The chassis is the structural component for the robot which contains the drivetrain and allows the robot to be mobile by using wheels, tank treads, or another method. A chassis is sometimes referred to as the robot’s frame. The chassis also provides a structure to attach manipulators such as arms, claws, lifts, plows, conveyor systems, object intakes, and other design features used to manipulate objects. It is important that the chassis is rigid because it is the framework which supports the robot.
There are a number of assembly mistakes which should be avoided and techniques which can be used to stiffen a chassis and make it more rigid.
Do not use a single screw to make a connection unless it is designed to pivot. As a general rule, the more stress a connection has, the more screws should be used. However more screws equals more weight for the design. 1-Post Hex Nut Retainers and 4-Post Hex Nut Retainers can also be used in these applications.
Do not use plates as structural components for a chassis. Use C-Channel, Rails, or Angles instead. Plates can be used very effectively to stiffen a chassis when used to connect two structural components together, such as assembling a piece of metal plate between two C-Channels to create a box structure or placing plate as a gusset for a 90 o connection between two structural pieces.
Gussets are angled metal pieces. Wherever structural components do not overlap, using Gussets will connect and strengthen joints.
Towers and other structures which only have one point of attachment need to have as many connection points as possible at the junction. In addition, supports for the structures can be made with Bar stock, Gussets or Plates.
A standoff is used to separate two parts from one another while creating a rigid connection. Standoffs can be used to stiffen structural components when placed between the components by providing additional connection points and keeping the metal structure from bending when it is under stress.
Structural metal and hardware can be purchased at https://www.vexrobotics.com/vexedr/products/structure.