HDTenEightyP/NetNews huggingface dataset:
From: fredm@media.mit.edu (Fred G Martin)
Subject: MiniBoard high speed bus
Organization: MIT Media Laboratory
Date: Fri, 14 Aug 1992 14:12:18 GMT

In article <bws.7@ccs.carleton.ca> bws@ccs.carleton.ca (Brian
Sullivan) writes: 

>One question. The documentation talks about a high speed bus. 
>What is it used for, and does the library provide any way to
>use it?


I have not yet written library functions to use the high-speed bus.
The hardware has been tested though.  The basic functionity is
provided by the SPI (Serial Peripheral Interface) intrinsic to 6811's
and many other Motorola microprocessors.

The way the Mini Board uses the SPI is as follows: one board chooses
to become network master, and one or more other boards must choose to
become network slave.  The master then controls the data flow: it
shifts a byte of data bits out on its MOSI (Master Out Slave In) line,
while receiving bits from the slave on the master's MISO (Master In
Slave Out) line.  (While multiple slaves may *receive* a transmission
from the master, only one is allowed to respond.) 

All slaves receive the master's data on their MOSI lines (the same
line that is output for a master is input for a slave!); the one
replying slave writes data back to the master---at the same time as
the data is coming in from the master---by use of its MISO line.  You
can see that this means that all the 6811 MOSI lines are wired
together; same with the MISO lines.

The master generates the clock which is synchronized to the data on
the SCK line (which also connects in parallel to all 6811's).

Motorola's SPI port also has a Slave Select (SS) line, which allows
the construction of hardware-selectable network locations.  This
requires the addition of extra non-6811 hardware---typically a
latch and a comparator, which selects a slave when the appropriate
number is written to the latch.

In the MiniBoard, extra hardware is eschewed.  The SS line is wired to
be always true, so slaves are always selected.  This means that a
network protocol must be constructed in software.

I mentioned earlier that only one of the slaves may respond to the
master's message at any given time (otherwise, there will be bus
contention on the MISO lines).  You may ask, ``How is this possible,
given that slaves are always selected by the hardware?''  The answer
is that slaves can disable their transmissions while they still are
active to receive data.  This is done by turning off the output enable
bit on the MISO line.  A slave in this configuration can "listen" for
network bytes, and pipe up to respond only when network protocol has
selected it.

If anyone goes ahead and implements a protocol, please post the code!
I'm sure others would appreciate it too.

If you want all the gory details on the SPI systems, get your hands on
some Motorola 6811 doc's.


	- Fred 


Fred Martin | fredm@media.mit.edu | (617) 253-7143 | 20 Ames St. Rm. E15-301
Epistemology and Learning Group, MIT Media Lab     | Cambridge, MA 02139 USA
Newsgroups: comp.robotics
From: root@amerie.mcrcim.mcgill.edu (Thunder Root)
Subject: Re: PUMA-560 ARM _ singular points
Keywords: PUMA,SINGULAR POINTS
Organization: McGill Research Centre for Intelligent Machines
Date: Mon, 17 Aug 92 21:59:25 GMT

In article <1992Aug12.171255.13584@morgan.ucs.mun.ca> raghu@morgan.ucs.mun.ca
(Raghu B) writes:
>Can any one tell me [...] where I can find the singular points for a PUMA-560
>arm. [...] Is there any algorithm or any set of equations which can be solved
>to get those arm joint angles theta1, theta2 and theta3.

The PUMA has three singularities: the ``alignment'' singularity
(wrist is as close to the axis of joint 1 as it can get),
the ``elbow'' singularity (elbow is fully extended or folded
up; the latter is not possible because of joint limits), and
the wrist singularity (the axes of joints 4 and 6 are aligned).

