Electrical City Bus: Functional Safety through Driving Tests and Simulations

Electrical City Bus: Functional Safety through Driving Tests and Simulations SAE 2017 Hybrid and Electric Vehicle Technologies Symposium Albert Tuertscher, Rolf Mueller, Tobias Oeser, Christian Gnandt TESIS DYNAware GmbH, www.tesis-dynaware.com 1

Motivation Situation Currently bus fleets consist almost exclusively of vehicles with combustion engines City busses hold up to 46 % of urban public transportation in Germany City busses are an ideal supplement to other modes of transport due to their flexibility Regional Train Tram & Subway Bus Source: VDV Advantages of City Bus Electrification Reduction of environmental and noise pollution Improvement of air quality in cities Energy-efficient daily operation 2

PRIMOVE Package for Electric Mobility TESIS DYNAware GmbH, www.tesis-dynaware.com 3

Completely Integrated PRIMOVE E-bus System PRIMOVE battery Propulsion system Cooling Pick-up Charging plate Base power electronics Onboard Sending Device Vehicle detection 4

PRIMOVE Propulsion System for E-bus: Technical Data 5

System Modelling and Validation TESIS DYNAware GmbH, www.tesis-dynaware.com 6

1 Type = Component Group = ControlUnits me = ebus_rearwheelhubmotorcontrolunit DynaComponentInfo AccPedalPos[0_1] BrakePedalPos[0_1] InputFromCTRL (Selector) Vel_wrt_WorldSys(VehSys)[m/s] HighVoltageBatterySOC[0_1] MaxMainBrakePress[Pa] t_wheel_braketrqpressratio[m**3] _Wheel_BrakeTrqPressRatio[m**3] ft_wheel_braketrqpressratio[m**3] 3 fromvehicle fromvehicle t_wheel_braketrqpressratio[m**3] TotalRatio[-] InSpd[rad/s] Gear[-4;20] RearLeftElecMotor RearRightElecMotor InputFromVehicle (Selector) 4 fromtraffic 2 fromtrailer ControlUnitsDataSetNumber 7 RearLeftElecMotorIntendedTrq[Nm] Terminator 8 IntendedTrq [Nm] RearRightElecMotorIntendedTrq[Nm] RMSVoltage [V] 5 InverterVoltage[V] Spd [rad/s] 6 MotorTemp [K] ElecMotorTemp[K] <InSpd[rad/s]> 9 ElecMotorIntendedTrq[Nm] <InSpd[rad/s]> IntendedTrq [Nm] RMSVoltage [V] Spd [rad/s] MotorTemp [K] <InSpd[rad/s]> <InAcc[rad/s**2]> <InSpd[rad/s]> <InAcc[rad/s**2]> RearLeftElecMotor RearRightElecMotor <InSpd[rad/s]> double 0 Constant Gear[-4;20] ElecMotorToWheelRatio[-] TotalRatio[-] RearLeftElecMotor RearRightElecMotor Trq [Nm] RMSCurr [A] Inrt [kg*m**2] HeatingPow [W] HeatCap [J/K] Trq [Nm] RMSCurr [A] Inrt [kg*m**2] HeatingPow [W] HeatCap [J/K] ElecMotorStates Trq[Nm] StatesToNext Curr[A] Inrt[kg*m**2] StatesToPrevious InSpd[rad/s] Info InAcc[rad/s**2] Create ElectricMotor Buses Trq[Nm] StatesToNext Curr[A] Inrt[kg*m**2] StatesToPrevious InSpd[rad/s] Info InAcc[rad/s**2] Create ElectricMotor Buses1 AccPedalPos[0_1] BrakePedalPos[0_1] EngSpd[rad/s] LongVehSpd(VehSys)[m/s] TransmissionInSpd[rad/s] BattSOC[0_1] MaxMainBrakePress[Pa] BrakeTrqPressRatio[m**3] ElecMotorToWheelRatio[-] ElecMotorStates TriggerBusSelector (Selector) TriggerBus RearLeftElecMotorIntendedTrq[Nm] RearRightElecMotorIntendedTrq[Nm] IntendedElecMotorTrq[Nm] IntendedTransmissionInTrq[Nm] WheelHubMotorVehicleControlUnit IntendedBrakeTrq[Nm] MainBrakePress[Pa] BrakeSwitch[1;3] DrivingState[-] StatesToNext StatesToPrevious States 2 RearLeftElecMotorStates Info Create ElectricMotor States Bus StatesToNext StatesToPrevious