Robot safety inspection is the systematic evaluation of industrial robots, collaborative robots, mobile robots, and service robots against international safety standards such as ISO 10218, ISO/TS 15066, ISO 13482, and ISO 3691-4. Performed by accredited third-party laboratories, it covers electrical safety, mechanical safety, functional safety, electromagnetic compatibility, and environmental performance to support CE marking, North American listing, and global market access. This article explains the scope, sample types, testing items, methods, and typical applications of robot safety inspection.
Technical Overview
Robot safety inspection is the structured assessment of a robot's design, construction, and performance to verify compliance with applicable safety standards and regulatory requirements. Its objective is to confirm that a robot, throughout its intended lifecycle, does not present unacceptable risks to operators, maintenance personnel, or bystanders, and that all safety functions perform reliably under both normal and single-fault conditions. The process is grounded in the risk assessment methodology of ISO 12100 and is executed through documentation review, laboratory type testing, and functional safety validation.
Because robots span many categories and applications, inspection programs are organized around product-specific standards. The most commonly applied frameworks include:
- ISO 10218-1 and ISO 10218-2: safety requirements for industrial robots and for robot systems and integration.
- ISO/TS 15066: collaborative robot operation, including power and force limiting and biomechanical limits.
- ISO 13482: safety requirements for personal care robots, including mobile servant, physical assistant, and person carrier robots.
- ISO 3691-4: safety requirements for driverless industrial trucks and their systems, applicable to automated guided vehicles (AGVs) and autonomous mobile robots (AMRs).
- IEC 60204-1: electrical equipment of machines, covering the electrical safety of robot controllers and power circuits.
- ISO 13849-1 and IEC 62061: functional safety of safety-related control systems, expressed as Performance Levels (PL) and Safety Integrity Levels (SIL).
- IEC 61000 series and CISPR 11: electromagnetic compatibility requirements.
- IEC 60529: ingress protection (IP) testing.
- UL 1740, UL 3300, and ANSI/RIA R15.06: North American requirements for industrial and service robots.
- GB 11291.1 and GB 11291.2: Chinese national adoptions of the ISO 10218 series.
On the regulatory side, robots placed on the EU market fall under the Machinery Directive 2006/42/EC, which is being superseded by the Machinery Regulation (EU) 2023/1230, and require CE marking following an appropriate conformity assessment. In North America, robots are typically evaluated against UL standards by Nationally Recognized Testing Laboratories (NRTLs). In China, compliance with GB standards is expected for domestic deployment. For wirelessly connected robots, radio and cybersecurity regulations add further evaluation requirements.
Testing Samples
Industrial Robots
Six-axis articulated robots, SCARA, delta/parallel, and cartesian/gantry robots, together with their controllers and teach pendants, form the core sample group. Units are typically submitted with representative payloads, end-effector interfaces, and the complete control cabinet, since the controller is treated as an integral part of the robot under ISO 10218-1.
Collaborative Robots
Lightweight manipulators designed to operate alongside humans without full perimeter guarding are assessed under ISO 10218-1 supplemented by ISO/TS 15066. Samples must be configured with the firmware, safety parameters, and tooling intended for the target collaborative application.
Mobile Robots
AGVs, AMRs, autonomous forklifts, and their docking and charging stations are evaluated against ISO 3691-4. Sample configurations should reflect the maximum speed, payload, lift height, and sensor layouts used in service.
Service and Personal Care Robots
Professional service robots (delivery, cleaning, disinfection, inspection, security) and consumer robots (vacuum, companion, and educational robots) are covered by ISO 13482, UL 3300, or relevant IEC 60335-based standards depending on use and market, with additional battery, EMC, and mechanical hazard requirements.
Robot Subsystems and Accessories
Controllers, servo drives, safety control modules, grippers, tool changers, collision sensors, safety laser scanners, chargers, and battery packs may be evaluated individually or as part of an integrated robot system, depending on the certification strategy.
Testing Items
A comprehensive robot safety inspection program combines the following testing categories, tailored to the robot type, collaborative mode, and target market.
Electrical Safety Testing
- Dielectric strength (hipot) verification between power circuits and accessible conductive parts.
- Insulation resistance measurement at specified test voltages.
- Protective bonding continuity between exposed conductive parts and the protective earth terminal.
- Touch current and leakage current measurement under normal and single-fault conditions.
- Residual voltage decay verification after disconnection from supply.
- Verification of rated voltage, overcurrent protection, terminal marking, and electrical clearances per IEC 60204-1 and the applicable product standard.
Mechanical Safety Testing
- Verification of axis range limiting by mechanical stops and safety-rated soft limits.
- Speed monitoring and speed limiting performance across operating modes.
- Protective stop and emergency stop behavior, including stopping time and stopping distance.
- Behavior under power loss and power restoration, including braking and any uncontrolled motion.
- Stability, tipping resistance, and payload verification for mobile platforms and person-carrying robots.
- Assessment of surface, edge, crushing, and trapping hazards on the robot structure.
Functional Safety Validation
- Verification of Performance Level (PL) or Safety Integrity Level (SIL) claims for each safety function per ISO 13849-1 or IEC 62061.
- Fault injection testing to confirm diagnostic coverage and safe behavior under component failures.
- Validation of safety-rated monitored stop, hand guiding, and speed and separation monitoring functions.
- Measurement of safety loop response times, including contributions from external sensing devices.
Power and Force Limiting
- Measurement of quasi-static (clamping) and transient contact forces at all contactable body regions.
- Measurement of contact pressure distribution over representative contact areas.
- Comparison of measured values against the biomechanical limits in ISO/TS 15066 Annex A.