The angles corresponding to these depend on the DH parameter assignment.
For the PUMA, the definitions given in [1] are perhaps the most commonly used
(and I _think_ are what Unimation uses). Using these, and letting A2, A3, D3,
and D4 denote the translational DH offsets, the singularities occur when the
following are true: 

Alignment:	D4*sin(ang2+ang3) + A2*cos(ang2) - A3*cos(ang2+ang3) == 0

Elbow:		sin(ang3 - atan2(A3,D4)) == 0

Wrist:		sin(ang5) == 0

Typical offset values for the PUMA 560 are

A2 =  431.80
D3 =  149.09
A3 =  20.32
D4 =  433.070	

Hope this is helpful,

John Lloyd			Research Center for Intelligent Machines
lloyd@curly.mcrcim.mcgill.edu   McGill University, Montreal
(514) 398-8281			Fax: (514) 398-7348

[1] Richard Paul, Brian Shimano, and Gordon Mayer, ``Kinematic Control 
    Equations for Simple Manipulators''. IEEE Transactions on Systems,
    Man, and Cybernetics, Vol SMC-11, No. 6, June 1981.
From: bies@sctc.com (Marty Bies)
Newsgroups: comp.robotics
Subject: Re: balancing_act
Date: 17 Aug 92 18:11:07 GMT
Article-I.D.: sctc.1992Aug17.181107.25084
Organization: SCTC

petesk@microsoft.com (Pete Skelly) writes:
>You can also take into account the fact that vertical lines
>exist alot in the world, especiall in man-made areas.  Use
>a vision system with a simple vertical line detector.

If you're not vertical, how can you determine a vertical line?

Marty
bies@sctc.com
From: jeremiahw@wl.aecl.ca
Newsgroups: comp.robotics
Subject: RE: balancing_act
Date: 17 Aug 92 22:11:14 GMT
Organization: AECL RESEARCH

>If you're not vertical, how can you determine a vertical line?

I thin he meant that you find lines and assume they are vertical.
Then you know which way is up.  If you watch the gradient you
should be able to make that assumption with reasonable accuracy.

>>Jerry
From: dg3338@eecs1.usma.edu (Rassatt Greg CPT)
Newsgroups: comp.robotics
Subject: Replacement for Hero II?
Summary: Looking for a replacement for Hero II.  Suggestions?
Keywords: Robot, Education
Date: 17 Aug 92 13:43:02 GMT
Organization: US Military Academy, West Point, NY

I am looking for a replacement for our Hero II robot.  Does anyone have a 
suggestion?  Who sells educational Robots?
Thanks -
-- 
      GREG S. RASSATT                           #####         #####
      CPT, EN                                    ###   #####   ###
      Assistant Professor                        ###    ###    ###
        Internet:  dg3338@trotter.usma.edu      #####ENGINEER######
From: fredm@media.mit.edu (Fred G Martin)
Newsgroups: comp.robotics
Subject: MiniBoard 2.0 serial line circuit
Date: 17 Aug 92 18:35:02 GMT
Organization: MIT Media Laboratory

A few people have asked how the line level converter circuit works on
the Mini Board.  I thought this might be important to discuss, since
the circuit is a bit obscure and may be incompatible with a few
existing computers.

Serial line voltages are normally +12 volts for logic low and -12
volts for logic high.  This is annoying because TTL/CMOS logic levels
are of course +5 volts for high and 0 volts for low.

In the past, people normally used a bipolar power supply to generate
the serial line levels; nowadays most people would use a single chip
solution like the MAX232 series of chips (which include an on-chip
charge pump and voltage inverter to generate +/- 10 volts from a 5
volt supply).  However, in a board as small as the Mini Board, even
one extra chip is one chip too many.

So, the Mini Board uses the following hack.

For its serial line logic high, the Mini Board "loops back" the logic
high (remember, this is a -12 volts) that the computer it is connected
to generates!  This is using a 1K resistor, which shouldn't cause much
of a voltage drop.

A PNP transistor pulls this line (Mini Board serial out) to +5 volts
to generate the serial line logic low.


     --->>--MB serial in--->>--+   +5V
	        	       |    |
HOST            	       /     \
                	   1K  \      >|
COMPUTER        	       /       |-----/\/\----<<-- Mini Board
	        	       \      /|		  TTL transmit
	        	       |     /
     ---<<--MB serial out--<<--+-----


For input, the Mini Board uses a spare CMOS inverter coupled with two
resistors.

The upshot of this solution is (1) the Mini Board can't transmit while
the host computer is transmitting, because the incoming -12v it needs
would be modulated by the host transmission; and (2) there might be
some computers that don't accept +5v as serial line low.

Regarding compatibility: I have personally tested the Mini Board on a
variety of IBM and clone PCs, a variety of Macintosh models,
DECstation 5000 computer.  I know that there is at least one type of
Sun SPARC that it works on.

