ISO 18646-5:2026

• Abstract:

  This document describes methods for specifying and evaluating the locomotion performance of legged robots. The tests listed in this document are mainly used to evaluate the complete machine. They can be also used for sample test, qualification test or check-and-accept test. This document is not intended for the verification or validation of safety requirements.

• Status: Published
• Publication Date: 23-Jul-2026
• ICS: 25.040.30 - Industrial robots. Manipulators
• Technical Committee: ISO/TC 299 - Robotics
• Drafting Committee: ISO/TC 299 - Robotics
• Current Stage: 6060 - International Standard published
• Start Date: 24-Jul-2026
• Due Date: 04-Sep-2026
• Completion Date: 24-Jul-2026

ISO 18646-5:2026 is an International Standard from ISO on how to specify and evaluate the locomotion performance of legged robots. It gives test methods for complete machines and can also be used for sample tests, qualification tests and check-and-accept tests. The document is aimed at people who need comparable performance data for legged robot mobility, not safety verification.

What does ISO 18646-5:2026 specify?

ISO 18646-5:2026 specifies methods for evaluating how well a legged robot moves. Its scope is limited to locomotion performance, and the tests are mainly intended for the complete machine.

The document is organized into general test conditions, then a set of performance tests, each with a purpose, test facility, procedure and result rule. Annex A gives the required test report content.

Part	What it covers
Clause 4	General test conditions for the robot, environment, travel surface and operating state
Clauses 5-13	Test methods for rated speed, stopping distance, maximum climbing height, capacity to climb stairs, maximum slope angle, dragging force, crossing capacity, minimum pass-through height and minimum travel width
Annex A	Normative test report content

ISO 18646-5:2026 is not intended for the verification or validation of safety requirements.

What are the key requirements of ISO 18646-5:2026?

ISO 18646-5:2026 requires controlled test conditions, repeatable trial rules and clear reporting so results can be compared. In practice, that means the robot, the test surface and the test setup all have to be described well enough that another lab could reproduce the measurement.

General conditions and reporting

Clause 4 requires the robot to be completely assembled, sufficiently charged and operational before testing. Manufacturer preparation steps, including relevant sensor calibration, have to be completed first. The tests are to be run under normal operating conditions unless the specific test says otherwise, and any other condition must be declared in the report.

Clause 4 also sets the default environment and surface conditions. The preferred ambient range is 10 °C to 30 °C and 0 % to 80 % relative humidity, and the default travel surface is hard, even and horizontal with a coefficient of friction between 0,75 and 1,0 measured according to ISO 7176-13. This matters because a legged robot can perform very differently on slippery, sloped or uneven ground, so the surface has to be known before comparing results.

Speed, stopping and slope performance

Clause 5 measures rated speed by testing forward and backward travel across a defined straight area. The reported rated speed is the minimum speed value after three consecutive successful trials, and the report has to include the friction condition and the angle of the travel surface. That gives a comparable value for how fast the robot can travel in normal use.

Clause 6 measures stopping distance from rated speed to a stable standing posture. The stopping distance is reported as the maximum value after three consecutive successful trials. This tells a buyer or engineer how much space the robot needs to stop safely and consistently.

Clause 9 measures maximum slope angle in four configurations - upward and downward, forward and backward. The reported value is the maximum angle reached after three consecutive successful trials for each configuration. That is important when a robot must work on ramps, grades or changing terrain.

Terrain and obstacle capability

Clause 7 covers maximum climbing height using a podium with adjustable height. The robot must climb up and down without assistance and maintain a stable standing posture, and the reported height is the podium height after three successful trials. This is a direct measure of step or ledge handling.

Clause 8 covers capacity to climb stairs on a stairway with at least 10 steps and high-end and low-end platforms. The robot has to go up and down the stairway and complete the full procedure three times in a row for a given stair configuration. The result is reported as the stair size that the robot can manage, which helps with building access and field use.

Clause 11 covers crossing capacity over a rectangular negative obstacle. The robot has to cross to the other side and remain standing for at least 5 s, and the maximum obstacle length after three successful trials represents the crossing capacity. Protective devices such as a tether or cushions are part of the setup, which shows that the method is focused on performance measurement under controlled risk.

Clearance and narrow-path performance

Clause 12 measures minimum pass-through height using a rectangular pillar from the ceiling. The gap starts at 95 % of the robot’s maximum height and decreases in steps, and the reported value is the minimum height that the robot can pass under after three successful trials. This is useful for checking whether the robot can move through low openings.

