Drives and Controls Magazine
Safety system allows easier access to robots
Published:  30 October, 2012

Kawasaki Robotics has announced an “intelligent” motion monitoring safety system that allows operators to access robot installations safely with fewer restrictions than usual. The Cubic-S system uses dual CPUs, that are independent of the robot’s control CPU, to monitor speed and position. Eight functions allow safety zones to be programmed easily without needing zone limit switches that can be difficult to adjust and maintain.

When used with external hardware such as pressure mats or light guards, the monitoring functions allow operators to intervene to inspect a component while it is being gripped by a robot under power.

By restricting a robot’s workspace to a programmed operational area, the system can save space on a factory floor. The need for other in-cell safety equipment can also be reduced because the system integrates with robot programs to take into account the location and operation of peripheral equipment.

A motion area monitoring function allows boundaries to be programmed, which can be enabled or disabled by inputs. Typical uses for this function include allowing an operator to access one side of a working envelope while a robot continues to operate on the other side (shown above).

An axis monitoring function can be used to set predefined axis motion limits, while a speed monitoring function shuts the robot down if predefined speeds are exceeded. Exceeding limits on axis, speed or motion monitoring causes the robot to stop automatically and its motors to be powered down.

Other functions provided include: stop monitoring (which shuts down the system if an axis that should be at a standstill, moves); tool orientation monitoring (which shuts the robot down if a tool, such as a laser, leaves a predefined area); and protective stop (which allows optional stop conditions when used with safety devices such as light curtains or mats).

The Cubic-SD system has been awarded TüV certification to EN ISO 13848-1, pL d / Cat 3.