So it does work on most machines.  Still, there is bound to be the
model that it won't work on.  A reader believes that it probably won't
work on Sun 3 workstations.  For these cases, it wouldn't be hard to
jumper the board and wire a voltage higher than +5 to the collector of
the transistor.  This should allow the board to work with these other
machines.

	- Fred


Acknowledgment: this circuit was the brainchild of Randy Sargent.
From: dg@cam-orl.co.uk (Dave Garnett)
Newsgroups: comp.robotics
Subject: Re: balancing_act
Date: 21 Aug 92 16:14:37 GMT
Reply-To: dg@cam-orl.co.uk (Dave Garnett)
Organization: Olivetti Reasearch Ltd, Cambridge, England

Re gyroscopes etc, Murata make some "Piezo-electric Vibratory
Gyroscopes", which are small, light, low power and pretty
cheap. E.G the ENV-05S (large model) is
 24 x 24 x 58 mm
 weighs 41g
 consumes 8-13v at 13ma
 and has an output of 22mv/deg/sec

They also make a smaller model (the ENC-05S) which runs off 5v,
and costs around 30 pounds in the UK.
 20 x 13 x 7mm, 3.5g
 5v at 7ma
 0.8 mv/deg/sec

I don't know yet how rugged they are.

Dave Garnett
From: demers@cs.ucsd.edu (David DeMers)
Newsgroups: comp.robotics
Subject: Re: PUMA-560 ARM _ singular points
Keywords: PUMA,SINGULAR POINTS
Date: 13 Aug 92 00:10:04 GMT
Organization: =CSE Dept., U.C. San Diego

In article <1992Aug12.171255.13584@morgan.ucs.mun.ca> raghu@morgan.ucs.mun.ca (Raghu B) writes:
>Can any one tell me any reference books are any valuable materials,
>from where I can find the singular points for a PUMA-560 arm.
>I know that they are the extreme ends of the workspace. But
>I don't know how to find those values. Is there any algorithm
>or any set of equations which can be solved to get those arm
>joint angles theta1, theta2 and theta3.

I'm assuming you're just interested in positioning, though there
is a wrist singularity as well.

Craig looks at the PUMA to some extent.  

Joel Burdick, in his thesis, shows how to find the singularities
of a general 3R positional manipulator (pp. 42--70; pp. 87--100).

Using DH parameters which place the zero position as the
arm straight over head (differing from Craig, and from Unimation...),
the following apply:

There are two boundaries, the external workspace boundary, 
which is when sin(theta3) = 0, (or theta3 = 0 degrees, since
-180 is not possible due to joint limits)
and the other is the internal workspace boundary
which is when the origin of frames 4-6 are directly over
the axis of frame 1 (assuming I'm numbering these correctly...)
which is when l2 * cos(theta2) + l3 * cos(theta2 + theta3) = 0.

You will have to do the trig to convert to Unimation's or
Craig's versions of DH parameters...

The (wristless) PUMA is an elbow manipulator; these formulas are 
generic for elbow manipulators (Z1 intersects Z2 at 90 degrees,
and Z3 is parallel to Z2).

Note that there is no dependence on theta1 - that is, if (a1, a2, a3)
is a set of joint angles which is a singular point, then (x, a2, a3)
will also be a singular point for any x within the joint limits of
joint 1.

Hope this helps.

Dave


-- 
Dave DeMers			 ddemers@UCSD   demers@cs.ucsd.edu
Computer Science & Engineering	C-014		demers%cs@ucsd.bitnet
UC San Diego					...!ucsd!cs!demers
La Jolla, CA 92093-0114	(619) 534-0688, or -8187, FAX: (619) 534-7029
Newsgroups: comp.robotics
From: raghu@morgan.ucs.mun.ca (Raghu B)
Subject: PUMA-560 ARM _ singular points
Keywords: PUMA,SINGULAR POINTS
Organization: Memorial University of Newfoundland
Date: Wed, 12 Aug 1992 17:12:55 GMT

Can any one tell me any reference books are any valuable materials,
from where I can find the singular points for a PUMA-560 arm.
I know that they are the extreme ends of the workspace. But
I don't know how to find those values. Is there any algorithm
or any set of equations which can be solved to get those arm
joint angles theta1, theta2 and theta3.

