ISO 22138:2022

INTERNATIONAL ISO
STANDARD 22138
First edition
2022-11
Heavy commercial vehicles — Vehicle
stability during tipper body operation
— Tilt-table test method
Véhicules utilitaires lourds — Stabilité du véhicule pendant
l'utilisation de benne basculante — Méthode d'essai avec table
basculante
Reference number
ISO 22138:2022(E)
© ISO 2022

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ISO 22138:2022(E)
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© ISO 2022
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Published in Switzerland
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ISO 22138:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 6
5 Variables . 7
6 Measuring equipment . 8
7 Test conditions .8
7.1 General . 8
7.2 Tilt table properties . 8
7.3 Ambient conditions. 9
7.4 Test vehicle . 9
7.4.1 General vehicle condition . 9
7.4.2 Loading conditions and suspension . 9
7.4.3 Fluids . 9
8 Test method for rearward tipping vehicle . 9
8.1 Preparation . 9
8.1.1 Measure unladen weight . 9
8.1.2 Loading of vehicle . 9
8.1.3 Measure axle load redistribution due to tipper body pitch angle . 10
8.2 Tilt table test procedure . 11
8.2.1 Installation of vehicle on tilt table . 11
8.2.2 Test execution on tilt table . 13
9 Test method for sideways tipping vehicle .15
9.1 Preparation . 15
9.1.1 Measure unladen weight . 15
9.1.2 Loading of vehicle . 15
9.1.3 Measure axle load redistribution due to tipper body roll angle .15
9.2 Tilt table test procedure . 15
9.2.1 Installation of vehicle on tilt table . 15
9.2.2 Test execution on tilt table . 16
10 Data evaluation and presentation of results .16
10.1 General . 16
10.2 Characteristic values . 17
Annex A (normative) Test report – General data and test conditions .18
Annex B (informative) Example of test reports .19
Annex C (informative) Test results versus real tipper operation.21
Bibliography .22
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ISO 22138:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 33,
Vehicle dynamics and chassis components.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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ISO 22138:2022(E)
Introduction
A test method is presented for estimating the steady-state rollover threshold of vehicles with a tipper
body, using a tilt table device at different inclination angles of the tipper body. Knowledge of a vehicle
unit’s lateral stability limits during tipping operation is important to prevent rollover, understand
operational safety limits, and validate vehicle modelling and design efforts.
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INTERNATIONAL STANDARD ISO 22138:2022(E)
Heavy commercial vehicles — Vehicle stability during
tipper body operation — Tilt-table test method
1 Scope
This document provides a tilt-table test method for estimating vehicle lateral stability during tipping
(or dump) operations. The test method results in a limit curve that creates an envelope of the tipper
vehicle unit’s rollover threshold, at different tipper body inclinations. This document is applicable to
both rear and side tipping vehicles.
This document applies to heavy commercial vehicles and commercial vehicle combinations, as defined
in ISO 3833, equipped with rearward or sideways tipping (or dump) bodies (trucks and trailers with
maximum weight above 3,5 tonnes, according to ECE and EC vehicle classification, categories N2, N3, O3
and O4).
NOTE The stability envelope can be applied to autonomous construction vehicles.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 8855, Road vehicles — Vehicle dynamics and road-holding ability — Vocabulary
ISO 15037-2:2002, Road vehicles — Vehicle dynamics test methods — Part 2: General conditions for heavy
vehicles and buses
ISO 16333:2011, Heavy commercial vehicles and buses — Steady-state rollover threshold — Tilt-table test
method
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8855, ISO 15037-2 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
tipper body
device on a commercial vehicle unit that contains the payload and can be rotated around an axis
Note 1 to entry: Unloading in a tipping operation is performed by tilting the tipper body around its pivot axis
until the payload is discharged.
Note 2 to entry: In some countries this term is more commonly known as a dump body.
3.2
tipping hinge
revolute joint between the tipper body (3.1) and associated subframe, forming the axis about which the
tipper body revolves during a tipping operation
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ISO 22138:2022(E)
3.3
sideways tipping
tipping operation performed with the tipper body (3.1) pivot axis nominally parallel to the x-axis of the
vehicle
Note 1 to entry: This is principally a roll motion of the tipper body.
3.4
rearward tipping
tipping operation performed with the tipper body (3.1) pivot axis nominally parallel to the y-axis of the
vehicle
Note 1 to entry: This is principally a pitch motion of the tipper body.
