RoboSavvy Forum

He Flaps like a Bird: Destructive Resonation in Robot's Arms

2008-10-05T23:27:00+01:00

Excellent work!
It is a shame Kondo discontinued the original KHR1 kit. IMHO they should have invested in licensing the kit to a toy company or just invest in Internationalization and safety/materials certification and made a batch of 10000 units with plastic brackets at a cost of 100$/robot targeted at APAC and US market markets that could have reached stores back in 2007 at $400 retail.
Don't know if you had noticed but we have quite a lot of info related to KHR1 on the left side of this page (Main Menu -> KHR-1) including the history and assembly.
RoboSavvy (UK) was the first ever company to export a bunch of these kits out of Japan in 2004.

Statistics: Posted by limor — Sun Oct 05, 2008 11:27 pm

He Flaps like a Bird: Destructive Resonation in Robot's Arms

2008-10-05T03:12:43+01:00

We just finished our Build Report on the KHR-1. We were able to successfully eliminate the shaking servos, thanks in large part to the information in this thread.

We documented the process to fix the shaking servos here

We've even got a video showing before and after the fix. Video

For our full Build Report on the KHR-1, check here

Statistics: Posted by RobotServicesGroup — Sun Oct 05, 2008 3:12 am

He Flaps like a Bird: Destructive Resonation in Robot's Arms

2008-07-30T18:24:07+01:00

We still have one of the original KHR1 radio control units in stock.
please send an email to sales@robosavvy.com
As for the USB ICS programmer.. I believe it should work with the 786 servos but need to confirm this with Kondo.

Statistics: Posted by limor — Wed Jul 30, 2008 6:24 pm

He Flaps like a Bird: Destructive Resonation in Robot's Arms

2008-07-27T19:42:27+01:00

Thanks for the info. Any new robot we purchase, we like to subject to our Human Emulation testing using the original equipment provided by the manufacturer. So we would prefer to get the robot working with the RCB-1 before considering the upgrade to RCB-3.

Fortunately, with a little more searching, it appears that the cable connection we need is also available in the USB radio control unit shown here. Product link. We were going to need some kind of remote control anyway, so this might just work out fine.

We just need someone to confirm that the package includes the cable we need to run the software to dampen the servos before spending that much money.

Statistics: Posted by RobotServicesGroup — Sun Jul 27, 2008 7:42 pm

He Flaps like a Bird: Destructive Resonation in Robot's Arms

2008-07-27T06:15:19+01:00

RobotServicesGroup wrote:
We hate to dredge up a really old forum post, but we need some help.

No problem.

We recently acquired a KHR-1, the original, not a 1HV, and we have encountered the same servo shaking problem mentioned in this thread. The shaking occurs on all servos, using either the motions provided on the CD, or on the Kondo website. We've got the KRS786 red servos, and we've tried H2H v1 and v1.4. The initial position and home positions look good compared to the manual, and all servos can be moved with no issues using the slider bars in H2H (no mis-wired servos).

This was a fairly common problem with the KHR-1, but not common enough for Kondo to incorporate the servo characteristics setting into H2H.

They addressed the problem with the RCB-3 and RCB-3J (KHR-2HV, KHR-1HV, and the MANOI AT01, PF01) by including the functionality in the controller firmware and H2H3.

The shaking is oscillation, and although it may appear to be in all servos, it is normally triggered by the upper body/arm servos which don't have a heavy load and hence don't have much damping. The controller tries to bring the servo to the right position, it overshoots slightly (either from momentum or geartrain play), the controller tries to correct, and the servo goes into oscillation.

So the solution proposed in this thread is to use the Servo Manager software to connect to the servos and change the Damping value to 1 instead of 2 on all servos.

Usually changing the upper arm servo characteristics is enough.

Of course, in order to do this, you need the special cable to connect from the PC to the servos. Robosavvy shows what appears to be a picture of this cable here in the Servo Manager, Gyro Manager and RCB Commander sections.

On the Kondo website, they list the software as "servo manager for2346REDVersion" and even mention "In order to connect, KOPROPO products ICS-PC interface is required". See here. Unfortunately, this product is listed under the Discontinued Items as part number 01018 from Kondo.

