Mitsubishi Electric has developed a new safety feature “MELFA SafePlus” for its MELFA F-series industrial robots. The new technology limits the robot’s speed, range of motion or torque when its safety sensors are activated, allowing operators to work in close proximity to a moving robot.
In today’s flexible manufacturing environments, humans and robots are increasingly working side by side. Mitsubishi Electric’s integrated safety solution enables manufacturers to increase productivity and improve human-machine collaboration by allowing the robot to continue working under strict constraints while workers enter its work cell.
The new “MELFA SafePlus” solution for F-series controllers manages the three main safety functions.
The activated speed limit restricts the robot’s speed to below 250 mm/s, allowing it to continue working at a safe speed while operators are present, e.g. loading or unloading material. Two different zones with different speed limits can be set, allowing the robot to adapt its behaviour to the likely proximity of the operator.
The limited working range prevents the robot from entering the operator's workstation within its work cell. The safety system monitors the position of the robot arm at four points and, once activated, prevents these points from leaving a predefined plane.
Torque monitoring controls the speed and motion of the robot to keep the estimated torque on its joints below a previously set limit. The actual torque on the joints is continuously monitored and the robot is stopped immediately if it exceeds this limit. This ensures that the robot will stop safely if it hits an operator, which also protects the equipment.
All F-Series robots also have Safe Torque Off and Safe Stop functions, which cut off the motor current and stop the robot if an error occurs. This virtually eliminates the risk of collision with surrounding equipment and other components.
All new safety functions can be triggered with dual-channel safety inputs, but can also be easily and safely integrated into safety systems controlled by a safety PLC. The new safety solution for the F-series hardware and software has been developed and certified according to a wide range of safety standards, including EN ISO 10218-1 (industrial robots), EN ISO 13849-1 (machine safety), EN62061 / IEC61508 (functional safety) and EN61800-5-2 (safety function control).
Mitsubishi Electric's RV-F series 6-axis robots are available with working ranges from 504 to 1503 mm and payloads from 2 to 20 kg. The Scara RH-F series robot product lineup includes models from 1 to 20 kg with a maximum arm reach of 1000 mm. Their high speed and easy integration with vision systems and other equipment make them ideally suited for a wide range of lifting and positioning tasks in automotive plants, as well as in the food and packaging industries.
“The Mitsubishi Electric F-Series’ outstanding speed, accuracy, connectivity, flexibility and cost-effectiveness are already expanding the use of our robots in new tasks and industries. The new optional safety concept “MELFA SafePlus” expands the existing range of safety features, enabling customers to integrate workers and robots on the same production lines in a smaller footprint, reducing costs and increasing overall productivity. For example, if a worker needs to manually insert products into the robot, downtime can be significantly reduced as the MELFA SafePlus function eliminates the need to stop and restart the robot.”