States 3 RearRightElecMotorStates Info Create ElectricMotor States Bus1 1 Signal User-defined Module: TriggerSignals ManipSignal Basic_Manip_Signal Enable SigManip_RearLeftElecMotorIntendedTrq Signal User-defined Module: TriggerSignals ManipSignal Basic_Manip_Signal Enable SigManip_RearRightElecMotorIntendedTrq 1 Fixed Gear StatesToNextLeft StarterSwitch[0;1] EngLoadSignal[0_1] EngFuelCutOff[0;1] UpperEngTrqSwitch[0;2] EngineControlUnit UpperEngTrqLimit[Nm] LowerEngTrqSwitch[0;2] LowerEngTrqLimit[Nm] EngineControlUnitOutput (Bus Creator) Gear[-4;20] LockUpClutchPos[0_1] TransmissionControlUnit AutomatedManualClutchPos[0_1] TransmissionControlUnitOutput (Bus Creator) RearLeftElecMotorIntendedTrq[Nm] RearRightElecMotorIntendedTrq[Nm] IntendedElecMotorTrq[Nm] IntendedTransmissionInTrq[Nm] HybridControlUnit IntendedBrakeTrq[Nm] DrivingState[-] ElecDriveClutchPos[0_1] HybridControlUnitOutput (Bus Creator) BrakeSwitch[1;3] MainBrakePress[Pa] FrontLeftWheelBrakePress[Pa] FrontRightWheelBrakePress[Pa] RearLeftWheelBrakePress[Pa] RearRightWheelBrakePress[Pa] Rear2LeftWheelBrakePress[Pa] Rear2RightWheelBrakePress[Pa] Rear3LeftWheelBrakePress[Pa] BrakeControlUnit Rear3RightWheelBrakePress[Pa] TrailerFrontLeftWheelBrakePress[Pa] TrailerFrontRightWheelBrakePress[Pa] TrailerRearLeftWheelBrakePress[Pa] TrailerRearRightWheelBrakePress[Pa] TrailerRear2LeftWheelBrakePress[Pa] TrailerRear2RightWheelBrakePress[Pa] TrailerRear3LeftWheelBrakePress[Pa] TrailerRear3RightWheelBrakePress[Pa] BrakeControlUnitOutput (Bus Creator) ShaftStatesToWheelLeft StatesToNextRight ShaftStatesToWheelRight 2 WheelSpds[rad/s] RearWheelSpds[rad/s] 3 WheelAcc[rad/s**2] WheelStatesToPreviousLeft RearWheelAccs[rad/s**2] 1 CircumferentialTrqs[Nm] RearCircumferentialTrqs[Nm] WheelStatesToPreviousRight 4 WheelInrts[kg*m**2] RearWheelInrts[kg*m**2] Rear WheelSystem Interface EngineControlUnit TransmissionControlUnit HybridControlUnit BrakeControlUnit ControlUnitsOutput (Bus Creator) ControlUnits 1 ControlUnits 1 RearShaftStates Simulation Model & Parameters Model Based on DYNA4 Commercial Vehicles Product Package Framework managed extendable Matlab Simulink model Multibody chassis containing axles and steering Tire model with the possibility of twin tires at any position Model Extensions Drivetrain replaced by electric wheel hub motors E-motor control unit and electrical system Parameter driven error injection on motor torques Parameterisation Physical values (mass distribution, E-motor torque curves,...) Typical commercial vehicle characteristic values fromcontrolunits fromtrailer fromvehicle fromtraffic fromtrailer fromvehicle fromvehicle fromenvironment fromtrailer fromenvironment fromtrailer fromvehicle fromvehicle fromtrailer fromvehicle SimulationControl Animation fromtraffic ControlUnits Trailer Vehicle fromtraffic Environment Traffic VehicleControl fromtraffic VehicleControl fromvehicle ControlUnits Trailer Vehicle Environment Traffic Trigger Bus Trigger_Signals_DYNA4 ControlUnits Trailer Vehicle Environment Traffic VehicleControl ControlUnits Trailer Vehicle Environment Components Traffic VehicleControl TriggerBus ComponentsOutput (Bus Creator) E-Bus Components SwitchBoard CTRL Electric Drivetrain Control Unit Wheel Hub Motors 7