Clause 13 measures minimum travel width in forward and sideways motion. The test area width is reduced stepwise, obstacle detection is disabled, and the robot has to cross the stop line without losing stability. The result tells users how narrow a passage the robot can handle while staying upright and in control.

Force to stop a moving robot

Clause 10 measures dragging force, the force needed to stop the robot while it is moving forward. The setup uses a solid connection device and a belt fixed above half the robot height, and the force value is the maximum from three successful trials. The note in the clause says this value can help when designing safety stopping objects such as fences.

What terms does ISO 18646-5:2026 define?

• legged robot - a mobile robot that travels using one or more legs.
• rated speed - the maximum speed of the legged robot in normal operating conditions.
• topography - the shape of the travel surface.
• capacity - the robot’s ability to accomplish a certain type of task.
• stride width - the minimum width perpendicular to the travel direction that can cover the robot’s projection on a horizontal travel surface.
• test configuration - a particular arrangement of test objects.
• trial - one instance of a test procedure performed under the same test configuration.
• travel surface - the surface on which the robot moves during the tests, used throughout the procedures even though it is not defined as a term.

Who uses ISO 18646-5:2026?

ISO 18646-5:2026 is used by robot designers and research and development teams who need data for product optimization. It is also used by manufacturing and quality staff who need a repeatable way to monitor product performance.

Testing and certification authorities use it to run comparable locomotion tests and prepare reports. System integration companies can use it to judge whether a robot fits a site or application. Buyers and end users can use the reported values to compare models and select a robot that matches the expected terrain, space and mobility needs.

Which standards are used with ISO 18646-5:2026?

• ISO 8373 - provides robotics vocabulary and the base definition of legged robot.
• ISO 18646-2 - provides shared terminology such as test configuration and trial, and links this part to the wider ISO 18646 series.
• ISO 7176-13 - gives the method for determining the coefficient of friction of test surfaces, which Clause 4 uses for the default travel surface.
• ISO 21542 - is cited in the stair test note for the rise and going of a step.

What does the ISO 18646-5:2026 document contain?

ISO 18646-5:2026 contains nine test methods with figures showing the test facilities for each method. It includes a formula for calculating rated speed, plus tables for stair dimensions, slope-test configurations and the slope-angle result presentation.

The procedures describe how to place the robot, how to start and finish each run, when a trial fails and how many successful trials are needed before reporting a result. The methods are set up for design checks, product comparison, test lab work, qualification testing and certification-style reporting.

Annex A gives the test report checklist, including the standard reference, test institution details, robot model and manufacturer, configuration, locomotion mode, test methods used, results, deviations, unusual observations and test date.

International
Standard
ISO 18646-5
First edition
Robotics — Performance criteria
2026-07
and related test methods for service
robots —
Part 5:
Locomotion for legged robots
Robotique — Critères de performance et méthodes d'essai
correspondantes pour robots de service —
Partie 5: Locomotion pour robots à pattes
Reference number
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ISO copyright office
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Published in Switzerland
ii
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test conditions . 2
4.1 General .2
4.2 Environmental conditions . .2
4.3 Travel surface conditions .2
4.4 Operating conditions .3
5 Rated speed . 3
5.1 Purpose .3
5.2 Test facility .3
5.3 Test procedure .3
5.4 Test result.4
6 Stopping distance . 4
6.1 Purpose .4
6.2 Test facility .4
6.3 Test procedure .5
6.4 Test result.5
7 Maximum climbing height . 5
7.1 Purpose .5
7.2 Test facility .6
7.3 Test procedure .6
7.4 Test result.6
8 Capacity to climb stairs . 6
8.1 Purpose .6
8.2 Test facility .7
8.3 Test procedure .7
8.4 Test result.8
9 Maximum slope angle . 8
9.1 Purpose .8
9.2 Test facility .8
9.3 Test procedure .9
9.4 Test result.9
10 Dragging force . 10
10.1 Purpose .10
10.2 Test facility .10
10.3 Test procedure .11
10.4 Test result.11
11 Crossing capacity .11
11.1 Purpose .11
11.2 Test facility .11
11.3 Test procedure . 13
11.4 Test result. 13
12 Minimum pass-through height .13
12.1 Purpose . 13
12.2 Test facility . 13
12.3 Test procedure .14
12.4 Test result.14

