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I have been thinking about the difficulty involved in robotic movement, and the fact that the complexity involved is beyond the imagination of very nearly everyone.
First of all, though, you have to understand cartesian coordinates, because that’s where it all starts.
The following is a drawing of a machine, showing it’s x, y, and z axis. it can move in a straight line in any of those axes, and by controlling speed, distance, and direction, it can interpolate any shape that can be generated in space, theoretically.
Each axis has an origin point, and movement in one direction from that origin is positive, and the other direction negative. This is the basis of nearly all machining. Once you understand this, everything else just builds on it.
Ignore the coordinate system for a bit and place the robot at its own (0,0,0) for relative movement.
Then ignore plain vectors and treat every movement as a complex curve defined at best by several high-order quadratic equations that overlay each other.
And then ignore the precision calculations required to ascertain whether the robot is at (x,y,z) precisely, but instead implement a heuristic to determine whether the robot is close enough “for government work”, making fine adjustments to compensate.
Once you understand this, you’re surprised how difficult it is for a robot to walk anywhere at all, and why CNC milling robots and other manufacturing robots have it easy.
Also, once you understand this, you also begin to understand why humans don’t have a “return to zero” innate sense of direction and movement, least of which one that looks anything like a true reversal of steps …
Thus any robot that can walk up to you in a way that does not instantly trigger the “uncanny valley” reaction is something that should be immediately impressive.
“See how they run …” :-)
And this is where I wax totally ignorant, and inquire as to the other two axis of the Hitachi “Five Axis” milling machine system?
The one that we let them build under license, and which they promptly sold to the USSR in the (I think) late ’80s or early ’90s.
So now, Russian subs have very quiet propellers, too.
But I never sussed that “Five Axis” thing, so there’s my question.
Jim
Sunk New Dawn
Galveston, TX
Reichart, it’s not only true but millions of times more complex than that.
Jim: Five axis means that there are two rotary axis, an A axis which rotates around the X axis, and a B axis which rotates around the Y axis
Like this.
Pretty hard to do it by hand for sure. Five axis is new to me but I have been out of machining for 40 years so there is that.
Would be fun to have something like the 3 axis in the basement. Could make all kinds of little things.
Alright, you’ve got my attention. A Cartesian coordinate system is the universal descriptor for just about everything. Latitude, longitude and altitude are the same concept, after all.
Thanks, Og.
That illustration did the trick. I’m more brained now, than I wuz yesterday.
Jim
Sunk New Dawn
Galveston, TX
Lat long and altitude are the same on a mercator projection, but not “actually” the same. That discussion is coming.
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