Design and Analysis of the
CES Semi-active Suspension System
by Öhlins Racing
Matteo Pelosi
2015 Hydraulikdagarna
March 16th, Linköping, Sweden
Contents
• Öhlins Racing AB, Intro
• Öhlins Systems, CES
• Öhlins Systems Analysis, CAE
• CES-TTX Damping System
– CES Valve
– TTX-CES Shock Absorber
– Force Feedback Control
– Vehicle Dynamics
• Conclusions
2
Öhlins Racing AB
ADVANCED SUSPENSION TECHNOLOGY
3
Öhlins Product Areas
HYDRAULIC SUSPENSION SYSTEMS
Damping through controlled oil flow metering
Different levels of system complexity…
4
Öhlins Racing Systems
Conventional & Mechatronics
Conventional Systems, damping adjusted by manual
fixed steps, i.e. clicks through screws and knobs
EC, damping adjusted electronically by stepper motors
based on fixed settings.
Smart EC, damping adjusted while riding based on state
information, i.e. throttle, brake, velocity, acceleration ...
CES, damping is continuously adjusted based on state
information, i.e. throttle, brake, velocity, acceleration …
5
Öhlins Semi-active Suspension
CES
• Proprietary technology developed since 1984
• In use by several major automotive OEMs, >4 million sold
• Semi-Active Damping
6
Öhlins Systems Analysis
CAE Support
Vehicle Dynamics
Cars, Motorcycles
Controls
Mechatronics
1D Multi-physics
Dampers
Valves
3D CFD, FSI, FEM
Sub-Assemblies
Success factor for truly accurate and useful results:
Co-Simulation!
7
CES-TTX Damping System
Overview
Öhlins mechatronic system modeling example, including hydraulic valves, shock
absorber, automatic controls and vehicle dynamics
Hypersport Motorcycle
Öhlins CES-TTX Shock
Öhlins CES Valve
Öhlins ECU
Application and coupling of different simulation domains/strategies: 1D modeling,
3D CFD/FSI, controls theory, vehicle dynamics
8
CES Valve Modeling
Overview
Solenoid
1D Model
Pilot Stage
1D Model
Öhlins TTX CES Shock
• 2-stage pilot operated pressure control valve
Main Stage
1D Model
• Capturing valve hydro-mechanical dynamics
• 1D model optimized to capture flow forces,
flow coefficients, friction…
• Model used to study novel valve designs &
several physical behaviours
9
CES Valve Modeling
Reduced Order Modeling
Special submodels for valve stages to include information
from 3D CFD/FSI analysis: weak/offline coupling
Metering
Shim Orifice Submodel
Pilot Stage CFD Enhanced
1D Model
ANSYS Fluent CFD
ASCII tables for flow
forces & flow
coefficients as input
to C++ submodels
Pelosi, M., Subramanya, K. and Lantz, J. 2013. Investigation on the Dynamic Behavior of a Solenoid
Hydraulic Valve for Automotive Semi-Active Suspensions Coupling 3D and 1D Modeling. Proc. of the 13th
Scandinavian International Conference on Fluid Power, Linköping, Sweden.
10
CES Valve Modeling
Validation
A p-Q test cycle is simulated, where the pilot stage is fed by successive ramps of
flow rate and excited at different levels of current
CES Super-component
11
CES Valve Modeling
Validation
Low speeds & high speed regions compare well at all currents thanks to ROM
i
i/imax
High Speeds
Low Speeds
12
CES-TTX Damping System
Shock Absorber
Hypersport Motorcycle
Öhlins CES-TTX Shock
Öhlins CES Valve
Öhlins ECU
13
CES-TTX Shock Modeling
Overview
Twin-tube shock absorber with double CES valves configuration
Separate compression & rebound
F damping
Velocity
Coupling of 1D super-components library
Parameterization through physical knowledge, distributed simulations and manual tuning
14
CES-TTX Shock Modeling
Static & Dynamic Validation
Dynamometer
CES-TTX shock model used to predict & understand shock
absorber behaviors:
- Static Testing: velocity ramp input
- Dynamic Testing: velocity sine wave input
vs
LMS AMESim
Sadeghi Reineh, M. and Pelosi, M., 2013. Physical Modeling and Simulation Analysis of
an Advanced Automotive Racing Shock Absorber using the 1D Simulation Tool AMESim.
SAE Int. J. Passeng. Cars - Mech. Syst. 6. doi: 10.4271/2013-01-0168.
15
Modeling Libraries
Encrypted Supercomponents, Black Box Export
Development of proprietary library of custom submodels & super-components
Internal and external sharing of advanced non-linear models
Super-components
•
CES valves
•
Öhlins forks, shocks
•
Other dampers
•
…
Submodels
•
Custom orifices
•
Special spools
•
Special poppets
•
…
16
CES-TTX Damping System
Automatic Controls
Hypersport Motorcycle
Öhlins CES-TTX Shock
Öhlins CES Valve
Öhlins ECU
17
Force Feedback Control
Main Objective
Develop a shock controller that tries to follow a given force reference
using feedback from a force sensor mounted inline with the damper rod
CES
solenoid
valves
Öhlins ECU
• Enhance understanding of input
control current to force dynamics
using model based approach
• Control structure in
Matlab/Simulink
Force Sensor
• Evaluate controller performance
using the damping system model as
“virtual hardware” through
AMESim/Simulink co-simulation
F damping
18
Force Feedback Control
The Controller
Co-Sim
Simulink
AMESim
• Damping system control
strategies development &
verification
• Environments cosimulations to study
mechatronic system
behaviour
• Ideal & real inputs to the
co-simulation model
19
Force Feedback Control
Numerical Results
Step Response
Clipped Sinusoidal Force Reference
Sinusoidal Velocity Input
Sinusoidal Force Reference
Sinusoidal Velocity Input
Input data from real
track/road testing
SiL, HiL
Testing on real damper
hardware
20
CES-TTX Damping System
Vehicle Dynamics
Hypersport Motorcycle
Öhlins CES-TTX Shock
Öhlins CES Valve
Öhlins ECU
21
Vehicle & Systems Co-Simulation
Intro
• Öhlins Mechatronic System coupled with vehicle dynamics simulation
• Study control strategy & mechatronics behavior on full vehicle
• Simulation of standard test cycles & full test tracks
Simulink
AMESim
Co-Sim
22
Vehicle & Systems Co-Simulation
Numerical Results
• Monitor several simulation parameters from front
and rear suspension and full vehicle
Damping Forces
Karlskoga Motorstadion - Gelleråsen
Vertical Acceleration
• Verify different control software and hydromechanical hardware settings before physical test
• Investigate influence of hardware and software
design changes over vehicle performance
• Correlate comments from expert riders with Öhlins
mechatronics behavior
23
Conclusions
•
The use of CAE tools within Öhlins Racing R&D has been shown: coupling
of modeling environments through 1D system co-simulations & 3D multiphysics simulations
•
3D simulations paramount for physical understanding at a detailed,
distributed components level (CFD, FSI, FEM)
•
1D modeling to deepen the knowledge of conventional and mechatronic
systems second order dynamics behavior
•
Co-simulations with Matlab Simulink allows implementation, study and
comparison of different control strategies
•
Vehicle dynamics modeling allows further understanding over interactions
of Öhlins products with driver/rider and OEM vehicles
24
Thank You! Questions?