[TC11] Regicide

[krtwood]

Let's start of showing you where I'm at now, then we'll talk about where I was and why that didn't work.

The weapon is a horizontal spinner, driven directly by two XL motors, with two loaded battery boxes in the blade.  I tried a couple variations of using belts and clutch gears to protect the motors but none of that really worked.  Ultimately it's remote controlled so the driver is the clutch gear, I suppose.  Because the spinner is fairly high off the ground, higher than I figure many of the other bots will be, I needed some way to reach out and touch those little guys.  I was originally thinking of doing a retractable ramp that would extend out from the middle of the bot and force them up into the spinner.  Then I decided to use linear actuators at the back and pivot the whole superstructure down.  At maximum lift the blade gets within 4L of the ground.  This approach sacrifices a lot of rigidity of the superstructure.  Well, it's still rigid, but it is not solidly connected to the body.  This means some of the impact when the spinner connects is going to be lost, but I like the idea of being able to target specific heights on the other bot.  I think it's a worthy trade-off.  When at max lift the bottom front edge of the superstructure rests on the top front of the base to help with this, as well as a lot of bracing on the vertical guides on either side of the superstructure.

A side effect is that the superstructure is easily detached from the base with the removal of two pins, two 3L thin liftarms, and one electrical connection.  I originally intended all the RC receivers to be in the back of the superstructure but once I added the lifting feature that would have required a ridiculous number of extension cables that I don't have.  So I put one on either side of the base and tried to make it not look too out of place.  The long panels unfortunately can't be any higher without getting brushed by the spinner.

Drive is two L motors through worm gears, so it's not a speedy bot.  The three wheel design with a lot of the weight on the third wheel almost directly under the center of the spinner makes it able to rotate almost in place.  The plan is keep the other bot in front of you and let them come to you.  It just has to be able to spin faster than they can drive around.  Lift mechanism is an M motor.  The base is pretty solid other than a few decorative fill in pieces.  Battery boxes are integral but you can replace the batteries just by removing the black 15L liftarms on the top.

Now we come to my tale of woe.  The bot's name was supposed to be "The King".  Bricklinked a bunch of 3L axles and yellow half bushes to make its crown.

Two sets of inverted tracks mounted on springs to soften any blows.  The King was quite proud of his sapphire in its bezel.  The color cast by the dark trans blue on the yellow was the inspiration for using bright green on the base.  There was just one slight problem once all the pieces came in and the crown was complete.

Too much weight on the turntables.  I guess I should have known.  I tried running a liftarm inside the two turntables to support weight very early on in the build but that actually made it much worse.  Anyway, without any complex drivetrain to protect the crown was much bigger than it needed to be and kind of pointless so its not the end of the world.  It had personality though.  So I changed the name to Regicide because The King is dead.  Now I have to come up with something much lighter to make the top look finished.  I'm not sure if I will even keep the yellow circle.  Getting rid of all that would bring the weight down a lot and speed up the spinner.  I have a bunch of the shorter bright green panels I could do something with.

Oh, it was 45x45x40 with the crown.  Now I think it's around 45x40x32.

[PKW]

First congratulations to the photo quality and look of the bot, then a couple of critics/suggestion:

 

I found the front wheels a really weird/bad choice mainly because wheels are so on the back that you are wasting all your momentum to turn, are you considering from wheel drive or caster wheels? Slow and sluggish bot never win ;)

 

For the weapon, coupling xl motor is not a really good idea for a spinner, it has a lot of mass so high rpm are not necessary but i'll focus on mechanism efficency (like you can move the motor under the disk and so you won'the have the weight problem, and even remove the turntable because they really have too many frictions, lego axles works good even with weight but it is better to swap to 2 battery for battery box, more speed and less friction )

The armour looks really solid, but all the angle moving mechanics looks really unstable and not male to absorb impact from a so big disk.

Another thing: worm gears are really inefficient with logo, of you use an equivalent ratiobut with gears only you'll a gain up to 50% power, so maybe you can reduce the ration by half and have more speed but same power

 

Looking forward to the next regicide!

[agrof]

Very original entry and well thought structure, despite the disadvantages I like it a lot! How much does it weight?

Also a good example, that You can build real monsters in 45x45x45. 

p.s.: I am super envy for Your woodshop, and the artistic products You make... I must quit...

[nerdsforprez]

Nice presentation and thanks for sharing the failed attempt of "the King" - Would have loved the idea had it worked.

Overall, I like the entry..... but have to admit I still have concerns for the range of the blade.  I like that you added its ability to direct the blade downward, but I still think the range might be a little short.  By the time an opponent is close enough for the blade to do any damage, you yourself are in danger of whatever damage they can inflict on your bot.  Kinda like a very sturdy, strong, boxer but with really short arms......

[krtwood]

10 hours ago, PKW said:

I found the front wheels a really weird/bad choice mainly because wheels are so on the back that you are wasting all your momentum to turn, are you considering from wheel drive or caster wheels? Slow and sluggish bot never win ;)

I think it turns quite well for what it is.  It pivots around the axis of the spinner.  If it had wheels out in the front they would reduce the reach of the spinner.

10 hours ago, PKW said:

For the weapon, coupling xl motor is not a really good idea for a spinner, it has a lot of mass so high rpm are not necessary but i'll focus on mechanism efficency (like you can move the motor under the disk and so you won'the have the weight problem, and even remove the turntable because they really have too many frictions, lego axles works good even with weight but it is better to swap to 2 battery for battery box, more speed and less friction )

If you don't think two motors is a good idea you aren't going to like four motors :)  Realistically it's much easier to make a strong chassis that will not come apart than it is to make a weapon that can do any real damage.  We would all be better off making solid bricks of liftarms that ram into each other but where is the fun in that?  So if you are going to make a weapon then it doesn't make sense to me to put more power into moving the bot around than you do into moving the weapon.  I did think about having two motors driving the spinner from the top and two motors driving from below but the way things worked out there was no room.  I have some ideas on reworking the superstructure.  With the cage removed from around the motors the length of the bot is now down to around 35L.  I think if I make the upper beam more rigid and extend it past the back of the bot I can hang a battery box at the end as a counterweight.  Then I can either remove a battery box from the base or add two more motors.

