Walker rule clarification? Unusual design.

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GeorgeR
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Walker rule clarification? Unusual design.

Post by GeorgeR » Thu Jun 07, 2018 9:48 am

I've been working on a new antweight design with an unusual method of movement, and was wondering if it would count as a walker under the rules.

The bot will move by waddling along on two stationary feet, with the waddling motion being caused by a combination of gyroscopic precession and torque reaction from two large horizontal spinners. The spinners will be the only moving parts of the bot.

Do you think this would count as a walker?
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Re: Walker rule clarification? Unusual design.

Post by DieGracefullyRobotics » Thu Jun 07, 2018 12:05 pm

Simply using 2 spinners to gyro your robot along (like Clean Sweeper in America, I'm guessing?) wouldn't be a walker because it's still just using rotational movement to propel forwards. The simplest way to change it to a walker would be some sort of twist foot mechanism, like Rex in Battlebots or his ant equivalent. Then you're not simply skating along on vibrations and gyro but converting the energy into a walking motion, though I still think that's a bit dubious in my opinion.

I guess, put simply, walkers (or technically shufflers) need some sort of mechanism to translate the roundy-roundy output of the motor into an uppy-downy movement on the legs. There's no mechanism in a skater or bristlebot, so it's not a walker.

If you wanted to bend the rules, you COULD put in a walking mechanism and then keep it stationary once activate has happened, skating along on the gyro instead but I think you'd have to prove it could at least walk at the start of a fight to qualify for the allowances in the first place. Not that I recommend bending rules of course :wink:
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Re: Walker rule clarification? Unusual design.

Post by MarkR » Thu Jun 07, 2018 2:00 pm

Would a bristle-bot or similar be allowed if it has no (visible?) rotating components in the drive? A vibration-motor or solenoid powered drive system?

(NB: I don't have any plans to build one)
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Re: Walker rule clarification? Unusual design.

Post by DieGracefullyRobotics » Thu Jun 07, 2018 2:38 pm

Like a back-and-forth vibration? It would still lack a mechanism to walk though. Directional bristles are more akin to the motion of a tracked robot than anything classed as legged.
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Re: Walker rule clarification? Unusual design.

Post by GeorgeR » Thu Jun 07, 2018 2:55 pm

Someone asked about bristlebots last year, and the general consensus was that they did count as a walker, (which was my also my opinion).

I wasn't actually thinking of a bristlebot, but something a bit more odd (Wrecks from battlebots would be the closest approximation).

The two spinners would run in opposite directions, increasing the speed of one while slowing down the other would turn the whole body of the bot. But by twisting the axis of the slightly diagonally mounted spinners the side moving forward will lift gyroscopically, allowing that side of the robot to step forward.

Maybe I'll build a proof of concept and see how people would classify it.
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Re: Walker rule clarification? Unusual design.

Post by DieGracefullyRobotics » Thu Jun 07, 2018 3:20 pm

It's the problem with asking at an event (or on here) and getting a concensus based on the opinion of the room vs what the actual rules say. Most people will answer a question on gut instinct with whatever their opinion is but not actually give it much thought and, in that context, most people will answer "yeah, sure, why not?". It's why people outside of the UK ant scene always moan that we have the 4" cube or the drop-offs because they haven't considered there might be a reason for them beyond what they think constitutes "good fighting".

I can't see any way that a bristlebot would count as a walker in the context of a rule. They are skaters, they don't walk, or make any movement that could convincingly be described as walking. They don't line up with the walker rules in any way so why should they get a weight advantage? They aren't a difficult or challenging build so why should they be rewarded in the same way as a true walker?

Sorry, going off on one about bristlebots. I think a "gyro walker" is much more of a challenge to get working well and I think creativity should be rewarded, especially in the current climate where people are seemingly happy to buy a robot rather than build something themselves. But the question was about rule clarification and rules aren't about my personal opinion, they are about being the bottom line to any debate.
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Re: Walker rule clarification? Unusual design.

Post by GeorgeR » Thu Jun 07, 2018 3:55 pm

Sorry not sure I explained myself properly, I didn't mean I was going to turn up with a working ant and try and enter. More that I might bodge a prototype together to check that the idea actually works, post a video and ask how the powers that be would classify it, then build to whichever weight is decided.

As for bristlebots, I wasn't even trying to start a discussion, I just remember seeing on here a while back that they are considered walkers, maybe that was wrong. I figured they're an unusual method of motion, definitely not wheels, and come with other downsides even compared to conventional walkers (no reverse, no grip), so they should probably count, given the rule is intended to promote unusual entries.

I certainly agree that the rules should be the definitive answer, but it's impossible to write an set of rules without some ambiguities, so there will always be a need to agree on an interpretation for unusual cases.
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Re: Walker rule clarification? Unusual design.

Post by DieGracefullyRobotics » Thu Jun 07, 2018 4:23 pm

I agree with you on all that, except the bit that says the walker rule was made to promote unusual designs. It wasn't, it was made to promote the challenge of building a walker, ha. People have talked about building a hovercraft style robot in the past, also a challenge, also not wheels, but not eligible for the walker perks because its not a walker. I guess there is an argument for making "any robot without wheels" eligible for the 4th slot/weight rewards which would reward creativity.

