I found out the value of clamping diodes from spikes so I def agree there. I am mostly using arduino now and if the setup I got doesn't work, I will try the
Sabertooth/Kangaroo combo a try. I was using rc servo type comands (aka pulsewidth) for position control, which worked well except for the ramping up and down. I had a gadget which plugged in between the controller and the servo controller that would repeat
the last signal to the servo so the controller (BASIC Stamp at the time) would not have to worry about the continous timing of the pulses. Kinda made it work more like a digital servo. Wanted at the time to keep everything RC signal compatible so I could run
the signal from the controller or from a RC receiver and select which went to the servo's (kind of like a flip flop in reverse), so if the radio sign dropped, the controller could 'cut in' and bring everything to a neutral postion.
I did not have a lot of luck with the ramping, sounds like your setup would handle that better. Is there more than one version of the ezb and which do you like?
I wonder if that would be better than the arduino?
Thanks again,
Tom
From: B9Builders@yahoogroups.com [mailto:B9Builders@yahoogroups.com]
Sent: Friday, November 20, 2015 11:33 AM
To: Tobor001@aol.com [B9Builders]
Subject: RE: [B9Builders] B9 Arm is now mounted on the CSS and working.
Thanks for the info Tom. Ya, there's lots of good quality motor controllers and hbridges. Seems like the secret is to get a well built one. One with good internal protection from voltage spikes or reversal and that's rated for the amps you'll be pulling
through it plus 1/4 more for inrush current. I love useing Sabertooth controllers with a Kangaroo X2 daughter board attached for speed and position control. I can easily command movement and speed through ezb's Uart port useing Simple Serial commands. You
can use pots or encoders with the kangaroo.
Dave Schulpius
On Nov 20, 2015 9:36 AM, "Thomas Ferraz tomf@brownellco.com [B9Builders]" wrote:
Hi Dave,
Vantec made a controller that accepted hobby servo inputs , but it was an h-bridge to drive any dc motor and it had an input for an external feedback pot. I got one a few years back but never got around to messing
with it. I think it was a bully servo or bully interface speed control or something like that. I don't remember the specs other than it would support a 12V motor with a 10 or 12 Amp peak (the motor I was planning on using). I was going to use it for torso
rotation with the feed back servo geared to center (The feedback servo wasn't 360 rotation).
Don't know if Vantec still makes these or not. Starting to get back into things now, let you guys know how well it works when I find it (all my stuff is in storage right now)
Thanks,
Tom
From:
B9Builders@yahoogroups.com [mailto:B9Builders@yahoogroups.com]
Sent: Thursday, November 19, 2015 11:10 PM
To: Tobor001@aol.com [B9Builders]
Subject: Re: [B9Builders] B9 Arm is now mounted on the CSS and working.
Hey Victor, one of the excellent benefits of clubs like this are meeting new friends with the same interests and learning new things from them. I'm grateful to be making friends like you and look forward to the day I can meet you and my other friends face to
face. This is the first robot I've even built and really knew nothing about robotics or servo and motor control before I started a few years ago. I have the builders who built these magnificent B9's before me to thank for sharing their parts, techniques and
experiences, Without them and other people in other robot forums I could not have come this far.
Anyway, enough of that mushy stuff. As far as the motors and feedback in this arm, there is a combination of DC motors and Servos. It took a long time and a lot of experimenting to find the best mix of motors of the right size. The claw and wrist is very heavy
and extended at such a length that it takes a big motor to lift. That's why I ended up having to use a DC motor for the elbow that is lifting the entire weight of the arm and the other servos that move the wrist and claw. Then as I got closer to the end of
the arm I was able to use smaller and less powerful servos to move the other joints. Still, I got the strongest and best built servos in their class. I tried to stick with analog servos because they are very silent. Digital servos are stronger and hold position
better but you get one with ultrasonic switching (dont even know if they even exist) you will get a whine as they try to hold position. I can't stand a noisy servo and won't tolerate one in a B9 arm that should be silent.
The thing about servos is that they have built in pots for positions and speed control. With the proper RC signal or microcontroller like EZ Robot's EZB or an Arduino you can move them to any spot at any speed. DC motors are much stronger and much quieter but
lack a feedback device to tell the controller where it's at so a motor controller can tell it where to go in which direction or speed. You need to figure out how to add a pot or encoder to it along with a motor controller or H-Bridge.
