Falling over during some basic moves

[finer9]

Hey All

Long term techie, noob robot guy.

In short

Carefully put together my RobotNova-I
Checked all horn numbers
Did the zero config
Tested each servo for full range of motion

When I do a bow, arms up, sit, all fine.

When I try to do flapping arms, anything more advanced, it seems like he goes through the motions, but falls over around halfway through.

I have read through most everything here - is this a zero config issue, a wrong assembly issue...not sure what else? What tests can I do to see what the issue may be?

Thanks in advance
JFF

[hivemind]

It certianly could be a zero config issue, especially if it looks like it is close to working correctly. I would suggest looking over to follow all the comments regarding how to zero (leveling the arms alone sometimes makes all the difference).

Also if you are working with a carpet or variable surface area you might have difficulty. I suggest using either wooden floors or foam mats (I prefer the foam because they seem stable, yet gentle when he does fall).

So tweak the zero positions a little more, maybe just lean him forward or back some, and hopefully that will do the trick

[finer9]

Thanks for the very quick reply!

One more question: When I load the zero config screen and click read, the robot mimics the picture and has his arms out like he is flying. I adjust and then write it to the memory.

Then I do a power on/off, and he goes back to having arms down at his side.

Does this make sense? I'd expect the same exact position as zero config when I first turn him on?

[hivemind]

His arms return to his side because that is his "standard_pose" which is called by the default template program. The zero positions are different, but you will notice differences in all poses by changing the zeros.

If you are referring to the "GETMOTORSET" command in the template which is the first read of the servos, it can be set to either 1 or 0. The value of 1 reads the present value and tells the servo to stay at that position, while a value of 0 should tell the servo to move to the zero position.

Hope that helps.

[XenoEvil]

There were some errors is the original build instructions to do with pictures not matching instruction. I think someone has posted the changes in the forum somewhere.

It might be worth looking into this too.

[finer9]

Thanks folks.

I am almost certain at this point that it is not assembly, but rather zero config.

Does anyone have tips for this? I really can't figure out if he needs to be leaning farther forward or what. The knees are aligned like in the picture, feet flat, arms parallel to the ground.

Any tips on zero config/how to diagnose what adjustments need to be made?

[Ric]

Hi

FWIW
My RN1 struggled to complete complex moves( i.e. fell over) when first built and I thought I'd probably made a construction error (especially considering the very confusing manual).
I found a few light 'tweaks' on the 'zero conditions' and it gave good balance.

Ric

[Zembot]

Does anyone have tips for this? I really can't figure out if he needs to be leaning farther forward or what.

At first I was eyeballing things and realized my eyeballs aren’t as accurate as I thought. You can use a small square to line up servos 1,3 and 19,21, along with the arms and body. I don’t own a square small enough, so I fold a standard sheet of letter paper. Precisely line up the edges of the paper before folding. You’ll have a ‘paper square’ with a near perfect 90 degree angle. Use your paper square to get things aligned. At least it’s a good starting point. After that only a few clicks on zero adjustments are needed.

[tempusmaster]

Does anyone have tips for this? I really can't figure out if he needs to be leaning farther forward or what.

At first I was eyeballing things and realized my eyeballs aren’t as accurate as I thought. You can use a small square to line up servos 1,3 and 19,21, along with the arms and body. I don’t own a square small enough, so I fold a standard sheet of letter paper. Precisely line up the edges of the paper before folding. You’ll have a ‘paper square’ with a near perfect 90 degree angle. Use your paper square to get things aligned. At least it’s a good starting point. After that only a few clicks on zero adjustments are needed.

A plumb bob - just a simple weight on a string - works great. Another handy tool is a simple bubble level. If you're working on a table or desktop that isn't level it's easy to run into problems when you adjust your robot in one spot, then change it's orientation. You'd be surprised how tilted most desks and tables are.

[finer9]

Just wanted to give this thread some closure for future RN-1 noobs....

...I feel kinda dumb, but it turns out my foot servos were flip flopped. As one of the first things you put together, I guess I wasnt careful enough.

After swapping them (which was a pain due to the wire ties) and doing some zero-config, my RN1 is happily doing cartwheels and head stands.

...gyro time???!?!