Fault-diagnosis applications : model-based condition monitoring : actuators, drives, machinery, plants, sensors, and fault-tolerant systems

Supervision, condition-monitoring, fault detection, fault diagnosis and fault management play an increasing role for technical processes and vehicles in order to improve reliability, availability, maintenance and lifetime. For safety-related processes fault-tolerant systems with redundancy are required in order to reach comprehensive system integrity. This book is a sequel of the book Fault-Diagnosis Systems published in 2006, where the basic methods were described. After a short introduction into fault-detection and fault-diagnosis methods the book shows how these methods can be applied for a selection of 20 real technical components and processes as examples, such as: Electrical drives (DC, AC) Electrical actuators Fluidic actuators (hydraulic, pneumatic) Centrifugal and reciprocating pumps Pipelines (leak detection) Industrial robots Machine tools (main and feed drive, drilling, milling, grinding) Heat exchangers Also realized fault-tolerant systems for electrical drives, actuators and sensors are presented. The book describes why and how the various signal-model-based and process-model-based methods were applied and which experimental results could be achieved. In several cases a combination of different methods was most successful. The book is dedicated to graduate students of electrical, mechanical, chemical engineering and computer science and for engineers. " References on terminology......Page 3 Chapter 2......Page 5 b) Hard switching over: fast reconfiguration......Page 7 b) Fault-tolerant single piston with double valve......Page 13 Cover......Page 1 Contents......Page 8 Chapter 3......Page 9 9.4.1 Two- and three-mass model......Page 10 Chapter 4......Page 11 Chapter 5......Page 12 List of Symbols......Page 14 d) Required instrumentation......Page 15 Chapter 8......Page 16 Chapter 9......Page 17 Part I Supervision, Fault Detection and Diagnosis......Page 18 2.1 Basic tasks of supervision......Page 19 Chapter 10......Page 20 b) Breakage detection......Page 22 12.4.6 Virtual drive dynamic sensors by model based analytical redundancy......Page 24 Fault:......Page 25 Failure:......Page 26 Reliability:......Page 27 Safety:......Page 28 Integrity:......Page 29 2.3.2 Heuristic symptom generation......Page 31 2.4.2 Trend checking......Page 33 2.4.3 Change detection with binary thresholds......Page 34 Fault Diagnosis Applications......Page 4 Preface......Page 6 Chapter 12......Page 21 12.4.4 Fault-tolerant flow sensor......Page 23 2.3.3 Fault diagnosis......Page 32 (iv) System properties......Page 2 2.4.4 Adaptive thresholds......Page 35 2.3.1 Analytic symptom generation......Page 30 2.4.5 Plausibility checks......Page 36 2.5 Process-model-based fault-detection methods2......Page 38 2.5.1 Process models and fault modeling......Page 40 2.4.6 Signal-analysis methods......Page 37 2.5.2 Fault detection with parameter estimation......Page 42 b) Output observers......Page 43 c) State estimation......Page 44 2.5.4 Fault detection with parity equations......Page 45 2.5.5 Direct reconstruction of non-measurable variables......Page 46 2.6.1 Classification methods......Page 47 2.6.2 Inference methods......Page 49 2.8 Data flow structure for supervision (condition monitoring)......Page 51 Concluding remarks......Page 52 Part II Drives and Actuators......Page 54 3.1.1 Structure and models of a DC motor......Page 55 3.1.2 Fault detection with parity equations......Page 58 3.1.3 Fault detection with parameter estimation......Page 60 3.1.4 Experimental results for fault detection (SELECT)......Page 61 a) The symptoms used......Page 63 b) Incorporation of structural knowledge......Page 64 c) Results with SELECT method......Page 65 d) Relation to fault trees......Page 67 e) Computational demands......Page 69 a) Electrical subsystem......Page 70 c) Thermal subsystem......Page 72 a) AC–DC converter (rectifier)......Page 73 b) DC–AC converter (inverter)......Page 75 a) Electrical part......Page 77 b) Mechanical subsystem......Page 81 d) AC motor at standstill......Page 82 3.2.4 Conclusions......Page 86 4.1 Electromagnetic actuator......Page 87 4.1.1 Position control......Page 89 4.1.2 Fault detection with parameter estimation......Page 91 4.2 Electrical automotive throttle valve actuator......Page 93 4.2.1 Structure and models of the actuator......Page 94 4.2.2 Input test cycle for quality control......Page 95 a) Parameter estimation for the dynamic behavior......Page 97 b) Parameter estimation for the static behavior......Page 98 4.2.4 Fault detection with parity equation......Page 100 4.2.5 Fault diagnosis......Page 101 4.2.6 Fault-diagnosis equipment......Page 102 4.3.1 Structure and models......Page 104 4.3.2 Fault detection with parameter estimation......Page 107 4.3.3 Fault detection with parity equations......Page 108 4.3.4 Conclusions......Page 110 5.1 Hydraulic servo axis1......Page 111 5.1.1 Hydraulic servo axis structure......Page 112 b) Cylinder model......Page 117 c) Combined model and choice of model output......Page 118 d) Temperature dependency......Page 120 a) Parity equations......Page 121 b) Parameter Estimation......Page 122 5.1.5 