MSR-H01 with springs

Hexapod Robots

MSR-H01 with springs

Postby Tim Beurskens » Fri May 28, 2010 3:17 pm

I modified my hexapod to use springs.

Image
femur with spring
Image
hexpod standing on its own, no power, battery disconnected.

i still need to disable wake and sleep position, probably the dpd setting
and cut the springs to size.

(sorry matt for the gmail chat thing, it's too easy :) , I know I should use the forum)

edit:
did set the dpd the same as dpu, but now the reset legs don't work. the leg lifting looks like it is dpu minus dpd.
is possible to fix it, and still have a working reset legs command
Tim Beurskens
 
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Re: MSR-H01 with springs

Postby Tim Beurskens » Sat May 29, 2010 1:40 pm

p.brain hexengine + servo's in sleep uses about 0.18A 6.0v (without battery pack)
p.brain hexengine + servo's in awake state and standing uses 0.45A 6.0v (with battery pack)
p.brain hexengine + servo's in awake state and standing uses 0.33A 6.0v (without battery pack)

servo's only, in sleep(p.brain from 9v block) 0.14A 6.0v (without battery pack)
servo's only, awake and standing (p.brain from 9v block) 0.33A 6.0v (with battery pack)
servo's only, awake and standing (p.brain from 9v block) 0.21A 6.0v (without battery pack)

i didn't measure the usage without the springs, but I remembered seeing something between 1A and 2A but don't know.
anyway, no need for those light, but expensive lipo battery's :)

but still improvements can be made by shutting the servos off when standing in neutral position.

another nice thing about this spring setup is that the spring force doesn't need to be 100% exact, because the servo's themselves have such high gearing and it takes some force to get them to move too.
When testing in z translation, on hight 10cm (bottom plate to table), where it has almost no spring support anymore it uses 1.85A 6.0v (with battery pack)
Last edited by Tim Beurskens on Tue Jun 15, 2010 12:17 pm, edited 1 time in total.
Tim Beurskens
 
Posts: 5
Joined: Wed Feb 17, 2010 11:11 pm
Location: Netherlands

Re: MSR-H01 with springs

Postby Matt Denton » Tue Jun 01, 2010 9:18 am

Hi Tim,

In order to leave the hexapod standing, and switch off the servos, you should be able to set the DPD height to something just below the DPU height, say 49 and 50. or alternatively under PIP or SIM control you could issue the "!" command which switches off all servos instantly, a bit like an E-stop.
Matt Denton
AKA: Winchy_Matt

micromagic systems ltd
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Re: MSR-H01 with springs

Postby Tim Beurskens » Tue Jun 01, 2010 10:03 am

yes but there is a problem

for example with the following settings
dpd=49
dpu=50
llh=25
llo=30

now the legs only move 1 up, when walking, not 25 or 30

when setting
dpd=40
dpu=50
llh=25
llo=30

now the legs only move 10 up, when walking, not 25 or 30

this is what I meant with dpu minus dpd on leg height
Tim Beurskens
 
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Joined: Wed Feb 17, 2010 11:11 pm
Location: Netherlands

Re: MSR-H01 with springs

Postby Matt Denton » Tue Jun 01, 2010 11:35 am

Yes your right, because the DPD is also used as a minimum limit for leg lift height, so the lift is being clipped. Try the "!" command instead.
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micromagic systems ltd
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Re: MSR-H01 with springs

Postby Tim Beurskens » Tue Jun 01, 2010 11:57 am

ok I tried the "!" command
but this does not work either

to walk correctly (leg lifting and all) i use the following settings
dpd=35
dpu=65
llh=25
llo=30

when apake, I use the "!" , this works
but now I want to walk again, and the only command it reacts to, is the wake command.
ok then, I'll issue the wake command, and it dives into the deep ( dpd=35 ) and then goes to 65 again. And is not really the thing I have in mind.
Tim Beurskens
 
Posts: 5
Joined: Wed Feb 17, 2010 11:11 pm
Location: Netherlands

Re: MSR-H01 with springs

Postby Matt Denton » Tue Jun 01, 2010 12:05 pm

Ok, then in the HexEngine's current state there is no way to do this. I would need to add an option to avoid power-up/down upon wake and sleep.
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micromagic systems ltd
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