Robot Safety Assessment: Standards, Testing Items, and Methods

Robot safety assessment is a systematic evaluation process that verifies whether industrial robots, collaborative robots, and mobile robotic systems comply with international safety standards such as ISO 10218, ISO/TS 15066, and ISO 13849-1. This article explains the scope of testing samples, key testing items, methods used by accredited third-party laboratories, and the industries that depend on robot safety evaluation for regulatory compliance and market access.

Robot safety assessment is a systematic evaluation process that verifies whether industrial robots, collaborative robots, and mobile robotic systems comply with international safety standards such as ISO 10218, ISO/TS 15066, and ISO 13849-1. This article explains the scope of testing samples, key testing items, methods used by accredited third-party laboratories, and the industries that depend on robot safety evaluation for regulatory compliance and market access.

Technical Overview

Robot safety assessment is a structured engineering evaluation designed to confirm that a robot or integrated robotic system achieves an acceptable level of risk reduction throughout its intended lifecycle. The process is grounded in the risk assessment methodology of ISO 12100, which requires hazard identification, risk estimation, and the implementation of a hierarchy of control measures covering inherent design safety, safeguarding, and information for use.

For industrial robots, the core requirements are defined in ISO 10218-1 for the robot itself and ISO 10218-2 for robot systems and cell integration. Collaborative applications are additionally governed by ISO/TS 15066, which specifies power and force limiting criteria and biomechanical thresholds for human-robot contact. Mobile and autonomous robots are evaluated against ISO 3691-4, while personal care robots fall under ISO 13482.

Depending on the target market, the assessment also incorporates electrical safety under IEC 60204-1, functional safety of control systems under ISO 13849-1 and IEC 62061, electromagnetic compatibility under the IEC 61000 series, and regional frameworks such as EN standards for European CE marking, GB standards for China, and UL 1740 together with ANSI/RIA R15.06 for North America. A complete assessment typically includes documentation review, type testing in accredited third-party laboratories, validation of safety functions, and surveillance or re-evaluation after significant modifications.

Testing Samples

Industrial Robot Arms

Six-axis articulated robots, SCARA robots, delta pick-and-place robots, gantry systems, and palletizing robots submitted for evaluation against the requirements of ISO 10218-1. These samples are assessed for mechanical integrity, axis limiting functions, and control reliability.

Collaborative Robots

Power- and force-limiting cobots intended for shared human-robot workspaces. These systems require verification of quasi-static and transient contact forces against the biomechanical limits published in ISO/TS 15066, together with speed and separation monitoring capabilities.

Autonomous and Mobile Robots

Automated guided vehicles, autonomous mobile robots, and mobile manipulators evaluated for obstacle detection, personnel detection, braking performance, speed control in shared corridors, and load handling stability in accordance with ISO 3691-4.

Service and Personal Care Robots

Household service robots, elderly-care and assistive robots, and mobile servant robots assessed against ISO 13482, with particular emphasis on contact hazards, stability, and user protection in unstructured environments.

Robot Subsystems and Peripherals

Robot controllers, teach pendants, servo drives, end-effectors, safety laser scanners, light curtains, interlocked guards, and safety-rated encoders, each verified for conformity with applicable electrical, functional safety, and EMC requirements.

Testing Items

A comprehensive robot safety assessment covers the following major categories of testing items:

• Protective stop and emergency stop function performance, including stopping time and stopping distance measurement
• Safety-rated monitored stop, hand guiding, speed and separation monitoring, and power and force limiting for collaborative operation
• Axis and space limiting functions, including safety-rated soft limits and safe zones
• Contact force and pressure measurement compared against biomechanical limits for specific body regions
• Electrical safety testing, including protection against electric shock, insulation resistance, dielectric strength, protective bonding continuity, and temperature rise
• Electromagnetic compatibility, covering radiated and conducted emissions as well as immunity to electrostatic discharge, radiated fields, and electrical fast transients
• Functional safety evaluation of safety-related control systems, including Performance Level (PL) and Safety Integrity Level (SIL) verification
• Mechanical safety verification, including stability under maximum payload, sharp edge assessment, and pinch point analysis
• Environmental testing for temperature, humidity, and vibration conditions relevant to the rated operating environment
• Software safety and cybersecurity review of safety-related software architecture and communication interfaces

Testing Methods

Testing begins with a documentation review that examines risk assessment files, circuit diagrams, component certifications, and the technical construction file. The assessment team then performs verification through inspection, measurement, and type testing in accredited third-party laboratories.

