Essential Components in Building a Base/Drive System

Chassis or Base

The chassis should be either made of a rectangular or square metal structure typically made of 80/20 or aluminium. The base should have mounting holes placed in a standard and consistent spot throughout the base and proper holes should be put in the side in order to mount wheel blocks. The holes for the wheel blocks NOT attached directly to the motor or gearbox should be designed for adjustment in either direction in order that you can tighten and loosen the chain to the correct tightness.

Brackets or connectors for chassis

The brackets for connecting the base should be designed in order to fit and line up with the mounting holes on the base and need to be thick enough to provide support for the robot. The brackets should be put on either side of the chassis at the joints in order to give a sturdy and reliable robot.

Wheels

There are many different types of wheels to choose from and based on your surface type and objectives for your robot. Types of wheels include mechanum, pneumatic, solid, carpet, and swivel. Mechanum wheels give you a serious advantage when you need to maneuver and position yourself accurately, but you need the wheels to be perfectly square on your robot to insure it will work. Pneumatic wheels are pretty standard, giving you good traction and adjustability in how much air you put in it. Solid wheels are the same, minus the adjustability. Carpet wheels are designed for carpet, but in my experience, have been tedious to assemble, and put way too much traction to even turn the robot. Swivel drive can be useful in speed objected competition, given that when turning, the drag is much less than that of a tank drive. Swivel wheels however are much more complicated to assemble and require more chain work and areas of possible failure. Wheels are typically mounted on the wheel shaft held in by collars or spacers.

Wheel Shafts

Wheel shafts are mounted inside the wheel block through two bearings and hold the wheels and the sprockets being driven by the gearbox if you are not using the shaft of the gear box to drive your wheel. Wheel shafts can have their components fastened either by collars or C-clips. If you use C-clips, you need to design your shafts specifically so that your C-clip is in the right spot and can fit on it.

Wheel Blocks

Wheel blocks house the bearing in which the wheel shaft goes through. The blocks are made of two pieces which go on either side of the chassis and screw into itself, giving you a secure and adjustable housing for your wheel shaft. Special wheel blocks are made to go directly into your gearbox and fasten to the gearbox without adjustability.

Cams

Cams are fasteners are for the wheel blocks so that when you set your length for chain, the block doesn't come loose and loosen your chain. To mount, you need to set the cam on the chassis on the side or the chain next to the wheel block with the jagged edge a couple millimeters from touching the wheel block and the point facing directly up. You then need to mark where it is by punching through the hole on the cam. Drill the proper size hole through the mark and fasten the cam through there. Then screw the cam in opposite the direction from the point so that the cam spins and touches the wheel block. Tighten the cam and make sure the wheel block does not move.

Chain/Belt

Chain and belt are used to move to driving force from the gearbox to the wheel shaft to drive the wheels. Belts are thicker and are in set lengths as opposed to chain which is relatively thin and fairly adjustable. Changing chain length however can become cumbersome so when you measure out how long your chain needs to be, always double check and make sure you are breaking the chain in the right spot. You cannot add chain. When using chain, you need proper size sprockets (either #25 or #32) depending on what type of chain you're using. When using belt, you need a hub. When using either of them, you need to make sure the two hubs/sprockets are perfectly lined up and on the same plane. You also need to make sure that the chain and belt are taught but not as hard as you can make it. You want to leave some give on it to have it work to its maximum ability.

Sprockets/Hubs

Sprockets and hubs are used for attaching chain and belt to a shaft. In the case of chain, you can have different sizes for #25 or #32 chain and different sizes for different shaft sizes. Belt is usually a standard width and hubs come in different sizes for different size shaft.

Wheel Hubs

Wheel hubs are used if your wheel doesn't attach directly to your shaft. You would screw the hub directly into the wheel and attach the wheel to the shaft through there. Like the sprockets/hubs, there are different sizes for different size shafts.

Spacers

Spacers are used to space out different components on a shaft. If your wheel is pressed up against your chassis, you would put in a spacer to separate them. Spacers come in different sizes for different size shaft and different lengths of spacing.