iii
13 Minimum travel width . 14
13.1 Purpose .14
13.2 Test facility .14
13.3 Test procedure . 15
13.4 Test result.16
Annex A (normative) Test report . 17
Bibliography .18

iv
Foreword
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This document was prepared by Technical Committee ISO/TC 299, Robotics.
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v
Introduction
With the development of service robot technology, legged robots have an increasing application range in the
fields of service, guide, life companion and family entertainment. This industry has developed a market of
a certain scale and at the same time, it has appreciable development prospects and huge market potential
in the fields of industrial manufacture, facility test and maintenance, special operations and depopulated
zone exploration. Currently, the product parameters of biped, quadruped and multi-legged robots are
claimed inconsistently by different companies, and the test conditions and test methods for the parameters
are inconsistent and unclarified. In this case, designers cannot achieve optimization through effective
tests for product performance; manufacturing staff cannot monitor product quality through consistent
evaluating method; and users can neither select products based on needs nor compare products of the same
type according to performance parameters. Furthermore, there appear to be unnecessary divergence and
conflicts between legged robot products from different countries in international trade because of the lack
of related International Standards, which can lead to an unhealthy development of the legged robot industry.
This document lists a series of specifications on the performance of legged robots, as well as test conditions,
test purpose, test facility, test procedures and the treatment of test results based on legged robot’s unique
characteristics, such as dispersed stepping movement, multiple limbs, multiple degrees-of-freedom, its
application in varied topography and human-machine interaction. The purpose of this document is to
establish a consistent system of performance representation and method of evaluation for legged robots, to
facilitate design optimization, performance claims, quality monitoring and product selection.
This document can provide:
— data foundation of product optimization for research and development staff;
— quality monitoring methods for manufacturing staff;
— accordance for testing and certification authorities;
— guidance of integration for system integration companies.

vi
International Standard ISO 18646-5:2026(en)
Robotics — Performance criteria and related test methods for
service robots —
Part 5:
Locomotion for legged robots
1 Scope
This document describes methods for specifying and evaluating the locomotion performance of legged
robots.
The tests listed in this document are mainly used to evaluate the complete machine. They can be also used
for sample test, qualification test or check-and-accept test.
This document is not intended for the verification or validation of safety requirements.
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 7176-13, Wheelchairs — Part 13: Determination of coefficient of friction of test surfaces
ISO 8373, Robotics — Vocabulary
ISO 18646-2, Robotics — Performance criteria and related test methods for service robots — Part 2: Navigation
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8373, ISO 18646-2 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
legged robot
mobile robot that travels using one or more legs
[SOURCE: ISO 8373:2021, 4.15.2, modified— Note 1 to entry has been removed.]
3.2
rated speed
maximum speed of the legged robot in normal operating conditions
3.3
topography
shape of the travel surface
3.4
capacity
ability of robot to accomplish a certain type of task
3.5
stride width
minimum width in the direction perpendicular to robot’s traveling direction that can cover the projection of
the robot on horizontal travel surface
3.6
test configuration
particular arrangement of test objects
[SOURCE: ISO 18646-2:2024, 3.19]
3.7
trial
single instance of test procedure performed under identical test configuration (3.6)
Note 1 to entry: A trial can be repeated multiple times.
[SOURCE: ISO 18646-2:2024, 3.20]
4 Test conditions
4.1 General
The legged robot shall be completely assembled, sufficiently charged and operational.
The tests shall be preceded by the preparations for operation as specified by the manufacturer, including
calibration of any relevant sensors that have an effect on the test results.
All conditions specified in Clause 4 shall be satisfied for the tests described in this document, unless it is
stated otherwise in the specific clauses.
Some of the tests described in this document have multiple test configurations which require separate test
procedures. For each test conformation, multiple trials may be conducted, if specified in the test procedure.
Each test shall be independent to locomotion modes (walking, jumping, running) and the applied locomotion
modes shall be noted in the test report. The test shall be reported based on the information in Annex A.
4.2 Environmental conditions
The following environmental conditions should be maintained during all tests:
— ambient temperature: 10 °C to 30 °C;
— relative humidity: 0 % to 80 %.
If the environmental conditions specified by the manufacturer exceed the given ranges, tests may be
conducted outside of the above ranges. These conditions shall be declared in the test results.
4.3 Travel surface conditions
If not specified, a hard and even surface with a coefficient of friction between 0,75 and 1,0 measured in
accordance with ISO 7176-13 shall be used to test the performance. The surface shall be horizontal, if not
specified.
...