	Any kind of help is highly appreciated.


				Raghu .B
From: rwmurphr@uokmax.ecn.uoknor.edu (Robert W Murphree)
Newsgroups: comp.robotics
Subject: Electronic Spirit Level
Summary: Reference to Electronic Level is provided
Keywords: inclination, balance, mobile robots
Date: 19 Aug 92 21:05:13 GMT
Article-I.D.: constell.1992Aug19.210513.27247
Organization: Engineering Computer Network, University of Oklahoma, Norman, OK, USA


SUBJECT:  electronic inclinometer

from New Scientist 1 february 1992 p 26

ELECTRONICALLY INCLINED TO STAY ON THE LEVEL

Spirit levels, which since the 17nth century have trustily
ensured that surfaces are level, may soon be pushed out by
a microprocessor-contolled rival that can set a true 
horizontal, a vertical or any angle in between, to one-tenth
of a degree.

	The heart of the SMARTLEVEL, produced by Wedge Innovations
in San Jose, California, is a device called a liquid-filled
inclinometer.  A sealed capsule contains two parallel conducting
discs with a space, partially filled with iquid between them.  

... Any pair of parallel conductors acts as a store of electrical
charge.  Its ability to store charge, its capacitance, is influenced
by what is between the conductors.




MY INFORMATION

ADDRRESS:  Wedge Innovations
	   2040 Fortune Drive, Suite 102
	   San Jose, CA 95131 
	   1-800-SMARTLEVEL(762-7853)

PRICE:  2 Ft. $120,  4 ft. $150



MY OPINION 

Since this is a liquid device, you"re not going to get 
millisecond sensing time, which would be nice if your
going to right yourself like a falling cat.

Also, it has to be reset if it gets jarred, a real
problem probably.



ADDITIONAL CITATIONS

J.M. CAMERON, R.c. Arkin, "Survival of falling robots,"
SPIE Proc Vol. 1613, 1992 
Newsgroups: comp.robotics
From: nagle@netcom.com (John Nagle)
Subject: Re: Electronic Spirit Level
Date: Thu, 20 Aug 92 00:27:26 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Keywords: inclination, balance, mobile robots

rwmurphr@uokmax.ecn.uoknor.edu (Robert W Murphree) writes:
>	The heart of the SMARTLEVEL, produced by Wedge Innovations
>in San Jose, California, is a device called a liquid-filled
>inclinometer.  A sealed capsule contains two parallel conducting
>discs with a space, partially filled with iquid between them.  

       Available at Orchard Supply Hardware.

       This is not a new idea; ETAK has built two-axis versions of 
such devices, packaged with a rate gyro, for their vehicle navigation
system.  These were supposed to be cheap (I paid about $125 a few years
ago) and of modest accuracy, but I doubt they still make them.
But the technology is cheap, although there are tricks to getting it to
work well during violent motion.

					John Nagle
From: nivek@cs.cmu.edu (Kevin Dowling)
Newsgroups: comp.robotics
Subject: FAQ
Date: 13 Aug 92 16:11:37 GMT
Article-I.D.: cs.BsxJnJ.5vM.1
Reply-To: nivek@cs.cmu.edu
Organization: Robotics Institute, Carnegie Mellon

For better and more frequent access to the FAQ, I'm in the middle of trying to do
the following:

Set up a copy in a ftp-able location at CMU.
Figure out the perl scripts to auto-post it.
Have it cross-posted to news.answers in the right format. (I'm muddling through this).
Continue to edit and add to the FAQ's.

I will post them again by the end of the weekend!

---

aka: Kevin Dowling			Carnegie Mellon University
tel: (412) 268-8830			The Robotics Institute
adr: nivek@rover.ri.cmu.edu		Pittsburgh, PA 15213
From: gt@prosun.first.gmd.de (Gerd Truschinski)
Newsgroups: comp.robotics
Subject: Re: FAQ
Date: 13 Aug 92 10:30:56 GMT
Organization: GMD Berlin (FIRST)

In article <BsvHEn.4D9@acsu.buffalo.edu>, hinkle@acsu.buffalo.edu (Steven Hinkle) writes:
|> Does this group have a FAQ somewhere?  I would like to start building and
|> programming robots as a hobby but have no real experience.  I need some
|> start-up information. 
|> 
|> Steven Hinkle


I have mailed the FAQ[12], which Kevin Dowling has posted at 4.June.92 to this
group, to Steven.

