Dual Bearing Heavy Duty ATR Support



The DB Heavy Duty ATR kit is an extremely rugged, well-built robot. The robot's chassis is very rigid, and can support heavy weights. We offer two types of chassis: one with an open bottom, and one that is totally enclosed. We also offer two different sizes: one to accommodate IG42 gear motors, and one for IG52 gear motors. The wheels are chain driven, and the axles are supported by two sealed ball bearings that carry the entire weight of the robot. This is our sturdiest design, since all the weight off the motor shafts rests on the chassis. Each of the four axles is driven by large gear motors via a 2:3 #25 chain reduction (10:15 for the IG42 DB and 14:21 for the IG52 DB). With chains, the powerful IG42 Gear 252 rpm motor and standard tires can handle loads less than 50 lbs. For added capacity, the tires can be foam filled, and a lower gear ratio motor can be used. Since it is chain driven, the inside of the wheel shafts is exposed, and optional encoders can easily be mounted. IG42 and IG52 gear motors with encoders are also available.



The frame is made of 1/8" thick aircraft grade aluminum. We cut all of the aluminum with our high definition plasma cutter and assemble the parts with mortise and tenon design for precise alignment and mating of the parts. The frame is ribbed and gusseted making it very rigid. The chassis is completely welded using TIG and MIG.

Motors and Motor Mounts

This ATR is available with our IG42 or IG52 gear motors. The standard motors in the IG42 DB are 252 RPM and the standard wheels are 10" in diameter. The motor to wheel gearing is 2:3.

As a result, 252*2/3*3.14*10/12 = ~440 fpm (~5mph) travel speed. These are quick and powerful robots; However, if you want more power, you can choose a lower RPM motor (which will also reduce the speed of the robot). See the IG42 DB and IG52 DB item pages for all motor options. If you would like to calculate the speed of a robot with a different configuration, see the speed calculator on our How to Build a Robot page

Wheels and Drive Shafts

This robot uses either our 10" pneumatic wheels or our 6" solid core foam wheels. The axles have a .5" diameter steel rod with a welded hub that bolts to the wheel hub.


The final item you need to make your kit complete is a hardware package.

The package includes nuts, bolts, washers, nylon spacers (for isolating your electronics and controller boards), cable ties and cable hold downs.

Chain Coupling

One option available with the DB ATR is the coupling of the front and rear axles on each side of the robot. In the standard configuration, the left two motors are wired together - as are the right two. For example, if driving on rough terrain or turning causes one wheel to stall or spin, the adjacent motor has to do all the work. When the axles are coupled together, though, power comes from both motors. We use #25 chain and the same size sprockets to couple the axles, and a UHMW block for chain tension.