30lb Fighting Robot Overview




This is the third generation of this design that I built. The first weighed 60lbs, the second exploded in testing and the third has survived Motorama 2011 with almost no damage.

Generation 1 is pictured with caution tape decorations
Generation 2 is shown in pieces

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Step 1: Design

The  new build uses waterjet cut 7075 Aluminum to create a strong, light chassis. The chassis was designed in Solidworks and sent out to teamwhyachi.com for cutting. Using this method meant that when the chassis components arrived it was essentially a large metal jigsaw puzzle.

The machine uses primarily off the shelf components for the internals. The drive motors are modified 18v dewalt drill motors with matching gearboxes, the weapon motor is an Ampflow A28-150 DC motor, the drive motor controllers are Holmes Hobby BR-XL controllers, the weapon controller is a IFI Victor 885, the radio system is a Spektrum DX6 tx and BR6000 rx, and the batteries are custom A123 packs, all of which are available in the used form or newer form in the case of the radio equipment online.

The top and rear armor is a custom composite layup made of Zylon. It is three layers thick and the layup was done on an open mold made of plywood and car body filler. 

The image of the electrical diagram shows a simplified version of how the wiring was done in Moros. As it shows, the drive and weapon are on independent power, this is to avoid serious voltage drop to the receiver and to allow a lower cell count battery to be used on the drive side for reduced weight.

Step 2: In Use

The robot competed at Motorama 2011 in the 30lb weight class under the name Moros. It finished with at 2-2 record and is still fully operational.

The video below is of one of its fights at Motorama-

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    9 Discussions

    Mr AbAk

    4 years ago

    Awesome Robo


    5 years ago on Introduction

    Hi!!! I´m trying to build a similar battlebot, but I´m having problems with the motors that I need to use. I can afford 100USD tops for the weapon motor, so that excludes the motor that you indicate, can you help me with that?? or someone who has an answer please?? I want to do an instructable of this!! Thanks!!

    MikeNCRViraj nayak

    Reply 6 years ago on Step 2

    It's an older version of this motor- http://www.robotmarketplace.com/products/0-A28-150.html


    6 years ago on Introduction

    I'm considering building a combat robot. The one I have in mind would be a 4 inch thick 12 inch by 12 inch box driven by two wheels, with a 5 pound bar (2 feet long, 4 inches wide, 1/2 inch thick) Aluminum 7075 bar driven directly by a F30-150 motor (overvolted to 29.6 volts - 8s) on top. I have a couple questions:
    1. When the aluminum bar hits the other robot, will it break? Top speed would be about 8000 rpm and 23000 joules.
    2. To save weight for a 30 lb robot, I'm planning to use 1/8 thick aluminum dust covers and put springs over it to cushion impacts. Will this be effective?
    3. Since a 4 inch robot is relatively tall, I'd like to put some metal underneath to hit a robot that's very thin. How do I do this?
    4. Will two wheels give enough power and traction? They are BaneBots wheels Shore A 40 and I'll have about 400 watts combined pushing.
    Sorry for all the specs, but I feel like most of them are necessary to get good answers.

    1 reply

    Reply 6 years ago on Introduction

    Aluminum would likely bend or break at that sort of speed. There's also a good chance the shaft would bend. In this robot, the gearbox has a 1" titanium output shaft which is quite a bit stronger than the 1/2" shaft on the F30-150.

    For a weapon focused bot, I tend to take the approach of "bolt everything to the weapon assembly" because it allows for a relatively durable, light setup. I think the springs will just add weight without helping your design much, and at least for components directly connected to the weapon I'd look more at 1/4" thick aluminum, preferably a higher grade like 7075, as it will be much stronger. Any area that isn't likely to be hit can use more of a dust cover approach. On this robot, I think the top composite armor was somewhere around .030" thick Zylon (similar to kevlar) and it served its purpose well.

    There's been a decent number of bots to go that route, but having impact heads hanging down off the bar adds a serious amount of bending force to the bar on an impact, which is why I went with the angled setup. If you have the weight, it may make more sense to have a wedge on the front side of the robot to guide low bots into your weapon.

    As far as drive power, I'd need to know which motors/gearboxes, gear ratio, voltage and wheel size to say for sure if it'll work.


    Reply 7 years ago on Introduction

    I'm using a Team Whyachi TWM3R gearbox with the spin shaft option and a 10deg angle machined on the bottom of the gearbox.



    7 years ago on Step 2

    Wow thats awesome!! Im gona try and make one!