We are looking at methods to improve ergonomic conditions for team members who must open and close the hood many times per shift causing shoulder issues.  It was suggested that a collaborative robot could be the solution, but my experience with them is very limited.  I would really like to hear some opinions on the viability of this idea, possible unit types, cost estimates, and any other caveats the wisdom of this group could provide.

It's possible that this could be done, how heavy is the hood that needs to be opened and how far does it need to move as that will determine the size of the robot.  Some other questions, does the latch mechanism need to be operated?  Is the vehicle moving to the robot or the robot to the vehicle?

Matthew, thanks for responding.  The force required to lift is about 12kG (24.5 lb.) to open the hood.  It moves about 36 inches in a slight arc.   The team member would operate the safety catch and then let the arm do the lift and hold.  The vehicle would move to the robot and stop at designated spot.  After completion of the operation, the vehicle will move forward, so the robot will have to have a home position that is clear of the vehicle path.

@mccartj is 12kg the amount of weight the robot needs to lift?  If so that will greatly limit the available arms to the Fanuc 35 collaborative as all of the UR models top out at a total payload of 10kg. That robot alone is in the $80-$90k range last I heard. 

If that hat really is the weight and you have some overhead supports we have done a little work using a lift assist device to help take some of the payload so that the robot is not doing all the lifting but you need to use relative slow moves as the lift assist only works in the z-direction so you don't want to move to fast is the other directions and not be able to control the weight which shouldn't be an issue in this application. You could also mount the robot overhead if you can use a UR10 which would allow the robot to retract into the ceiling to get out of the way of the car. That robot has a 51" reach but can only handle a 10kg total payload. 

Thanks for the info Matthew.

@mccartj  and @matthewd92
We have seen some lift assist systems on some industries. Such systems are used to help humans transport heavy weights. They are really nice to see operate. I would see no problem in having a robot, such as the UR, operate such a system. Here is a video of a system being used by a human operator. I think that in this video the human could easily be replaced by a UR robot.
https://www.youtube.com/watch?v=xq6UcthW2_Y

What do you think?

That's what we think as well. We've suspended some tools on a cable neutral balance as well. Were able to handle tools weighing about 5kg with a UR 3. Total weight including gripper was close to 6 kg. We balanced the tools to have a weight of about 1 kg. 

@matthewd92
Do you have some pictures or videos of this?

@Sebastien here is a video of us doing some of the preliminary work on the cell with the robot handling the tools.  You can see the cable attached to a lifting eye between the two tools.  This is the neutral balance which is mounted above the cell.