Author Topic: Brainstorm: Crazy walking revese pendulum  (Read 1242 times)

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Offline AsellithTopic starter

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Brainstorm: Crazy walking revese pendulum
« on: May 17, 2010, 08:41:48 AM »
Ok so I had a crazy idea. I will be a while before I get to trying it and maybe not ever but I wanted to bring it up and see what people thought.

Watching the mech warefare videos got me thinking. Why couldn't the lower actuator be a simple reverse pendulum robot. Battery life would be horrible and the kinematics might kill it with different points of connection causing the corrections to not be able to compensate right without nasty math BUT here is my idea...

Instead of a foot the biped has a DC motor driven wheel. (A servo might work the same way not sure) The gait becomes simple because you just pickup and leg and move it forward then adjust the set point of the wheel to let the robot fall onto the other leg and repeat. The motor/wheel/foot simply uses an accelerometer and works like a segway to keep the leg vertical as much as possible. Horizontal force might be an issue but a servo and the accelerometer might help keep it from falling to the side. Again the wheel might be redundant and a servo attached to the foot like normal might work fine. Having no experience with Pendulum robots and bipeds I thought i would open this up to discussion and see if my crazy idea has any merit :)
Jonathan Bowen
CorSec Engineering
www.corseceng.com

Offline TK

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Re: Brainstorm: Crazy walking revese pendulum
« Reply #1 on: May 17, 2010, 05:52:14 PM »
That would be a interesting idea to try out.... Getting the balance of the bot itself would be a challenge and programming would require lots of trial and error but personally I don't see why it wouldn't work with the proper materials and hardware.  Maybe do up a rough sketch?

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Re: Brainstorm: Crazy walking revese pendulum
« Reply #2 on: May 19, 2010, 08:57:29 AM »
Don't you mean an inverted pendulum? :P

And your idea has already been done, its called a 'passive walker'. I call it a 'dynamic walker', where dynamic forces are taken into account. The type you saw at mech warfare are 'static walkers'.

Google those terms, you'll find a lot of useful information.

Passive Walker

Offline AsellithTopic starter

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Re: Brainstorm: Crazy walking revese pendulum
« Reply #3 on: May 20, 2010, 09:33:22 AM »
Ok yes but not really... Picture this an inverted pendulum robot like a segway where a two wheel design is able to stand straight up and down. Now take a second segway and attach the two with a set of knees and a hip system. Lean the robots weight onto the first leg and lift the second. Then you can move the second leg where ever you want without it affecting the balance because the foot of the first leg is compensating. obviously there is a limit.

It seems to me that the passive walkers where more about designing legs that couldn't fall down or provided the balancing for the robot by rounding them and adding weights. I was thinking more of an active solution that would put the less emphasis on the entire body being in balance and just have a beefy motor in the ankle to force the robot upright. Now some of the more advanced examples I found for passive walkers might fit this description but I only saw one that got close and it was hard to tell.

As and after thought the pendulum system will need to be 2 axis unlike the segway to compensate for the higher center of gravity. So two motors in the ankles :)
Jonathan Bowen
CorSec Engineering
www.corseceng.com

 


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