Hello all, I'm new...

SN96

Hello guys,

I have a project I want to do. I want to create a 10 servo biped walking humanoid. I think I am going to go with the Basic Stamp 2px. I looked at the Basic Atom, but I don't like the program interface software. The Atom is much faster but I don't think I need that much speed for what I want to do.

I love the Parallax program interface. it is very streight forward and what I like most of all is the tons of example material that can be found on this site to help me along.

Mikey

Paul Baker

The biggest issue will be generating 10 different servo signals simultaneously, fortunately Parallax sells the Parallax Servo Controller which is capable of controlling upto 16 seperate servos. Using the PSC will offload the responsibilty of driving the servos, leaving your stamp to work on higher level functions such as movement control, navigation, sensor interfaces, etc.

Another issue you need to seriously consider is that 10 servos will require a considerable battery pack to operate. In a biped robot, it is absolutley nessesary to keep your center of gravity over your support base. The larger your battery is, the higher center of gravity of the robot will be and have more mass (increasing the dynamic instability of the system, just like an SUV is nearly 5 times more likely to roll over in an accident than a sports car). This means if your center of gravity moves beyond your base of support even for a split second your biped will crash to the ground. Issues such as walking over uneven terrain or walking·up/down/across slopes can cause your robot to loose it's upright stability.·This isn't meant as discouragement, just a heads up on issues you will need to pay particular attention to.

Take a look at the Toddler, Parallax's robot that is most like your desired robot.

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·1+1=10

Post Edited (Paul Baker) : 8/25/2005 7:42:21 PM GMT

SN96

Thanks Paul,

Yeah, I have put a ton of thought into this project. The feet will have a rather large surface area to allow for more stability. I plan on basic movement to learn the maximum limits as to how much it can lean / bend before falling. I'm not too concerned how well it is going to walk. I just will enjoy building and trying to get it to walk.

I have not thought much about the battery. Thanks for giving me some tips, I appreciate it.

Mikey

Jon Williams

Use your BS2px to manage the robot, and the PSC to manage the servos.

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Jon Williams
Applications Engineer, Parallax

SN96

I definitely will have a servo controller to run the servos to allow the movement required.·My biped is going to have:

For just one of the two legs:

2 servos for the hip
2 servos for the ankle
1 servo for the knee

5 servos per leg x 2. Total servos =10

I plan on shifting the torso so that is directly over one foot like so:

···Centerline
·_____|_____···<

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Base of torso
··· \····|···· \
···· \···|····· \·
····· \··|······ \ <---This leg is ready to move one step
······ \·|········\
······· \|·········\
····

---

···

---

This will allow movement of the outside leg to bend at the knee and move forward, and at the same time, the leg that is centered·under the torso will pivot at the ankle taking a first step. Obviously there will need to be a lot of experimentation as to the proper sequencing, speed, and travel, to get it right. This is the basic starting point I will use.

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