How to Conduct a Risk Assessment for Cobot Applications

Collaborative robots, or cobots, have transformed industrial automation by enabling human-robot collaboration and boosting productivity. Unlike traditional robots confined to cages for safety reasons, cobots come equipped with integrated safety features allowing closer human interaction. However, these features alone do not eliminate all hazards, making thorough risk assessments crucial for maintaining safety and compliance with industry standards.

Key standards, such as ISO 10218 (safety requirements for industrial robots) and ISO/TS 15066 (technical specification for cobot safety), guide this risk assessment process. Adhering to these standards helps identify and mitigate risks, ensuring a safe, efficient workplace.

Enhance Risk Assessments with Accurate Pressure and Force Measurements

To ensure precise and reliable risk assessments, tools like the Cobosafe Measurement Device are essential. Designed specifically for collaborative robotic applications, this device measures pressure and force to help businesses validate compliance with safety standards like ISO/TS 15066. By providing accurate data, Cobosafe enables safer and more effective human-robot interaction. Learn more about the Cobosafe device and how it can optimise your risk assessment process: Cobosafe Measurement Device.

Why Conduct Risk Assessments for Cobots?

The importance of conducting risk assessments for cobot applications lies in several key areas:

1. Ensuring Workplace Safety: Cobots are designed with built-in sensors and force-limiting capabilities, but potential dangers like pinch points, unexpected movements, and tool malfunctions can still pose risks. Assessing these factors helps create tailored safety measures specific to the workspace.

2. Compliance with Industry Standards: Conducting risk assessments is essential for adhering to regulations like ISO 10218 and ISO/TS 15066, which outline how to identify, evaluate, and mitigate risks. Compliance builds trust with stakeholders and helps avoid legal issues.

3. Optimizing Human-Robot Interaction: Effective risk assessments streamline the integration of cobots by identifying potential interaction challenges and optimizing performance without compromising safety.

Key Steps in Cobot Risk Assessment

A thorough risk assessment involves a series of structured steps to identify hazards and develop mitigation strategies.

1. Identifying Potential Hazards

Start by observing the cobot’s tasks and interactions within its workspace. Look for common hazards such as:

• Pinch Points: Where cobot arms or moving parts could trap fingers, limbs, or clothing.
• Unexpected Movements: Resulting from programming errors or unforeseen external factors.
• Tool Malfunctions: Potential issues with end effectors that could detach or malfunction.
• Workspace Intrusions: Situations where unauthorized personnel might enter the cobot’s operation area.

Gather information through observational assessments, employee feedback, and scenario analysis to capture the full range of possible hazards.

2. Evaluating Risks with a Risk Matrix

Evaluate identified hazards based on their severity and likelihood using a risk matrix:

• Severity Ratings: Rank risks as minor, moderate, severe, or critical.
• Likelihood Ratings: Estimate the probability of occurrence, from rare to frequent.

This visual tool helps prioritize which risks require immediate attention and informs decisions on mitigation strategies.

3. Documenting Findings

Keep detailed documentation to support risk management and compliance. Include:

• Identified Hazards: A complete list of observed risks.
• Risk Ratings: Assigned severity and likelihood for each hazard.
• Proposed Mitigation Measures: Actions to reduce or eliminate risks.

Detailed reports facilitate continuous improvement, training, and future safety audits.

Ensuring Compliance with ISO 10218 and ISO/TS 15066

Adherence to these safety standards ensures compliance and enhances risk management:

Overview of ISO 10218

ISO 10218 outlines safety requirements for industrial robots, covering:

• Design Requirements: Safety features such as emergency stops and fail-safes.
• Installation Guidelines: Safe placement and integration within the workspace.
• Maintenance Protocols: Preventative practices to reduce operational failures.

Understanding ISO/TS 15066

ISO/TS 15066 complements ISO 10218 with specific guidelines for collaborative robot applications:

• Pain Threshold Data: Defines safe force limits to prevent injuries.
• Risk Assessment Criteria: Structured approaches for assessing human-cobot interactions.
• Protective Measures: Safety-rated monitored stops and power and force limiting (PFL) functions for safe shared spaces.

Practical Steps for Compliance

1. Integrate Safety Features: Equip cobots with emergency stops, sensors, and monitoring systems.
2. Employee Training: Ensure all operators understand safety protocols.
3. Regular Audits: Schedule periodic safety checks to reassess risks.
4. Documentation: Keep comprehensive records of safety assessments and updates.

Detailed Risk Mitigation Strategies

Risk mitigation involves engineering controls, administrative practices, and the use of Personal Protective Equipment (PPE).

1. Engineering Controls

Physical measures to reduce risks:

• Safety-Rated Monitored Stops: Stop the cobot when a human enters its workspace.
• Power and Force Limiting (PFL): Adjust cobot force to stay within safe thresholds.
• Advanced Sensors: Detect human presence and slow or stop operations.
• Barrier Systems: Install physical barriers or light curtains to limit interaction zones.

2. Administrative Controls

Procedural strategies to enhance safety:

• Employee Training: Regular training on safe cobot interaction.
• Clear Protocols and Signage: Standard operating procedures and visible safety warnings.
• Safety Drills: Practice emergency responses to incidents.
• Access Control: Limit workspace entry to authorized personnel only.

3. Personal Protective Equipment (PPE)

PPE adds another safety layer:

• Protective Gloves: For tasks requiring close proximity to the cobot.
• Safety Glasses: Protect against potential debris.
• Specialized Gear: Helmets or footwear for specific tasks.

Real-World Example: BMW Group's Cobot Implementation

Source: BMW Press Release 9/2023

In BMW's automotive assembly plants, cobots assist with tasks such as installing door seals and performing precision assembly work. This setup allows workers to focus on complex tasks while cobots manage repetitive actions.

• Engineering Controls: BMW incorporated safety-rated monitored stops that activate when a worker approaches a cobot. Cobots operate at reduced speeds and forces to align with ISO/TS 15066 safety limits.
• Administrative Controls: Employees were trained to interact with cobots only during designated phases of production.
• PPE: Workers used protective gloves and safety glasses to safeguard against pinch points and potential debris.

This integration resulted in improved ergonomics, productivity, and safety, showcasing the importance of a comprehensive risk assessment and effective safety measures.

Conclusion

Risk assessments are crucial for ensuring safe cobot applications. By following a structured approach to identify hazards, complying with standards like ISO 10218 and ISO/TS 15066, and implementing effective mitigation strategies, companies can create a safe and efficient work environment. Practical examples like BMW's demonstrate that continuous training and comprehensive safety protocols are vital for success.