Integration of an Active Brake Pedal Simulator in the CarMaker Environment for Design and Evaluation of Haptic Driver Assistance Systems IPG apply & innovate 2014, September 23/24 Simon Rothfuss, Michael Flad, Sören Hohmann Karlsruhe Institute of Technology (KIT) / Institute of Control Systems (IRS) KIT University of the state of Baden-Württemberg and National Laboratory of the Helmholtz Association www.kit.edu
Research Fields of the IRS Automation Solutions Cooperative Assistance Systems Alternative Energy Storage Solutions Haptic Cooperative Advanced Driving Assistance System (ADAS) Sources: http://people.tuke.sk/ivo.petras/rld.gif cdn.redmondpie.com/wp-content/uploads/2012/11/ios-battery-logo.png bosch-kraftfahrzeugtechnik.de/media/ubk_europe/db_application/stage_funktion/bilder/esp_function_w982.jpg 2 09/24/2014
Haptic Cooperative ADAS Direct Perception Direct Integration Instant Communication Intuitive Cooperative System Source: http://commons.wikimedia.org/wiki/file:american_shepherd3.jpg 3 09/24/2014
Cooperative ADAS Development Cooperative ADAS development requires test environment Virtual Car Simulation HW-in-the-loop Human 4 09/24/2014
Overview Driving Simulator Brake Simulator HiL Integration Overview Mechanics Overview Components Electronics Concepts Control Validation 5 09/24/2014
Advanced Driving Simulator Steering Wheel Realtime System Sound Throttle Screen Brake Sources: pk-soundandmusic.com/imagebase/7-1417505.gif sensodrive.de/ we_thumbs /1035_5_s-pr-wheelHT-1.jpg autosieger.de/images/articles/continental_gaspedal_3.jpg bosch-automotivetechnology.com/media/en/ubk_europe/db_application/......downloads/pdf/antrieb/de_5/gs_datenbl_apm_de.pdf dspace.com/files/jpg2/px4_px10_px20-de-002_desktopversion_schraeg......_refl_dp_300dpi_200x250mm_cmyk_081218.jpg 6 09/24/2014
Overview Driving Simulator Brake Simulator HiL Integration Overview Mechanics Overview Components Electronics Concepts Control Validation 7 09/24/2014
Requirements Conventional Hybrid Human car perception characteristic pedal force characteristic Recuperation only Recuperation & Conventional Brake Nonlinear force characteristic Nonlinear dynamic Accuracy according perception Short response time 8 09/24/2014
New Concept Requirements Accuracy according perception Nonlinear force characteristic Short response time Nonlinear dynamic Basic concepts for pedal force simulator Passive Active New Concept: Brake Feedback Force Generation by Electric Drive 9 09/24/2014
Brake Pedal Simulator - Mechanics Gearbox Connector Synchronous Motor Torque Sensor Pedal 10 09/24/2014
Brake Pedal Simulator - Mechanics Spring Limit Stops Incremental Encoder 11 09/24/2014
Electrical System Torque Sensor A/ D DSP CAN Interface Incremental Encoder QEI PWM CAN Bus Pedal Control Unit Gate SM Converter µc Unit QEI Drive Control Unit 12 09/24/2014
Software Architecture Sensor Input Filtering System State Estimation Reference Calculation Control Algorithm Emergency Stop Failure Detection System Supervision Output Enable & Limit Pedal Control Unit (DSP) Gate Signals Field-Oriented Control PWM Signal Drive Control Unit (μc) 13 09/24/2014