Conclusions......Page 127 5.2.1 Pneumatic-actuator construction......Page 128 5.2.2 Faults of pneumatic valves......Page 130 5.2.3 Models of pneumatic valves......Page 131 5.2.4 Fault detection with valve characteristics......Page 134 a) Measurement of fluid flow rate and reference value of position controller......Page 136 b) Measurement of valve position and chamber pressure......Page 142 c) Additional measurement of chamber pressure and pressure drop......Page 143 5.2.6 Fault detection of flow valves with electronic position controller......Page 144 5.2.7 Conclusions......Page 145 Part III Machines and Plants......Page 147 6.1.1 State of the art in pump supervision and fault detection......Page 148 a) Pump......Page 151 b) Pipe system......Page 152 c) Pump and closed pipe circuit system......Page 153 a) Constant speed operation and shut-off......Page 154 b) Dynamic operation for stepwise speed changes......Page 160 6.1.4 Fault detection with nonlinear parity equations and parameter estimation......Page 161 a) Measurement of I, ω, ∆p, V......Page 165 b) Measurement of I, ω......Page 170 6.1.6 Conclusions......Page 174 6.2 Reciprocating pumps......Page 175 6.2.1 Structure of a diaphragm pump......Page 176 a) Pressure signal......Page 177 b) Acceleration signal......Page 178 6.2.4 Fault detection of the pump drive......Page 182 6.2.5 Conclusions......Page 183 7.1 State of the art in pipeline supervision......Page 185 7.2 Models of pipelines......Page 186 7.3 Model-based leak detection......Page 191 7.3.1 Leak detection with state observers......Page 192 a) State observer as fault-sensitive filter......Page 193 7.3.2 Leak detection with mass balance and correlation analysis for liquid pipelines......Page 194 a) Gas pipeline models......Page 199 b) Leak detection with state reconstruction and correlation functions......Page 200 7.4.1 Gasoline pipeline......Page 205 7.4.2 Gas pipeline......Page 206 7.4.3 Conclusions......Page 208 8.1 Structure of a six-axis robot......Page 209 8.2 Model of a robot axis and parameter estimation......Page 210 b) Heuristic symptoms......Page 212 c) Process history and fault statistics......Page 213 8.3.3 Faults, heuristic symptoms and events of the robot......Page 214 8.4 Experimental results......Page 215 8.4.1 Fault diagnosis with analytical knowledge......Page 216 8.4.2 Fault diagnosis with analytical and heuristic knowledge......Page 217 8.5 Conclusions......Page 219 9.1 Structures of machine tools......Page 220 9.2 Status of machine tools supervision......Page 222 9.3.1 Two-mass model......Page 224 9.3.2 Parameter estimation......Page 226 9.3.3 Fault detection with parameter estimation......Page 228 9.4.1 Two- and three-mass model......Page 229 9.4.3 Fault detection of a feed drive test rig......Page 232 9.5.1 Models of the drilling process......Page 237 a) Static model......Page 238 a) Wear detection......Page 240 b) Breakage detection......Page 241 9.6.1 Models for the milling process......Page 242 a) Feed drive model......Page 243 b) Cutting-force model......Page 245 a) Fault detection with force measurement......Page 248 b) Fault detection with position measurements......Page 249 c) Fault diagnosis by classification......Page 251 d) Fault detection with parity equations......Page 254 9.7.1 Grinding-process models......Page 255 9.7.2 Fault detection with parameter estimation......Page 257 9.7.3 Fault detection with signal-analysis methods......Page 259 10.1.1 Heat exchanger types......Page 261 10.1.2 Heat exchanger models for stationary behavior......Page 264 a) Heated tube with distributed parameters......Page 266 b) Simplified models of heated tubes......Page 269 10.2.1 Static models of heat exchangers......Page 272 a) Parity equation......Page 273 b) Characteristic quantity......Page 274 d) Required instrumentation......Page 275 10.3.1 Fault detection with linear dynamic models and parameter estimation......Page 276 10.3.2 Fault detection with parameter variable local linear dynamic models......Page 280 10.4 Conclusions......Page 283 Part IV Fault-tolerant Systems......Page 284 11.1 Basic redundant structures......Page 285 11.2 Degradation steps......Page 287 12.1 A fault-tolerant control system......Page 290 12.2.1 A fault-tolerant duplex AC motor......Page 293 a) Soft switching over: slow reconfiguration......Page 296 12.2.2 Fault-tolerant frequency converter......Page 297 12.2.3 Multi-phase motors......Page 300 12.3.1 Fault-tolerant hydraulic actuators......Page 301 b) Fault-tolerant single piston with double valve......Page 302 c) Fault-tolerant dual valve and pump......Page 305 12.4.1 Hardware sensor redundancy......Page 307 12.4.3 Steering angle sensor......Page 310 12.4.4 Fault-tolerant flow sensor......Page 312 12.4.6 Virtual drive dynamic sensors by model based analytical redundancy......Page 313 Part V Appendix......Page 318 (i) States and signals......Page 319 (iv) System properties......Page 320 References on terminology......Page 321 Concluding remarks......Page 322 References......Page 326 Chapter 3......Page 330 Chapter 4......Page 332 Chapter 5......Page 333 Chapter 6......Page 335 Chapter 8......Page 337 Chapter 9......Page 338 Chapter 10......Page 341 Chapter 11......Page 342 Chapter 13......Page 346 Index......Page 347