Technical Information
Passive Force Feedback Electric Steering Wheel Base
powersolutions.danfoss.com
Technical Information e-Wheel 100
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January 2020 |
Second Edition : Corrected RPM operating speed |
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September 2019 |
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© 2019 Danfoss A/S. All rights reserved
All trademarks in this material are properties of their respective owners.
PLUS+1, GUIDE and Sauer-Danfoss are trademarks of Danfoss A/S.
2 | © Danfoss | September 2019 |
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Technical Information |
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e-Wheel 100 |
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Table of Contents |
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Literature References ...................................................................................................................................................................... |
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OEM responsibility........................................................................................................................................................................... |
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Introduction ..................................................................................................................................................................................... |
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e-Wheel 100 ...................................................................................................................................................................................................................................... |
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Features of e-Wheel ....................................................................................................................................................................................................................... |
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Benefits of e-Wheel ........................................................................................................................................................................................................................ |
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e-Wheel Safety Functions ............................................................................................................................................................................................................ |
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Application Example...................................................................................................................................................................................................................... |
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Different steering wheel sizes .................................................................................................................................................................................................... |
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e-Wheel Torque Control Algorithms ............................................................................................................................................ |
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Information Flow Block Diagram............................................................................................................................................................................................. |
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Graphical Representation of Torque featuring various control algorithms ............................................................................................................ |
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End-Stop Torque Control ........................................................................................................................................................................................................... |
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Base Torque Control..................................................................................................................................................................................................................... |
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RPM Torque Control..................................................................................................................................................................................................................... |
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Warning Control Torque............................................................................................................................................................................................................. |
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Vehicle Speed Torque Control ................................................................................................................................................................................................. |
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Technical Data................................................................................................................................................................................ |
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Mechanical characteristics......................................................................................................................................................................................................... |
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Electrical characteristics.............................................................................................................................................................................................................. |
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CAN (Controller Area Network)................................................................................................................................................................................................ |
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Connector type and Pin Configuration................................................................................................................................................................................. |
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Environmental characteristics .................................................................................................................................................................................................. |
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Functional Safety........................................................................................................................................................................................................................... |
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Communication Protocol .............................................................................................................................................................. |
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Messages from e-Wheel to steering controller [AUX_STW_P and AUX_STW_R] ................................................................................................... |
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Messages from Vehicle speed sensor to steering controller and to e-Wheel [VSP_P and VSP_R].................................................................. |
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Messages from steering controller to e-Wheel .................................................................................................................................................................. |
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Installations.................................................................................................................................................................................... |
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Dimensions...................................................................................................................................................................................................................................... |
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Instructions...................................................................................................................................................................................................................................... |
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Variant and ordering specifications............................................................................................................................................. |
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e-Wheel MMC ................................................................................................................................................................................................................................. |
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Code Numbers ............................................................................................................................................................................................................................... |
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Variants codes for e-Wheel MMC ............................................................................................................................................................................................ |
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Technical Information e-Wheel 100
Purpose of the document
This document describes the technical specifications and features’ information of the e-Wheel, applied with Danfoss electro-hydraulic steering valves and steering controller.
References
Literature |
Type |
Reference number |
PVED-CLS |
Communication Protocol |
L1425546 |
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PVED-CLS |
User Manual |
L1525062 |
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PVED-CLS |
Safety Manual |
BC00000331 |
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OSPE Steering valve, SASA |
Technical Information |
11068682 |
Sensor |
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EHi Steering Valve |
Technical Information |
BC00000379 |
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Definitions and Abbreviations
e-Wheel |
Electric Steering Wheel Base |
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SbW |
Steer-by-Wire |
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AgPL |
Agricultural Performance Level |
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SIL |
Safety Integrity Level |
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CAN |
Controller Area Network |
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PL |
Performance Level |
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Proportional Valve Digital – Closed Loop - Safety (steering valve controller) |
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PVED-CLS |
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Orbital Steering Product – Electro-hydraulic steering valve |
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OSPE |
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EHi |
Electro-hydraulic in-line steering valve |
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Fail Safe |
To detect fault, indicate fault to safe state system and revert to a safe |
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condition in the event of a breakdown or malfunction |
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Fail Operational |
To detect fault, indicate fault to safe state system and continue full |
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operation with enough redundancy level |
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PAE |
Product Application Engineering |
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Technical Information e-Wheel 100
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 jeopardizessafety.
5 | © Danfoss | September 2019 |
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Technical Information e-Wheel 100
Danfoss steering products are used in vehicles where the driver must control high steering forces, reliably, comfortably and with maximum safety.
With the introduction of electro-hydraulic steering systems and 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’ stands for Electric Steering Wheel Base, ‘100’ represents first of the series of Danfoss electric steering input devices. ‘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 steeringresponse.
•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 3architecture (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.
•‘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
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Technical Information e-Wheel 100
•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
1.Safe Steering Angular Position and Safe Steering Speed:
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)
2.Safe Force-Feedback Brake Torque:
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 e- Wheel will also carry out independent monitoring of sub-systems elements to identify and react to subsystem faults.
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:
Components |
Description |
e-Wheel 100 |
Primary steering input device |
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EHi (configuration type 7) |
Electro-hydraulic steering unit |
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PVED-CLS |
Steering valve Controller |
WAS |
Dual Analogue Wheel Angle sensor |
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VSP |
CAN Vehicle Speed Sensor (Dual Channel) |
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MMI |
Man-Machine Interface as well as a Gateway for primary vehicle speed message |
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(Dual Channel) |
MC012 |
External Controller (as a redundant controller) for secondary vehicle speed |
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message |
Vehicle ECU |
OEM controller for braking function during any malfunction or events of failure |
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Technical Information e-Wheel 100
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 MC012 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.
8 | © Danfoss | September 2019 |
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Technical Information e-Wheel 100
Danfoss offers e-Wheel – I without mounting any top steering 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
Figure 2
The steering wheels to be mounted on top, must be machined 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:
Examples* |
Steering wheel sizes to fit on |
Recommended Torque for |
Recommended |
Part |
(* Danfoss does not offer the |
e-Wheel |
corresponding steering |
Numbers |
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steering wheels, below are |
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wheel size |
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just the possibilities with the |
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e-Wheel) |
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Mini-steering wheel |
2 Nm |
11224128 / 11198022 |
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Medium size steering wheel |
5 Nm |
11224129 / 11243182 |
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Larger size steering wheel |
5 Nm |
11224129 / 11243182 |
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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.
9 | © Danfoss | September 2019 |
BC318774147046en-000101 |