System Model Mechanics φ i Shaft Angle left/right side J M/G Inertia of Motor/Gearbox J 1 Inertia of connecting elements left J 2 Inertia right k DK Spring Constant of Torque Sensor & Connector Damping Rate d DK M M M F M P M G M Ri i Motor Torque Spring Torque Pedal Torque Pedal Mass Torque Friction Torque Gear Ratio 14 09/24/2014
System Equations Coupled nonlinear differential equations J ( t) k ( t) ( t) d ( t) ( t) i M ( t) M ( () t ) 1 1 DK 1 2 DK 1 2 M R1 1 J ( t) k ( t) ( t) d ( t) ( t) M ( t) M ( ( t) )... 2 2 DK 1 2 DK 1 2 p R2 2 M G ( ( t) ) M ( ( t) ) 2 F 2 with J J i J J 2 1 1' ( M G) Constraints 0 ( t) : Angle of Limit Stops 2-120 Nm i M ( t) 120 Nm M 15 09/24/2014
Software Architecture Sensor Input Filtering System State Estimation Reference Calculation Control Algorithm Emergency Stop Failure Detection System Supervision Output Enable & Limit Pedal Control Unit Gate Signals Field-Oriented Control PWM Signal Drive Control Unit 16 09/24/2014
PI-State Feedback Control V M S - ʃ K p K i - u z System M P x K x M P M S x u z Pedal torque Reference torque System states Command input torque to motor Disturbances 17 09/24/2014
System State Estimation Measurement equation ( t) 0 0 1 0 () t 1 2 1() t 2( t) 0 0 0 1 2() t MMes( t) kdk 0 kdk 0 2() t Problem: Not all system states x and pedal torque M P can be measured Use of Extended Kalmanfilter for estimation Estimated quantities System states ˆ 1( t) ˆ 1( t) ˆ 2( t) ˆ 2( t) T Pedal torque ˆM P 18 09/24/2014
PI-State Feedback Control V K p z M S - ʃ K i - u System y K x ˆx ˆM P Kalmanfilter z k ˆM P M S ˆx z k Pedal torque, estimated Command input torque System states, estimated Disturbances, known, used in Kalmanfilter 19 09/24/2014
Measurement Results Deviations Root-Mean-Square-Error below human perception < 12N 20 09/24/2014
Summary Brake Pedal Simulator System Model Control Algorithm 0 1 0 0 1( t) k 1 1( ) DK ddk d kdk d DK t d 1( t) J1 J1 J1 J 1 1( t)... dt 2( t) 0 0 0 1 2( t) 2( t) k DK S F ( 2) 2 2( t) DK ddk k g k ddk d J2 J2 J2 J2 0 0 0 0 1 i 0 0 sign( 1) M R10 J1 J1 MM () t ( 2) 20 0 0 0 sign MR 0 MP( t) Mg 0( 2) MF 0( 2) 1 1 0 0 J2 J2 M S - ʃ V K p K i - x' Kalmanfilter M P ' K x z u System z k y System control and state estimation designed Simulator emulates arbitrary nonlinear force characteristics Required accuracy of pedal force achieved 21 09/24/2014
Overview Driving Simulator Brake Simulator HiL Integration Overview Mechanics Overview Components Electronics Concepts Control Validation 22 09/24/2014
Brake Pedal Simulator Integration CAN Brake Pedal Simulator CarMaker Source: duden.de/_media_/small/p/pc-201100281327.jpg dspace.com/files/jpg2/px4_px10_px20-de-002_desktopversion_schraeg......_refl_dp_300dpi_200x250mm_cmyk_081218.jpg 23 09/24/2014
Integration Concepts Concept 1 Brake pedal simulation in CarMaker Feedback force command to brake simulator Pedal position used in CarMaker Complex brake pedal simulation possible Concept 2 Brake pedal characteristic implemented on brake pedal simulator CarMaker selects characteristic Pedal position returned to CarMaker Higher torque / time resolution Brake Pedal Simulator CarMaker CAN 24 09/24/2014
Conclusion Advanced Driving Simulator presented Haptic interfaces available Test bench for cooperative ADAS 25 09/24/2014
