ISO/TC 22/SC 33/WG 6 - Vehicle dynamics of heavy commercial vehicles and buses

This document describes a method for calculating steady-state rollover threshold of heavy commercial vehicles and buses, not considering the effects of active control systems. The calculation method considers the main factors that influence the rollover threshold, namely the height of centre of gravity, the track, the tyre lateral stiffness, and all factors that affect the vehicle roll stiffness. The considered compliances (e.g. tyre deformation) have a considerable influence on the effective track, and consequently on the steady-state rollover threshold. NOTE As an alternative to the described calculation method standard, the steady-state rollover threshold can be measured on a test track or with a tilt-table test as described in ISO 16333.

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.

This document applies to heavy vehicles—that is, to commercial vehicles and buses as defined in ISO 3833—that are covered by the categories M3, N2, N3, O3, and O4 of ECE and EC vehicle regulations. These categories pertain to trucks and trailers with maximum weights above 3,5 tonnes and to buses with maximum weights above 5 tonnes. Vehicle suspension kinematic and compliance (K&C) properties that impact vehicle stability and dynamic behaviour are described in this document and common methods of measurement are outlined. These methods are applicable to heavy vehicles. The measurements are performed on a single unit and typically one or two axles at a time. This document will define or reference the key suspension kinematic and compliance parameters necessary for characterizing and simulating vehicle suspension performance. These parameters also provide system-level descriptions of quasi-static behaviour that can be cascaded into subsystem and component performance targets. The suspension variables required for determining suspension characterization of one vehicle end, i.e. for a single axle or for multiple axles inter-related through suspension configuration (for example, walking-beam), are provided. Metrics pertaining to the chassis connection between the front and rear suspensions are not included. Some typical methods of measurement will be discussed, however detail on how the measurements are executed is not within the scope of this document.

This document provides standard methods for determining a vehicle’s roll, pitch, and yaw mass moments of inertia (MOI) and roll-yaw product of inertia (POI). It applies to heavy vehicles, that is commercial vehicles and buses as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 tons and buses and articulated buses with maximum weight above 5 tons, according to ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4). Mass moment of inertia measurements are performed separately for each single unit.

This document specifies a test method for steering effort measurement when manoeuvring a vehicle at low speed or with the vehicle stationary. It is mainly applicable to trucks having a mass exceeding 3,5 tonnes and buses and articulated buses having a mass exceeding 5 tonnes, according to ECE and EC vehicle classification, i.e. categories M3, N2, N3. This document can also be applicable to trucks having a mass not exceeding 3,5 tonnes and buses and articulated buses having a mass not exceeding 5 tonnes, i.e. categories M2, N1.

This document specifies a method for comparing simulation results from a vehicle model to measured test data for an existing vehicle according to closing-curve tests as specified in ISO 11026. The purpose of the validation is to demonstrate that the vehicle dynamics simulation, combined with an integrated electronic stability control (ESC) system, can predict the roll and yaw stability behaviour of a physical vehicle, including the ESC system interventions, during a closing-curve test. The simulation method can be either hardware-in-the-loop [with the original electronic control unit (ECU) on a HiL test stand] or software-in-the-loop, based on a software code generated from the same source as for the ECU in the real vehicle. This document applies to heavy vehicles, including commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833 (trucks and trailers with a maximum weight above 3,5 tonnes and buses and articulated buses with a maximum weight above 5 tonnes, according to ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4).

This document specifies a method for comparing simulation results from a vehicle model to measured test data for an existing vehicle according to steady-state circular driving tests as specified in ISO 14792. The comparison is made for the purpose of validating the vehicle model for this type of test. This document applies to heavy vehicles, including commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833 (trucks and trailers with a maximum weight above 3,5 tonnes and buses and articulated buses with a maximum weight above 5 tonnes, according to ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4).

This document specifies a method for comparing simulation results from a vehicle model to measured test data for an existing vehicle combination's lateral stability according to driving tests as specified in ISO 14791. The comparison is made for the purpose of validating the simulation model for this type of test. A complete validation comprises the comparison for at least one tested vehicle and one variant of this vehicle, covered by a parameter variation in the vehicle model. The document applies to heavy vehicles, including commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 tonnes and buses and articulated buses with maximum weight above 5 tonnes, according to ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4).

This document describes a standard method for measuring a vehicle's longitudinal and lateral (horizontal plane) centre of gravity (CG) positions and three methods for estimating a vehicle's vertical CG position, the axle lift, tilt-table, and stable pendulum methods. It applies to heavy vehicles, that is commercial vehicles and buses as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 tonnes and buses and articulated buses with maximum weight above 5 tonnes, according to ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4). CG measurements are performed separately for each single unit.

ISO 19377:2017 describes test methods for determining the deviation of the path travelled by a vehicle during a braking manoeuvre induced by an emergency braking system from a pre-defined desired path. The purpose of this document is the evaluation of the vehicle path during and following the system intervention. The corrective steering actions for keeping the vehicle on the desired path can be applied either by the driver or by a steering machine or by a driver assistance system. By making this document open for either open-loop or closed-loop testing, it is possible to apply the test method for evaluating how well the vehicle can be kept within user-defined lane markings after the system intervention, and also for evaluating the precision of the interaction between the emergency braking system and an active lane keeping system. This document applies to heavy vehicles equipped with an advanced emergency braking system (AEBS), including commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 tonnes and buses and articulated buses with maximum weight above 5 tonnes, according to ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4). NOTE The test method is intended to evaluate the entire vehicle behaviour, not for defining system requirements for the AEBS, which is done in the respective standards created by ISO/TC 204.

