Status report Informal Working Group on the Electronic Vehicle Stability Control

REPUBLIC OF HUNGARYMINISTRY OF ECONOMY AND TRANSPORT

Status reportStatus report

Informal Working Group on the Informal Working Group on the Electronic Vehicle Electronic Vehicle Stability ControlStability Control

Dr. Laszlo Palkovics

Geneve, February 2, 2005

Informal document No. GRRF-57-30

(57th GRRF, 31 January-4 February 2005,

agenda item 6.1.)


Mandate and targets of the Working GroupMandate and targets of the Working Group

Mandate of the EVSC Working Group

“ Regarding the consideration of electronically controlled stability enhancement systems, the Chairman requested the consent of WP.29 to establish an informal group in order to investigate that issue in greater detail. WP.29 gave its consent.”

• How to understand this mandate? 1. Make a consolidated concept for the future regulation clarifying

the following issues:1. What to regulate (system, vehicle) – definition of the EVSC

system2. Where to include (Reg. 13, Reg. 111, separate, etc.)?3. How to regulate – only technical aspects, no economical or

political aspect are considered.

2. Based on the concept, prepare a text proposal for the regulation.


Project Project pplanlan

Target deadline Activities Output Remarks

November, 2004 1st EVCS meeting Concept proposal for the regulation

End of January, 2004 2nd Meeting in Paris

Finalize the concept, make agreement

Preparation to the February GRRF meeting

February, 2004 GRRF Meeting Accept the concept proposal, comments

April 15, 2004 Working meeting 1

First consolidation of the text

Meeting in Brussels

July, 2004 Working meeting 2

Second consolidation of the text

September, 2004 GRRF Meeting Accept text proposal


Summary of the aSummary of the activitiesctivities and results and results

• 1st meeting of the ad hoc group (Budapest, November 25-26, 2004). Major activities and achievements:– Definition of the tasks for the working group– Text proposal for the future regulation – embedded in Reg. 13.

Basis: draft paper from the European industry work group.– Identification of potential problem areas – nomination of persons

dealing with those topics– Over 40 persons participated at the meeting, industry is well

represented• 2nd meeting

– Discussion of the identified problem areas– No conceptual change in the text generated during the first

meeting, refinements at some points. Valuable contribution from the Russian delegation

– Principal agreement about the structure of the proposal– More than 30 participants at the meeting, good mixture of

participants (industry, government, technical services)


The most important issuesThe most important issues

• Why should we regulate the EVSC systems?

• How complex should the regulation be?

• Where the regulation should be embedded?

• Definition of the EVSC system – no unified definition for power driven vehicle and trailer.

• Design requirement (+demonstration of the functionality) vs. performance requirement.

• How to demonstrate functionality? Vehicle test and/or simulation.

• Warning signal to driver – light vs. audible signal.

• Compatibility between tractor – semi trailer, or truck – trailer

• Align activities with the ISO 11992 Working Group


Why EVSC should be regulated? Why EVSC should be regulated?

• Increased society demand for enhanced traffic safety, signaled by facts that

– EVSC is becoming typical in the higher passenger vehicle classes

– Attempts to mandate it for some special service vehicles

– Local attempts for mandating EVSC systems for buses (either government initiative, or manufacturers initiative)

• Different kind of systems are available on the market (developed, industrialized), which would fulfill the society demand

• Legislation has to bridge the society demand with the existing and future systems in order to provide terms of references


Why EVSC should be regulated?Why EVSC should be regulated?

• Denmark will mandate stability control system for coaches of class M3 as of 01.05.2005.

• This attempt is highly welcome, since the stability control system significantly contributes to the traffic as well as passenger safety.

• However, there are several problems with the current formulation:

– Definition of the required stability control system (called ESP in the document) is not sufficient

– There are no clear requirements defined

– EVSC in class M3 is only available for the heavy coaches (> 10 tons) with electro-pneumatic brake system. The system is not available for lower category coaches.

