Noob Intro: Broken Femisapien Arm

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Perry
Perry's picture
Noob Intro: Broken Femisapien Arm

Hi everyone,

I'm a 55 year old who has recently become very interested in getting off the sidelines and actually getting into robotics. I recently purchased a Femisapien as well as a Lego Mindstorm 2.0 NXT system. I want to start learning all about this stuff.

I'm very handy with tools.

I saw the thread about the insides of the Femisapien (with lots of photos) so I'm inspired to fix her rather than send her right back to amazon.com

Here's the problem: Her right 'elbow' makes a loud "snap! snap! snap!" sound when her 'forearm' rotates. It will rotate a little but makes the snapping and you can tell it's trying to rotate more but cant.

She is brand new, so I have only run the "dance demo" routine and that is when i heard this obviously wrong sound.

So should I attempt to fix her? an email exchange with Wowwee Tech Support has already happened and they suggest a broken gear and that I return her to amazon.com.

I haven't opened her up yet. Wanted to get your advice first.

Thanks,

Perry

Rudolph
Rudolph's picture

Mostly it boils down to "are you willing to void your warranty?". Right now you have the option of getting a (hopefully) non-broken replacement sent to you. If you open her up and find an irreparable part then you may be stuck with an un-working bot. WowWee doesn't really seem to sell replacement parts (some folks have had some luck though).

Personally I'd have it replaced. Then when the new one is verified to be working correctly I'd tear into that one ;)

Perry
Perry's picture

Hi Rudolph,

For me, this is all about learning. So I opened her up. didn't see too much wrong, but I enjoyed being able to look inside. I checked the drive shafts and gears...then put her back together...same noise.

nothing really appeared broken. (I took photos). Tomorrow I think I'll open the other arm and see how the two compare. The "wrist joint" has a very cool mechanism...sort of a spring loaded stop so that , I guess, if the 'hand' encounters resistance, this will give at the spring and reset rather than snap something.

I'm going to try comparing arms and also...gonna make sure that the wrist joint is smooth and not impeding rotation. I'll sand it if it needs it.

Maybe others can chime in here with advice. I certainly don't know what I'm doing. lol. but am having fun. This thing is amazing to me.

Perry

Rudolph
Rudolph's picture

"I certainly don't know what I'm doing. lol. but am having fun."

Rock on ;)

I don't have a femisapien so I've no idea what to look for. I know some people here have ripped theirs down. If the gears and shafts look correct, my wild guess would be whatever is supposed to retain those parts in the housing may be cracked or broken off.

GWJax
GWJax's picture

Welcome aboard Perry!!!!!!

The first time I ripped down Femi and reattached her arms I too had the clicking noise. The problem was that the arms were not aligned correctly since both arms move together. One suggestion is to remove the arms that is clicking or the one that is binging up against her body then turn her on so that she will align the arm gears to the correct location then turn her off. At this point move the one attached arm to her side and then match up the other arm in the exact position as the other. Taking care not to move the arms attach the one back on. You may have to do this a few times like I had too and also make sure that the wrist is in the correct position as well. What is happening is when she moves one arm the other arm is locking up against her body thus stopping the other arm from moving freely. If this does not fix the problem please post your photos and a video if you can, to help us out in solving your problem.

Jax

GWJax
GWJax's picture

One other thing Perry, Here is the link to my gallery of the rip-down of the Femi. I still have not finished up my article but at least you can see the insides of her and sorry for some of the blurry images but these will be replaced at some time..

the link: http://www.robocommunity.com/gallery/15337/Gallery-Femisapien-Rip-Down/

Jax

Perry
Perry's picture

Hiya Jax,

Thank you for the welcome aboard.

I took both arms apart and had a very close look under the magnifier for damage, then did what you said. That didn't help so I moved her forearm about 45 degrees more of rotation so it perfectly matched the left arm. Still no luck. So I did a video.

If the embed code works it will appear here. but I'll put in the URL first just in case.

http://www.youtube.com/watch?v=NsKWczwT7vk

GWJax
GWJax's picture

Man that looks nasty. Let me rip her down again and get into the arm motor assembly. The drive gears are out of time, this might have happened during assembly because I do not hear any gear grinding and both arms are moving. So give me a bit to see what is going on and I'll post a video or photos to help you out with your Femi.

Jax

Perry
Perry's picture

Jax,

Hang on. I opened her up again...took both arms of....and the problem is the light greenish blue arm drive thingie that is round but flattened on two sides. For lack of better words call it the "shoulder drive". It has the metal gear head protruding from it's center.

I can see it trying to move and going snap! snap! (2x) on power up.

I'll do a fast video if you don't mind troubleshooting here and now.

GWJax
GWJax's picture

Your going to have to pull apart the motor assemblies and re-align the gears or one of your VR sensors are bad or just misaligned.

