Single Bearing ATR Support

https://www.superdroidrobots.com/shop/custom.aspx/atr-mechanical-overview/51/

Summary

These robots are our medium duty platforms that are supported at each axle by one sealed ball bearing. This takes most of the load off of the motor shafts and puts it on the chassis allowing the robot to carry more weight than if the axle was directly mounted to the motor. See the chart below for approximate maximum loading. These robots work on any indoor surface and most outdoor surfaces. Below are the links to different parts you can add onto the robot platform to customize it to your needs.

Keep in mind when building this kit, that the wheels protrude past the front part of the chassis and with enough power, the robot will climb a wall. This gives it he ability to climb curbs and rough terrain, however if the obstacle is high enough the robot will likely flip over. So you want to make sure you have all your components on the top protected and secured for such an event.

Pictures

View a SolidWorks EDrawing to see a 3D image of the robot. You can manipulate the model and see all the pieces from every orientation. A simple way to see all the views is to hit play and it will automatically rotate the robot around for you so you can see all the views. Please note our models are done to a level of completion to get the parts made and metal cut.

• IG32 and IG42 Robot Platform EDrawings (128kb zip file)

Platforms

We offer several different platforms of ATR SBs. One for the IG32 motors, another for the IG42 motors. The same chassis is used for 4WD or 6WD, on the 4WD version, the middle wheels are just omitted and can be added later. The platform made of .125" aluminum, which we cut with our high definition plasma cutter, which is welded together for a solid chassis. We also offer chassis composed of machined tubing that can be custom sized for your application.

• ATR Welded Aluminum Base for 42mm Motors - SB
• ATR Welded Aluminum Base for 32mm Motors - SB
• Custom Length Motor Tube Chassis - IG32 and IG42 - SB
• Custom Length Motor Tube Chassis - IG52 - DB

Dimensions and weight are listed on the item pages. Note that these dimensions do not include weld filler, which adds a little to the overall dimensions.

Motors and Motor Mounts

Many different motor sizes are available for this kit. The IG32P sized motor is recommended for most applications and will drive the robot over any indoor surface and most outdoor surfaces. The IG32 motors will work fine too depending on how much weight you plan on stacking on the robot (if >10 lbs the medium or larger motors should be used). The larger IG42 and IG52 motors are typically overkill for indoor stuff, but can be used if you want ultimate power. If you want to climb hills, curbs, and other obstacles you should use the large IG42 and IG52 motors.

We carry many different gear motors, these are our standard items.

• 24VDC IG32 195 RPM Gear Motor
• 24VDC IG32P 190 RPM Gear Motor
• 24VDCIG42 240 RPM Gear Motor (for 6" wheels)
• 24VDCIG42 122 RPM Gear Motor (for 10" wheels)
• 24VDCIG52 285 RPM Gear Motor

For mounting the motors we also carry motor mounting plates and tube mounts. To mount the motor, you'll need a plate and a tube. For more information on how to use these see the Motor and Wheel Mounting Methods support page

• IG32 Motor Plate
• IG42 Motor Plate
• IG52 Motor Plate
• IG32 and IG42 Motor Mount Tube
• IG52 Motor Mount Tube
• IG32 and IG42 Custom Length Chassis Plate

Wheels and Drive Shafts

The ATR wheels and shafts are sold are sold in sets of two or individually. The SB wheel and shaft sets come with two bearings (one per shaft) and four lock collars (two per shaft), one to secure the axles to the motors and the other to secure the bearing to the chassis. We offer many different types of wheels that allow the robot drive on just about any terrain:

• 6" pneumatic tires
• 10" pneumatic tires
• 10" traction lug tires
• 13" traction lug tires
• omni and mecanum wheels

SB Shafts:

• ATR Shaft 6mm Bore for 6 inch Tire
• ATR Shaft 8mm Bore for 6 inch Tire
• ATR Shaft 8mm Bore for 10 inch Tire
• ATR Shaft 12mm Bore for 10 inch Tire
• ATR Shaft 12mm Bore for 13 inch Tire

To turn, the robot uses "skid steering" which means that the motors are turned at different speeds or in different directions. For example, to turn left, the left two wheels will be turned slower than the right two wheels which will let the robot skid to the left. To make a "pivot turn" or a turn in place the wheels are driven in opposite directions which makes the robot spin. Since the wheels have to overcome friction to skid, the robot will perform differently depending on the surface on which it is driven and the components selected. If the robot is heavy and/or driven on a high-friction surface such as carpet, lower RPM motors should be used since they offer more torque. If you are ordering ATR wheel and shaft sets, you only need 2 sets (for a total of 4 wheels and shafts) for a typical 4WD assembly.

SB Wheel and Shaft Sets:

• ATR Wheel Shaft Set Pair 6mm Bore - 6 inch pneumatic
• ATR Wheel Shaft Set Pair 8mm Bore - 6 inch pneumatic
• ATR Wheel and Shaft Set Pair 8mm bore - 10 inch pneumatic
• ATR Wheel and Shaft Set Pair 12mm bore - 10 inch pneumatic
• ATR Wheel and Shaft Set Pair 8mm bore - 10 inch Traction Lug
• ATR Wheel and Shaft Set Pair 12mm bore - 10 inch Traction Lug

Another option is to use omni wheels, which are comprised of rollers that eliminate any skidding during turning. These wheels are the best option for high friction, flat surfaces. The Omni wheels and shafts are also sold together as one unit. The shaft comes with a bearing and lock collar that fit right into/onto the motors and motor mounts. The wheels are 4" in diameter. The traction wheels are made of durable urethane to help grip the floor. These wheels also work outdoors. The wheels are either single row wheels or double row wheels. The double row wheels provide a little smoother operation, but both work great. One thing to note with the omni wheels is if you run sideways to a hill, the wheels will side slip down the hill, but if the robot angles up the hill slightly it can overcome this. If you are ordering omni wheels, you will need 4 individual shaft and wheel sets for a 4WD robot.

• Nexus Omni-Wheel and Shaft Assembly - 6mm Bore
• Nexus Omni-Wheel and Shaft Assembly - 8mm Bore

Hardware

The final item you need to make your kit complete is a hardware package. It includes nuts, bolts washers, nylon spacers (for isolating your electronics and control boards), cable ties, and cable hold downs. We also sell hardware kits for mounting motors and servos.

• Hardware Package (mounts most components to the robot base)
• IG32 and IG42 Motor Plate Hardware Kit (mounts motor plates to chassis)
• Servo Standoff Hardware Package (used to mount servos onto the base of the robot)

Chain Coupling

One option that is available with the SB 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. While driving on rough terrain, turning, etc., if one wheel stalls or starts to spin, the adjacent motor has to do all the work. When the axles are coupled together it provides power from both motors. We use #25 chain and the same size sprockets to couple the axles along with a UHMW block for chain tensioning (see image below).