Flight control systems: practical issues in design and implementation

Front Matter......Page 1
Contributors......Page 4
Nomenclature......Page 11
Preface......Page 6
Table of Contents......Page 0
Table of Contents......Page 14
1.1 Introduction......Page 20
1.2 The General Objectives of Flight Control......Page 21
1.2.2 Civil Aircraft......Page 25
1.3.1 History......Page 26
1.3.2 Military Aircraft Developments......Page 28
1.3.3 Civil Aircraft Developments......Page 31
1.4.1 Military Aircraft Operations......Page 32
1.4.2 Civil Aircraft Operations......Page 34
1.5 The Benefits of Fly-by-Wire......Page 36
1.5.1 Military Aircraft Benefits......Page 37
1.5.2 Civil Aircraft Benefits......Page 38
1.6.1 Military Aircraft-Design Considerations and Systems Overview......Page 39
1.6.2 Civil Aircraft - Design Considerations and Systems Overview......Page 46
1.7.1 Eurofighter Typhoon......Page 49
1.7.2 Future Challenges for Military Aircraft......Page 52
1.8.1 The Airbus Fly-by-Wire Family......Page 53
1.8.3 Future Challenges for Civil Aircraft......Page 61
1.9.1 The Current Situation......Page 62
1.9.2 The System Development Process......Page 63
1.9.3 The Flight Control Laws Development Process......Page 65
1.9.4 Cost Considerations - Recurring and Nonrecurring Costs......Page 69
1.10 Closing Discussion......Page 70
1.12 References......Page 72
2.1 Introduction......Page 75
2.2 A Mathematical Framework......Page 76
2.3.1 Earth Axes......Page 78
2.3.2 Aeroplane-Body INHERIT_ZOOM Axes......Page 79
2.3.3 Perturbation Variables......Page 80
2.3.4 Angular Relationships in Symmetric Flight......Page 82
2.3.5 Choice of Axes......Page 83
2.4 Euler Angles and Aeroplane Attitude......Page 84
2.4.2 Angular Velocities Transformation......Page 85
2.5.2 Engine Control......Page 86
2.6.1 The Equations of Longitudinal Symmetric Motion......Page 87
2.7 The Equations of Motion in State-Space Form......Page 88
2.7.1 The Equations of Longitudinal Motion......Page 89
2.8 Aircraft-Response Transfer Functions......Page 91
2.9 The Transfer Function Matrix......Page 92
2.10.1 The Longitudinal Transfer Function Matrix......Page 93
2.10.3 The Short-Period Pitching Oscillation......Page 95
2.10.4 The Phugoid......Page 98
2.11.1 The Lateral Transfer Function Matrix......Page 100
2.11.2 The Lateral-Directional Characteristic Equation......Page 103
2.11.3 The Roll-Subsidence Mode......Page 104
2.11.4 The Spiral Mode......Page 105
2.11.5 The Dutch-Roll Mode......Page 106
2.13 Reference......Page 108
3.2.1 Control-Surface Types......Page 109
3.2.2 Actuator Operation......Page 110
3.3 Actuation System-Performance Criteria......Page 115
3.3.1 Stall Load......Page 117
3.3.2 Maximum Rate Capability......Page 118
3.3.3 Frequency Response......Page 119
3.3.4 Dynamic Stiffness......Page 123
3.3.5 Failure Transients......Page 124
3.4 Actuation System Modelling......Page 126
3.5 Nonlinear Frequency Response......Page 128
3.6 Saturation Analysis......Page 129
3.8 Failure Transients......Page 131
3.9 Conclusions......Page 135
3.10 Acknowledgements......Page 137
4.1 Introduction......Page 138
4.2.2 Modal Criteria......Page 140
4.2.3 Phugoid Flying Qualities......Page 141
4.2.4 Short-Period Flying Qualities......Page 142
4.2.5 Criteria for the Longitudinal Short-Period Dynamics......Page 143
4.2.7 Other Short-Period Criteria......Page 145
4.2.8 Equivalent Systems......Page 146
4.2.9 Equivalent Time Delay......Page 150
4.2.11 The Neal-Smith Method......Page 151
4.2.13 Time-History Criteria......Page 153
4.3.1 Roll Mode......Page 155
4.3.4 Dutch-roll Mode......Page 158
4.3.5 The Parameter t%/~a......Page 159
4.3.6 Phi-to-Beta Ratio, ~b//3......Page 160
4.4.1 The Influence of Feedback......Page 161
4.4.2 The Influence of Actuators, Sensors and Processors......Page 163
