All Terrain Robot Building Page
General Description
This is a robot series utilizes four super swamper tires to drive over just about any terrain. It works on any indoor surface and most outdoor
surfaces (check out the hill climbing video and curb climbing videos on our
main ATR page. Below are the links to different configurations and platforms you can select to customize the ATR to your needs.
There are a lot of other people selling 4WD Robots. We encourage you to look closely at them and compare.
- Our Frames: Our frames are aircraft aluminum. They are laser cut then fully welded and gusseted. They can handle virtually anything you dish out to them. They are not light gauge sheet metal or plastic.
- Our Wheel mounts: With the exception of the mini ATR, our wheels are mounted on shafts that are supported by heavy duty sealed ball bearings. The deluxe and Heavy Duty ATRs have two bearings per shaft. Our competitors just mount the wheels to motors; motors are not rated to handle any significant load or impact when configured like this. Don't be embarrassed by getting a robot whose wheels fall off...
- Our Gear Motors: We use 24VDC planetary gear motors with steel gears. 24VDC equals more power at less current. Our gear housings are very stout and can take the abuse. We tested other gear motors and sometimes did not even get a full battery charge before the motors were smoked or the plastic gears or sintered metal gears were wasted...
- Our Support: We are not "Fly by night". You need support, call us or email us. We are here to help you! Our website has more than 500 web pages filled with information about our products. When you purchase any of the ATR packages you get access to download our full color highly illustrated detailed manuals.
- Our Knowledge: We love robotics, its what we do. We will be glad to help you with your needs whether its a custom robot or standard kit.
Load Capacity
This is a common question. Unfortunately, there is not a straight forward answer. A lot of factors come into play when picking the right robot in terms of capacity. 1st off is understanding our robots are skid steering. This means in order to turn the wheels must skid. So the more weight the harder it is to turn. Pivot turns are the most difficult (one side in forward, one in reverse).
Frictional force is dependent on only two things. (1) the weight and (2) the
coefficient of friction. If you are driving on a slick surface such as smooth concrete, hardwood floors,
linoleum floors, etc. its easier to turn than if you are driving on shag carpet, deep grass, etc.
So that said the more weight you add, the more power you will need to turn.
More power does not need to be bigger motors, you can go with smaller wheels to
get more torque, slower RPM motors will have higher torque. Below is
a typical current drain of a IG42 ATR robot with 122 RPM motors riding with 10"
tires.
- Drive straight concrete: 2.75A
- Drive straight grass: 3A
- Pivot Turn smooth concrete 10A
- Pivot Turn rough concrete 16A
- Pivot Turn asphalt 16A
- Pivot Turn grass 16-17A
- Pivot Turn carpet 14A
- Right Turn or Left Turn Asphalt 8A
- Uphill (loading dock ramp) 5A
Softer tires will typically grip better increasing friction. Softer
tires will also squish down and not be able to support the weight at some point
too. Our 6.75 inch ATR tires are semi pneumatic, meaning they are air
filled, but only with atmospheric air (i.e. you can't inflate them).
We do offer a foam filled option for these tires for our HD ATR base. Our
10" pneumatic tires are going to
offer the heaviest duty. They have steel rims and steel shafts, but since
they are bigger in diameter, the motors need to be geared down so you will have
the power to turn. To through another variable into the mix, you can use
our 4 inch Omni wheels. These
wheels will eliminate the skidding torque issues with a pivot turn since they
roll sideways. The downside of them is they are only 4 inches and not good
on side slopes or in outdoor or dirty environments.
Most of our ATR kits use a single axle that is supported with a bearing, then
coupled to the gear motors. See mechanical descriptions below. The
Heavy Duty ATRs use a shaft that is supported with two bearings, then chain
driven. Using this method removes all the dead load from weight off the
motors.
Yet another thing to consider is how the robot is going to be used and its
duty cycle. If the robot is just going to be used for fun and controlled
with a RC controller is a lot different than industrial use where the motors are
run 100% duty cycle and autonomously. If running autonomously,
consideration must be taken into account for stalling conditions, etc. If
a motor is held in a stall condition for a period of time the motors will burn
up. If you are running a heavy duty cycle you will want to run on the
lighter side of the limits and use higher torque motors so the motors will not
overheat and wear out prematurely.
TThe following table is only based on our experience and should only be used
as guide lines. Results will definitely vary depending on a ton of factors
as discussed above. Also don't forget to add the weight of your
batteries, controls, etc. The weight of the robot with motors is figured
into these guidelines. If you are going with 6WD, you can just multiply
the weight by a factor of 1.3.
Deluxe ATR
Our Deluxe ATR is just that, Deluxe. It offers a totally enclosed chassis. The robot can operate in all weather conditions and can be made water tight so you can completely immerse it in water. The wheels are axle mounted and supported using two sealed ball bearings. Each of the four axles are driven by a large and powerful href="../shop/item.aspx?itemid=375&catid=7">IG42 Gear motor via a cogged timing belt to yield a very smooth and slip free mode of operation. The ends of the shafts are exposed on the inside if you wish to mount encoders to them. Plus many more features. Follow these links for more information about the Deluxe ATR.
Heavy Duty ATR
The Heavy Duty (HD) ATR has the same dual bearing belt drive system as the deluxe ATR, but without the enclosure. The HD ATR allows you to put encoders on the wheel shafts and also allows higher loading than the standard ATR since the wheels are supported by two ball bearings each and the motor does not share the dead load. Follow these links for more information about the HD ATR.
2nd Generation Standard ATR
Our Standard ATR is an ideal platform for building a rugged 4WD or 6WD robot that can handle harsh terrain and offers a lot of power. It comes in two basic sizes (Standard - IG32 gear motors and Large - IG42 gear motors). Follow these links for more information about the ATR.
1st Generation Standard ATR
Our original standard ATR is an ideal platform for building a rugged 4WD robot that can handle harsh terrain and offers a lot of power. It comes in two basic sizes (Standard and Large).Follow these links for more information about the ATR. We no longer offer these as kits, it has been replaced by the 2nd Generation ATRs, but all the parts are still available if you want to piece your own robot kit together.
Mini ATR
This is our Mini ATR that is a smaller more economical robot kit. It still offers 4WD. The wheels are direct coupled to the motors. The wheels are only 4" diameter as opposed to the 6.75" tires on our standard ATRs. Use this robot kit for navigating in tight spaces where the larger ATR power and size is not needed. Follow these links for more information about the Mini ATR.
ATR Support Equipment and Parts
The above descriptions lead you to the mechanical assembly of the ATR Robots, but in order to make the robot run, you need to hook up the electrical power and controls.
Sensors
In order to make your robot autonomous, you will need to add sensors. You can always add sensors later. Be sure to use sensors that are best suited for the micro controller you have selected. If you are using the RF04 CM02 Telemetry kit, you should only use sensors that are I2C, such as our
SRF08 ultrasonic sensors.
Cameras
Nothing is better than a wireless camera to see what your robot sees. We have a large variety of wireless camera including pan and tilt systems.
