Pay the shipping and I’ll put them in a box and send them to you... if the arms actually go to scrap and I’m able to. There’s a chance they go into studio holding.
You are correct about the brakes as well. From what I can tell, the brake takes a 24V DC signal to disengage. Easily done with the VFD RS-232 brake output and most likely a relay.
As to safety... yes. It’s a major concern. Another reason to use the VFDs. I will set an E-stop for all three drives. Safety is ALWAYS my first concern. Especially with people who are insured for more than I’ll make in my lifetime. I did most of the design work and my crew and I built the Gremlin Tom Cruise chases in “American Made”. Talk about rigamarole. They wanted the effect of a satchel-charge under the drivers seat... of a gremlin... with Tom Cruise running behind it. The whole gag was done pneumatically; hydraulic cylinders, powered by high-pressure nitrogen did all of the work. The only pyrotechnic device was 18” or so of cannon fuse to put some smoke in the car.
Regarding safety from the robots... yes. I was fully aware even before my new friend at Fanuc reminded me: “these robots are ALWAYS fully separated from their human overlords by cages...” Funny enough, my first industrial “big-boy job” was as a welder/fabricator making component machine guards in an injection molding plant. I see the safety issue as another reason to use the VFDs. I can vary both frequency and voltage to slow the motors down from their peak parameter. I expect to wind up supplying the motors with less than the 161V and 200Hz they expect.
As I’m bypassing the positioning elements and driving the motors directly I figure as long as I don’t deviate too far from the motor-plate parameters I shouldn’t let magic smoke out. At least not immediately. I already know the magic smoke doesn’t come out with suicide wiring into delta-wye, spike-leg, 208V, 60Hz shop power.
The biggest difference between my current world and that of most of the members of this forum is the impermanence of my world. My job is to make these things move, safely, a maximum of thirty times, plus whatever I do to gain confidence to present that much. Worst case for me is I do burn up my spare motors and have to punt. Punting will be reducing drag and dropping weight as best I can and using cylinders to make the move. Then I pose the rest of the arms to suit camera.
The goal is noticeable rotation plus a knuckle movement on one robot and the knuckle moving on the second. 2”-3” bore, 6”-12” stroke cylinders will accomplish that goal. The casting is plenty thick enough to just drill and tap for a mount for a rod-clevis.
I’ve got a good selection of “Bimba” low-pressure cylinders, likely more than enough for my purposes here. I’ve got fittings, solenoids, shuttle valves and the like. I should have the VFDs and switches tomorrow. Biggest issue I have is time. I’m gonna give myself tomorrow to play with the motors, first just on the bench and then I plan to start with the rotary drive at the machines base. I figure I’ll lock the rest of the arm off, sticking straight up, and prove my theory with that axis. You know, make sure the magic smoke stays in with a load and that the limit switches will work fast enough I don’t tear them off. Once I’m comfortable there I’ll move on to the knuckle pivoting.
If I burn up a VFD, I’ll punt. If I smoke a motor immediately, I’ll punt. If I can’t slow the motion down enough and I’m worried the unit will overwhelm the limit switches... I’ll punt.
As long as I have SOMETHING, I’m good. And the project gave me the excuse to add a couple of decent VFDs to my inventory.
Here’s a couple fun ones from a car gag early last year:
Pyrotechnic cannon, hence all the fire and smoke. If memory serves, we got the car on a Monday or Tuesday and I was cutting the cannon out LATE the next Thursday.
Be safe and stay healthy
Jeremy