- Verification of speed, momentum, and power limitation settings and their triggering logic.
Electromagnetic Compatibility
- Conducted and radiated emissions testing per CISPR 11 or IEC 61000-6-4 as applicable.
- Immunity to electrostatic discharge, radiated RF fields, electrical fast transients, surges, and voltage dips per IEC 61000-6-2 and the IEC 61000-4 series.
Environmental and Ingress Protection Testing
- IP code verification for dust and water ingress per IEC 60529.
- Dry heat, cold, and damp heat testing per the IEC 60068-2 series.
- Vibration and mechanical shock testing simulating transport and in-service conditions.
Battery and Charging Safety
- Cell and pack evaluation per IEC 62133-2 for lithium-based systems, including overcharge, over-discharge, short-circuit, and thermal abuse tests.
- UN 38.3 transport safety testing for lithium battery shipments.
- Charger and docking station safety, output characteristics, and protection function verification.
Additional Evaluations
- Cybersecurity assessment of networked robots per IEC 62443.
- Noise emission measurement under representative operating conditions.
- Laser safety verification for robots integrating Class 3B or Class 4 lasers per IEC 60825-1.
- Review of markings, warning labels, and instruction documentation.
Testing Methods
Inspection begins with a documentation review covering the risk assessment file, electrical schematics, bills of materials with component certifications, the list of safety functions with their PL or SIL claims, and the operating manuals. This review confirms that the design intent is consistent with the standards before physical testing begins.
Electrical safety tests are performed in the laboratory using calibrated hipot testers, insulation resistance meters, and earth bond testers applying high test currents. EMC tests are conducted in semi-anechoic chambers and shielded rooms using spectrum analyzers, artificial mains networks, and immunity test generators in accordance with the IEC 61000-4 series.
Stopping performance is measured with position and time instrumentation while the robot executes worst-case moves; the resulting stopping times and distances are used to derive minimum protective separation distances per ISO 13855. For collaborative applications, contact forces and pressures are captured with calibrated force gauges, load cells, and pressure-indicating film applied at the worst-case contact scenarios identified during risk assessment, with the robot running at maximum permitted speed and payload.
Functional safety validation combines analytical verification of the safety architecture with practical fault injection, such as open circuits and short circuits on safety-critical signals, to confirm diagnostics and fail-safe behavior. Response times of the complete safety loop, including external light curtains and scanners, are measured with suitable timing instrumentation.
Environmental tests are carried out in climate chambers, dust and water IP test enclosures, and on vibration tables at the severity levels appropriate to the declared rating of the robot. For integrated cells, on-site verification per ISO 10218-2 validates the safety functions of the complete installation, including interfaces to external safeguards.
Results are compiled into a test report stating measurement conditions and uncertainty. Nonconformities are documented, corrective actions are agreed with the manufacturer, and retesting is performed where necessary before a test report, certificate, or listing is issued.
Applications
Robot safety inspection supports product certification and market access across major jurisdictions, including CE marking under the EU machinery framework, NRTL listing for North America, and GB compliance for the Chinese market, as well as similar national schemes. Beyond certification, inspection reports are used for design verification, procurement acceptance, and supplier qualification.
- Automotive and metal fabrication lines employing heavy-payload articulated robots.
- Electronics assembly utilizing SCARA, delta, and collaborative robots.
- Logistics and warehousing operations running AGV and AMR fleets.
- Healthcare settings with surgical assistance, disinfection, and rehabilitation robots.
- Hospitality, retail, and commercial cleaning service robots.
- Agriculture, construction, and inspection robots operating in harsh environments.
In-service applications include periodic inspection of deployed robots, re-evaluation after modifications, repairs, or changes of application, and technical support for incident investigations and workplace safety audits.
FAQ
Which standards apply to collaborative robots?
Collaborative robots are evaluated against ISO 10218-1 as the baseline, supplemented by ISO/TS 15066. Each of the four collaborative operation modes — safety-rated monitored stop, hand guiding, speed and separation monitoring, and power and force limiting — must be separately validated for the specific application, tooling, and workspace geometry.
Is third-party testing mandatory for robots?
Requirements depend on the target market. In the EU, the manufacturer must complete a conformity assessment, and notified body involvement is required for certain machinery categories; in North America, listing generally requires evaluation by an NRTL. Even where third-party testing is not strictly mandatory, reports from accredited third-party laboratories are widely recognized as objective evidence of conformity and due diligence.
What is the difference between PL and SIL?
Both metrics quantify the reliability of safety-related control functions. Performance Level (PL a to e) is defined in ISO 13849-1, while Safety Integrity Level (SIL 1 to 3) is defined in IEC 62061. Industrial robot safety functions typically require PL d with Category 3 architecture or SIL 2, and the claimed level must be substantiated by calculation and fault injection testing.
How is power and force limiting verified?
Contact forces and pressures are measured with calibrated instruments at worst-case robot postures and speeds for each foreseeable contact scenario identified in the risk assessment. Both quasi-static clamping contact and transient impact contact are evaluated, and measured values are compared against the biomechanical limits for each body region published in ISO/TS 15066 Annex A.
How long does a robot safety inspection take?
Timelines vary with scope. A focused electrical safety and EMC program may be completed in two to four weeks, while full collaborative robot validation, including power and force limiting and functional safety assessment, typically takes longer. Schedule depends heavily on documentation readiness, sample availability, and whether corrective actions are needed.
What should manufacturers prepare before submitting samples?
Manufacturers should provide the risk assessment, electrical schematics, a bill of materials with certifications for safety-critical components, the safety function list with PL or SIL claims, firmware documentation, user manuals, and representative sample units configured with production hardware and the intended safety parameters.