11 hours ago, PKW said:

The armour looks really solid, but all the angle moving mechanics looks really unstable and not male to absorb impact from a so big disk.

It's more solid than it looks in the back.  I don't think you can see all the bracing in the back in the pictures.  The two vertical supports are actually being pulled in so they pinch the superstructure.  There is more movement at the pivot point in the front than in the back.  I think it would be better to have a couple of small turntables instead of just pins.

11 hours ago, PKW said:

Another thing: worm gears are really inefficient with logo, of you use an equivalent ratiobut with gears only you'll a gain up to 50% power, so maybe you can reduce the ration by half and have more speed but same power

Honestly I never considered anything else.  It got the gear reduction and the motors turned 90 degrees so it would fit.  I had been trying to make the battery boxes removable so there is some wasted space in the middle of the bot.  I could open up more space but I doubt I will have time to rework the base very much

 

11 hours ago, agrof said:

Very original entry and well thought structure, despite the disadvantages I like it a lot! How much does it weight?

Also a good example, that You can build real monsters in 45x45x45. 

p.s.: I am super envy for Your woodshop, and the artistic products You make... I must quit...

Thank you!  I am better at making things in wood than in lego, but it is easier to fix your mistakes :)  The weight is about 2.5 kg right now.

 

8 hours ago, nerdsforprez said:

Nice presentation and thanks for sharing the failed attempt of "the King" - Would have loved the idea had it worked.

Overall, I like the entry..... but have to admit I still have concerns for the range of the blade.  I like that you added its ability to direct the blade downward, but I still think the range might be a little short.  By the time an opponent is close enough for the blade to do any damage, you yourself are in danger of whatever damage they can inflict on your bot.  Kinda like a very sturdy, strong, boxer but with really short arms......

Thanks.  There are some very effective Battlebots, like Minotaur, that have hardly any reach at all.  The spinner can reach between 14L and 12L depending on how far off center the other bot is, which I think is pretty respectable.  The crown stuck out much further than that but it was really pretty indestructible.

[krtwood]

MUAHAHAHA!  When in doubt, add more motors!  I didn't think four XLs would run off one receiver but it does.  I have 2 V1 and 2 V2 receivers and using one of the V2s for the drive so I would have had to use two V1s if it was going to be two.  Tried it off of the one V2 that was already there and it worked.  It does of course cut out when the spinner gets stalled but I don't see that as a bad thing.  It spins fast enough now that you think twice about sticking your hand in the way of it.  That's all I really wanted.  

 

[agrof]

Looks good, I like the new upper structure. If you don't have the place to build back the crone, there is still one legitime solution by using this part: http://brickset.com/parts/4100457

Maybe with a skeleton minifig...

[PKW]

Weapons  speed is OK and u really like the new superstructure, but that bot is really slow, it could be out maneuvered by other bot and pitted/flipped or attached on the weak points.

For what i've said about front wheel drive and weapon motor under the blade look at "robot wars APEX", sorry for not providing photos but can't resize them and the photo I found on Google are too big to be posted 

[krtwood]

On 3/16/2017 at 2:38 AM, agrof said:

Looks good, I like the new upper structure. If you don't have the place to build back the crone, there is still one legitime solution by using this part: http://brickset.com/parts/4100457

Maybe with a skeleton minifig...

Ha ha ha!  Yes, this is going to happen.

I think I have fully addressed the speed issue and now have the opposite problem of it being so fast that it's hard to control.  My only experience with RC technic was 8043 and 42030 which are both slow so the bot didn't really seem slow to me before.  Now it is fun to play around with.

I have been through a few revisions on the chassis.  It's hard to do this backwards and change out the guts from the inside rather than build around them.  Moved the two battery boxes in the base into the middle which made room for two sets of two L motors for the drive through adders.  There was no room for any gear reduction after the adders.  The two BBs in the base are now just for the drive and raising of the superstructure.  Which means there are now two more battery boxes hanging off the back of the superstructure to power the spinner.  It did not turn well until I switched the front wheels to not having tires.  The weight is up to just over 8 lbs / 3.7 kg.  The back end of the chassis drags slightly on the ground because the drive wheels are moved forward but it does not impair the performance.  I moved the spinner up one stud which allowed closing in of the top side and a much better looking bulldozer style front end.  The receivers are no longer sticking up at the back.  You can't see the two in the base, they are in the opposite corner.  There will be one more in the corner that you can see for raising the superstructure.  I tried using the small turntables for the superstructure to pivot on but that relied on pin connections to stay together and I had trouble bracing it so it wouldn't come apart.  I ended up going back to the pins.  I will get proper pictures once I get in my Bricklink order with the extra receiver I needed, that one black #3 connector I was short on, and the skeleton king :)  Otherwise I think it's just about done.

[aminnich]

It looks really good, I must say the yellow and green combo looks good together like that 

You said about wanting to slow down your bot, I am going to guess that you mean the drive.... I might have a suggestion.  

I am going to send a you PM, if you are ok with what I send you, we can put it on here.  

 

[PKW]

That new drive place your bot in 2nd place on my tierlist (before is was at the bottom) congratulations! Also good work on the new spinner gearing and spinner pivot support, still don't like the spinner bar but looks really tough now and this is a good point