How to integrate safety devices on a robotics system
“I put a good sensor, the most expensive and my machine is safe”
But this is not the case!
If you have a machine you want to de-risk, the design and the choice of the components must be very accurate.
IT’S NOT ENOUGH CHOOSE THE MOSTE EXPENSIVE SENSOR.
You have to choose the right component depending on the safety functions and the level of risk and frequency of use.
It’s important to install safety components in the right way.
If a safety barrier is installed too close to a rotary table, the MACHINE CANNOT BE CONSIDERED SAFE!
Each type of machine has its risks and its peculiarities.
LET’S TAKE FOR EXAMPLE A ROBOTIZED PLANT.
When it comes to security, we do not talk only talk about sensors and installation. We have to talk about procedures also (and this is in my opinion the most important point).
The machine must force the operator to use it safely.
The operator has not to bypass the safety devices to use the machine and must not evade the security!
DO YOU REMEMBER HOW MANY MAINTAINERS HAD A BUNCH OF DRIVES TO EVADE THE SHUTTER MICRO?
There is a solution today.
The safety sensors detect their actuator using RFID.
But as I said, we need to make usable machines
So if you have a robot you have to use devices that allow you to get close to mechanical arms safely, by using for example dead man switch.
Starting from today, robots have an option called “save move” too (every robot manufacturer calls it with a different name, but it always works in the same way).
This new feature provides substantially 2 advantages:
- Space limitation
- Safety speed reduction
The robot has a second processor that controls what does the first. It checks the position of the mechanical arm and its speed.
If years ago, it was necessary to put the protections far away so that the mechanical arm could not break them down, today it is enough say to the robot how big the work space is.
Compact and safe machines, until yesterday it was impossible!
The same functionality can be used to reduce the speed of the robot when the operator comes close. Just put a laser scanner and when an operator approaches the robot, it automatically reduces the speed reducing so the risk.
You can get close to the robot, without risk and without pushing any safety device!
Today the machines are built following mandatory requirements. The first among many points is the technicians training, then we will find the risk analysis according to EN… of course finally you have to follow the correct installation and programming devices.
