W.A.L.T.E.R.

spacejunk · April 9, 2007, 4:27pm

You can rotate the 3D pdfs!?

linuxguy · April 9, 2007, 4:36pm

WALTER’s new front pan/tilt sensor thing can be tilted back far enough for two sensors to see anything from floor level up.

When I get the new body for WALTER built and the new top deck sensor/gripper arm installed, there won’t be much he can’t see.

8-Dale

linuxguy · April 9, 2007, 4:40pm

Yes, indeed they can be! It even works under Linux with the latest version of the Linux flash player. That’s why I have started making everything in PDFs. That way everyone can see things from whatever angle they are interested in.

8-Dale

linuxguy · April 10, 2007, 4:49am

I received my order with WALTER’s new gearhead motors, motor mounts. quadrature encoders, tires, Sabertooth controller and, hubs today!

8-Dale

spacejunk · April 11, 2007, 1:01am

Cool! I hope to see some pics soon!

linuxguy · April 16, 2007, 11:09pm

I will get some new pictures of W.A.L.T.E.R. as soon as I have his new brain and SSC-32 wired up. I just got the new Atom PRO on an ABB today.

I will have to reprogram his software to run on the Atom PRO since it was originally written for the Basic Atom. I’ve already done some adjusting, but need to rewrite the servo controls to use the SSC-32 now, instead of being run directly by the Atom PRO, which will only handle sensors from now on. I need to get a friend to help me with assembling the new wheels/tires because they have to be glued.

For now, W.A.L.T.E.R. will just have a single PING sensor and two Sharp IR rangers. I have not got all the parts for the new top arm or the new body built for W.A.L.T.E.R. yet. I need the new body so I have more room to stuff things on him, and so I can proceed to hook up the new GHM-04 motors and quadrature encoders with 5" off road tires.

I wonder if anyone has ever put a wheelie bar on the back of a two wheeled rover… W.A.L.T.E.R. may be the first!

8-Dale

linuxguy · April 21, 2007, 11:55pm

I have the Atom PRO communicating with the SSC-32 now, and can home the new PING turret. I am working on the code conversion from the Basic Atom code to Atom PRO, and am having some issues I am not sure I can fix.

Right now I am concentrating on a small part of the code at a time, which is the PING sensor code right now. This is due to the fact that the PING sensor is mounted in WALTER’s new front sensor turret.

I will have to put a Sharp IR Ranger in place of the PING sensor if I can’t ge tthe PING code to work properly. I would rather have the PING on the turrent since it can be moved 45 degrees either side of WALTER’s center point, and I prefer having the IR Rangers on the side pointing across each wheel.

8-Dale

spacejunk · April 22, 2007, 12:00pm

You need an SSC-32 for the turret only? And check out the ping and atom pro code in the sticky. It is working for me.

linuxguy · April 22, 2007, 3:50pm

No, not just for the turret. The motors too. There will also be a new arm attached to the top deck which will be able to reach to the floor and pick stuff up.

I started out with that code. Two of us are having the same problem, so I do not know what is wrong.

8-Dale

spacejunk · April 22, 2007, 5:01pm

The SSC-32 still seems a little overkill.

linuxguy · April 22, 2007, 5:27pm

Capability wise, perhaps, but I am not going to spend more money on a servo controller that does less. Sure, I don’t need to control 32 servos for WALTER, but remember that WALTER is my experimental and learning platform for robotics. I do pretty much everything first on WALTER, and this will be true even after I get The BiPod completed.

I still think the SSC-32 is by far the best value in servo controllers over any of the others I have looked at. I have looked at quite a few. The only reason I see to use anything else would be if I had a very constrained space to work in where the SSC-32 would not fit.

8-Dale

linuxguy · May 16, 2007, 11:11am

I am making some progress in converting W.A.L.T.E.R. to use the SSC-32 for servo and eventual motor control using the Sabertooth 2x5 motor controller. I believe the new code will work without change (or very little change) with the Sabertooth and SSC-32 controller combination.

I can get both motors turning in the same direction now. However, they do not start up at the same speed… My code looks like everything should be working right, but I am getting some odd behavior. The motors do not ramp up to maximum speed at the same rate, even though I am currently using the same speed control variable for both motors. I am thinking about using different motor speed control variables so the speed of each motor can be tweaked easily.

I am hoping I will get more precise speed control once I have the new gear head motors and Sabertooth 2x5 controller wired up to the SSC-32. I just don’t seem to be getting the precision I would like from the continuous rotation servos W.A.L.T.E.R. currently uses for locomotion and am not sure why. I am not currently using the SSC-32 pulse offset feature and am handling the servo offsets within my code.

I’ll take a break from working on motor control and work on converting the Scan_Turret routines to use the new front mounted sensor turret. I have also replaced the front mounted PING Ultrasonic sensor with another Sharp IR Ranger, and will eventually mount the IRPD on the back of the bottom deck so it will be harder to sneak up on W.A.L.T.E.R.

8-Dale

spacejunk · May 16, 2007, 11:48am

Is the sabertooth connected through the SSC-32?

linuxguy · May 16, 2007, 3:36pm

The Sabertooth and motors are not connected up yet. However, the Sabertooth probably will be connected through the SSC-32, but I will probably try it direct from the Basic Atom first.

8-Dale

spacejunk · May 17, 2007, 12:58am

Try using serial control mode, it will work MUCH better than the SSC-32.

linuxguy · May 17, 2007, 1:18am

Once I get the Sabertooth and motors connected up and working, I will be trying out all the various modes of control it has. I still need to get some caps for noise supression and cables to connect from the Sabertooth to the SSC-32 (for PWM control) and/or bot board (for serial control). I don’t want to connect anything until I have all the right stuff.

8-Dale

adam-21 · May 17, 2007, 1:42am

I think I may have been the other person you are referring to who had the problem, but I actually resolved it when that thread was current.

Here is my Pro code to test the Ping … it moves the servo between left and center when something is in range. It works!

[code]'PING servo test

pingRangeCm var word
i var byte

servoPort con p8
low servoPort

main
gosub readPing[15], pingRangeCm
if (pingRangeCm < 10) then
for i = 0 to 50
gosub servoLeft
pause 20
next
for i = 0 to 50
gosub servoStop
pause 20
next
endif
pause 250
goto main

’ readPing: Parallax PING Ultrasonic Ranger Subroutine
pingValue var word
pingPort var byte
readPing[pingPort]
low pingPort
pulsout pingPort, 5 'input trigger 5 uS pulse length
rctime pingPort, 1, pingValue
if pingValue > 65000 then goto error
rctime pingPort, 0, pingValue

' Convert to cm
pingValue = (pingValue */ 2251) / 2

return pingValue

servoLeft:
pulsout servoPort, 1150
return

servoStop:
pulsout servoPort, 3050
return

servoRight:
pulsout servoPort, 4950
return

error
goto main
[/code]

linuxguy · May 17, 2007, 3:50am

Thanks.

Yes, I believe you were the other one having problems with the PRO and PING.

I’ll try your code the next time I have the Atom PRO active. Right now I have switched back to the Basic Atom for W.A.L.T.E.R.

8-Dale

spacejunk · May 22, 2007, 10:23pm

Good luck!

eddieb · May 23, 2007, 11:33pm

the guts of A-Bot’s code for reading the ping)) seems to work fine on my BAP. sitting on my desk it is returning 151 cm which is roughly 5 feet… 8 foot ceiling - about 3 feet from floor to tip of ping transducer is pretty close.