Result 26 09/24/2014
Thank you for your attention 27 09/24/2014
Appendix 28 09/24/2014
Pedal Feedback Force Characteristic Real brake pedal force introduced by braking system Modelling with pedal force characteristic F ( ( )) Static s t F ( s( t), s( t)) F ( s( t)) Pedal Static F ( s( t), s( t)) Hysteresis F ( s( t), s( t)) Damping st ( ): Pedal Travel 29 09/24/2014
Pedal Feedback Force Characteristic F ( s( t)) F ( s( t), s( t)) d( s( t)) Static Hysteresis 30 09/24/2014
Pedal Feedback Force Characteristic Idealized pedal force characteristic for 2 different pedal velocities 31 09/24/2014
Software Architecture Emergency Stop Failure Detection System Supervision Drive Control Unit Sensor Input Filtering Output Enable & Limit PWM Signal CAN Signal Internal Signal System State Estimation Reference Calculation Pedal Control Unit Control Algorithm Field- Oriented Control Gate Signals 32 09/24/2014
System Equations Coupled differential equations J ( t) k ( t) ( t) d ( t) ( t) i M ( t) M ( () t ) 1 1 DK 1 2 DK 1 2 M R1 1 J ( t) k ( t) ( t) d ( t) ( t) M ( t) M ( () t )... 2 2 DK 1 2 DK 1 2 p R2 2 M G ( ( t)) M ( ( t)) 2 F 2 Friction model M ( ) sign( ) M d Ri i i Ri 0 Ri i 33 09/24/2014
System Equations Coupled differnetial equations Non-Linearities l MG( 2) mp g sin 2( t) 2 Linearization through 0 and l sin MG( 2) mp g sin 2( t) 2 g g () t O t t J ( t) k ( t) ( t) d ( t) ( t) im ( t) M ( ) 1 1 DK 1 2 DK 1 2 M R1 1 J ( t) k ( t) ( t) d ( ) ( ) M ( t) M ( ) M ( ) M ( ) 2 2 DK 1 2 DK 1 2 p R2 2 G 2 F 2 S 2 2 2 34 09/24/2014
System Equations Coupled differnetial equations J ( t) k ( t) ( t) d ( t) ( t) im ( t) M ( ) 1 1 DK 1 2 DK 1 2 M R1 1 J ( t) k ( t) ( t) d ( t) ( t) M ( t) M ( ) M ( ) M ( ) 2 2 DK 1 2 DK 1 2 p R2 2 G 2 F 2 Non-Linearities M k a sin t cos t ( ) ( ) ( ) F 2 2 2 Linearization through and cos sin MF ( 2) k a 2( t) M ( ) k ( ) ( t) F0 2 F 2 2 2 2 35 09/24/2014
Control Concepts Overview State Feedback SISO - Control H - Control Control Compensator Constant State Feedback Deadbeat Controller PI State Feedback 36 09/24/2014
Control Implementation with additional Spring V K p z M S -M F - ʃ K i - u System y ˆx K x ˆM P -M F Kalmanfilter z k 37 09/24/2014
Identification 38 09/24/2014
State Space Model for Kalmanfilter System equation 0 1 0 0 0 ˆ 1( t) k ˆ1( ) DK ddk d1 kdk d t DK 0 ˆ 1( t) J ˆ 1 J1 J1 J1 1( t) ˆ 2( t) 0 0 0 1 0 ˆ 2( t)... ˆ ( 2( t) kdk ddk kdk gs kf 2) ddk d2 1 ˆ 2( t) Mˆ ( ) J2 J2 J2 J2 J 2 ˆ P t MP( t) 0 0 0 0 0 39 09/24/2014 0 0 1 0 J1 i MM( t) sign( 1) MR10 0 0 Mg 0 MF 0( 2) sign( 2) M R20 1 0 J2 0 0
State Space Model for Kalmanfilter Measurement equation ˆ 1() t ˆ 2( t) 0 0 1 0 0 1() t ( t) 0 0 0 1 0 ˆ () t 2 2 MMes( t) k DK 0 kdk 0 0 ˆ 2() t ˆ MP () t 40 09/24/2014
Kalmanfilter - Simulation Time [s] 41 09/24/2014
Kalmanfilter - Simulation Time [s] 42 09/24/2014
Kalmanfilter - Measurement 43 09/24/2014
Measurement Setup Pedal force sensor attached to pedal Actuation via human foot Hence, no possibility to apply velocity profiles Record command input torque Used pedal characteristics: Quelle: http://www.kistler.co m/medias/sys_mast er/ celum_assets/88247 08071454_934-073_web_6407_png.jpg?2 44 09/24/2014