4.4.3 Multiple-Input, Multiple-Output Flying Quality Possibilities......Page 165
4.5.1 Integration in the Forward Path......Page 166
4.5.2 Notch Filters......Page 168
4.6.1 PIO Categories......Page 169
4.6.3 Criteria for Category I PIOs......Page 170
4.7.1 STI High-Gain Asymptote Parameter......Page 171
4.8 Non-Modal PIO Criteria......Page 174
4.8.1 Some Current Criteria......Page 175
4.8.2 Effectiveness of the Criteria......Page 180
4.9.1 Criteria for Category II PIOs......Page 183
4.9.2 The Consequences of Rate Limiting......Page 184
4.11 References......Page 186
5.1.1 Study Phase/Vendor Selection......Page 189
5.1.6 System Integration and Test......Page 191
5.1.11 Design Reviews......Page 192
5.2.1 Introduction......Page 193
5.2.2 Design and Test Methodology......Page 194
5.2.3 Safety Considerations......Page 195
5.3.1 Primary Considerations......Page 197
5.4.3 AFCS System Interfaces......Page 203
5.4.4 AFCS Configurations......Page 207
5.4.5 Flight Control Computer Data Processing......Page 208
6.1 Introduction......Page 216
6.2 Philosophy of Flight Testing......Page 219
6.2.1 Ground Testing......Page 220
6.2.2 Simulator and Rig Testing......Page 221
6.3 Aircraft Ground Testing......Page 228
6.3.3 Structural-Coupling Tests......Page 229
6.3.4 Electromagnetic-Compatibility Testing......Page 230
6.4 Flight Test Tools and Techniques......Page 232
6.5.1 FBW Jaguar Demonstrator Flight Test Programme......Page 233
6.5.2 The EAP Demonstrator Flight Test Programme......Page 236
6.8 References......Page 242
7.1 Introduction......Page 244
7.2.2 Inertial Excitation of the Flexible-Aircraft Control Surface......Page 245
7.2.3 Actuators, Flight Control Computers and the Aircraft-Motion Sensor Unit......Page 247
7.2.6 Formulation for Solution and Design Trade-Offs......Page 249
7.3 FCS-SC Structural Coupling: Design Examples......Page 253
7.3.1 Jaguar-First Flight 1968......Page 254
7.3.2 Tornado - First Flight 1974......Page 255
7.3.3 Experimental Aircraft Programme (EAP) - First Flight 1986......Page 256
7.3.4 Eurofighter 2000 (EF2000) - First Flight 1994......Page 267
7.4.1 Limit-Cycle Prediction and Specification of Alternative Clearance Requirements......Page 279
7.4.2 Active Control for Rigid Body and Structural-Mode Stabilisation......Page 303
7.4.3 Flexible Aircraft Modelling......Page 316
7.5 Conclusions......Page 317
7.6 References......Page 318
8.1 Introduction......Page 320
8.2 The RCAM Control Problem......Page 321
8.2.1 A Landing-Approach Simulation......Page 323
8.2.2 Performance Specifications......Page 324
8.2.5 Safety Specifications......Page 325
8.3.1 Eigenstructure Analysis......Page 326
8.3.2 Eigenstructure Assignment......Page 329
8.4.1 Controller Structure......Page 335
8.4.2 Construction of a Desired Eigenstructure......Page 339
8.4.4 Methods of Controller Analysis......Page 343
8.4.5 Analysis of the Longitudinal Controller......Page 346
8.4.6 Analysis of the Lateral Controller......Page 348
8.4.7 0ptimisation of the Controllers......Page 349
8.5 Nonlinear Simulation of the Controlled Aircraft......Page 350
8.5.1 Performance Specifications......Page 352
8.5.3 Ride-Quality Specifications......Page 356
8.5.5 Control-Activity Specifications......Page 357
8.5.6 Evaluation Using a Landing-Approach Simulation......Page 358
8.6 Conclusions......Page 362
8.7 References......Page 365
9.1 Introduction......Page 367
9.3 Ha Loop Shaping......Page 369
9.4 Linear Design for the VAAC......Page 373
9.5.1 Gain Scheduling......Page 378
9.5.2 Anti-Windup......Page 379
9.5.3 Flight Modes......Page 381
9.5.4 Flight Testing......Page 383
9.6 Flight Clearance......Page 385
9.7 The Way Ahead......Page 390
9.8 References......Page 391
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