Step and Direction

Over my years learning motion control from the bottom up,  I've absorbed a lot of tech-lingo. Some of it resonates. Programs I've written go all the way down to the very bottom of digital position control - what is referred to as a “step” - the smallest increment of controlled movement possible. I think of steps as “motion-pixels”. Stepper motors are designed to physically embody this:  the “driver” electronics takes its orders in a step by step fashion, and accordingly makes the motor rotate a tiny, reproducible quantum for each incoming step command. Since a step can either go forward or backward, there is one more bit of information required as well - direction. Position control along a path is about getting bazillions of steps and each of their directions exactly right for each motor. And full motion control adds the right timing of these steps to produce the desired flow along the path (speed and acceleration profiles).

I've many times thought about how "step and direction" applies to life in general, itself often described as a path. To be desirable, action must be applied in a proper direction,  with proper timing. I've been asked, on occasion, if I regret having trained as a physician, only to have practiced for 5 years. It could be seen as a rather large waste of time and energy, which might have instead been spent on my art. To this logic, I have two responses:

  1. I've always been glad I pursued my childhood dream of being a doctor, for many reasons. Maybe the strongest, is that there are few trainings that reveal such a full view of the human condition to a young person (being in the military, the police, the clergy are others that come to mind). Another, is that I wouldn't have met, in my first year of medical school, a classmate named Beverly.

  2. Though it is impossible to know, I feel relatively sure that had I set out to make a career in the arts immediately after high school or college, it  would not have gone well.  And almost certainly I would not have landed in the medium of motion control, as 40 years ago, this technology was essentially inaccessible to artists.

Unlike Sisyphus, whose steppers' every move is controlled down to the minutest level, preordained by numbers in path-files stored in a computer, my path is an amalgam of rational planning,  luck, and emotion-driven feelings for which I have no analytic explanation. That may sound like a good description of “random”, but it is anything but. No more than the shape of a river viewed from my window seat, or a tree as it grows over its life, balancing the need for sun, water, and the ability to withstand wind, rain and snow. 


Bruce Shapiro