Shop OBEX P1 Docs P2 Docs Learn Events
Rotational velocity or How fast am I going? — Parallax Forums

Rotational velocity or How fast am I going?

JimGJimG Posts: 84
edited 2006-09-16 03:50 in Robotics
I just put together my first Boe Bot.· In the manual it shows a·graph (on page 115) of the velocity curve for the Parallax servos.· It suggests creating your own table of data by running the wheel/servo at various pulse widths and count the revolutions.· There has got to be a more accurate way of doing this...isn't there?

Also, the graph they show isn't linear and I don't understand why.· If I sent a range of values to the servos from 750 to 850 in 2 ms steps I would think it would follow a very linear curve.· Anyone know why it isn't that way?

Thanks,

Jim

Comments

  • allanlane5allanlane5 Posts: 3,815
    edited 2006-09-16 03:50
    Sure. A Servo is designed to move to a commanded position. Exactly how fast it moves to that commanded position is not really one of the needed parameters. In fact, you WANT the Servo speed to be pretty non-linear. You want it to reach the commanded position quickly, with little overshoot.

    Now, when you modify a servo so it can rotate continuously (which is what the BOE-Bot servos are), there IS a modification that can be made to 'widen' the speed cycle. It's not trivial though. Failing that, experimenting with the range of settings to find the speed adjustement IS the best you can do.

    Oh, and since this is not one of the needed parameters, it's also possible that two servo's are slightly different in their settings. More experimentation.
Sign In or Register to comment.