Model Files Download
•See the “Arm Stick Sketch” file for the first design work I did in my example. It includes the basic robot size constraints and the field sizes to allow the user to play around with overall dimensions of the arm.
•The “ArmAssemblyPractice” assembly is a reasonably complicated model that is built on the “dummy” robot base mockup. Eventually I want to create some tutorials that show the process for getting to a finished product like that. Notice that the field elements are also in the assembly for testing different configurations of the robot.
•Quite of the few details of the model could use a good explanation, but feel free to try to pick it apart on your own and figure out how the robot would work, and how one would go about fabricating it.
This guide (under construction) is intended to take you through the process of designing a robot arm in Autodesk Inventor, starting with defining constraints and simple geometry sketches up through motor and gearing math and detailed mechanical design.
Robot Size Constraints
- The robot will have a 26″x30″ frame perimeter. It must be able to fit within a box such that none of its parts extend past the vertical projection of this frame perimeter. It can be capable of extending outside this perimeter, but it has to be capable of being completely contained within the perimeter (except for its bumpers).
- The robot must be able to fold to a height of 36″ or less while staying within its frame perimeter. It may extend higher than 36″ as long as it’s capable of folding beneath this maximum starting height.
- The robot will have standard FRC bumpers (5″ tall, 3.25″ thick) whose bottom edge is 2″ off the floor.
- Robot must have an arm (not an elevator, and not a telescoping arm) with an end effector (device that picks up and releases game piece)
- Arm must have no more than two articulating (moving) joints
- The robot’s base will be a “west coast drive” style drive base with a 1″x2″ hollow tube frame. The top of this frame will be 3″ off the floor, and it will be the base upon which structure for the arm will be built.
- The arm, its structure, and its power source must not interfere with the drive gearboxes or the electronics, as defined by the attached “dummy robot base” model files.
Robot Task Requirementsd
- Pick up a single 2.8″ diameter whiffle ball from floor
- Reach the ball while the robot is behind a 1 foot tall / 1″ wide wall; reach ball that is to 2 feet away from behind the wall
- Drop ball into 48″ tall / 4″ wide goal whose edge is up to 3 feet away from the front edge of robot bumpers