Validation with Measurement Data Measurements with Real Vehicle Vehicle CAN network trace and additional measurement equipment (differential GPS) Standard longitudinal and lateral maneuvers for vehicle dynamics (full acceleration / full brake, steering wheel step, steady state circular driving,...) Error injection with development ECUs / datasets Validation Comparison of characteristic values (e.g. chassis movement) Feeding of measurement values into simulation with specific interfaces (e.g. motor torques) Sensitivity analysis 8

System Simulation and Virtual Driving Maneuver TESIS DYNAware GmbH, www.tesis-dynaware.com 9

Error Definition and Error Injection Example: Erroneous torque on driven wheels Identify possible combinations Define strength (worst case) Torque build up time Torque effective time No error Left_Accel_T1_x_y_z Left_Accel_T2_x_y_z Left_Brake_T1_x_y_z Left_Brake_T2_x_y_z Sync_Accel_T1_x_y_z Sync_Accel_T2_x_y_z Sync_Brake_T1_x_y_z Sync_Brake_T2_x_y_z Async_T1_x_y_z Async_T2_x_y_z 10

Maneuver Definition and Parameter Variation Example: Define driving maneuver, maneuver parameters, environmental conditions and vehicle variations 11

Maneuver Definition and Parameter Variation Example: Define driving maneuver, maneuver parameters, environmental conditions and vehicle variations Different road layouts (e.g. straight line driving, circle driving, ) Simulate with different vehicle speeds (standstill, moving slow, moving fast, ) Variation of road friction (dry, wet, ice, ) Respect different load conditions (empty vehicle, medium load, maximum load, ) Speed 1 [km/h] Radius 1 [m] Speed 2 [km/h] Speed 3 [km/h] Friction 1 [-] Friction 2 [-] Friction 3 [-] Friction 1 [-] Friction 2 [-] Friction 3 [-] Friction 1 [-] Friction 2 [-] Friction 3 [-] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] 12

