Features of e-Wheel ....................................................................................................................................................................................................................... 6
Benefits of e-Wheel ........................................................................................................................................................................................................................ 7
Application Example ...................................................................................................................................................................................................................... 7
Different steering wheel sizes .................................................................................................................................................................................................... 9
e-Wheel Torque Control Algorithms ............................................................................................................................................ 10
Information Flow Block Diagram .............................................................................................................................................................................................10
Graphical Representation of Torque featuring various control algorithms ............................................................................................................11
End-Stop Torque Control ...........................................................................................................................................................................................................12
Base Torque Control .....................................................................................................................................................................................................................12
RPM Torque Control .....................................................................................................................................................................................................................12
Warning Control Torque .............................................................................................................................................................................................................14
Vehicle Speed Torque Control .................................................................................................................................................................................................15
Technical Data ................................................................................................................................................................................ 16
CAN (Controller Area Network) ................................................................................................................................................................................................16
Connector type and Pin Configuration .................................................................................................................................................................................16
Communication Protocol .............................................................................................................................................................. 18
Messages from e-Wheel to steering controller [AUX_STW_P and AUX
Messages from Vehicle speed sensor to steering controller and to e-Wheel [VSP_P and VSP_R] ..................................................................20
Messages from steering controller to e-Wheel ..................................................................................................................................................................21
This document describes the technical specifications and features’ information of the e-Wheel,
applied with Danfoss electro-hydraulic steering valves and steering controller.
Literature Type Reference number
PVED-CLS Communication Protocol L1425546
PVED-CLS Safety Manual BC00000331
OSPE Steering valve, SASA
Sensor
EHi Steering Valve Technical Information BC00000379
The OEM of a machine or vehicle in which Danfoss products are installed has the full responsibility for all consequences that
might occur. Danfoss has no responsibility for any consequences, direct or indirect, caused by failures or malfunctions.
•
The OEM shall perform a hazard and risk analysis for the target system to analyze if the relevant risks are
sufficiently reduced by the safety functions. The safety functions are provided by the involved functional safety
elements.
•
Danfoss has no responsibility for any accidents caused by incorrectly mounted or maintained equipment.
•
Danfoss does not assume any responsibility for Danfoss products being incorrectly applied or the system being
programmed in a manner that jeopardizes safety.
With the introduction of electro-hydraulic steering systems and
‘e-Wheel 100’ stands for Electric Steering Wheel Base, ‘100’ represents first of the series of Danfoss electric steering input devices.
Technical Information
e-Wheel 100
Introduction
eel 100
e-Wh
Danfoss steering products are used in vehicles where the driver must control high steering forces, reliably, comfortably and with
maximum safety.
Steer-by-Wire steering systems, applying electric steering wheel
advanced steering features like variable lock to lock ratio, softstop, anti-drift are possible, as easy integration in new vehicles
as well as retrofit to upgrade the existing vehicles. Primarily,
the objective of electric steering wheel is to offer high quality
steering feel, providing better operator comfort and reduce
operator fatigue. To meet this objective, Danfoss is now
offering electric steering input device ‘e-Wheel 100’.
‘e-Wheel 100’ is a haptic steering input device with passive force-feedback torque. ‘e-Wheel 100’ is referred to as ‘e-Wheel’
further in this document. The measured input steering angular position and the rate of change of steering angle from e-Wheel
are transmitted to steering valve controller, which determines the preferred steering response.
•e-Wheel is a ‘Plug and Play solution’ when interfaced directly to steering valve controller - PVED-CLS (for details refer
PVED-CLS User Manual), together with electro-hydraulic steering units OSPE / EHi.
•The communication protocol between e-Wheel and steering valve controller is based on the Danfoss proprietary safety
CAN protocol (refer PVED-CLS Communication Protocol).
•e-Wheel sub-system with PVED-CLS, supports realizing safe steering solutions designed to meet SIL 2/ PL d/ AgPL d by
designing the sub-system to a category 3 architecture (refer mini-steering wheel sub-system in PVED-CLS Safety
Manual).
In applications where e-Wheel is used as a primary steering input device or auxiliary steering input device, force-feedback is
necessary as the steering is expected not only to replicate same functions of conventional mechanically linked steering systems
(such as hydro-static enforced feedback) but also to provide advanced steering functions like:
•Directional control and wheel synchronization
•Variable steering ratio
•Smooth steering feel
The absence of hydro-static enforced feedback makes operator disconnected with the vehicle steering feedback which may
cause over or under steering. So, e-Wheel haptic passive force-feedback, mimics the feel of conventional steering systems, which
makes it a special attribute.