Stopping performance is measured with calibrated position and timing instrumentation under defined load and speed conditions, and the resulting data are used to calculate minimum safe distances in line with ISO 13855. For collaborative robots, pressure and force are measured at representative contact locations using calibrated force and pressure mapping devices, and results are compared with the permissible thresholds defined in ISO/TS 15066.

Electrical safety is verified through insulation resistance testing, dielectric strength tests, protective continuity measurement, and temperature rise monitoring under rated load, following the principles of IEC 60204-1. EMC evaluation is performed in shielded chambers against the applicable IEC 61000-4 immunity series and applicable emission limits.

Functional safety is validated through fault injection testing, review of safety architecture, and verification of calculated metrics such as MTTFd, Category, DC, and PFH against the target PL or SIL defined in ISO 13849-1 and IEC 62061. Environmental tests are conducted in climate and vibration chambers to confirm performance under declared operating limits.

Applications

Robot safety assessment services support compliance and product qualification across a wide range of industries:

• Automotive manufacturing, where welding, painting, assembly, and material handling robots require conformity before line integration
• Electronics and semiconductor production, involving high-speed SCARA and delta robots operating near human operators
• Logistics, warehousing, and e-commerce fulfillment, driven by the rapid deployment of AMRs and AGVs in mixed-traffic environments
• Food, beverage, and pharmaceutical processing, where hygienic robot designs must also satisfy safety requirements
• Healthcare and laboratory automation, including assistive and service robots operating in close proximity to patients
• Research institutions and educational facilities that deploy robots in shared collaborative workspaces

Assessment outcomes are used to support CE marking declarations, North American market access, and voluntary certifications that demonstrate due diligence to customers, insurers, and regulators.

FAQ

What is the difference between verification and validation in robot safety?

Verification confirms that each safety requirement has been correctly implemented, such as measuring an actual stopping distance against a specified limit. Validation confirms that the complete robot or system achieves the intended risk reduction in its real application, typically through inspection and functional trials at the integrated installation.

Which standard applies to collaborative robots?

Collaborative robots must satisfy ISO 10218-1 and ISO 10218-2, supplemented by ISO/TS 15066, which defines the four collaborative operating modes and the biomechanical force and pressure limits for human contact. Power and force limiting applications always require measurement against these thresholds.

Is robot safety assessment legally mandatory?

Requirements vary by market. In the European Union, robots placed on the market as machinery must satisfy the essential health and safety requirements and undergo appropriate conformity assessment before CE marking. In other regions, assessment may be voluntary but is frequently required by customers, insurers, or occupational safety regulators.

How long does a robot safety assessment take?

Timelines depend on robot complexity and the scope of testing. A straightforward industrial robot arm may require several weeks for type testing, while a collaborative or mobile robot with extensive functional safety validation can require several months, particularly if design modifications are needed.

What do PL and SIL mean in robot safety?

PL, or Performance Level, is the classification defined in ISO 13849-1 for safety-related parts of control systems, ranging from PLa to PLe. SIL, or Safety Integrity Level, is the equivalent classification in IEC 62061. Most robot safety functions are expected to achieve PL d with Category 3 architecture, or SIL 2, unless the risk assessment justifies a different target.

When should a robot be re-assessed?

Re-assessment is recommended after significant modifications, such as changes to the control system, safety functions, payload, reach, or application context, and after relocation to a new installation with different safeguarding layouts.