Hi Kevin, is it possible to post the FAQs monthly?

/gT/
Newsgroups: comp.robotics
From: monty@sagpd1 ()
Subject: Re: balancing_act
Reply-To: monty@sagpd1.UUCP (Monty Saine)
Organization: Scientific Atlanta, Government Products Div, San Diego, CA
Date: Thu, 20 Aug 1992 14:44:48 GMT

In article <1992Aug19.210807.27401@constellation.ecn.uoknor.edu> rwmurphr@uokmax.ecn.uoknor.edu (Robert W Murphree) writes:
>See my post on wedge innovations electronic spirit level. 
>I suppose  my inclination would be to go with accelerometers at
>3 perpindiculars and some kind of cheap gyroscope.  
>Some cheaper gyroscopes, where cheap means on the order of 
>1000 dollars are now being made available.
>

	I ran across an ad/article about a very small (golf ball size) gyro
    a few months ago and posted information to this group. Since that time I
    have mislaid the orginal article. If any one out there is archiving this
    group, could you please look back and see if you can resurrect my orgianl
    post. This gyro (if memory serves) was real cheap, i.e. about 1-200 dollars
    and was extremely small.


	In the mean time I'll dig through my paper archives and see if I can
    find the orginal.

    Monty Saine
From: alex@cs.uow.edu.au (Alex Zelinsky)
Newsgroups: comp.robotics
Subject: Re: balancing_act
Date: 20 Aug 92 03:07:54 GMT
Organization: Dept of Computer Science, Wollongong University, Australia

ktc@onan.jhuapl.edu writes:

>In article <1992Aug14.181900.26605@ee.ubc.ca> williamb@ee.ubc.ca (william  
>burchill) writes:
>> Could somebody post some information or suggest a book on sensors 
>> for detecting balance, i.e. orientation relative to the horizontal plane?
>> I'm praticularly interested in knowing what different types are available. 
>> Are there any without moving parts?
>> 
>> I recently saw a t.v. program which showed a 1 legged hopping robot in
>> action. How did this sense its balance? Could someone direct me to a 
>> technical publication on this work?
>> 
>> thanks.

>Check out anything by Marc Raibert (e.g, Legged Robots that Balance, MIT Press,  
>1986, or CMU reports CMU-RI-TR-83-20, CMU-LL-4-1985). The machine in question  
>used an inertial reference (gyroscope) to sense up. I seem to recall he had  
>problems with keeping bearings in the gyros due to impact loading (falling  
>down?)

>Kim

The YAMABICO Project, at the Intelligent Robot Lab, Tsukuba University,
of Prof. Shin'ichi Yuta, recently completed a balancing 2-wheeled mobile 
robot. The robot can executed planned motion paths, and is very stable. 
It uses an inertial reference (gyro). I don't know the exact details of 
the specifc sensor make and model used in this project.
I spent 7 months at the lab, and saw numerous experiments. It works well.

Unfortunately, the only publications are in Japanese. I believe an English
paper is in preparation. You would be best to contact the Prof. Yuta
directly email address yuta@roboken.is.tsukuba.jp

Good Luck

Alex Zelinsky
Univ. Wollongong
Australia
From: g9218955@cs.uow.edu.au (James Mathew)
Newsgroups: comp.robotics
Subject: echolocation
Date: 20 Aug 92 00:58:07 GMT
Organization: Dept of Computer Science, Wollongong University, Australia

I am currently working in a ECHOLOCATION research group in University Of
Wollongong. I am interested in beamforming for linear arrays of ultrasonic
transducers. I'm planning to implement this by delay - sum and DFT method.
I've heard that Frequency approach using vector method is more efficient than
other methods. I would like to have more information about this method.
If anyone is working in this field , please e-mail to me.

