legged/wheel robot

[Starlight]

I'm doing a quadruped robot with legged/wheel mode using AX-12s motor. There is a similar project as link below:

http://www.robotis.com/zbxe/?mid=galler ... t_srl=5728

The robot is called starlight, made by Korean student. Did you all got any opinion about this quadruped robot ?[/quote]

[StuartL]

That's pretty cool. We developed a lot of our code using Matt's quadruped robot to get a feel for the libraries without having the costs of balancing. The only thing I think Matt's can do that you haven't taught Starlight yet is rough terrain walking, where it picks up one leg at a time and puts it down wherever it can find purchase.

Your walking gaits are very smooth, they're hard to get smooth like that

[BillB]

The only thing I think Matt's can do that you haven't taught Starlight yet is rough terrain walking, where it picks up one leg at a time and puts it down wherever it can find purchase

Out of interest how does Random Matt's quad detect the purchase. Are these sensors on the feet - or is it achieved through by monitoring the current and position feedback of the AX12's?

[Starlight]

without using the any sensor, how can the Starlight walking on the rough terrain using AX-12s? any idea?

I'm also facing the problem of walking algorithm. how's the Starlight can walking by moving 2 leg in the same time and without falling down. I know maybe need calculation on robot's center of mass.

[Starlight]

For the wheel mode, I think I'll using the DC geared motor attach with robot's wheel. while for the legged mode, of course AX-12s as the actuator.

[StuartL]

The only thing I think Matt's can do that you haven't taught Starlight yet is rough terrain walking, where it picks up one leg at a time and puts it down wherever it can find purchase

Out of interest how does Random Matt's quad detect the purchase. Are these sensors on the feet - or is it achieved through by monitoring the current and position feedback of the AX12's?

Effectively we pick the leg up too high, surge a high current to get it moving under its own inertia and then limit the power to just enough for it to keep moving. When it stops moving we know that it's hit something.

[BillB]

Effectively we pick the leg up too high, surge a high current to get it moving under its own inertia and then limit the power to just enough for it to keep moving. When it stops moving we know that it's hit something.

Interesting trick. Out of interest do you think that this could work very well with the stock AX12 firmware? - or do you need a use custom AX12 firmware?

[StuartL]

Effectively we pick the leg up too high, surge a high current to get it moving under its own inertia and then limit the power to just enough for it to keep moving. When it stops moving we know that it's hit something.

Interesting trick. Out of interest do you think that this could work very well with the stock AX12 firmware? - or do you need a use custom AX12 firmware?

I think it's workable, you'd have to fake the leg positions to 'chase' the torque as the leg moves as the torque curve for offset from goal position seems to be much more usable than the torque limiter.

However I don't see why not...

I keep thinking about scratching the humanoid and building a massive octopod with both Bioloid kits...

There's a Matt to convince of course...

[BillB]

I keep thinking about scratching the humanoid and building a massive octopod with both Bioloid kits...

Well with 2 Bioloid Kits you could make a gigantic Dodecapod (12 legs) . Might be worth doing it just to for the sake of making a worlds first.

Mind you I have converted mine to a Hexapod - and that is challenging enough with 6 legs.