Robot Safety Application Series (2): Manual Loading and Unloading

The Risks of Manual Tasks in Robotics

In many industrial settings, robots are frequently used for tasks that require manual intervention, such as loading and unloading parts or adjusting fixtures. These operations often involve direct human interaction with the robot’s tools, which can expose workers to various hazards.

When humans and robots work in the same area, there's a risk of dangerous movements like crushing, shearing, or entanglement, especially when tools are equipped with moving parts such as jaws or cylinders. This makes it crucial to implement proper safety measures to protect operators from potential injuries.

To ensure the safety of personnel involved in these tasks, specific protective measures must be in place. These include both physical barriers and advanced control systems designed to prevent access to hazardous areas during operation.

Operator Intervention

Main Protective Measures

According to ISO 12100, interlocks and mechanical guards are considered the most effective methods for reducing risks in robotic applications. These measures are also covered in the Robot Safety Standard ISO 10218-2, ensuring compliance with international safety guidelines.

A fixed guard should meet certain requirements, such as being removable only with a specific tool, having screws that remain attached to the machine, and standing at least 1400 mm above the ground. These standards help minimize the chances of accidental exposure to danger.

The Main Guard of the Robot

Additional Safety Measures

For frequent manual tasks, physical barriers may not always be practical. In such cases, additional protection methods like time limits, light curtains, and collaborative workspace limitations can be implemented to enhance safety.

One such method is the use of a stop time limit, where the system ensures that the robot comes to a safe state before an operator enters the hazardous area. This involves delay mechanisms, speed monitoring, and static detection to maintain a safe environment.

Use the Light Curtain to Trigger Machine Stop

Another approach is to limit the collaborative workspace so that the robot and the operator do not occupy the same space at the same time. If they do, the system triggers a safe stop, preventing any potential collisions or injuries.

For more comprehensive solutions, companies like Pilz have developed training programs based on ISO/TS 15066, offering engineers practical guidance on safely integrating robots into shared workspaces.

Limit Collaborative Space