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Inertial-Mass

Last seen: 2 days ago

Thomas is a 42 year old guy from Denver, Colorado, USA 

When I was a kid, I wanted to be Mr. Spock from Star Trek.

I studied astrophysics in college for 15 years, but, hard as it is
for me to admit it, I like studying algorithms and writing computer
programs at least as much as I like physics and astronomy.  In any
event, I can make more money writing computer programs, and so that's
what I do for a living.  In the aerospace industry, I write software
that controls and simulates star trackers.

While I was in college, I ran into a woman who was also studying
physics.  She ended up wanting to be a home-maker and a teacher in the
home even more than she wanted to study physics and math.  We are
married and have seven children.

In the early 1990s, I discovered the GNU operating system based on
the Linux kernel.  I have been a proponent of free software ever
since.

In the late 1990s, my wife and I, who were nominally Catholic, became
actually Catholic.  The Church continues to be much more interesting,
reasonable, and challenging than I ever realized when I was younger.  As
a result of my conversion, my conscience has dictated that I leave the
Democratic Party, which seems not to understand the difference between
freedom and license.  The so-called right to abortion (killing) of
unborn human beings is just the grossest feature of the problem.  So now
I'm independent of party affiliation.

  • What is the difference between a DC motor and servo...

    Rated Jun 30 • 2 reviews • robotics • handyboard.com



    From the page:

    If you switch the power on and off fast enough, then it just seems like
    the motor is running weaker--there's no stuttering. This is what PWM
    means when referring to DC motors. The Handy Board's DC motor power
    drive circuits simply switch on and off, and the motor runs more slowly
    because it's only receiving power for 25%, 50%, or some other fractional
    percentage of the time.

    A servo motor is an entirely different story. The servo motor is
    actually an assembly of four things: a normal DC motor, a gear reduction
    unit, a position-sensing device (usually a potentiometer--a volume
    control knob), and a control circuit.

    The function of the servo is to receive a control signal that represents
    a desired output position of the servo shaft, and apply power to its DC
    motor until its shaft turns to that position. It uses the
    position-sensing device to determine the rotational position of the
    shaft, so it knows which way the motor must turn to move the shaft to
    the commanded position. The shaft typically does not rotate freely round
    and round like a DC motor, but rather can only turn 200 degrees or so
    back and forth.

    The servo has a 3 wire connection: power, ground, and control. The power
    source must be constantly applied; the servo has its own drive
    electronics that draw current from the power lead to drive the motor.

    The control signal is pulse width modulated (PWM), but here the duration
    of the positive-going pulse determines the position of the servo shaft.