
dmzimbelman
So I have my JD assembled and sort of running, as I was working on the walking frames I noticed something odd. When I have the edit frames window open and I am looking at the assembled JD in the front view. The servos on the left, that would be my left as I am facing the JD are moving opposite in direction from the servos on the right. So for example if I click the left servo directly below the main body (his left hip) and drag the mouse up towards the top of the window the servo moves forward towards me (it leans his body towards me) If I do the same thing to the the right hip servo it leans his body away from me. To my mind it would seems like they should both move in the same direction. IE an upward drag on either would move either one towards me. Maybe I am missing something here.....I also noticed it is the same with the knees and the arms and shoulders. I did the initial calibration of the servos and created a servo profile and all that. Most of the motions like a wave and a bow seems to be working right. Although his walking and sitting motions are really rough. I have double checked my assembly and that seems okay so for example on his legs the servo horns are all facing in and on his arms they are all facing up or forward.......Any thoughts?
The moving of the servos is moving the degrees - there is no reference to degrees. 10 degrees is the same for any servo in any position.
A servo is specified in degrees. The degrees are between 1 and 180. If you move a servo to 90 degrees, it will look the same from any direction that you look at it. But if you move a servo to 70 degrees, it will look different from each angle.
How about this. If you open your door 30 degrees, it will look different from the inside or outside of your house. It depends on what side of the door that you're standing on. Does that make more sense?
Guess it's something that not a lot of people use in the real-world, but degrees are relative to the source of the arc.
What are you stabbing in your photo? Better not be a robot!
And yeah I am stabbing, a lobster, when I am not playing with robots I cook and when I am not doing either of those I inspect aerospace parts!
The only way a servo could know it's position relative to another servo position is if there was some sort of localized sensor. Or maybe a compass and accelerometer built into the servo. Then each servo could report it's position and placement so the software could understand it.
Of course, it technically is possible for us to create servos with built-in accelerometer and compasses - but they would cost a pretty penny
I suspect the areo space industry may be able to afford servos with built-in sensors
You would be surprised at how amazingly low tech Aerospace Manufacturing can be, I measure .0001 of an inch with equipment from 60 years ago, it's still very accurate but no where near as cool and flashy as robotics. LOL if you were to take a look at G code which we still use to program CNC machines compared to your software, it would be like comparing the Wright Brothers plane to the Space Shuttle!
The direction that the servo moves is based on the way it is mounted. 1 degree is the same direction for every servo ever made. 180 degrees is also the same direction. Now, keep in mind that not all servo manufacturers and models work in degrees, so it's not always the same position but it is the same direction.
So if you move the slider UP, then the number on the screen that you're moving is the degrees. The degrees will increase, such as 1... 2... 3... 4... 5... all the way to 180. And if you slide the numbers in a decreasing order, for example 180, 179, 178, 177, etc.. then the degrees will decrease.
So the number 1 on any servo control in ARC (this includes the auto positioner) is degree 1. And a 180 is degree 180.
The servos will move between 1 and 180 degrees with an increment of 1.