Features of e-Wheel
•
‘Plug and Play’ solution with PVED-CLS as steering controller
•
SIL Claim limit : 2
•
Dual channel redundant CAN bus interface
•
High quality steering feel
•Smooth steering torque control
•Absence of traditional steering wheel backlash and drift
•End-Stop feeling when vehicle wheels steered to extreme end-locks
•RPM torque for better controllability during Quick Steer
•Warning or event signal via steering wheel vibration
Man-Machine Interface as well as a Gateway for primary vehicle speed message
(Dual Channel)
MC012
External Controller (as a redundant controller) for secondary vehicle speed
message
Vehicle ECU
OEM controller for braking function during any malfunction or events of failure
Technical Information
e-Wheel 100
Benefits of e-W
•
•
•
•
•
e-Wheel Safety Functions
1.Safe Steering Angular Position and Safe Steering Speed:
2.Safe Force-Feedback Brake Torque:
heel
Reduced operator fatigues due to improved ergonomics
Benefits for different steering solutions
•Electro-hydraulic steering solutions
•e-Wheel applied as auxiliary steering input device
•In case of failures, reliable fallback to the primary manual steering wheel
•Fail-Safe SbW solutions
•Eliminates steering column
•Cabin design freedom for OEMs
•Better accessibility for operator, flexibility in seat movements and orientation
Low power consumption
Compact and robust design
Easy to install
Two Channels of e-Wheel (each channel provides sub-system elements as the hall effect angle sensors, microprocessor
logic blocks, power supply conditioning and protection , CAN transceivers) independently measure angular positions,
calculate steering speeds and transmit both steering angular positions and steering speeds onto CAN bus (safety
protocol as per PVED-CLS communication protocol)
Applying force-feedback torque by e-Wheel as response to the data received via CAN bus (safety protocol as per PVEDCLS communication protocol). Software in the microprocessors will run various torque algorithms in response to the
system inputs, defining the required current for force feedback brake torque of e-Wheel. Both microprocessors within eWheel will also carry out independent monitoring of sub-systems elements to identify and react to subsystem faults.
Application Example
e-Wheel supports category 3 architecture and can be integrated in a Danfoss CAT 3 Fail-Safe Steering System with Danfoss EHi /
OSPE and PVED-CLS as steering valve controller (refer to EHi / OSPE Technical Information Document). In below example shown in
figure 1, we consider a Fail-Safe steering solution with Steer-by-Wire (SbW) system:
Figure 1 Fail-Safe Steer-by-Wire steering sub-system with e-Wheel
Here, e-Wheel is the primary steering input device in the vehicle with Fail-Safe steering system, which transmits the steering
angular positions and the rate of change of steering angle, via CAN bus, to the steering valve controller. The steering valve
controller uses the dual redundant analogue wheel angle sensor inputs, dual redundant vehicle speed messages and dual MMI
(display) message, as per PVED-CLS communication protocol. In this example, vehicle speed (VSP) message is as per standard CAN
J1939 protocol. So, the VSP messages further needs to be converted from standard CAN protocol to PVED-CLS communication
protocol using PLUS+1 functional block in the two redundant external controllers (Danfoss Display and Danfoss MC- 012
Controller). With above messages along-with the e-Wheel inputs, steering valve controller determines the appropriate steering
response.
For vehicles with Fail-Safe SbW steering systems only using EHi steering valve, manual activated emergency steering will not be
possible. Such steering systems must be set up with complete redundancy and limited only for off road usage. In case of failures,
vehicles must be brought to a defined safe state, for instance by stopping the vehicle or switching to a backup steering system. As
shown in figure 1, during the malfunction or events of failure, based on the operational status message from the steering
controller and the vehicle speed CAN safety message from the two plus+1 controllers, the vehicle ECU can signal the vehicle brake
systems for reduction of the speed and stopping the vehicle as a safe state response. Vehicle builder necessarily must perform
hazard and risk analysis, to have a “safe vehicle brake” safety function which the steering sub-system can demand. In order to
integrate with above steering system, suggested category is category 3. The steering controller will not monitor any status
message from the braking system and no action is intended to steering system related to the status of the braking system.
Danfoss offers e-Wheel – I without mounting any top steering
Figure 2
The steering wheels to be mounted on top, must be machined
Examples*
(* Danfoss does not offer the
possibilities with the
Steering wheel sizes to fit on
Recommended Torque for
Recommended Part
Mini-steering wheel
2 Nm
11224128 / 11198022
Medium size steering wheel
5 Nm
11224129 / 11243182
Larger size steering wheel
5 Nm
11224129 / 11243182
Technical Information
e-Wheel 100
Different steering wheel sizes
wheel, shown as per figure 2.
The shaft of e-Wheel is a ‘flat D-shaped’ shaft with:
•with a maximum axial force of 1500 N
•bending moment of 50 Nm
in a way that they accept the ‘flat D-shaped’ shaft of e-Wheel,
as shown in figure 3.
Figure 3
Below are few possibilities of different steering wheel sizes that can fit on shaft of the e-Wheel:
e-Wheel
steering wheels, below are
just the
e-Wheel)
corresponding steering
wheel size
Numbers
Recommendation:
•Danfoss offers e-Wheel with 5 Nm and 2 Nm as standard variants for maximum operating torque; choice of these
variants majorly depends on the type of application and the type of steering wheel size required in respective
application.