1、 SURFACE VEHICLE INFORMATION REPORT J3081 APR2015 Issued 2015-04 Heavy Vehicle Controls Prioritization and Conflict Resolution RATIONALE This document is offered as a proactive response to the “sudden acceleration” issues that periodically receive notoriety within the transportation industry. In man
2、y cases the need for better driver training and more rigid licensing standards has been highlighted as much as any weakness in vehicle control systems. However, there is a growing desire advance vehicle control technology so that it can compensate for errors in vehicle operation; hence the ongoing p
3、ublicity for driverless vehicles. 1. SCOPE This document is written to address acceleration and deceleration control issues related to Heavy Duty Trucks and Buses greater than 10 000 GVW. 1.1 Purpose Establish criteria and rationale for prioritized response to operator control inputs in order to ena
4、ble acceptable operation of heavy vehicles especially in cases where there may be conflicting priorities. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publicatio
5、ns shall apply. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. SAE J1939 Serial Control and Communications Heavy Duty Vehicle Network - Top Level Docu
6、ment 2.1.2 ISO Publications Available from American National Standards Institute, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org. ISO 26262 Road Vehicles - Functional Safety _ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance
7、 the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every
8、 five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2015 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by an
9、y means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.
10、org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J3081_201504 SAE INTERNATIONAL J3081 Issued APR2015 Page 2 of 4 2.1.3 Related Publications The following publications are provided for information purposes only and are not a r
11、equired part of this SAE Technical Report. Code of Federal Regulations, 49 CFR, Part 571, Crash Avoidance Standard No. 105 Hydraulic and Electric Brake Systems Standard No. 121 Air Brake Systems Standard No. 124 Accelerator Control Systems 3. TRADITIONAL MECHANICAL CONTROL SYSTEMS Traditionally oper
12、ator control of commercial vehicles has been accomplished with a variety of mechanical devices. 1. Accelerator Pedal coupled to mechanical governor 2. Brake Treadle - pneumatic valve control of brake chambers 3. Engine Brakes and Drive Line retarders 4. Shift Selector - Typically lever or cable coup
13、ling to shift forks 5. Mechanical Clutches 6. Steering Wheel - geared coupling to steer arms Care has been taken in the design of these systems to achieve acceptable operation while avoiding the addition of costly redundancy. In general the goal is to bring the vehicle to a controlled stop, out of h
14、arms way, in the event of failure of a significant control system component. At least in North America, the goal has not been to provide redundancy that would permit mission completion. For example, in case of a stuck accelerator or governor, the operator can operate the clutch and/or shift to neutr
15、al while applying the brakes if necessary. The brake system is split front rear so that complete loss of braking capability is unlikely. The steering system is possibly the most critical control system. It is for this reason that significant effort is put into assuring the robustness and reliability
16、 of the mechanical components used within this system. 4. TRANSITION TO ELECTRONIC CONTROL SYSTEMS As a result of the need to reduce vehicle emissions and to improve vehicle safety, basic mechanical controls are being converted to electronic control or “drive-by-wire” systems. 1. Electronic Charging
17、 System (voltage regulators) 2. Electronic Engine Controls 3. Automatic Transmission Controls 4. Antilock Brake Systems 5. Traction Control Systems 6. Vehicle Stability Systems 7. Hybrid Vehicle Systems 8. Steer by wire systems (future) As these drive-by-wire systems are being engineered, care is be
18、ing taken to assure that the new systems perform in a manner at least as acceptable in their operation as the prior mechanical systems. However there is a need for constant vigilance to assess the performance of advanced control systems that provide features not previously available on commercial ve
19、hicles. For example, automatic traction control, electronically controlled transmissions, adaptive cruise control, and hybrid systems technology. SAE INTERNATIONAL J3081 Issued APR2015 Page 3 of 4 At the same time the advent of advanced control systems has raised the possibility of enhancing vehicle
20、 stability, and in particular, compensating to some extent for operator errors. For Example: 1. Antilock systems override engine and driveline retarders to avoid inadvertent lockup of drive wheels. 2. Vehicle controls can respond to service brake inputs preferentially over commands for vehicle accel
21、eration. 3. Adaptive Cruise is being extended into Automatic Collision Avoidance 4. Stability controls can compensate for driver operation at excessive speed or with inappropriate steering angles. Caution should be taken in developing controls that affect the operation of vehicles to avoid introduci
22、ng unforeseen consequences. For example: 1. Collision avoidance systems must account for the possibility that the driver may wish to maneuver around an obstacle rather than to perform a maximum performance stop. 2. Overly aggressive stability control systems can result in producing vehicles that are
23、 perceived as lacking performance and uncomfortable to drive. 3. Adding technology can increase complexity which can reduce reliability. 5. GENERAL PRIORITIZATION OF SYSTEM CONTROL SHOULD BE AS FOLLOWS: 1. Steering Controls 2. Stability Controls System/ABS/ATC 3. Collision Avoidance 4. Foundation Br
24、ake Controls 5. Electronic Transmission Controls 6. Engine/Acceleration Control 7. Engine Foundation Brake/Drive Line Retarder Systems 6. COMMUNICATION LINK MESSAGE PRIORITIZATION The SAE J1939 technical report as used with CAN2.0b provides for well thought out control message prioritization. This a
25、ssures that when timing is a consideration, higher priority messages will be transmitted preferentially over lower priority messages. However in cases where multiple data links are used, it is possible for conflicting messages to be received essentially simultaneously from different networks. In all
26、 cases intelligent control strategy must be used within the system responsible for vehicle control to assure acceptable operation regardless of the data link configuration. 7. SPECIFIC RECOMMENDATIONS: 1. It may be desirable to add sensors to the vehicle in order to facilitate appropriate vehicle re
27、sponse and control (For example, service brake treadle sensors for cases where they are not already available.) 2. Operator control inputs should be ascertained by use of robust sensors designed to facilitate reliable failure detection. 3. Data link message prioritization is encouraged but should no
28、t in any way be considered a substitute for the implementation of fault tolerant vehicle controls. 4. In many cases the engine control unit can be considered the default vehicle control unit. In other cases there may be a dedicated vehicle control unit. This is especially likely to be the case for h
29、ybrid system where a hybrid control unit is typically needed for electric drive control and energy management. Responsible and flexible control strategy must be applied to assure acceptable vehicle operation. 5. Where control is managed via a data link it is important that, failure of the data link
30、be considered and provision be made for determining acceptable system performance in that event. 6. In cases where the operator provides conflicting control requests, the system responsible for vehicle control should err on the side; best stability, and lowest kinetic energy. 7. Caution should be ta
31、ken in developing vehicle controls so as not to introduce unforeseen consequences. SAE INTERNATIONAL J3081 Issued APR2015 Page 4 of 4 8. NOTES 8.1 Marginal Indicia A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editoria
32、l changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. PREPARED BY THE SAE TRUCK AND BUS BRAKE SYSTEMS COMMITTEE
