ISO 18646-4:2021

Overview

ISO 18646-4:2021 - "Robotics - Performance criteria and related test methods for service robots - Part 4: Lower-back support robots" defines standardized methods to specify and evaluate the performance of lower-back support robots (wearable robots that reduce lumbar load). The standard applies across drive types (electric, hydraulic, pneumatic) and use-cases but excludes medical robots (although its test methods can be applied to medical devices). It is expressly not a safety verification or validation standard.

Key topics and technical requirements

• Performance indices: The standard defines quantitative measures including the Assistive Torque Index (ATI) and Lumbar Compression Reduction (LCR) to assess how much the robot reduces user torque and lumbar compression during defined movements.
• Rate of assistance: Methods to measure the integrated reduction of torque over a motion profile (useful for comparing assistive timing and responsiveness).
• Test conditions: Requirements for ambient test conditions (ambient temperature 10 °C to 30 °C; relative humidity 0 % to 80 %) and the need to run tests under the robot’s normal operating conditions or to clearly declare deviations.
• Test apparatus and procedures: Descriptions of required test equipment, reference movements/target trajectories, calibration and operational preparation, and separate procedures for ATI/LCR and rate-of-assistance measurements.
• Terms and definitions: Clear definitions for wearable robot concepts (robot, wearable robot, restraint part, assistive torque, input methods - biological, kinematic, command).
• Informative annexes: Examples of lower-back support robots, time ranges for ATI/LCR, sample test-result tables, and example implementations of test apparatuses.

Practical applications and intended users

ISO 18646-4 is practical for:

• Manufacturers of wearable lower-back support robots who need to specify product performance and produce comparable data for marketing and regulatory submissions.
• Test laboratories and certification bodies conducting objective performance testing.
• R&D teams and researchers developing assistive devices and validating assist strategies (ATI, LCR, rate of assistance).
• Procurement and occupational safety professionals evaluating assistive device claims for industrial, logistics, or occupational health use.
• System integrators who must verify performance across different actuator types (electric, pneumatic, hydraulic).

Use of ISO 18646-4 enables consistent, repeatable evaluation of assistive effectiveness, supports product comparison, and informs design improvements for ergonomics and user support.

Related standards

• ISO 8373 - Robots and robotic devices: Vocabulary (normative reference)
• ISO 13482 - Robots and robotic devices: Safety requirements for personal care robots (normative reference)

Keywords: ISO 18646-4, lower-back support robots, assistive torque index, lumbar compression reduction, wearable robots, robot testing, performance criteria, service robots.