How to work with a cobot?
Cobots (collaborative robots) have been news in the world of automation in recent years. Many believe that there is only one solution for a collaborative robotic system – it is a specialized non-industrial robot. The good news is that there are actually different options for achieving a collaborative system. Most traditional robots can actually become “collaborative” with additional security devices and proper integration. Integrators play a major role in this transformation.
Cobots can work in many ways According to ISO 10218-1 safety standard published in 2012, there are four different types: 1) Safety controlled stop stop 2) Hand guidance 3) Speed and separation control 4) Limiting power and force inherent design.
Collaborative operation of robots with “controlled stop safety monitoring” does not allow the robot to move when the operator is in a “collaborative workspace”, but robot drives can maintain power. Collaboration workspace is a workspace where both the robot and the operator can perform tasks. For this type of work, a standard industrial robot can operate at high speeds while the collaboration workspace is clear from the operator, allowing faster cycle times. The robot can automatically back up without direct input from the operator after clearing the collaborative workspace.
It is common to use a manually supervised stop-over with a manual loading location. In this scenario, the handheld device can manually load the part into the robot tool or into the handheld device. This allows the operator to periodically inspect parts while the robot unloads them from the machine. To achieve this type of application, light curtains and safety mats can replace the fence panel.
Robot Hand Operation allows the robot to move through the operator’s direct input from a manually operated device. When the operator enters a common workspace, the robot will remain in a safe-guarded stopped position until the operator activates the hand-guided device via the enable switch. These devices are often used on robots as an intelligent lifting aid because they can be easier to operate than average elevators but can also operate autonomously when there is no operator nearby.
“Speed and separation monitoring”, also referred to as an “unrestricted” robotic system, is where both the robot and the operator can move simultaneously in a collaborative workspace as long as the operator maintains a predetermined protective separation distance from the robot. .
A security rating laser scanner usually controls this type of collaborative application. If the operator breaks the separation, the robot will stop until the person moves away from the robot – after the robot is removed it can continue the process autonomously. The separation distance is determined by calculating on the basis of the robot speed, the speed of the starter and the response time of the system (both the robot and the safety devices). The faster the robot moves, the longer the distance will be. The more often operators violate separation separation, the more often the robot will be kept at zero speed.
Working together to “limit force and force inherent design or control” requires a special robot that is designed to incorporate back force or force that enables it to detect contact with a person. This is the most popular type of robot collaboration and is ideal for applications that require the operator to often be in the same workspace as the robot. It requires the most comprehensive risk assessment given that the robot is able to continue its task while the operator remains within the reach of the robot. The maximum speed of the robot will also be less than that of a traditional robot.
Each of the four types of collaborative work operations allows different amounts of human-robot interaction. Based on a risk assessment, each type will also allow you to remove some or all of the security fences.
Identifying the right collaboration app for you requires an assessment of the following:
- how much interaction will be required between your operator and the robot
- if there is no direct interaction, how close will the operators have to be to the robot?
- how much space is available?
- is the application dangerous?
- what time is at your disposal?
For all calculations, it is best to consult experienced integrators to avoid any risk to operators.