Collaborative Robot Safety

International standards establish requirements for collaborative robot applications, defining safety categories, risk assessment procedures, and technical requirements. Understanding these standards enables practitioners to design compliant collaborative systems.

ISO 10218-1 and ISO 10218-2 provide fundamental requirements for industrial robot safety. Part 1 covers robot design while Part 2 addresses robot integration into systems. These standards define four collaborative operation modes that enable human-robot interaction.

ISO/TS 15066 supplements ISO 10218 with detailed technical specifications for collaborative robot applications. This specification provides guidance on speed and separation monitoring, hand guiding, safety-rated monitored stop, and power and force limiting. Biomechanical limits establish maximum contact forces and pressures that avoid injury.

Safety-Rated Monitored Stop pauses robot motion when humans enter collaborative workspaces. Robots can operate at industrial speeds when humans are absent but stop immediately upon human entry. Production can resume automatically when humans leave or with deliberate restart.

Hand Guiding enables operators to manually move robots through desired paths. Safety features ensure robots move only when operators activate enabling devices and apply hand guidance. This mode supports programming and cooperative positioning tasks.

Speed and Separation Monitoring adjusts robot speed based on distance from humans. Robots slow as humans approach and stop before contact can occur. This approach enables higher speeds when humans are distant while ensuring safety at close range.

Power and Force Limiting designs robots and end effectors to prevent injury through inherent limitations. Contact is allowed but forces and pressures remain below injury thresholds. This approach enables true human-robot contact applications like cooperative assembly.

Collaborative robot applications require thorough risk assessment that identifies hazards, evaluates risks, and determines appropriate safeguards. Structured risk assessment processes ensure comprehensive coverage while documenting compliance.

Hazard Identification examines all potential harm sources in collaborative applications. Beyond robot motion hazards, assessment considers end effector hazards, workpiece hazards, and environmental factors. Task analysis reveals hazards specific to intended operations.

Task-Based Assessment evaluates risks for each task humans and robots perform, considering potential interactions. Tasks with different risk profiles may require different safeguards. Assessment covers normal operation, setup, maintenance, and foreseeable abnormal conditions.

Contact Scenario Analysis defines how human-robot contact might occur during collaborative operations. Transient contact (glancing impacts) differs from quasi-static contact (clamping situations). Contact location on the human body affects allowable forces. Scenario analysis informs safeguard selection.

Risk Estimation evaluates severity of potential harm and likelihood of occurrence for identified hazards. ISO 12100 provides risk estimation guidance while ISO/TS 15066 provides biomechanical data for contact assessments. Estimation results drive risk reduction requirements.

Risk Reduction applies safeguards following the hierarchy: inherent safe design, protective devices, and information/training. Collaborative modes like power and force limiting provide inherent protection. Sensing systems provide protective functions. Documentation ensures users understand residual risks.

Validation confirms that implemented safeguards achieve required risk reduction. Testing verifies that robot performance meets design specifications. Force and pressure measurements confirm compliance with biomechanical limits. Documentation demonstrates validation completion.

Various technologies enable safe human-robot collaboration by detecting human presence, limiting robot capability, and ensuring safe interaction. Understanding available technologies enables practitioners to select appropriate solutions for specific applications.

Force/Torque Sensing in robot joints enables detection of contact forces and collision detection. Sensitive force monitoring enables immediate stop upon unexpected contact. Force limits can be programmed for specific applications and contact scenarios.

Skin Sensors cover robot surfaces with tactile sensing that detects contact before significant force develops. Capacitive and resistive technologies can detect proximity before physical contact. Skin sensors complement joint-based sensing with surface-level detection.

Presence Detection Systems monitor workspace for human entry using various technologies. Safety scanners using laser or ultrasonic sensing detect humans entering defined zones. Camera-based systems provide presence detection with 3D awareness. System selection depends on detection requirements and environmental conditions.

Speed and Position Monitoring tracks robot pose and velocity to enable safety-rated motion supervision. Safety PLCs verify that speed limits are not exceeded and robots remain within defined operating envelopes. Violations trigger immediate stop.

End Effector Design affects collaborative safety significantly. Padded grippers, rounded edges, and compliant structures reduce contact severity. Tool-specific risk assessment ensures end effectors don't introduce unacceptable hazards.

Safety-Rated Controllers implement safety functions with appropriate reliability for intended risk reduction. Safety PLCs, safety-rated drives, and certified safety controllers provide the reliability required for safety-critical functions.

Successful collaborative robot implementation requires systematic approaches that address safety throughout the application lifecycle. Following structured implementation processes ensures safe and effective human-robot collaboration.

Application Definition clearly specifies collaborative tasks, human roles, and interaction requirements. Understanding intended use enables appropriate safety design. Ambiguous application definition leads to inadequate safeguarding or excessive restriction.

Workspace Design establishes physical layout for collaborative operation. Workspace zoning defines areas with different safety requirements. Human access paths and robot motion paths require careful coordination. Workspace design affects both safety and productivity.

Safety System Design selects and configures safeguards based on risk assessment results. Multiple technologies may combine to achieve required protection. Safety system architecture addresses reliability requirements while enabling intended operation.

Integration and Installation implements designed safety systems with appropriate rigor. Installation verification confirms correct implementation. Commissioning tests verify safety function performance. Documentation records as-built conditions.

Operator Training ensures workers understand collaborative system operation and safety requirements. Training covers normal operation, limits of collaboration, emergency procedures, and residual risks. Competency verification confirms understanding before operation.

Ongoing Monitoring verifies that safety performance continues meeting requirements. Regular inspection and testing confirm continued function. Change management addresses modifications that could affect safety. Incident investigation identifies improvement opportunities.

Continuous Improvement enhances collaborative applications based on operational experience. User feedback identifies workflow improvements. Safety data reveals opportunities for enhanced protection. Technology updates may enable new capabilities.