Walking Robot from Vex Kit?

[jeffmorris]

Is it possible to build a walking robot from the Vex Robotics Kit? Which is easier to build: two legs, four legs, or six legs?

[lynca]

I would start from lego if the lego parts are available then try to step up to vex. There have not been many designs posted on arms and actuating. However, if you are really motivated, just check out KR 1 for more info,

http://robogames.net/videos.php
~Andrew Lynch

[artdutra04]

Originally Posted by jeffmorris

Is it possible to build a walking robot from the Vex Robotics Kit? Which is easier to build: two legs, four legs, or six legs?

Anything is possible with Vex kits! I haven't built any walking Vex robots (yet... ), but I have built walking Lego Mindstorms robots. The four and six legged ones were easier to stabilize while walking. The two legged one required me to shift the center of gravity while it walked. Building a two-legged Vex robot will need a shifting COG; the COG will always need to be over the leg that is on the ground. A four-legged robot will need a COG that is centered over the two legs in contact with the ground. A six-legged robot should never fall over, since three legs should be in contact with the ground at all times.

[Jeff K.]

Yeah, I agree with art. Nearly anything is possible with a VEX kit...or two. It would be easier to build a 4 or 6 legged robot than a biped. With a biped, it might fall over due to being unbalanced and a gyroscope or two might have to be used to keep it balanced. You could use programming now with the VEX kits so it shouldn't be too hard though. You may not even need a gyroscope if you get all the timing right for the different movements, like the bending of the knee joint, the hip movement, and the ankle rolling to make it walk.

Here are some bipeds if you're interested in different designs.







Good luck making one. Should be somewhat of a challenge.

[foobert]

i would be concerned about the weight of the vex parts, and the number of parts required to keep an axle attached to a motor. also, a walker requires quite a few motors. a quadruped with two degrees of freedom per leg will need eight. servos would be preferred over continuous rotation motors so that you could control joint position without adding sensors at every joint. at eight motors, of course, you will have used all the motor outputs on the controller and would have to code your own pwm, (not so hard, except that the way the vex handles its pwn makes it difficult to time anything else.

my personal feeling is that the vex kit is all about rolling robots, but of course someone's bound to make me look an idiot. some things one must learn to accept.

[ChrisH]

I think a walking robot would be difficult with just the starter kit, especially if you can't cut the pieces that come in the kit. (many schools would have that rule so the parts will be there for next year) But if you can add motors, sensors, etc it could be done with a bit of work. If you have unlimited materials, then it can certainly be done.

Using the servos instead of motors might make things easier because you basically have built in position control.

ChrisH

[jeffmorris]

Parallax has Toddler robot that uses only two servos to make it walk. Is it possible to build it using Vex Robotics Kit? I think that I committed a crime of cutting a long bar into three pieces for my car-type robot. I use the Vex Robotics Kit and add-on kits at home, not at school.