3.5
tipper body pitch angle
θ
B
pitch angle between the chassis frame and the tipper body (3.1), to be measured within a distance less
than 1 000 mm from the tipping hinge (3.2)
Note 1 to entry: See Figure 1.
Key
1 road plane
2 ground plane
3 gravity vector
4 chassis frame
5 tipping hinge
6 subframe
7 tipper body
8 tipper body pitch angle (θ )
B
Figure 1 — Side view of tipper vehicle with rearward tipping
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ISO 22138:2022(E)
3.6
chassis frame pitch angle
θ
Ch
pitch angle between the chassis frame and the ground plane, to be measured within a distance less
than 1 000 mm from the tipping hinge (3.2)
Note 1 to entry: See Figure 2.
Note 2 to entry: Chassis frame pitch angle includes contributions from road plane elevation angle (3.9) (see
ISO 8855:2011, 2.7.1), chassis suspension pitch, tyre compression, etc.
3.7
angle of repose
α
steepest angle at which a sloping surface formed of a particular loose material is stable
3.8
global tipper body pitch angle
θ
G
pitch angle between the tipper body (3.1) and the ground plane
Note 1 to entry: It is calculated as the sum of chassis frame pitch angle (3.6) and tipper body pitch angle (3.5),
which is θ = θ + θ .
G Ch B
Note 2 to entry: See Figure 2.
Note 3 to entry: This angle is influenced by the payload’s angle of repose (3.7).
3.9
road plane tipper body pitch angle
θ
R
pitch angle between the tipper body (3.1) and the road plane
Note 1 to entry: See Figure 2.
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ISO 22138:2022(E)
Key
1 road plane
2 ground plane
3 gravity vector
4 chassis frame pitch angle (θ )
Ch
5 tipper body pitch angle (θ )
B
6 road plane tipper body pitch angle (θ )
R
7 global tipper body pitch angle (θ )
G
Figure 2 — Tipper vehicle pitch angles
3.10
tilt table
apparatus for supporting a vehicle on a nominally planar surface and for tilting the vehicle in roll by
rotating that surface about an axis nominally parallel to the x-axis of the vehicle
Note 1 to entry: A tilt table is composed of a single structure supporting all tyres of the vehicle on a contiguous
surface, alternatively multiple structures supporting one or more axles on separated but nominally coplanar
surfaces.
3.11
tilt axis
axis around which the tilt table (3.10) rotates, nominally parallel to the x-axis of the vehicle
3.12
tilt angle
ϕ
T
angle between the ground plane and a vector that is in the plane of the tilt table (3.10) surface and is
perpendicular to the tilt axis (3.11)
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ISO 22138:2022(E)
3.13
critical wheel lift
first moment when one or more wheels lifts from the table surface, following which stable roll
equilibrium of the vehicle cannot be maintained
3.14
trip rail
rail or kerb fixed to the tilt table (3.10) surface and oriented longitudinally beside the low-side wheels
when tipping in the vehicles roll direction, to prevent the vehicle from sliding sideways
3.15
critical tilt angle
ϕ
Tc
tilt angle (3.12) at critical wheel lift (3.13)
3.16
tipper body roll angle
φ
B
roll angle between the chassis frame and the tipper body (3.1), to be measured within a distance less
than 500 mm from the tipping hinge (3.2)
Note 1 to entry: See Figure 3.
Key
1 road plane
2 ground plane
3 gravity vector
4 tipping hinge
Figure 3 — Rear view of sideways tipping vehicle
3.17
chassis frame roll angle
φ
Ch
roll angle between chassis frame and the ground plane, to be measured within a distance less than
500 mm from the tipping hinge (3.2)
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ISO 22138:2022(E)
3.18
global tipper body roll angle
φ
G
roll angle between tipper body (3.1) and ground plane
Note 1 to entry: It is equal to the sum of the chassis frame roll angle (3.17) and the tipper body roll angle (3.16)
φ = φ + φ .
G Ch B
4 Principle
This document specifies a test method for determining vehicle lateral stability during tipping operation.
The tipper stability test conducted on a tilt table is a physical simulation of the roll-plane quasi-static
response of a tipper vehicle subjected to a roll moment. In real-world operation, the roll moment may
result from tipper body use, as well as uneven lateral loading (e.g. generated by uneven discharge
during tipping operation), side-slope conditions of the road plane, deformation of the road surface at
one wheel, strong side-wind and similar.
In this test method, the tipper vehicle, with a given tipper body pitch or roll angle, is installed on a tilt
table with the vehicle’s longitudinal axis oriented parallel to the tilt axis. The roll moment is gradually
increased by increasing the tilt angle, until the vehicle becomes unstable in roll, as shown in Figure 4.