Test Matrix Execution Example: complete test matrix Radius 1 [m] Speed 1 [km/h] Speed 2 [km/h] Speed 3 [km/h] Friction 1 [-] Friction 2 [-] Friction 3 [-] Friction 1 [-] Friction 2 [-] Friction 3 [-] Friction 1 [-] Friction 2 [-] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] No error 1 x 27 x 53 x 79 x 105 x 131 x 157 x 183 x 209 x 235 x 261 x 287 x 313 x 339 x 365 x 391 x 417 x 443 x 469 x 495 x 521 x 547 x 573 x 599 x Left_Accel_T1_x_y_z 2 x 28 x 54 x 80 x 106 x 132 x 158 x 184 x 210 x 236 x 262 x 288 x 314 x 340 x 366 x 392 x 418 x 444 x 470 x 496 x 522 x 548 x 574 x 600 x Left_Accel_T2_x_y_z 3 x 29 x 55 x 81 x 107 x 133 x 159 x 185 x 211 x 237 x 263 x 289 x 315 x 341 x 367 x 393 x 419 x 445 x 471 x 497 x 523 x 549 x 575 x 601 x 4 30 56 82 x 108 x 134 x 160 x 186 x 212 x 238 x 264 x 290 x 316 x 342 x 368 x 394 x 420 x 446 x 472 x 498 x 524 x 550 x 576 x 602 x 5 31 57 83 x 109 x 135 x 161 x 187 x 213 x 239 x 265 x 291 x 317 x 343 x 369 x 395 x 421 x 447 x 473 x 499 x 525 x 551 x 577 x 603 x 6 x 32 x 58 x 84 110 136 162 x 188 x 214 x 240 x 266 x 292 x 318 x 344 x 370 x 396 x 422 x 448 x 474 x 500 x 526 x 552 x 578 x 604 x Left_Brake_T1_x_y_z 7 x 33 x 59 x 85 111 137 163 x 189 x 215 x 241 x 267 x 293 x 319 x 345 x 371 x 397 x 423 x 449 x 475 x 501 x 527 x 553 x 579 x 605 x Left_Brake_T2_x_y_z 8 x 34 x 60 x 86 x 112 x 138 x 164 190 216 242 x 268 x 294 x 320 x 346 x 372 x 398 x 424 x 450 x 476 x 502 x 528 x 554 x 580 x 606 x 9 x 35 x 61 x 87 x 113 x 139 x 165 191 217 243 x 269 x 295 x 321 x 347 x 373 x 399 x 425 x 451 x 477 x 503 x 529 x 555 x 581 x 607 x 10 x 36 x 62 x 88 x 114 x 140 x 166 x 192 x 218 x 244 270 296 322 x 348 x 374 x 400 x 426 x 452 x 478 x 504 x 530 x 556 x 582 x 608 x 11 x 37 x 63 x 89 x 115 x 141 x 167 x 193 x 219 x 245 271 297 323 x 349 x 375 x 401 x 427 x 453 x 479 x 505 x 531 x 557 x 583 x 609 x Sync_Accel_T1_x_y_z 12 x 38 x 64 x 90 x 116 x 142 x 168 x 194 x 220 x 246 x 272 x 298 x 324 350 376 402 x 428 x 454 x 480 x 506 x 532 x 558 x 584 x 610 x Sync_Accel_T2_x_y_z 13 x 39 x 65 x 91 x 117 x 143 x 169 x 195 x 221 x 247 x 273 x 299 x 325 351 377 403 x 429 x 455 x 481 x 507 x 533 x 559 x 585 x 611 x 14 x 40 x 66 x 92 x 118 x 144 x 170 x 196 x 222 x 248 x 274 x 300 x 326 x 352 x 378 x 404 430 456 482 x 508 x 534 x 560 x 586 x 612 x 15 x 41 x 67 x 93 x 119 x 145 x 171 x 197 x 223 x 249 x 275 x 301 x 327 x 353 x 379 x 405 431 457 483 x 509 x 535 x 561 x 587 x 613 x 16 x 42 x 68 x 94 x 120 x 146 x 172 x 198 x 224 x 250 x 276 x 302 x 328 x 354 x 380 x 406 x 432 x 458 x 484 510 536 562 x 588 x 614 x Sync_Brake_T1_x_y_z 17 x 43 x 69 x 95 x 121 x 147 x 173 x 199 x 225 x 251 x 277 x 303 x 329 x 355 x 381 x 407 x 433 x 459 x 485 511 537 563 x 589 x 615 x Sync_Brake_T2_x_y_z 18 x 44 x 70 x 96 x 122 x 148 x 174 x 200 x 226 x 252 x 278 x 304 x 330 x 356 x 382 x 408 x 434 x 460 x 486 x 512 x 538 x 564 590 616 19 x 45 x 71 x 97 x 123 x 149 x 175 x 201 x 227 x 253 x 279 x 305 x 331 x 357 x 383 x 409 x 435 x 461 x 487 x 513 x 539 x 565 591 617 20 x 46 x 72 x 98 x 124 x 150 x 176 x 202 x 228 x 254 x 280 x 306 x 332 x 358 x 384 x 410 x 436 x 462 x 488 x 514 x 540 x 566 x 592 x 618 x 21 x 47 x 73 x 99 x 125 x 151 x 177 x 203 x 229 x 255 x 281 x 307 x 333 x 359 x 385 x 411 x 437 x 463 x 489 x 515 x 541 x 567 x 593 x 619 x Async_T1_x_y_z 22 x 48 x 74 x 100 x 126 x 152 x 178 x 204 x 230 x 256 x 282 x 308 x 334 x 360 x 386 x 412 x 438 x 464 x 490 x 516 x 542 x 568 x 594 x 620 x Async_T2_x_y_z 23 x 49 x 75 x 101 x 127 x 153 x 179 x 205 x 231 x 257 x 283 x 309 x 335 x 361 x 387 x 413 x 439 x 465 x 491 x 517 x 543 x 569 x 595 x 621 x 24 x 50 x 76 x 102 x 128 x 154 x 180 x 206 x 232 x 258 x 284 x 310 x 336 x 362 x 388 x 414 x 440 x 466 x 492 x 518 x 544 x 570 x 596 x 622 x 25 x 51 x 77 x 103 x 129 x 155 x 181 x 207 x 233 x 259 x 285 x 311 x 337 x 363 x 389 x 415 x 441 x 467 x 493 x 519 x 545 x 571 x 597 x 623 x 26 x 52 x 78 x 104 x 130 x 156 x 182 x 208 x 234 x 260 x 286 x 312 x 338 x 364 x 390 x 416 x 442 x 468 x 494 x 520 x 546 x 572 x 598 x 624 x peed 3 [km/h] Friction 2 [-] Friction 3 [-] Load 2 [kg] Load 3 [kg] Load 1 [kg] Load 2 [kg] Load 3 [kg] 1977 x 2003 x 2029 x 2055 x 2081 x 1978 x 2004 x 2030 x 2056 x 2082 x 1979 x 2005 x 2031 x 2057 x 2083 x 1980 x 2006 x 2032 x 2058 x 2084 x 1981 x 2007 x 2033 x 2059 x 2085 x 1982 x 2008 x 2034 x 2060 x 2086 x 1983 x 2009 x 2035 x 2061 x 2087 x 1984 x 2010 x 2036 x 2062 x 2088 x 1985 x 2011 x 2037 x 2063 x 2089 x 1986 x 2012 x 2038 x 2064 x 2090 x 1987 x 2013 x 2039 x 2065 x 2091 x 1988 x 2014 x 2040 x 2066 x 2092 x 1989 x 2015 x 2041 x 2067 x 2093 x 1990 x 2016 x 2042 x 2068 x 2094 x 1991 x 2017 x 2043 x 2069 x 2095 x 1992 x 2018 x 2044 x 2070 x 2096 x 1993 x 2019 x 2045 x 2071 x 2097 x 1994 x 2020 x 2046 x 2072 x 2098 x 1995 x 2021 x 2047 x 2073 x 2099 x 1996 x 2022 x 2048 x 2074 x 2100 x 1997 x 2023 x 2049 x 2075 x 2101 x 1998 x 2024 x 2050 x 2076 x 2102 x 1999 x 2025 x 2051 x 2077 x 2103 x 2000 x 2026 x 2052 x 2078 x 2104 x 2001 x 2027 x 2053 x 2079 x 2105 x 2002 x 2028 x 2054 x 2080 x 2106 x Communication (design of experiment) Defines simulations to be executed (API) First row is maneuver reference Automatic result data storage (values over time) with meta information (applied variations,...) 13