– Even in M3 > 10 tons class most of the delivered bus chassis will not have the stability control system, that must be applied for this vehicles


Cornerstones of the future regulationsCornerstones of the future regulations

• The regulation shall not be very complex, and put a very high burden on the manufacturers and the Technical Services to fulfill its requirements, but

• It must be comprehensive enough and provide terms of references in order to exclude the systems not performing on the expected level

• It should appear as soon as possible in order to follow the demand of the society.

• The mandated types must be selected according to their impact on the traffic safety (most common, high volume vehicles).

A fair trade-off should be found


Where to include? Where to include?

• Regulation 13 has been selected, since almost all of the state-of-the-art EVSC systems are using the brake as intervention actuator

• However, where other intervention is possible, this regulation should comply with the relevant other regulations, such as Reg. 79 in case of superimposed steering (a footnote has been created)

Proposed amendments to ECE Reg.13, Explanatory Note – not part of proposal: Within the GRRF forum there is still an open point as to whether specific requirements concerning electronic vehicle stability controls should be integrated into R13 or R111 – this document has been prepared on the basis assumption that it will would be part of R13, but implies no recommendation. Reg. 79 to be considered in the formulation of this amendment of Reg. 13.


Definition for power driven vehicleDefinition for power driven vehicle

Add a new paragraph 2.28 to read: 2.28 “Vehicle Stability Function” means an electronic control function for a power-driven

vehicle which improves the dynamic stability of the vehicle and shall include a directional control and may include a roll-over control as defined below:

2.28.1 “Directional control” means a function within a vehicle stability function that assists

the driver in maintaining the vehicle in the direction intended by the driver. 2.28.2 “Roll-over control” means a function within a vehicle stability function that reacts to

the potential of roll-over to stabilise the vehicle or towing vehicle and trailer combination during dynamic manoeuvres.

Definition of the EVSC system for individual vehicle units but not for combinations


Definition for trailerDefinition for trailer

Add new paragraph 2.29 to read: 2.29 “Trailer Stability Function” means an electronic control function for a trailer which

improves the dynamic stability of the trailer and shall include rollover control and may include direction control as defined below: that reacts to the potential of roll-over to stabilise the trailer during dynamic manoeuvres.

2.29.1 “Trailer roll-over control” means a function within a trailer stability function that reacts to the potential of roll-over to stabilise the trailer during dynamic manoeuvres. 2.29.2 “Trailer directional control” means a function within a trailer stability function that

assists in maintaining the direction of the trailer with that of the towing vehicle.

Separate definition for trailer because of the most complex dynamics


Compatibility matrix for multi-unit vehiclesCompatibility matrix for multi-unit vehicles

Semi-Trailers

Centre Axle Trailers

Full (Drawbar) Trailers

Towing Vehicle

Wit

ho

ut

ISO

763

8

Wit

h

AB

S

Wit

h

RS

F

Wit

h

YC

+ R

SF

Wit

ho

ut

ISO

763

8

Wit

h

AB

S

Wit

h

RS

F

Wit

h

YC

+ R

SF

Wit

ho

ut

ISO

763

8

Wit

h

AB

S

Wit

h

RS

F

Wit

h

YC

+ R

SF

Without ISO7638

NC

NC

NC 1/

With ISO7638

NC

NC

IMP

With DC

IMP

IMP

IMP

Tractor

With DC + ROC

IMP

IMP

IMP

Without ISO7638

NC

NC

NC 1/

NC 1/

NC

NC

NC 1/

NC 1/

With ABS

NC

NC

IMP

IMP

NC

NC

IMP

IMP

With DC

IMP 2/

IMP 2/

IMP

IMP 3/

IMP 2/

IMP 2/

IMP 3/

IMP 3/

Truck

With DC + ROC

IMP 2/

IMP 2/

IMP

IMP 3/

IMP 2/

IMP 2/

IMP 3/

IMP 3/

1/: Stability function(s) not functional as the tractor has no ISO7638 power supply is available2/: Identification problem between centre axle and full trailers as the trailer has no electric control line to identify the trailer type3/: It is not clear how the respective truck and trailer systems will interact and how this will impact on combination stability therefore it may be necessary to define priorities to inhibit either the truck or trailer stability system.


