Normal and reduced mode settings

abeachy_HG24

What does everyone typically have the normal and reduced mode safety settings set at whenever they are not using light curtains, area scanners, or pressure mates for a UR 10? I have a unique challenge with my project. We want each robot to perform their tasks in ideally 20 second cycles, but our absolute max time is 23 or 24 second cycles. I was doing well with this originally but my boss didn't like how hard the UR would hit you before it stopped, the way I originally had it set up it met the guidelines laid out in ISO/TS 15066. So it was safe to work around but he is afraid people will see how fast it is moving and be afraid to work with it. I played around with the all of the settings and came up with a pretty good combination that stops quickly, but now the issue is with the changes the UR is significantly slower so we won't meet our cycle times for most of the stations. Right now this is what my settings look like, Normal Mode: Force 100 N, Power 80 W, Speed 3000 mm/s, and Momentum 10 kg m/s. Reduced Mode: Force 100 N, Power 80 W, Speed 2800 mm/s, and Momentum 7 kg m/s. Any thoughts on how I can make it stop with little force but move quicker? 
Thanks!

Sebastien

@abeachy_HG24
this is a really good challenge that you are facing. We ran into the same issue in the past with light curtains on a robot cell. Operators were constantly walking through the robot zone, making the robot go into reduced mode. However, the operator did not have to go next to the robot that often, the robot cell was simply just to close to a walking trail where operators would walk and take a shortcut that was entering the robot's safe zone. If like us, the operator does not have to work to much close to the robot, you can do like we did, we added a simple Danger plastic fence just to make sure people did not take the shortcut that was crossing the robot's zone. 

Otherwise, I know this may sound silly, but if you look at the variables that you need to address if you want to reduce force of the impact would be to increase impact time and dissipate impact force. Have you considered adding some sort of padding material on the UR like we see on the green Fanuc CR35iA? I did not see this anywhere else but I think it would be an idea.

Catherine_Bernier

@Grady_Turner @Cody_James Any insight on this matter with any projects you've been working on?

abeachy_HG24

@Sebastien Our operators will be working placing parts into fixtures for the robot to pick up, and with the robot picking a part roughly every 20 seconds the operator has to be in that space quite often. We have considered adding light curtains so the robot could actually run faster than it is right now when the light curtain is not broke. But that means we would 30 more light curtains as we have 30 robots going into production. 

We have considered that, but my boss did not like that idea very much. He believes people would see that and think that it was too dangerous to begin with so we gave it sort of a "bandaid" to cover up the issue instead of actually fixing it. 

matthewd92

We had a similar issue, what we did was to create a safety plane right where the robot and human interacted. When the robot entered the human zone, crossed that plane, he went jnto reduced mode. Behind the plane where the robot was working in his environment he would go back to running at full speed so we could hit cycle times. This allowed the operators to feel that the robot was safe to work with but allowed the robot to run at full speed where possible to meet cycle times. 

We we just had a physical demarcation between the robot and the human/robot zones so the employees knew where the robot would slow down. 

abeachy_HG24

Our operators will be stocking the parts within the pink box so this is where the robots and operators are most likely to come in contact with each other. It is possible that they could reach past and interfere with the other operations, they shouldn't but they could. Right now I have a horizontal safety plane set up about 6 inches above where the robots are picking the parts and the safety plane triggers reduced mode. What I have been considering trying is removing that safety plane and putting a vertical safety plane in right at the edge that is furthest from the operator. That way any time the robot is behind the safety plane it can run faster, but whenever it is over any of the parts it would be in reduced mode. Not sure if this would gain us the cycle time, but it might. 

matthewd92

That would probably help to speed things up. Another thought that we have done is to put the downward moves inside of an if loop that is looking to keep the force below a threshold.  Make sure you check the box for checking the condition constantly. This way if you are moving down and come into contact you could always pull back and then pop a message up to have the operator tell it to continue or it could just move up, wait a couple seconds and then try picking again. 

Just an observation, I recommend being careful using cable ties to hold the cables to the robot. We have had issues where the cable gets in a bind and we have cut the outer sheath on the cable and rendered the cable non operational. We were fortunate that it was not the pigtail coming from the gripper so it was an easy fix. We use 2 sided Velcro to hold the cables in place of our new cable management system we designed. 

abeachy_HG24

Okay that makes. I like that idea, I might have to try that. 

Yeah we don't necessarily like the cable ties, they work but they are definitely not the best way to go about it. We have been talking about trying to come up with something different for the cable management. Do have a specific brand of the velcro that you guys like to use? 

matthewd92

It's a 3M product. Industrial grade. I'll see if I have a package lying around I can shoot a picture of.