ISO 18375:2016 describes an open-loop test method for determining the yaw stability of a vehicle on a low friction road surface. It applies to heavy vehicles, that is commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 tonnes and buses and articulated buses with maximum weight above 5 tonnes, according to ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4). The method is intended for vehicles equipped with electronic yaw-stability control systems. As the results of this test depend largely on local and temporary changes in road surface friction, this International Standard gives recommendations about keeping the friction level as uniform as possible for good reproducibility of the test results.

ISO 16552:2014 describes test methods for determining the stopping distance during a straight-line braking manoeuvre with the braking system fully operational. It applies to heavy vehicles equipped with an anti-lock braking system (ABS), including commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 tonnes and buses and articulated buses with maximum weight above 5 tonnes, according to ECE and EC vehicle classification, categories M3, N2, N3, O3, and O4).

ISO 14792:2011 specifies tests for determining the steady-state directional control response of heavy vehicles, one of the factors composing vehicle dynamics and road-holding properties. ISO 14792:2011 is applicable to heavy vehicles, i.e. commercial vehicles, combinations, buses and articulated buses as defined in ISO 3833, covered by Categories M3, N2, N3, O3, and O4 of UNECE (United Nations Economic Commission for Europe) and EC vehicle regulations. These categories pertain to trucks and trailers with a maximum mass above 3,5 t and to buses and articulated buses with a maximum mass above 5 t.

ISO 16333:2011 specifies a tilt-table test method for estimating the steady-state rollover threshold of a heavy commercial vehicle or bus, i.e. the maximum lateral acceleration that the test vehicle could sustain in steady-state turning without rolling over. ISO 16333:2011 is applicable to complete roll units/combinations of roll-coupled vehicle units, e.g. single-unit vehicles, tractor semitrailer combinations, articulated buses, full trailers, B-train combinations, of commercial vehicles, commercial vehicle combinations, buses or articulated buses as defined in ISO 3833, and under Categories M3, N2, N3, O3 and O4 of ECE and EC vehicle regulations (trucks and trailers with maximum weights above 3,5 t and buses and articulated buses with maximum weights above 5 t). ISO 16333:2011 does not cover transient, vibratory or dynamic rollover situations; nor does it consider the influences of dynamic stability control systems. Furthermore, the quality of the estimate of the steady-state rollover threshold provided by the test method decreases as the tilt angle required to produce rollover increases. Even so, the results for heavy vehicles with high rollover thresholds can be used for comparing their relative steady-state roll stability.

ISO 14793:2011 specifies test methods for determining the transient response behaviour of heavy commercial vehicles, heavy commercial vehicle combinations, buses and articulated buses, as defined in ISO 3833 for trucks and trailers above 3,5 t and buses above 5 t maximum weight, and in UNECE (United Nations Economic Commission for Europe) and EC vehicle classification, categories M3, N2, N3, O3 and O4.

ISO 14794:2011 specifies open-loop test methods for determining the effect of braking on the course-holding and directional behaviour of heavy vehicles or heavy vehicle combinations when braking is accomplished using the service-brake system, or the retarder or engine brake only. ISO 14794:2011 is applicable to heavy vehicles, i.e. commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833, covered by Categories M3, N2, N3, O3 and O4 of UNECE (United Nations Economic Commission for Europe) and EC vehicle regulations. These categories pertain to trucks and trailers with a maximum mass above 3,5 t and to buses and articulated buses with a maximum mass above 5 t.

ISO 11026:2010 specifies an open-loop test method for determining the roll stability of a vehicle negotiating a curve on dry surface. It applies to heavy vehicles, that is commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 t and buses and articulated buses with maximum weight above 5 t, according to ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4). The method is intended for vehicles equipped with electronic roll stability control systems.

ISO 11012:2009 describes two open-loop test methods for determining on-centre handling characteristics of a vehicle in response to specific types of steering input under closely controlled test conditions: the weave test, and the transition test. ISO 11012:2009 applies to heavy vehicles, i.e. commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 tonnes and buses and articulated buses with maximum weight above 5 tonnes, in accordance with ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4).

ISO 16234:2006 describes an open-loop test method for determining vehicle reactions during a straight-line braking manoeuvre on a surface having a split coefficient of friction. It applies to heavy vehicles, i.e. commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 tonnes and buses and articulated buses with maximum weight above 5 tonnes, according to ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4). The method is limited to vehicles in which at least the first unit is equipped with an anti-lock braking system. It is valid for braking with service-brake systems only or in combination with retarders and/or engine brakes.

ISO 15037-2:2002 specifies the general conditions that apply when vehicle dynamics properties are determined according to ISO test methods carried out on heavy vehicles. These are commercial vehicles, combinations, buses and articulated buses, as defined in ISO 3833 for trucks and trailers above 3,5 t and buses above 5 t maximum weight, and in UNECE (United Nations Economic Commission for Europe) and EC vehicle classification, categories M3, N2, N3, O3 and O4.

This International Standard specifies test methods to determine the lateral stability of heavy commercial vehicle combinations as defined in ISO 3833, including truck centre-axle trailer combinations and articulated buses. It is applicable to trucks and trailers having a mass exceeding 3,5 t and buses having a mass exceeding 5 t, i.e. vehicle categories N2, N3, O3, O4 and M3 according to 92/53/EEC. The manoeuvres specified in these test methods are not fully representative of real driving conditions, but are useful for determining the lateral stability of a heavy vehicle combination.