Evaluation and Post-Processing Post processing - loop through generated results Compare signals from reference simulation with error injection simulation Comparison logic with user defined Matlab function (e.g. deviation of one- or multidimensional signals) Comparison result is added to the result file of the error simulation to enable re-use for further calculations Calculate characteristic values from signals Characteristic value = scalar value for specific time interval Characteristic value logic with user defined Matlab function (e.g. maximum, minimum, integral) 14

Calculation Results and their Format Results Overview table Flat representation of all simulations Any number of characteristic values in columns Test verdicts (e.g. limit violation) via different cell colours Hyperlink to PDF reports Reports One report per error simulation Any number of diagrams, tables,... for selected signals Path to result mat file Error Definition Mass Speed Friction Man. Param. n Max. Track Deviation t1[ms] Charac.Value 2 Charac.Value n Hyperlink Reference m1 [t] v1 [km/h] μ1 [-] not available not available not available not available Definition 1 m1 [t] v1 [km/h] μ1 [-] 0,00 Report_1.pdf Definition 2 m1 [t] v1 [km/h] μ1 [-] 0,00 Report_2.pdf Reference m2 [t] v1 [km/h] μ1 [-] not available not available not available not available Definition 1 m2 [t] v1 [km/h] μ1 [-] 0,00 Report_3.pdf Definition 2 m2 [t] v1 [km/h] μ1 [-] 0,00 Report_4.pdf Reference m1 [t] v2 [km/h] μ1 [-] not available not available not available not available Definition 3 m1 [t] v2 [km/h] μ1 [-] 0,05 Report_5.pdf Definition 3 m1 [t] v2 [km/h] μ1 [-] 0,05 Report_6.pdf Definition 1 m1 [t] v2 [km/h] μ1 [-] 0,02 Report_7.pdf Definition 2 m1 [t] v2 [km/h] μ1 [-] 0,02 Report_8.pdf Reference m2 [t] v2 [km/h] μ1 [-] not available not available not available not available Reference m2 [t] v3 [km/h] μ3 [-] not available not available not available not available Definition 1 m2 [t] v3 [km/h] μ3 [-] 0,02 Report_n.pdf Definition 2 m2 [t] v3 [km/h] μ3 [-] 0,02 Report_n+1.pdf Trajectory Comparison Reference vs. Error-Simulation Y X Reference Signal Vehicle Pos. Time1 Vehicle Pos. Time2 15

Project Results: Some Videos Measurements Simulations 16

Conclusion and Outlook Conclusion System electrical city bus successfully modelled and validated Extendable test plan can be simulated and interpreted automatically Driving test & simulation in combination as basis for assessment, implementation and parameterisation of safety functions Outlook System variants (drivetrain, chassis) Human reaction (driver model, driver-in-the-loop) 17