Safety restraints or supports are used to prevent the actual complete rollover of the vehicle. The test is
repeated for several tipper body pitch or roll angles, respectively, to generate an envelope of the tipper
vehicle’s stability performance, both with respect to tipper body angle and tilt angle. In the case of
rearward tipping vehicle, the tyres of the first axle should be in contact with the tilt table surface at the
start of each test attempt.
As the tilt angle increases during the test, vertical load is gradually transferred from the tyres on
one side of the vehicle (high-side) to the other side (low-side). Tyres on the unloaded high-side will
eventually lift from the tilt table surface. Typically, wheel lift does not take place simultaneously for all
axles. In many cases, lift-off occurs at different tilt angles for each axle. The increase of tilt angle should
be stopped simultaneously with the vehicle becoming unstable in roll. Safety restraints or supports
should be arranged in such a manner that the roll motion of the vehicle is arrested immediately after
critical wheel lift occurs.
ISO 16333:2011, Annex B presents a discussion on the conceptual and practical sources of error when
using a tilt table, which are applicable to the test method in this document.
Results from this test method are valid for the conditions present during test execution. During
unloading of a tipper vehicle, conditions may vary (wind speed, road surface inclination, payload
distribution, etc.), which shall be considered when comparing test results with real-world tipper
operation. See Annex C for additional information on the stability envelope of tipper vehicles and a
comparison of test results with real life tipper operation.
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ISO 22138:2022(E)
Key
X tilt angle (ϕ )
T
Y vehicle roll angle
1 rigid body motion
2 critical tilt angle (ϕ )
Tc
3 instability, critical wheel lift
4 tipper vehicle roll angle
Figure 4 — Vehicle roll angle versus tilt angle
Sufficient knowledge is not available concerning the relationship between overall vehicle dynamic
properties and accident avoidance, during tipping operation. A substantial amount of work is necessary
to acquire sufficient and reliable data on the correlation between accident avoidance and tipper vehicle
stability properties. Consequently, any application of this test method for regulation purposes will
require proven correlation between test results and accident statistics.
Body angle and vehicle roll angle sensors are necessary features for autonomous tipping vehicles to
safely control or limit tipping operation relative to the envelope of tipper stability.
5 Variables
The variables that shall be determined for conformance with this document are:
— critical tilt angle (ϕ ) at each studied tipper body angle (in pitch or roll);
Tc
— axle loads as function of tipper body angle (in pitch or roll), on flat and horizontal road surface.
It is recommended that the following variables are also determined:
— tilt angle (ϕ ) at each individual axle’s wheel lift;
T
— tipper body angle relative to ground plane (see Table B.1);
— chassis frame angle relative to ground plane (see Table B.1).
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ISO 22138:2022(E)
6 Measuring equipment
The measuring equipment, transducer installation and data processing shall be in accordance with
ISO 15037-2. Typical operating ranges of the variables to be determined for this document are shown in
Table 1 and in ISO 15037-2.
It is recommended to use inclinometers to determine tipper body pitch and roll angles, or other angular
transducers with sufficient accuracy (see Table 1).
Table 1 — Variables, typical operating ranges and recommended maximum errors of variables
not listed in ISO 15037-2:2002
Recommended maximum
errors of the combined
Variable Typical operating range
transducer and recorder
system
Tilt angle ±30° ±0,1°
Maximum tilt-angle variance at axle
±0,2° ±0,05°
a
positions
Maximum heading angle error between
±1,0° ±0,5°
vehicle and tilt table axis
Tilt rate <0,1°/s 0,2 %
Distance ≤2 000 mm ±2 mm
Axle load (0 to 20) t ±10 kg or ±0,2 %
Tipper body pitch angle ±60° ±0,5°
Chassis frame pitch angle ±10° ±0,5°
Global tipper body pitch angle ±70° ±0,5°
Tipper body roll angle ±60° ±0,5°
Chassis frame roll angle ±10° ±0,5°
Global tipper body roll angle ±70° ±0,5°
a
Tilt table property.
7 Test conditions
7.1 General
The test conditions described in ISO 15037-2 shall apply to this document. General data of the test
vehicle shall be recorded, in applicable parts, as specified in ISO 15037-2 (see Annex A). Test conditions
shall be recorded as specified in ISO 15037-2 and ISO 16333 (see Annex A).
The limits and specifications indicated below shall be maintained during the test. Any deviations shall
be identified in the test report.
