Revas-Inast Public Results Project Set-up Vehicle dynamics server: state estimator Picture from Triphase Rapid prototyping software platform Active safety demonstrator Innovative sensors With support of Active suspension
Targets Decrease vehicle movement to increase comfort and safety Safety should be maintained when active suspension system fails Balance between function/performance and energy consumption developed in a short time Simulation with system targets to generate force-velocity couples Current situation (e.g. primary ride on road ISO 868 Class D) Defined heave, pitch and roll targets for primary ride Also targets defined for secondary and NVH
Safety Integrity and criterion Drivers can/ cannot cope Vehicle no longer controllable System reaction dangerous System reaction disturbing System reaction noticeable 1 Nothing noticed 9 8 7 6 5 4 3 2 1 Source: IZVW / Audi AG Safety criterion NOT SAFE SAFE Architecture Electrical and software architecture Hydraulic analyses (e.g. slalom manouver) +
Safety functions in software architecture Error Handler Error co code ode xx Sky-Hook Signal out of range accelerometers Signal out of Signal Si S irange gnal gn al Input IInp npu ut u displacement sensors Gradient monitoring body Gradient monitoring rattle accelerations velocities Signal Sign Si gnal gn g n na al al State Sta St atte a Gradient rattleestimator Validation V Vali Va alilid damonitoring dati da tion ti o on Estim Es ma ato tor Instability monitoring Cont Co ntro trollllller err e Controller displacements Valve current limits Signal Sign Si gnal gn g all Ouput Oupu Ou p power t Valve monitoring RPT power stage errors/warnings Offsets monitoring Vehicle CAN interrupted Private CAN interrupted Safety function CAN signal quality checks RPT input module errors Balancing function/performance and consumption Power supply required to drive with active suspension on defined road profiles + Energy flow Energy efficient actuator Optimization performed by Need for SW integrated energy management
Key Components a. The hydraulic actuator in the suspension Safety is maintained when system fails. = Key Components b. The hydraulic power pack determination =
16 14 12 1 8 6 4 2 UC needed current load pumps alternator current 1 2 time (s) 3 4 Current load pumps & alternator current with ultra cap box - 5l/min - Road ISO 868 Class C Pumps current load 1 l/min - Road ISO 868 Class B 12 1 current (A) Current load pumps & alternator current without ultra cap box - 5l/min - Road ISO 868 Class C With integrated energy management 8 6 4 with UC 2 without UC current (A) current (A) Key Components c. Ultracap limits effect on power supply 16 14 12 1 8 6 4 2 Alternator can deliver pump power current load pumps Energy management needed 1 2 3 4 1 2 3 alternator current 4 5 time (s) time (s) Key Components d. The state estimator Estimation of wheel forces via wheel displacements and accellero s Derivation of modal velocities as input for sky hook control Reduction of needed sensors Actual force estimation needed for safety y reasons
Integration test Implementation & Testing System test Successful outdoor road test on rough road Implementation & Testing Current situation New Vehicle behavior OK! Normal suspension Active suspension in same vehicle type and same road section
Future concept of high voltage architecture for full active suspension For (H)EV Simultaneous estimated current consumption by dynamic high power 12V-users ESP 7 A EPS 11 A Torque vectoring 3 A Active front steering/dynamic steering 5 A Full active suspension 1-7 A Sum 27-33 A 3-4V E M EP S E- AB C DC/DC shift Proposed architecture. 14V High currents means big power loss Local power solution needed for each system like DC/DC or super caps, which enlarges individual system costs Use of high voltage bus for high power (chassis) applications to lower the currents and package