With the phase-out of the original KHR-1, the servo manager became obsolete.

There are three options.

1) Find someone that has some still in stock, or can get one for you. I would suggest starting with Limor on this forum. If he can't help you, then contact RT Corp. Last time I visited their shop a couple weeks ago they still had some KHR-1 kits on the shelf, and might have the servo manager as well, and they speak English.

2) If you go back through the historical posts on this forum you'll find other threads about the same problem. I seem to recall that someone fabricated the required cable.

3) Upgrade the KHR-1 to use the RCB-3. That's the route I took with my KHR-1, and allows me to use both the original KHR-1 motions (after conversion) and the KHR-2HV motions also. It's a simple and pretty straight forward change. There are posts describing it, and the motion conversions, on Robots Dreams.

Shown here

So now on to the fun part. Where can we get this special cable so that we can fix the servos and enjoy our wonderful new KHR-1?

Will this USB product do the same thing as the part that has been discontinued? We are hopeful because the Robosavvy description specifically mentions Servo Manager and damping. Product link

From the description, it appears so - if you also get the software that's mentioned in the description. Limor can confirm it for you, and tell you whether or not they have it in stock.

Statistics: Posted by tempusmaster — Sun Jul 27, 2008 6:15 am

He Flaps like a Bird: Destructive Resonation in Robot's Arms

2008-07-27T05:21:18+01:00

We hate to dredge up a really old forum post, but we need some help. We recently acquired a KHR-1, the original, not a 1HV, and we have encountered the same servo shaking problem mentioned in this thread. The shaking occurs on all servos, using either the motions provided on the CD, or on the Kondo website. We've got the KRS786 red servos, and we've tried H2H v1 and v1.4. The initial position and home positions look good compared to the manual, and all servos can be moved with no issues using the slider bars in H2H (no mis-wired servos).

So the solution proposed in this thread is to use the Servo Manager software to connect to the servos and change the Damping value to 1 instead of 2 on all servos. Of course, in order to do this, you need the special cable to connect from the PC to the servos. Robosavvy shows what appears to be a picture of this cable here in the Servo Manager, Gyro Manager and RCB Commander sections.

On the Kondo website, they list the software as "servo manager for2346REDVersion" and even mention "In order to connect, KOPROPO products ICS-PC interface is required". See here. Unfortunately, this product is listed under the Discontinued Items as part number 01018 from Kondo. Shown here

So now on to the fun part. Where can we get this special cable so that we can fix the servos and enjoy our wonderful new KHR-1?

Will this USB product do the same thing as the part that has been discontinued? We are hopeful because the Robosavvy description specifically mentions Servo Manager and damping. Product link

Any help provided would be greatly appreciated!

Statistics: Posted by RobotServicesGroup — Sun Jul 27, 2008 5:21 am

instruction

2007-09-16T02:35:46+01:00

Thanks tempusmaster
Good luck with your journey

cheers,

ryann2k1

Statistics: Posted by ryann2k1 — Sun Sep 16, 2007 2:35 am

Re: walking gaits

2007-09-13T13:23:14+01:00

ryann2k1 wrote:
Thank you tempumaster.
by the way, do you mean COG is Center of Gravity?

Yes, exactly

sorry, a bit confused

No problem.

Here's a post that I put together about a year and half ago that you might find useful.

KHR-1: Learning How to Walk

If you compare what's happening with your robot versus the one in the post then you could get some idea of where your setup or home position is off, or if there is some other problem.

The video is the stock Kondo footage (at least at the time I put the tutorial together) but my KHR-1 performed exactly the same way, without gyros, once I got the home position setup properly.

By the way, I may not be checking the forum for the next couple of days since I leave tomorrow for Takamatsu. I'll be back by Monday night (Japan time) though.

