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[DPRG] Processing unit for mobile robot
Subject: [DPRG] Processing unit for mobile robot
From: ed at okerson.com
ed at okerson.com
Date: Sun Apr 20 10:22:21 CDT 2008
> Chris Jang
>> The winner of last year's SRS Robomagellan used a Pentium-M
>> mini-ITX mainboard on a RC truck chassis.
>> http://jandmworks.com/intrepid.html
>
>>From that web site:
>
> There are several microprocessors onboard, including a BDMICRO
> MAVRIC-IIB Atmel ATMega128 controller, used to manage the
> sensors, compass, IMU and drive system. A Pentium-M mini-ITX
> board running MATLAB is the mission controller and image
> processor. The main processor communicates to the embedded
> controllers via serial link.
>
> So it fails the test I was asking about, a robot with a PC but
> no micros running it.
It is a somewhat unfair test, as even a PC in it's general intended use
fails. The mouse, keyboard, LCD Monitor, grapics card, network adapter,
and Hard drives all have microcontrollers in them. The modern PC is very
good at distributed processing.
>> I think though that with highly miniaturized ultraportable
>> PCs becoming mass market items (e.g.
>> Asus Eee PC), the design tradeoffs are shifting. If you can
>> buy a 1 GHz class palmtop that uses flash memory for under
>> $500, then it becomes cheap enough to use for a robot.
>
> I hear your suggestion, but I also think it is still a false
> promise. The option is not a micro or a PC, but a micro. And
> then maybe a PC for higher functions.
>
> So I have to wonder, if a robot with only a micro can be a
> functioning robot, but a robot with only a PC cannot be a
> functioning robot, which one really is the higher brain
> function? And which is really the coprocessor?
Does your mouse run your PC, or only provide it input? Does your grapics
card run your PC, or only provide it output?
> But there's this sense to so many hobbiest you start with a PC.
> My conclusion is if you start with a PC, your robot project is
> already ended, and it may take you half a dozen years before you
> figure that out.
Only if you put unrealistic bounds on yourself that to have a PC based
robot you cannot use other tools to interface subsystems. The OAP project
uses a mini-ITX motherboard for it's main processor, but various PIC
processors to generate PWM and read encoders, etc.:
http://oap.sourceforge.net/
Then LEAF project uses laptops for the main processor, and a Motorola
HC9S12DP256 for the low level motor controls.
http://www.leafproject.org/
Then there are Phidgets, lots of little USB devices that control all kinds
of sensors, each one probably has a microcontroller on it:
http://www.phidgets.com/
All successful ongoing projects, all require a PC. Can robots be built
without PC's, of course, will they be functionally equivalent to the ones
with a PC? Probably not. Some things just require more CPU power, like
vision processing. Sure it could be done with specialized hardware with
DSP's designed for video, but it can also be done more easily by the
hobbiest with a PC. After all, for most on these mailing lists (DPRG,
SRS, PARTS, etc) are hobbiests, not academics. Hobbiests want to
experiment, try different things and learn from what works and what
doesn't. It isn't about academic purity, it is about playing with things
that occupy our time and give us personal enjoyment.
Ed
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