7.2 Tilt table properties
The tilt table shall have the properties given in Table 1. Tilt-angle variance at each vehicle axle during
measurements shall not exceed ±0,1°. Maximum tilt-angle variance implies requirements on tilt table
stiffness; surface flatness and/or alignment of individual axle tables (see ISO 16333:2011, Annex B). All
tests shall be carried out on a hard platform surface with a uniform coefficient of friction. The surface
friction shall be sufficient to prevent the vehicle from sliding sideways or a trip rail shall be used (see
8.2.1.2).
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ISO 22138:2022(E)
7.3 Ambient conditions
Indoor testing is recommended, but outdoor testing is permitted. However, in the outdoor case, wind
speeds shall be recorded and reported. Ambient wind speed is recommended to be less than 2 m/s.
NOTE The test results are only valid for low wind speed conditions and tipper operation at higher wind
speeds should be handled with care. See Annex C for information on deviations between test conditions and real
tipper vehicle usage.
7.4 Test vehicle
7.4.1 General vehicle condition
The test vehicle condition shall be in accordance with the vehicle manufacturer’s configuration,
particularly with respect to bodywork design, chassis suspension and tyre configuration. The tyre
pressure should be set to the recommended pressure for the static tyre load with tipper body down.
If inclination sensors are integrated on-board the vehicle unit, corresponding values shall be recorded
throughout test execution and included in the report.
7.4.2 Loading conditions and suspension
The payload shall be secured in such a manner that it cannot move, leak or be discharged. The vehicle
should have all its intended equipment mounted during the test.
The suspension should be in normal height position for the intended tipping operation, so the test results
are representative of real-world operations. Furthermore, any suspension control system should be
active in such a manner that its behaviour represents real-world usage, including temporal effects. The
test procedure typically takes longer than real-world operations, given maximum tilt rate limits. Hence,
time effects associated with any vehicle control system shall be considered. Any deviation between test
and real application behaviour shall be reported.
7.4.3 Fluids
Consumable liquids, such as fuel, should be at the level that yields the most conservative values of the
stability performance. Liquid levels elsewise (e.g. hydraulic oil) should be at normal operation level.
8 Test method for rearward tipping vehicle
8.1 Preparation
8.1.1 Measure unladen weight
Measure and record the unladen vehicle weight, so that once the laden vehicle weight is measured the
payload weight can be determined by calculation. It is recommended to measure and include individual
static axle loads in the test report.
8.1.2 Loading of vehicle
Load the vehicle until the desired test weight is reached for the intended application. The test weight
may be equal to the legal weight or the maximum technical weight.
The load shall be equally distributed throughout the tipper body and secured in such a way that it
does not move during the test. This will give repeatable and comparable test results, useful for future
reference. It will also provide a straightforward comparison of corresponding results from simulations.
It is recommended that the loading material density is consistent with the intended application, so the
centre of gravity is representative at the given vehicle weight. The angle of repose (3.7) of most materials
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ISO 22138:2022(E)
(sand, gravel, rocks, etc.) subjected to tipping operation is typically less than the maximum tipper body
pitch angle. If such material is applied, it is recommended that the load is secured by inserting several
temporary bulkheads inside the load container, preventing movement during the test. These bulkheads
may, for example, be produced from sheets of plywood or similar.
8.1.3 Measure axle load redistribution due to tipper body pitch angle
The purpose of this measurement is to observe the redistribution of axle loads as a function of the
tipper body pitch angle, on a flat and horizontal road surface.
Measure static axle loads of each axle as function of the tipper body pitch angle. Report the results in
graphical and tabular form, examples shown in Figure 5 and Table B.2. Measure the axle weights on
a flat and horizontal road surface, i.e. with negligible road plane elevation and camber angles. Start
with the tipper body down (i.e. at zero degrees tipper body pitch angle), then repeat the axle load
measurements at 10° increments of the tipper body pitch angle until the maximum tipper body pitch
angle is reached. Check the front axle weight at each increment, to evaluate the risk of vehicle pitch
instability at the next test increment. Stop increasing the tipper body pitch angle if instability (zero
front axle weight) is likely at the next test increment.
NOTE This measurement also serves as a test to confirm that the vehicle configuration has sufficient pitch
stability during rearward tipping.
Key
X tipper body pitch angle [°]
Y axle load [tonne]
1 first axle
2 second axle
3 third axle
4 fourth axle
Figure 5 — Example of axle load as function of tipper body pitch angle, on horizontal road
surface
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