With that said I have a worm gear windshield wiper motor for my elbow that lifts all the weight mounted on a bracket that lifts the weight out front of it. For feedback I'm using a flat "Softpot". When a stylist is pressed against it as the arm pivots the softpot
sends back a differing voltage to the motor controller to identify where the motor is and how fast it's going. I'm using the same concept on the Arm Retraction System. Only down there I'm using a electric car window motor and an encoder attached to the motor
shaft for feedback.
The up and down wrist servo is mounted in a Servo city gearbox with a ratio of 7 to 1 because at this location there is still a lot of weight to lift. this servo was a digital servo but the whining it produced was unacceptable so I gutted it and wired in a
ultrasonic motor controller. It now runs very precise, cool and is very quiet while holding position.
Hope this helps in some way. Good luck with your build and have fun with it.
Dave Schulpius
On Thu, Nov 19, 2015 at 2:22 PM, Tobor001@aol.com [B9Builders] wrote:
Hi Dave:
That really is something on the control of this arm. So all the movements are all feedback control. Since the first arm is a success, how long would it take to create the second arm.
Dave I think you have to offer the blueprints to the club one day!!!. Truly amazing...
Sure would like to meet you at one of the club events.
This is like MIT stuff, maybe better.
Victor
-----Original Message-----
From: David Schulpius dschulpius@wi.rr.com [B9Builders]
To: Tobor001@aol.com [B9Builders]
Sent: Thu, Nov 19, 2015 2:14 pm
Subject: Re: [B9Builders] B9 Arm is now mounted on the CSS and working.
Thanks so much Victor. I won't have to add any more control devices to control the other arm. I'll only have to run about 4 servo cables to one of the two EZB'S mounted on the top of my CSS. Then with some ez script
writing in ez builder both arms will move independently in any position or speed I can think of. I haven't tried it yet but they should also be able to accept RC through the kangaroos and sabertooth controllers and a little ingenuity.
Dave Schulpius
On Nov 18, 2015 8:13 PM, "Tobor001@aol.com [B9Builders]" wrote:
Hi Dave:
That is a truly amazing mechanical arm. I always wondered when you build the other arm, how much more of the control electronics would you have to add? Another EZ Board?
Will the arms work independently? Basically one arm doing one thing and the other another thing?
So interesting on how this will work. Any thoughts about motorizing the treadsection later down the line, Oh man, I am asking for too much.
Beautiful work
Victor
In a message dated 11/18/2015 2:08:49 P.M. Eastern Standard Time,
B9Builders@yahoogroups.com writes:
Geesh Dave If I didn't see your progression videos of your b9 once you completed it I would have sworn you had bob may and Dick Tufield inside that beast!!
On Wed, Nov 18, 2015 at 2:03 PM, David Schulpius
dschulpius@wi.rr.com [B9Builders] wrote:
Thanks everyone for your kind words and interest. They keep me going. More so when something doesn't fit right, works like I expect or goes up in smoke as often happens. Lol!
Dave Schulpius
On Nov 18, 2015 12:52 PM, "Bob Ross robertr609@yahoo.com [B9Builders]" wrote:
Dave,
That's truly a magnificent piece of work !!
Bob Ross
From: "David Schulpius
dschulpius@wi.rr.com [B9Builders]"
To: "Tobor001@aol.com [B9Builders]"
Sent: Tuesday, November 17, 2015 11:11 PM
Subject: [B9Builders] B9 Arm is now mounted on the CSS and working.
OK, the past month has been spent working through a few bugs, adjustments and recovery from stupid mistakes caused by being in a hurry. I've been away from coding and working in EZ Builder for a while. It was spent wrench turning and
getting this thing built.
Anyway, I've got my B9 Arm mounted on the robot now and it's working well. It still needs a few tweaks (of course) but I'm really happy with where I'm at with this now.
Here's my latest vid showing where I at now with this mechanical nightmare. LOL. Enjoy!
Dave Schulpius
https://youtu.be/UHhLiHd8uVI