Thanking  You in advance,

James Mathew,
Computer Science Dept.,
University Of Wollongong,
P.O.Box  :1144,
N.S.W.  -  2500,
Ausrtalia.

e-mail  :g9218955@cs.uow.edu.au
From: mathis@tigger.cs.Colorado.EDU (Don Mathis)
Newsgroups: comp.robotics
Subject: Re: Trouble with stepper motor
Date: 21 Aug 92 18:46:24 GMT
Organization: University of Colorado, Boulder

For those who were following this thread,  I found my problem.

My batteries weren't delivering enough current to the motor.  Simple
enough.  It turned out that my stepper motor needed 1 amp per phase,
and the batteries were supplying far less than that.  Since for
stepper motors, torque DECREASES as rpms increase, the motor did not
have enough torque to overcome its (slight) internal friction at high
speeds.  That is why the motor would do progressively worse at high
speeds.

-Don Mathis
From: ktc@onan.jhuapl.edu
Newsgroups: comp.robotics
Subject: Re: balancing_act
Date: 21 Aug 92 12:29:48 GMT
Organization: Johns Hopkins University

The most excellent solution to this problem is the fiber-optic Sagnac  
interferometer. I read several years ago that a French group had  
microfabricated a fiber-Sagnac sensor, but I don't know the status of the work  
at this time. The reason that the technology is so exiting is that the  
reference has 1) no moving parts 2) potentially awesome sensitivity and  
accuracy and 3) is small. More info on the basic method (used by Michelson to  
measure the earth's angular velocity) can be found in Hecht and Zajac,  
"Optics", Addison-Wesley, pp323.
Newsgroups: comp.robotics
From: raghu@morgan.ucs.mun.ca (Raghu B)
Subject: PUMA-560 SPECIFICATION
Organization: Memorial University of Newfoundland
Date: Wed, 19 Aug 1992 22:38:52 GMT

	
	Can any one send me specifications of a typical industrial
PUMA - 560 robot with details like the mass of each link,length
and their characteristics. If any one of you have any details,
and can agree to send by mail or by email, i shall be grateful to them.

	Thanx dear netters.


			Raghu, Balasubramanian
			Box. 59, Faculty of Engineering,
			Memorial University of Newfoundland
			St.John's , Newfoundland
			Canada - A1B 3X5

			email: raghu@engr.mun.ca
				raghu@morgan.ucs.mun.ca  
Newsgroups: comp.robotics
From: gratclif@magnus.acs.ohio-state.edu (Gregory W Ratcliff)
Subject: Re: balancing_act
Organization: The Ohio State University
Date: Sat, 15 Aug 1992 04:34:43 GMT

Now with the new quartz gyros the one legged hopper would be a real
posibility.

It seems to me the quartz type gyros operate in a cyclic, rather than
a rotational mode.  What are the problems associated with this method
compared to rotational.  The accel-decel cycle must have nodes that
would be unusable........hmm.

Greg Ratcliff


-- 
Gregory W. Ratcliff  Ratcliff.8@osu.edu  on the internet   
Columbus, Ohio     ICBM
nz8r@w8cqk 	 on the air
N1697X     	 in the air
From: jw7348@norway.medtronic.com (Jeff Wilkinson)
Newsgroups: comp.robotics
Subject: Micro-mouse, BEAM Olympics and Similar Competitions
Date: 20 Aug 92 20:10:52 GMT
Organization: Medtronic, Inc., Minneapolis, MN

Does anyone have any contact information for the people who run the
micro-mouse or BEAM Olympics contests?  E-mail, phone or regular mail
addresses would be useful. You can e-mail me at the address in the .sig.

Are there any other similar contests out there?

Thanks for your help,
------------------------------------------------------------------------
Jeff Wilkinson                          Internet: wilk@medtronic.com
Medtronic, Inc.                         Voice +1-612-574-3770
7000 Central Ave NE                     FAX   +1-612-574-4306
Minneapolis, MN  55432  
Newsgroups: comp.robotics
From: mathis@tigger.cs.Colorado.EDU (Don Mathis)
Subject: Re: Trouble with stepper motor
Keywords: stepper motor
Organization: University of Colorado, Boulder
Date: Mon, 17 Aug 1992 20:24:24 GMT

Sorry, I should have mentioned in my original post that the motor gets
confused even at very slow speeds, like 2 pulses per second, so it's
not just that I'm pulsing it too fast.  It happens anywhere from 2 to
200 pulses per second.



Newsgroups: comp.robotics