Anyway, yeah, none of this is necessary. I'm always a killjoy in these situations because nobody else wants to be. I think most people would rather avoid all debate and just have a weight limit, a 4-robot-per-team entry and anything goes within that. Seemingly it's just in my nature to try and keep things official and ruin it for everyone.
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Re: Walker rule clarification? Unusual design.

Post by peterwaller » Thu Jun 07, 2018 6:15 pm

The actual rule which can be found here http://www.antweight.co.uk/rules.htm states
Walker - A robot whose final drive output rotates through less than 180 degrees (e.g. legs)
So unless the bristles rotate through more than 180 degrees it must be a walker. :roll:

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Re: Walker rule clarification? Unusual design.

Post by DieGracefullyRobotics » Thu Jun 07, 2018 6:48 pm

But the final drive output isn't the bristles, it's the motor causing the vibration. The bristles don't 'drive', they are static. Otherwise, that would also definine a hovercraft as a "walker" as the cushion would count as the final output, not the fan...
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Re: Walker rule clarification? Unusual design.

Post by AntRoboteer » Thu Jun 07, 2018 8:25 pm

Without the bristles in that scenario, there would be no movement from the robot; the bristles are the moving legs.

It's like saying walkers like Drumbledore aren't walkers because they use a motor which rotates more than 180 degrees spinning a cam shaft which would not make sense.

I would classify this machine as more of a shufflebot but if anything is certain, it is definitely not a 'roller'.

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Re: Walker rule clarification? Unusual design.

Post by DieGracefullyRobotics » Thu Jun 07, 2018 8:42 pm

No, because the mechanism on, say, Drumbledore translates the circular output of the motor into a walking motion. It is the mechanism that turns it from one to the other. A bristlebot doesn't do that. It has no mechanism, just vibration, which is caused by circular motion. No, it's not a roller, but robots aren't split exclusively into rollers or walkers/shufflers. By this logic, I could put a mobile phone in the arena set to vibrate and ring it and it would be classed as a walker. Which I think is nonsense.

Obviously I'm the only one to think this way so I'm happy to shut up about it. I just think it's a slippery slope away from what the walker rule is supposed to represent.

In tangent, the wording that Peter posted would outlaw Wrecks as a walker as its back "foot" rotates through 360 degrees. So to get back to George's original question about his design, I think the key will be the pivot that the robot performs. Purely by the wording of that rule as it stands and disregarding my personal opinion, it would definitely qualify for the walker allowance.
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Re: Walker rule clarification? Unusual design.

Post by Shakey » Thu Jun 07, 2018 8:57 pm

I don't agree with bristle bots being walkers. I consider the final drive output to be the last directly driven component in the drive, not just a part that vibrates. Bristlebots in my mind have a final output that is rotating through 360 degrees.
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Re: Walker rule clarification? Unusual design.

Post by AntRoboteer » Thu Jun 07, 2018 9:11 pm

The final output would be the contact surface with the arena.

Wheels are the contact surface of any roller and rotate more than 360 degrees. Legs are the contact surface of most walkers and they rarely rotate, merely move up and down (although you could class as an approx 90 degree movement of the foot as it walks).

Bristlebots utilise vibration motors in order to agitate bristles. The bristles tend to move in a leg like movement, and as such have a similar type of movement to a conventional walker. They would border on being walkers.

Another way to think about this is as follows:

An example walking spinner robot has legs and a cam shaft system to drive it. When the spinner spins up, there is a gyroscopic force applied to the robot. If one of the sets of legs were to lock up, the robot would likely still be able to 'gyro dance' using one set of legs and the spinner.

So,

a) Under current rules, that would be fine and the robot would be considered as mobile and competition legal as it can still move around the arena in a controlled manner.

b) Through the classification that any part of final drive output must not rotate more than 180 degrees, since the spinner is providing a significant component of the robot's final movement at that point, it would not be classified as competition legal despite clear mobility.

Clearly, a) is the sensible option. However, if the final output were not to be classed as the contact surface, b) would come into play and disqualify the robot. This is why it is clear the rules mean that the contact surface should not be rotating more than 180 degrees.

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Re: Walker rule clarification? Unusual design.

Post by Lincoln » Thu Jun 07, 2018 9:26 pm

your not the only one that thinks that way Dave just the most vocal.
having designed what i believe to be one of the most effective walking mechanisms implemented in antwights. i would agree that a bristle bot should not get the extra wight allowance of a walker, without getting into anything about how much the "final drive" rotates. it simply should not get the extra wight because a bristle bot mechanism would require less wight than just having wheels. even with a 2 sided system to have control, a tiny offset wight on a small fast motor and a tooth brush head seems like less wight and less effort than putting wheels on the end of heavy metal gear-motors. whereas my walking mechanism is about 10 grams per motor heaver than using wheels.

however, i think people may be scared of bristle bots becoming a thing because of hex-bugs and things, or as Dave said a vibrating phone. but theses are already addressed by the no commercial product without significant modification rule. if someone builds a bristle bot and proves that it takes more wight than wheels ill change my opinion but for now, bristle bots are neither roller or walker, they are bristle bots and such do not count to get the extra wight allowance.

but back to the original question, what i think George is describing would count as a walker and a pretty cleaver one at that. imagine a cube with 2 giro effect spinning masses inside. suddenly speeding up or slowing down of these would cause the cube to tilt up on one side then as the other spinning mass was moved would cause the cube to pivot round on one corner. doing this repeatedly would make a definite walking motion.
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