Collaborative Robots and Safety

Collaborative Robots

A robot that can be used in a collaborative operation

Defined by the operation that they are doing not by the type of robot itself

Collaborative Operation

A state in which a robot works in direct cooperation with a human within a defined collaborative workspace

Collaborative Workspace

A workspace within the safeguarded space where the robot and human can perform tasks simultaneously during production operation

The Robot Risk Model

Robot Risk Reduction

ISO 10218 Part 1

Outlines the six steps to be considered as part of a risk assessment

1. The intended operations of the robot, including teaching, maintenance, setting and cleaning

2. Unexpected startup

3. Access by personal from all directions

4. Reasonably foreseeable misuse of the robot

5. The effect of failure in the control system

6. Where necessary, the hazards associated with the specific robot application

ISO 10218 Part 2

Requires a risk assessment for collaborative applications to evaluate task/hazard combinations and set appropriate limits

• Means of anticipating tasks and hazards with the goal of applying suitable risk reduction measures

• Uses iterative process to determine the desired effect is achieved

• Avoids “one size fits all”

ISO TS 15066

Technical Specification about collaborative operations, which may include one or more of the following methods:

• Safety rated monitored stop

• Hand guiding

• Speed and separation monitoring

• Power and force limiting

Safety Rated Monitored Stop

What the collaborative robot does in the presence of an operator or obstruction

• Stop motion condition ensured

• Drive power remains on

• Motion resumes after obstruction clears

• Robot motion resumes without additional action

• Protective stop delivered if stop condition is violated

Hand Guiding

Where an operator leads robot movement through direct interface

• Robot stops when operateor arrives

• Operator grasps enabling device, activating motion

• Robot motion responds to operator commands

• Non-collaborative operation resumes when operator leaves collaborative workspace

Speed and Separation Monitoring

Where the robot speed reduces when an obstruction is detected

• Separation distances are monitored

• Robot speed directly correlates to sparation distance

  • Stop given if direct contact proximity is attained

Power and Force Limiting

Where incidental contact initiated by robot are limited in energy to not cause the operator harm

• Forces robot can exert are limited

• Robot system design eliminates pinch points, sharp edges, to prevent the robot trapping operators

• Robot complies and reacts when contact is made

• Reduce robot velocity or inertia

• Modify robot posture, to increase possible exposure surface area (reduce pressure)

  • Avoid sensitive body areas

ISO TS 15066 Onset of Pain Study

Guidance for power and force limits based on study examining these conditions and the onset of pain in 29 body regions.