HRC: Direct cooperation between humans and robots

Page: 2/2

Once the robot’s application has been clarified, the question now is whether the robot provides the required safety functions. KUKA implements the following functions, for example:

  • Safe collision detection
  • Safe force monitoring
  • Safe workspaces and protected spaces
  • Safe position monitoring
  • Safe velocity monitoring
  • Safe inputs and outputs
  • Safe tool detection
  • Safe orientation monitoring
  • Safe state switching to allow for changing back and forth between safety strategies within a particular application

KUKA has also had these safety functions certified in accordance with DIN EN ISO 13849 PLd Cat 3 and DIN EN 62061: SIL 2. The safety functions are built up from a range of components, such as sensors, evaluation electronics, means of communication and control. Each component contributes to the overall safety function and each in turn should be certified.

The next step is configuring the robot safely within its workspace. Are the safety functions, such as collision detection or force monitoring, effective throughout the robot’s workspace? What if the measurement accuracy is limited or non-existent at certain points within the workspace or on certain parts of the robot structure? Is safety then still ensured?

Next comes the accuracy of the force measurement in safe technology. If, for example, a force limit of 120 N is set, it is not sufficient if the robot can only reliably measure with an accuracy of 130 N. If the robot measures with an accuracy of 110 N, it may then only exert a force of 10 N, which would restrict the application scope.

The resilience of a robot should also be tested. Sensitive, safe robots are equipped with measuring technology but must nevertheless be robust. It is thus important to know how much a robot can endure and how this was tested – with no load, a partial load or a full load.

Last but not least, the robot must undergo the crash test at KUKA. This is the only way to tell whether our robots are still safe even after being overloaded or having experienced a crash. As mentioned above, people are the focus in human-robot collaboration. All these questions must therefore be resolved at the latest during the risk analysis of a particular application. This is much easier if the robot incorporates certified safety functions. The safety of the application can also be simply confirmed if the CE mark required by the Machinery Directive is present. If a CE mark is improperly awarded, there is a great risk of liability – including personal liability – in the event of damage.

Humans and robots collaborate optimally

The answer to the question addressed at the beginning is that robots are machines and people are responsible for their safe operation. There is no need for anyone to fear human-robot collaboration if reliable and robust safety measures are implemented.