Physical Modeling with SimScape

Transcription

1 Physical Modeling with SimScape Saving energy with Physical Modeling Adriaan van den Brand Mday V1.4 A. Van den Brand, Mday

2 Bio Adriaan van den Brand System architect Sogeti High Tech Embedded systems experience: Embedded Software Software architecture, system architecture 7 years automotive (Ford, BMW, Visteon, NXP) Adriaan.vanden.Brand@sogeti.nl Current role System architect at Philips Innovation Services Hybrid drive trains for commercial vehicles A. Van den Brand, Mday

3 Recognizable? How long does your energy supply really last? Car: 3.9 l/100km in brochure 5.8 l/100km in real life? Smart phone : 300 hour standby-tijd or 1 day usage? A. Van den Brand, Mday

4 Agenda Title & Bio Agenda Project Model Common vs. physical modeling abstract to reality Wat, how & why Experiences & Conclusions Q&A A. Van den Brand, Mday

5 Project Goals Challenges Role A. Van den Brand, Mday Titel & Bio Agenda Project Model Conclusions Q&A

6 Project background Hybrid drive train commercial vehicles Requirements (!) Maximum CO2 reduction Maximum fuel savings Realistic estimations fuel usage Info: A. Van den Brand, Mday

7 Goal : Model Model is used to determine Energy saving potential (and CO2,.) Optimum system architecture Component selection Strategies (regeneration) Understand before building Validation based on existing vehicles and setups A. Van den Brand, Mday

8 Challenge 1 What is maximum? Which knobs to turn? What to model? Modeling energy streams Chemical (Internal combustion engine) Electrical (Battery) Mechanical (Rotation) Mechanical(Translation) Physical Modeling (Matlab/Simulink+SimScape) A. Van den Brand, Mday

9 Understanding energy flows Saving starts with understanding energy flows Regenerative Breaking Vehicle Inertia Rolling resistance Air Resistance HVAC Brakes (Hydraulic/Pneumatic) Aux Battery Losses Waste Heat Cooling Mechanic losses vehicle Mechanic losses body A. Van den Brand, Mday

10 Challenge 2 : Multi-disciplinary model Disciplines Electric, Mechanics, Pneumatics, Hydraulics, Software Interfaces? Environment? Re-use of existing Simulink models? How to fill the missing pieces? A. Van den Brand, Mday

11 Project : model centric Real world data System model Key Performance Indicators control & software Mechanics Electric A. Van den Brand, Mday

12 Steps 1. Understanding energy in basic function Traction, air drag, rolling resistance, electric system Domains: Mechanical (Newton s laws) Electrical (iso-efficiency curves) 2. Understanding real use Observing the users, harvesting data from measurements 3. Understanding energy in ALL other functions Air-conditioning, power steering, braking,. Domains: mechanic, electric, hydraulic, pneumatic, thermal 4. Refinement & control model Dynamics A. Van den Brand, Mday

13 Design Space Exploration (project) Analysis of optimal system Top down analysis Application domain Model refinement Energy conservation Component -choices Users Application F=M*a P=½mv 2 Hybrid mode series parallel Design Space E-Motor-x E-Motor-y Available technology A. Van den Brand, Mday

14 Model in project 1st model: simplicity brick on wheels Simple, cheap Determine ideal results Best case prediction 2nd iteration Model with detailed subsystems Motor-behavior, gear boxes, battery models etc. Finally Virtual prototype with the same interfaces as the real product Model with scaleable simulation times A. Van den Brand, Mday

15 Models Reference process Physical modeling Titel & Bio Agenda Project Model Conclusions Q&A A. Van den Brand, Mday

16 Models : Backward facing (reference) Reference Environment Backward facing Model model Result Standard drive cycle speed = f(t) A. Van den Brand, Mday

17 Models: Backward facing (common) (2) Vehicle pulls at the wheels Wheels turn the gears Gears turn the motor Calculate required energy extraction from battery reverse world. Model!= reality doesn t fit expectations P mech / η wheel / η gear / η motor / η battery = P electric 1T M + v vehicle F roll +F drag ω wheel gear ω motor Τ motor U batt i batt A. Van den Brand, Mday

18 Realistic model (forward facing/physical) Action = - Reaction Route Traffic Driver Controls G + M 1T Engine Alternator Battery E-motor Gear&diff Tyre Model Vehicle Model reflects reality A. Van den Brand, Mday

