GB/T 12549-2013 English PDF (GBT12549-2013)

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GB/T 12549-2013: Terms and definitions for vehicle controllability and stability
GB/T 12549-2013
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.50
T 23
Replacing GB/T 12549-1990
Terms and definitions for vehicle controllability and stability
ISSUED ON: NOVEMBER 27, 2013
IMPLEMENTED ON: JULY 01, 2014
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Steering system ... 4 
4 Suspension system ... 7 
5 Tires and wheels ... 13 
6 Axis systems and motion ... 22 
7 Movement characteristics ... 32 
8 Characteristics of limit maneuver and abnormal motion ... 40 
9 Test and evaluation ... 43 
10 Aerodynamics ... 51 
Index in English ... 68 
Foreword
This standard was drafted in accordance with the rules given in GB/T 1.1-2009 and
GB/T 20000.2-2009.
This standard replaces GB/T 12549-1990 "Terms and definitions for vehicle
controllability and stability".
This standard was formulated with reference to such documents as ISO 8855:1991
"Road vehicles - Vehicle dynamics and road-holding ability - Vocabulary", SAE J670e
"Vehicle dynamics terminology".
This standard is a revision of GB/T 12549-1990 "Terms and definitions for vehicle
controllability and stability". Compared with GB/T 12549-1990, the main changes are
as follows:
- ADD the terminology of vehicle aerodynamics (see Chapter 10);
- ADD the definitions of wheelbase change rate, longitudinal slip rate, wheel linear
free rolling angular velocity, longitudinal slip angular velocity, etc.;
- DELETE the definitions of slip rate, rudder holding force, rudder holding moment,
etc.;
- MODIFY the definitions of Ackerman angle, steering force, kingpin offset,
disturbance response, closed-loop control, total variance, etc.
This standard has collected and screened the automotive aerodynamic terms, which are
used in China for many years. Some terms and symbols in Chapter 10 are coordinated
and consistent with Clause 3.1 Aerodynamic fundamentals in GB/T 16638.1-2008
"Aerodynamics - Concepts quantities and symbols - Part 1: Aerodynamic terms in
common use".
This standard was proposed by the Ministry of Industry and Information Technology of
the People's Republic of China.
This standard shall be under the jurisdiction of the National Automotive Standardization
Technical Committee (SAC/TC 114).
Drafting organization of this standard: China FAW Group Technology Center.
The main drafters of this standard: Huang Chaosheng, Wang Debao, Ma Zhimin, Liu
Minghui, Zhu Hongwei, Ying Guozeng, Wu Zhenxin, Ling Qisheng.
This standard replaces the standard previously issued as follows:
- GB/T 12549-1990.
Terms and definitions for vehicle controllability and stability
1 Scope
This standard specifies the terms and definitions of vehicle controllability and stability.
This standard applies to all types of vehicles.
2 Normative references
The following documents are essential to the application of this document. For the dated
documents, only the versions with the dates indicated are applicable to this document;
for the undated documents, only the latest version (including all the amendments) is
applicable to this standard.
GB/T 3730.3-1992 Motor vehicles and towed vehicles - Dimensions of vehicles -
Terms and definitions
GB/T 6326-2005 Tyre terms and definitions
GB/T 16638.1-2008 Aerodynamics - Concepts quantities and symbols - Part 1:
Aerodynamic terms in common use
3 Steering system
3.1 Angles in steering system
3.1.1
Steer angle
δs
The angle, BETWEEN the vehicle's longitudinal symmetry plane (see 6.1.6) and the
center plane of the steering wheel (see 4.1.1) AND the intersection of the pavement
(see Figure 1).
vehicle steered.
3.2.2
Steering force
When the vehicle is turning, the operating force, which is applied to the steering
wheel, in the same rotation direction as the steering wheel. It is equal to the steering
wheel moment divided by the steering wheel radius.
3.2.3
Friction force of steering system
The minimum steering force, which is necessary to initiate angular displacement of
the steering wheels. It does not include the friction between the wheels and the
pavement.
3.2.4
Forward efficiency
The ratio -- of rocker shaft or rack's output power TO steering shaft's input power.
3.2.5
Steering system stiffness
When the steering knuckle is fixed, the ratio -- of the torque increment input by the
steering wheel TO the angular displacement increment it produces.
3.2.6
Moment of inertia of steering system
The equivalent moment of inertia, which converts the moving parts of the steering
system and the steering wheel to the rotating body, which rotates around the steering
shaft (or kingpin).
4 Suspension system
4.1 Suspension geometry
4.1.1
Wheel plane
For a single wheel, the wheel plane is the plane, which is equidistant from the inner
edge of the wheel rim, on both sides.
For double wheel, the wheel plane is the plane, which is equidistant from the inner
rim of the outer wheel rim AND the outer rim of the inner wheel rim.
[GB/T 3730.3-1992, definition 2.2] (see Figure 4)
4.1.2
Wheel center
The intersection, between the wheel plane and the wheel centerline of rotation.
[GB/T 3730.3-1992, definition 2.3] (see Figure 1)
4.1.3
Wheel alignment
The angular relationship, between the wheel and the body (or pavement), namely
the general term of the inclination of the steering kingpin (see 4.1.9), the caster angle
of the steering kingpin (see 4.1.6), the camber angle (see 4.1.8), the toe-in (see 4.1.4).
4.1.4
Toe-in
When the end point of the horizontal diameter of the inner contour line of the wheel
rim, at both ends of the same axis, is taken as the vertex of the isosceles trapezoid,
the difference between the lengths of the front and rear base sides of the isosceles
trapezoid is the toe-in. When the front base of the trapezoid is smaller than the back
base, the toe-in is positive; otherwise, it is negative. The angle between the
horizontal diameter of the wheel and the Y plane is the toe angle.
[GB/T 3730.3-1992, definition 3.28]
4.1.5
Toe angle
According to the provisions of 4.1.4.
4.1.6
Caster angle
The angle, between the projection of the centerline of the steering kingpin on the
4.1.9
Kingpin inclination
In a plane perpendicular to both the Y and X planes, the acute angle, which is formed
by the projection of the axis of the real or imaginary kingpin, on this plane, AND
the line which is perpendicular to the X plane.
[GB/T 3730.3-1992, definition 3.26]
4.1.10
Kingpin offset
The length of the projection of the line, which connects the intersection of the
kingpin's extension line and the pavement AND the center of tire contact (see 5.1.1),
on the Y'-axis (see 5.1.2). If the center of tire contact is outside the intersection of
the kingpin's extension line and the pavement relative to the vehicle body, the
kingpin offset is positive; otherwise, it is negative.
Note: Rewrite GB/T 3730.3-1992, definition 3.27.
4.1.11
Lateral slip
The lateral slip value of the straight-running tire, per unit travel distance, which is
measured on the lateral slip test bench. It is expressed in m/km, mm/m.
4.1.12
Wheelbase
The distance, between two planes that pass through point A or (B) of two adjacent
whee...