24.5;20.5 Modules and Modularization of Steering Systems;554
24.6;20.6 Future Markets;554
24.7;20.7 Changes in Steering Technology;555
24.8;20.8 Steering Wheel Developments;556
24.9;20.9 Steering Column Developments;556
24.10;References;557
25;Advertisements;558
26;Index;563

Introduction and History.- Basic Principles of the Steering Process.- Steering.- Steering kinematics.- Basics of transverse dynamics.- Acoustics and vibrations.- Layout of steering systems.- Steering wheel.- Steering column and intermediate steering shaft.- Mechanical and hydraulic gears.- Tie rods.- Hydraulic power supply.- Electrically powered hydraulic steering.- Electric Power Steering systems.- Superimposed steering system.- All-wheel steering.- Steer-by-Wire.- Overview - driver assistance system.- Outlook - The future of steering.