Jax

Perry
Perry's picture

ok. I'm willing to give that a try. Don't know what a VR sensor is, but I'll check the manual

I'll start taking her further apart and see how comfortable I am with that.

GWJax
GWJax's picture

A VR is a Variable Resistor and this will not be in the manual. The VR tells the main board where the motor is in conjunction with gears. The connectors are as follows: her right arm is on J18 and the left arm VR is on J19. The VRs total resistance should be around 10K ohms. You can check this by using your meter and disconnecting J19 and measure on the black and red lines and the same for J18.

Jax

GWJax
GWJax's picture

OK before you open up the gear system, remove the back plate here you will see 2 yellow VR's one for each side. remove 2 tiny screws that hold the plate on and remove the VR with the gear. If you look at the VR's center you'll see a white tab. Move the gear until the white tab is horizontal with the 3 wires. At this time just let the arms hang down to their side and carefully re install the VR. Do this to both sides. After that attach the back plate and turn her on. This will realign her settings back to where they should be. If the white tab does not move when you move the gear then the tab is broken and must be repaired.

Jax

Perry
Perry's picture

Thank you Jax. I will do as you said and report back later this evening or tomorrow. This took up more of my time that I realized it would. And though I'm having fun, I have some other things I need to get knocked out today.

Perry

Perry
Perry's picture

oh yeah, here's that other video I shot

http://www.youtube.com/watch?v=8iQ4PUp2zE8

GWJax
GWJax's picture

that clicking is the anti-slip-gear. The VR's are the problem. What has happen is that the MCU is looking for the correct distance for the arm travel and since it does not get the correct value until it exceeds it's range after the two clicks I would have to say the the small white tab is misaligned. refer back to my last post and this should correct your problem.

Jax

Perry
Perry's picture

Will do Jax.

Thank you very much for taking the time to look this over. Hopefully I'll have that done tomorrow morning and can report back.

MrScott
MrScott's picture

Just a side note to GW's otherwise excellent debugging.

It's not an anti-slip gear so much as it's an anti-break gear that slips. It's designed to slip and relieve the torque building up when a gear jams. It protects the motors and gears from breakage.

NanoTek
NanoTek's picture

...and Jax had a slip of the tongue. :-D

MrScott
MrScott's picture

Maybe he should check on his anti-slip gear. :-)

Perry
Perry's picture

ok, just finished 2 hours of work. still get the clicking on the right shoulder only (her right).

I aligned both VRs....but I get the same problem on the same side.

Good news is: this is a hell of a cool education for me. Bad news is: I go out of town tomorrow so I cannot spend any more time on the robot today.....well, maybe an hour or so this evening if I get all my crap done.

BTW, before you told me not to...I had already opened up the gearbox from the front. I took photos, didn't see any damage on cursory look...but it would have to have been obvious...I was mainly just checking gear teeth without rotating the mechanism or disturbing it.

Too bad we didn't get it fixed with this.

Shai Alyt NEMO
Shai Alyt NEMO's picture

Hello, Perry!

As a Femi's owner and modder, I guess I can help you. Your problem may be much simpler then you think. I think, it's not with gearboxes or VRs.

Notice: her head is (slightly) actuated left-right from her left hand gearbox and a whole her upper body also is (slightly) actuated left-right from her RIGHT hand. I think it's supposed to add some "organic" or "feminine" feel  to her motions. Look carefully at the photo 66 by GWJax:

http://www.robocommunity.com/gallery/15337/Gallery-Femisapien-Rip-Down/?...

Right between her left and right arm motors (below the two screws) you can see a horizontal white plastic disc on axle with a short cylindric cam on it. This disc is driven from her right arm gearbox. And notice, this cam sould be IN BETWEEN of the two ends of the horizontal metal spring (fixed to her lower body). It's this cam that turns her upper body slightly left-right. And under a certain circumstances (forcibly turning her upper body left or right at quite large angle) one of a spring ends can "jump over" a cam so the cam is no longer "catched" between the spring ends and a disc could not turn reely full circle, thus preventing right arm from moving to the uppermost position.

GWJax
GWJax's picture

MrScott said:
Just a side note to GW's otherwise excellent debugging.
It's not an anti-slip gear so much as it's an anti-break gear that slips. It's designed to slip and relieve the torque building up when a gear jams. It protects the motors and gears from breakage.