Design requirement for the interventionDesign requirement for the intervention

5.2.1.31.1. Where a vehicle is equipped with a vehicle stability function as defined in paragraph 2.28 the following shall apply:

In the case of directional control the function shall have the ability to automatically control individual wheel speeds by selective braking based on the evaluation of actual vehicle behaviour in comparison with a determination of vehicle behaviour demanded by the driver. 1/

In the case of roll-over control the function shall have the ability to automatically control individual or multiple wheel speeds by selective braking or automatically commanded braking based on the evaluation of actual vehicle behaviour that may lead to vehicle roll-over. 1/

Brake system based intervention – a clear design requirement


Design requirement for the dynamic estimationDesign requirement for the dynamic estimation

5.2.1.31.2. To realise the functionality defined above a vehicle stability function shall include, in addition to selective braking and where appropriate automatically commanded braking, at least the following:

The ability to regulate engine power output. The determination of vehicle behaviour from measured values of yaw

rate, lateral acceleration and wheel speeds and from the driver’s control input to the braking system, to the steering system, and to the engine.

5.2.1.31.3. A vehicle stability function of a different design to that described in paragraph 5.2.1.31.2. above shall be deemed to fulfil the requirements of a vehicle stability function provided that at least equivalent performance is achievable.

The assessment procedure used shall be agreed between the vehicle manufacturer and Technical Service to ensure the objectives defined in 2.28. are fulfilled and shall require comparative testing with a representative vehicle fulfilling the specification defined in 5.2.1.31.2. above.

Design requirement – derived from state-of-the-art systems as necessary and sufficient requirement


Performance requirementPerformance requirementss??

• The most severe discussion has been induced by the question: should we define performance requirements?

• Difficulties with performance requirements:

– There is no uniquely defined performance level for the EVSC systems

– Definition of the possible tests is not obvious (all ISO standards have been analyzed)

– Repeatability of the tests on the stability limit is not possible

– Complex test requirements (similar to those conducted by the OEs and system manufacturers during the release process) is hardly possible at the Technical Services, puts additional very high burden an the system

Conclusion: if there is no obviously defined, realistically measurable performance requirement – better not to define

anything


Compromise: “performance demonstration”Compromise: “performance demonstration”

5.2.1.31.5 The operation of the vehicle stability control shall be demonstrated by means of checked by a dynamic test or alternatively by the submission of test results from a representative vehicle or from computer simulation 2/. The method by which this demonstration check is carried out shall be agreed between the vehicle manufacturer and the Technical Service and shall include the critical conditions of under-steer, over-steer and rollover as appropriate to the vehicle stability function installed on the vehicle with the method of demonstration assessment and results being appended to the type approval report.

An acceptable compromise has been found – vehicle demonstration as well as simulation is possible


Alignment with the informal ISO 11992 WGAlignment with the informal ISO 11992 WG

• An informal ISO WG is active in re-considering the ISO 11992-2003. Activities in the EVSC WG will be aligned

• Proposals for several new information transmitted via the electronic control line. Some of the most relevant ones:

– EVSC active on the truck/trailer

– Request for relative brake demand side and axle-wise on the trailer

– Geometric data content of the trailer

– Trailer identification data

– Motor vehicle/trailer is/is not equipped with EVSC system

– Disable of complete/partial EVSC function on motor vehicle/trailer

Input from EVSC WG fits to the schedule of the ISO WG


Summary of the current statusSummary of the current status

• Generally: the progress in the working group is much higher as we expected.

• A draft version of the text proposal for the EVSC regulation embedded in Reg.13 is available

• The major characteristics are:– Clear design requirements for the intervening actuators and

sensors, as minimum set– Demonstration of the functionality during critical maneuvers is

required– The proposal does not put very high burden an the end user,

manufacturer, but comprehensive enough to give clear terms of references

– To introduce the regulation in the proposed form as soon as possible, and re-visit performance demonstration issue in 2 years based on the experience collected by the Technical Services


Thanks to the participants of the ad hoc Thanks to the participants of the ad hoc group for their commitment and work what group for their commitment and work what

they provided during last period. they provided during last period.

Documents

Status report Informal Working Group on the Electronic Vehicle Stability Control