Robots.
The end point of this discussion is the robot, and how it moves. TO understand this you have to have a comprehension of the cartesian coordinates. This is a triad.
This is one given away as a teaching tool by Fanuc. You can see the X Y and Z axis, and you can also see the A, B, and C rotary axis.
it is a common trap to get into to think that each axis is a line, and the triad can add to that confusion; just looking at the X axis, think of it as not a line of motion but a direction. Anything anywhere moving parallel to the X axis is moving in an X direction. The triad shows the positive direction, but if you pick up a jack, you will find it’s almost the same piece.
The Jack has six “Directions” corresponding to the six sides of a cube, and those six directions are x,y,z positive, and x,y,z negative.
What the triad does represent is Origin. The X, Y, and Z axis all originate in the same spot, and the triad helps you to visualize that. Think of the corner of a box represnting the origin, while the edges of the box represnt X, Y, and Z.
But a robot doesn’t have straight axis, or any mechanical way to move in a straight line. Witness:
The robot has six axis, and each axis is a rotary and not a linear axis. So it can’t move in a straight line. Right? Wrong. Comp[lex algorithms allow the robot to move according to a cartesian coordinate system. Imagine that the triad above was at the center of the base of the robot. The robot can easily and accurately move in a straight line, moving all the axis to do so. It can move in X, Y, and Z as easily as jogging a machine tool, and it can do so within very nearly machining tolerances.
This is where it gets weird. The robot also has some kind of an end effector- a gripper, maybe, or a welding torch. That gripper might be double ended, it might even have three grippers all at 120 degrees to each other. Jogging this gripper into position using the basic “Triad” at the base of the robot gets you back to etch-a-sketch type moves again.
Except.
Except the robot has the math in it, to put a ‘Virtual” triad in the center of every gripper, so that you can switch from the robot base triad to the gripper triad to move the robot based on the orientation of the gripper or welding torch.
Now let’s think about what the robot is working on. It’s almost impossible to have the robots base triad lined up perfectly with the table of a machine, or the conveyor bringing parts into the cell, so there are OTHER virtual triads that you can place literally on every component in the system. And you can use vision to change those tiads (Called “Frames”) in real time. And you can manipulate those frames either by using sensory apparatus in the system, or by simply calculating and moving numbers into the frame.
A classic example of this is a process called ‘Through Arc Seam Tracking” or “Tast”. Through arc monitors the amp draw of the robot as it weaves around a weld, and when it “Wobbles” the torch back and forth, if the current on one side of the “Wobble” is bigger than the current of the other side of the “Wobble”, it will modify the path of the weld in real time to make sure the weld metal is deposited in exactly the correct location. And this is only a hint at what the programming is capable of doing. More on that later.
Back in the 1980s Radio Shack had a toy robot arm thingy, I was in college but I bought one with the intent of hooking it up to my computer (Trash-80 Model III) to play with robotics. Never made the connection, and the thing was hard to manage with my Mark I brain doing the computing.
This stuff makes my brain hurt.
As if you don’t have enough to do, you should collect this series into a single post to archive here. A permalink on the side.
I don’t know WordPress, but blogger allows “pages” in addition to posts. I have a handful of permanent pages.
I haz a case of teh dumz.
Mark D said it correctly, above. “Brain Hurt.”
This isn’t a false humility, and I can wrap my mind around a great many problems in many other realms, as you well know.
But trying to compile all of the information you’ve provided in the last few posts, I’m suffering from a “error-stacking” malf of my own making.
MUCH admiration, amigo, for how you’ve mastered what you do.
Snowflakes have no idea what makes their world actually work. Yet, their world would grind to a halt without you and your peers.
While a “Day Without Techs” might not shut things down, I think it wouldn’t take all too many days for the fails to multiply across the industrial and distribution spectrum.
And then, you’d have all the overtime you could want, and then some.
The screaming of the snowflakes would be…precious.
Jim
Sunk New Dawn
Galveston, TX
Jim: I’m reminded of the Y2K “bug” from the close of the last century, and how the popular consensus is that it was overblown and a non-issue. Wrong, lots of programmers spent LOTS of time and effort MAKING it a non-issue (I know, I was one of them). Otherwise your bank account WOULD have been debited with 99 years of negative interest.
There are advantages to having a skill set that’s rare and getting rarer. I’m in the same boat, I’m a mainframe programmer (mostly batch Cobol, Natural and PL/I currently, but I’ve done LOTS of other languages). At 53 I’m one of the younger ones out there, and among the most experienced now, as the old timers retire. Every big company has some old legacy systems they can’t do without, and the people who can keep them running and keep updating them are getting fewer and fewer.
Left COBOL behind decades ago.
This discussion does remind me of an effort back in the late 70’s to automate a welding job I was doing. It was bumper guards and you had to drop a bead on either side of the bolt bracket to reinforce the spot weld. Course we had the feed and heat high to make it a fast weld. Sometimes blew through the side of the guard, which triggered rework.
One guy convinced management he could build a robot to do the job. He made all kinds of actuators and piston arrangement to send it out at the needed angle. We ended up with a really big table that we loaded on one side, welded at up to two stations and then took them off on the other side. Made those parts for a year and the robot never did one.
They still kept at it though.
Oh, and on the coding side I have been doing that for a while, 3 decades? anyway, the more we modernize the more it looks like those old mainframe systems.
I can still do Cobol, Jsam, vsam, jcl and all that crap, but SQL keeps me fed better.