HEHEHEHE, That what I meant to say, LOL thanks MrScott as always for the correction and yes it was a slip of the fingers,ha ha

 

 

Perry
Perry's picture

Shai Alyt NEMO said:

Right between her left and right arm motors (below the two screws) you can see a horizontal white plastic disc on axle with a short cylindric cam on it. This disc is driven from her right arm gearbox. And notice, this cam sould be IN BETWEEN of the two ends of the horizontal metal spring (fixed to her lower body). It's this cam that turns her upper body slightly left-right. And under a certain circumstances (forcibly turning her upper body left or right at quite large angle) one of a spring ends can "jump over" a cam so the cam is no longer "catched" between the spring ends and a disc could not turn reely full circle, thus preventing right arm from moving to the uppermost position.

NEMO,

You are CORRECT!!! Wow. Ok, so how do I reposition the disk and cam in a way that I do not harm the doll?

Perry

GWJax
GWJax's picture

Nemo, Yes you are correct about the spring this will cause the gear to slip. The only thing that gets me is that the Femi is bran new out of the box, that's why I did not think of that first. Not only that but when I pulled apart my Femi I had the same problem with the arm alignment. The spring just does not pop off even if you rotate the arm in a 360. The cam nub in the center of the 2 ends of the tension spring just won't pop out unless the ends are too short or the torso was removed. I just sat down with her with the gear box ripped apart so I could test this out. Yet I have to say this gearbox is just too cool and well engineered. If this is it then this one really slipped through QA check. WOW! or should I say WowWee!!! LOL Got to love them all..

Jax

GWJax
GWJax's picture

Perry, GREAT glad that was it. Just put the cam nub back in the spring arms. You can remove the upper torso with one screw that is under the front side of the spring. After that lift up the torso and then set the cam back in place and insert the screw.

Jax

MrScott
MrScott's picture

Perry said:

Shai Alyt NEMO said:
Right between her left and right arm motors (below the two screws) you can see a horizontal white plastic disc on axle with a short cylindric cam on it. This disc is driven from her right arm gearbox. And notice, this cam sould be IN BETWEEN of the two ends of the horizontal metal spring (fixed to her lower body). It's this cam that turns her upper body slightly left-right. And under a certain circumstances (forcibly turning her upper body left or right at quite large angle) one of a spring ends can "jump over" a cam so the cam is no longer "catched" between the spring ends and a disc could not turn reely full circle, thus preventing right arm from moving to the uppermost position.

NEMO,
You are CORRECT!!! Wow. Ok, so how do I reposition the disk and cam in a way that I do not harm the doll?
Perry

 

Ah! AHHH!  AHHHHHH!

 Doll? Doll?!

 

This is a doll.

 

This is an Action Figure

 

THIS is a ROBOT!

 

 

That would be a joke, I say, a joke, folks.

Shai Alyt NEMO
Shai Alyt NEMO's picture

I'm happy, my guess was right and helpful for someone! Cool

Good luck, Perry, in fixing your Femi!

In fact, I had experienced this "jump over" issue on my Femi. Maybe, the spring ends or a cam itself are a little too short, allowing the spring pop out of it's place when you turn Femi's torso manually up to the physical limits. To prewent this problem in future, I screwed a tiny screw with a very flat head to this cam making it look like a mushroom with a metallic cap. WARNING! It's important to drill an appropriate axial hole for the screw. The plastic of a disk with cam is elastic enough, but if a hole will be too tight or you will try to force the screw in without drilling a hole at all, the disk with cam can be easily  torn apart. So, be careful.

P.S. But right out of the box... It just confirms me in a thought, that anyway, chinese quality control is not, errm..., very trustworthy.  

 

Perry
Perry's picture

Ok, I'm back in the shop with Femi. Did the fix, no more clicking. yay

Now, there's a problem. Her "default" position has the shoulder cams (those light greenish blue things that are round with flat spots on 2 sides) that drive the arms in the 'wrong' position. i.e., when I try to put her arms back on they are way up in the "wave hello" position. Not down at her sides in the "ready" position (for lack of better term).

If I rotate the shoulder cams to where I think they should be, that round cam on the disc at her waist moves all the way around to almost in front of her (not exactly in line with her belly button), and NOT centered at her back.

I'm thinking about opening the entire gearbox and reorienting the disc. Jeez.....

This is quite an exercise.

Shai Alyt NEMO
Shai Alyt NEMO's picture

Congratulations on your successful fix!

It's hard to understand your new problem just from words. Maybe, photos can help.

P.S. Don't hurry with gearboxes disassembly. Maybe it's time to realign her arms VRs (see posts before).

Perry
Perry's picture

NEMO, (and Jax)

I'm reading the "....how does Femi stand in default" thread. I think I'll get to work on that tomorrow. I don't know how to read an Ohm meter yet, but I'll try it out and see what I get.

Also, I think I may start by just rotating the VM 180 degrees from where I have the white tabs horizontal currently. just to see what happens. because it's AFU as is.

But like I said....If I get her arms down by her sides, the cam on that horizontal disc is up near her belly button. Is that gonna be trouble??

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