Statistics: Posted by tempusmaster — Thu Sep 13, 2007 1:23 pm

walking gaits

2007-09-13T12:50:05+01:00

Thank you tempumaster.
by the way, do you mean COG is Center of Gravity?
sorry, a bit confused

cheers,

ryann2k1

Statistics: Posted by ryann2k1 — Thu Sep 13, 2007 12:50 pm

Re: Gyro

2007-09-13T07:04:41+01:00

ryann2k1 wrote:
Hi...
The video link for the robot.
http://www.youtube.com/watch?v=Ukpoc-bUnRc

It looks really awkward..
it is really different from the website.

cheers

ryann2k1

You're right. Very awkward.
It's executing the basic motion sequences, but is getting way out of balance.

Here's a few suggestions:

Do you have the gyros installed and operating? If so, then you should turn them off until it can do the canned motions without them. They could be contributing to the wobble and instability.

When I step through your video frame by frame it's not keeping the COG positioned correctly, which usually means the home position (most likely) or setup is off. In general, it's tilting too much and over-compensating (which is why I was wondering if the gyros are turned on), throwing off the COG, and walking in a circle.

Comparing your video to the sample video on a frame by frame basis is helpful to figure out where the setup is off.

Statistics: Posted by tempusmaster — Thu Sep 13, 2007 7:04 am

Re: Gyro

2007-09-13T05:32:18+01:00

Hi...
The video link for the robot.
http://www.youtube.com/watch?v=Ukpoc-bUnRc

It looks really awkward..
it is really different from the website.

cheers

ryann2k1

Statistics: Posted by ryann2k1 — Thu Sep 13, 2007 5:32 am

Re: Gyro

2007-09-08T10:54:09+01:00

ryann2k1 wrote:
tempusmaster wrote:Carpet is really, really tough. Even if you use the thin, industrial carpeting, there is still too much instability, though the RoboCup humanoids manage to handle it well enough to get by, as long as they don't move very fast.

Yes. I agree with that.
But the walking gaits downloaded from kondo site
http://www.kondo-robot.com/html/Product ... pport.html
look different on my robot.

How are they different?
Can you give an accurate description or upload a video to YouTube?
For a KHR-1 using the RCB-1 controllers those routines should perform almost exactly the same as the videos as long as the Home Position/Trim is setup correctly.

There is also some bugs on the H2H application. Im using H2H 3rd version.

Can you click the 'i' (About) box and let us know what version it says you're running? I think there were four Japanese releases of the original H2H software, and one or two that were translated into English. Some of them did have bugs, of course.

it seems I have to refine the gaits..

Could be, though if it isn't close to begin with then there is probably some other problem that needs to be fixed.

Statistics: Posted by tempusmaster — Sat Sep 08, 2007 10:54 am

Re: Gyro

2007-09-08T03:06:19+01:00

[quote="tempusmaster"Carpet is really, really tough. Even if you use the thin, industrial carpeting, there is still too much instability, though the RoboCup humanoids manage to handle it well enough to get by, as long as they don't move very fast.[/quote]

Yes. I agree with that.
But the walking gaits downloaded from kondo site
http://www.kondo-robot.com/html/Product ... pport.html
look different on my robot.
There is also some bugs on the H2H application. Im using H2H 3rd version.
it seems I have to refine the gaits..

cheers,
ryann2k1

Statistics: Posted by ryann2k1 — Sat Sep 08, 2007 3:06 am

Re: Gyro

2007-09-07T14:30:56+01:00

ryann2k1 wrote:
Thanks guys.
My gyro is working now, but once I try my robot to walk on a carpet, it keeps falling. something wrong the gaits or the gyro setting, still dont know.
any idea guys?

cheers,

ryann2k1

Carpet is really, really tough. Even if you use the thin, industrial carpeting, there is still too much instability, though the RoboCup humanoids manage to handle it well enough to get by, as long as they don't move very fast.

Statistics: Posted by tempusmaster — Fri Sep 07, 2007 2:30 pm

Gyro

2007-09-03T12:29:12+01:00

Thanks guys.
My gyro is working now, but once I try my robot to walk on a carpet, it keeps falling. something wrong the gaits or the gyro setting, still dont know.
any idea guys?

cheers,

ryann2k1

Statistics: Posted by ryann2k1 — Mon Sep 03, 2007 12:29 pm