By Motionwell Team
January 5, 2025
Technical
What Makes a Robot “Collaborative”?
“Collaborative robot” describes a robot designed for use around people, but safe collaboration is achieved by system design, not by the robot alone.
| Topic |
What it means in practice |
| Cobot as a product |
The robot has built-in safety functions and a design intended for human proximity |
| Collaboration as an application |
The workcell is engineered so that the risk level is acceptable for the intended task |
ISO/TS 15066 is the reference that helps you engineer the second part: the application.
Standards You Actually Use (And What Each Covers)
| Standard |
Scope |
Why it matters |
| ISO 10218-1 / ISO 10218-2 |
Industrial robot safety (robot and integration) |
Baseline safety expectations for industrial robot systems |
| ISO/TS 15066 |
Collaborative operation guidance |
Defines collaboration modes and provides guidance for risk reduction |
| ISO 12100 |
Risk assessment methodology |
How to systematically identify and mitigate hazards |
| ISO 13849 (or IEC 62061) |
Functional safety design |
How to implement safety functions to required performance levels |
Four Collaboration Modes (ISO/TS 15066)
ISO/TS 15066 describes four commonly used ways to achieve safe collaboration. The “best” mode depends on the task, tooling, and exposure.
| Collaboration mode |
What happens |
Typical fit |
Typical safety functions |
| Safety-rated monitored stop |
Robot stops when a person enters the collaborative space |
Occasional human intervention |
Safety-rated sensors, stop and reset logic |
| Hand guiding |
Operator guides robot motion directly |
Teaching, setup, ergonomic assist |
Enable device, reduced speed mode, accessible e-stop |
| Speed and separation monitoring |
Robot slows/stops based on distance to a person |
Shared area with predictable traffic |
Safety scanners, zoning, dynamic speed limits |
| Power and force limiting (PFL) |
Robot limits impact energy in contact scenarios |
Close interaction tasks |
Force/torque limits, speed limits, validated tooling design |
ISO/TS 15066 also provides guidance on body-region-specific transient contact thresholds and measurement methods. Always consult the latest revision and validate your specific end-effector and workpiece risks.
Risk Assessment Workflow (Engineering View)
| Step |
Output you should expect |
| Identify hazards |
A hazard list that includes tooling, workpieces, pinch points, and unexpected motion |
| Estimate risk |
Severity and probability assumptions documented (not “in someone’s head”) |
| Select safeguards |
Engineering controls prioritized before administrative controls |
| Implement safety functions |
Safety I/O map, safety PLC or safety relay logic, verified stop behavior |
| Validate and document |
Test records, measured limits where required, and sign-off evidence |
Typical Safety Functions in a Cobot Cell
| Safety area |
Typical implementation patterns |
| Zone awareness |
Safety scanners or interlocked doors defining speed-limited and stop zones |
| Stop architecture |
System-level e-stop network, controlled stop categories, safe restart rules |
| Tooling and workpiece safety |
Rounded edges, limited protrusions, controlled pinch points, breakaway or compliance features where suitable |
| Verification and recovery |
Vision/position checks, grip confirmation, error states that prevent unsafe retries |
| Documentation |
Risk assessment, safety function validation, operating instructions, training records |
Motionwell References (Where Cobots Meet Real Production)
| Project reference |
Where the cobot is used |
Why safety design is non-negotiable |
| Project P23078 (QA Lab Automation) |
Cobot-assisted sample handling and station loading |
Shared lab environments require clear zoning, predictable recovery, and traceable state transitions |
| Project P23022 / P23019 (EV Battery Disassembly Line) |
Collaborative robot used at a vision-related station within a broader automated line |
Mixed automation with high-risk workpieces makes risk assessment and safeguarding strategy essential |
Frequently Asked Questions
| Question |
Answer |
| If I buy a cobot, do I automatically comply with ISO/TS 15066? |
No. Compliance depends on the complete application: tooling, workpiece, speeds, zones, and validation evidence. The robot is only one part of the safety case. |
| Do collaborative cells always require no guarding? |
Not necessarily. Many real cells are hybrid: collaborative behavior in one zone and physical safeguarding in another, depending on risks and tooling. |
| Is power-and-force limiting (PFL) always the best choice? |
Not always. PFL is useful for close interaction tasks, but speed/separation monitoring or monitored stop can be a better fit when tooling or workpiece risks dominate. |
| What is the single most common mistake in cobot safety projects? |
Treating safety as a late-stage add-on. Safety zoning, stop architecture, and recovery logic should be defined during concept design, not during commissioning. |
Conclusion
Safe human-robot collaboration is a design outcome. ISO/TS 15066 helps you choose an appropriate collaboration mode, execute a structured risk assessment, and implement validated safety functions that match your workflow.
If you are planning a collaborative robot application, contact us at /contact/ to review the safety concept before you lock the layout and tooling decisions.
Tags:
Cobot
Safety
ISO 15066
Collaborative Robot