19 Physical Modeling Physical signals Voltage and currents (electric domain) Torque and ω (mechanic domain) Flow and pressure (and temperature) (pneumatic domain) interface independent of implementation! Energy in Watt Preservation of energy Energy preserving ports (bi-directional) Direction of signals is determined by solver Action = - reaction Energy can be translated to other domains Waste energy (heat) is also energy A. Van den Brand, Mday

20 Physical Modeling : Electric Motor Current source Cause: current i U M rotatie Result: torque Electric motor : current rotation ground Mechanic reference (chassis) A. Van den Brand, Mday

21 Physical Modeling : Electric Motor (2) Result: current/voltage i U M rotation Cause: torque ground Mechanic reference (chassis) 100 Nm Regenerative braking Kinetic energy of vehicle is converted in electricity Motor as alternator A. Van den Brand, Mday

22 Physical Modeling : inside E-motor i friction Electric Interface U R L inertia rotation (Rotating) Mechanic interface ground Τ:=K*i U:=K*ω (K=constant of proportionality V/ (rad/s) ) Motor is also a model Parameters Electric substitution Non ideal attributes A. Van den Brand, Mday

23 Physical interfaces Simulink Normal Simulink model: Physical model Fewer connections Better maintainability Physical model Standardization of interfaces A. Van den Brand, Mday

24 Physical Modeling : Top Down G + M 1T Engine Alternator Battery E-motor Gear&diff Tyre Model Vehicle 1 i rotatie ground U M Electric Interface U i R L friction inertia rotation (R Me in Mechanic reference (chassis) 2 ground Τ:=K*i 3 U:=K*ω (K=constant of proportionality V/ A. Van den Brand, Mday

25 Physical Modeling: energy centric Energy is important: in all domains - Concepts comparable - (resistance, load, buffer) - Coupling domains using converters - Motor = converter (electric rotering mechanic) Energy Losses (heat) = thermal energy Piston (Pneumatic/hydraulic) Pump. A. Van den Brand, Mday

26 Same interfaces, different models Interfaces are stabile Components exchangeable using variants Runtime configurable variants Scalable simulation accuracy System level: >>2x real time Lookup tables (datasheet info); straightforward Mean level : 1-2x real time i.e. E-motor model reveals 3-phase control Detailed level:10-20x slower than real time i.e. PWM modulation of E-motor inverter Current focus: mean level. Good results, reasonable time 27 A. Van den Brand, Mday

27 Model features Variation of Driving cycles Components & Component parameters Topology Driver behaviour Environmental conditions (i.e. weather) A. Van den Brand, Mday

28 Conclusions Experiences Conclusions Project Conclusions Method A. Van den Brand, Mday Titel & Bio Agenda Project Model Conclusions Q&A

29 Project: scaleable model Evolutionary model (grows with project) Top down (system) to detailed level Further refinement possible No surprises in model validation Maximum energy saving Multi-disciplinairy Energy centric Interfaces stabile Physical interfaces = reality Tooling Matlab/Simulink Extra SimScape/SimDriveline (physical modeling) Users E-Motor-x Application F=M*a P=½mv 2 Hybrid mode series parallel Design Space E-Motor-y Available technology A. Van den Brand, Mday

30 Experiences Learning time Physical model!= average Simulink model Idealized models don t work (physically impossible) Limited knowledge in industry Modeling is learning about the domain Tool SimScape family is very powerful Little need to dive into bondgraphs and diff. equations SimDriveline: powerful interfaces, (too) simple components SimElectronics, SimMechanics: interesting toolboxes A. Van den Brand, Mday

31 Experiences: tool improvements Room for improvements in tools: Hard-to-find Solver issues Infinite logging to HD Much time is lost into squeezing logging into <2GB Sampled logging No interest in femto-second events decimation doesn t scale with large step size Diff/Merge support Wish list for our model Nightly builds/runs 32 A. Van den Brand, Mday

32 Conclusions Physical modeling Excellent for mechatronic models Modeler is forced into realistic designs (Extremely) scaleable model Ideal for for energy saving Good interfaces Fewer interfaces, with higher quality Re-useable components Disadvantages Learning time from simulink (different way of thinking) Solver limitations for control & plant A. Van den Brand, Mday

33 Judgement Physical Modeling is a powerful tool - to save energy (by modeling) - To save energy (making the model) A. Van den Brand, Mday

34 Physical Modeling with SimScape Questions? Titel & Bio Agenda Project Model Conclusions Q&A A. Van den Brand, Mday

35 Interface types A. Van den Brand, Mday