ARTICULATION

What is articulation? It’s the way a robot interacts with the field and game objects Articulation systems usually have manipulators (mechanisms that interface game objects directly) Many different types

Example Dumper in Clean Sweep – Articulation system consists of dumper and intake (manipulation) – Wheels roll balls into dumper – Dumper lifts to unload on other side – System accomplishes its task

Designing for Articulation Depends on object Light? Heavy? Strong? Weak? Shape: Round? Square? Where? Ground? Raised? Autoloaders? (put pics of diff objects)

Motors Different types for different uses o 3-wire motor (standard) o 2-wire motor: more torque, same speed/ more speed, same torque o servo: 180º, good for claws, limited motion

Pneumatics Use air pressure Good for two position articulation systems that require lot of torque (claw)/ transmissions No risk of motor stripping Needs compressor or else limited in number of throws

Collection Systems

Intake Rollers Quickly grab objects off ground Relatively simple design BUT... may jam (low torque)

Conveyor Systems Intake objects from ground and move around with objects (Elevation) Chains, belts, tank treads w/ zip ties, flaps

Claws Can grab almost everything BUT... can only grab one object at a time and harder to drive Suitable for pneumatics o one motion o motor has to keep running o servo only moves in desired positions

Fixed/Mechanical Can do simple basic tasks without using a motor to do it (knocking down footballs, Green Eggs triangle goals)

Scoring Systems

4-Bar Linkage Can raise manipulator at a constant angle Use 4 bars Need lots of torque to lift, esp. if heavy load

Elevators Use sliders to lift loads vertically Need to make sure low friction Also need a lot of force

Arms/Basket/Dump Can be used to reach a wide range of positions Depending on placement of forces, loads, and fulcrum, may require a lot of torque to function

Shooter/Catapult Fire objects to places cannot access Need VERY HIGH RPM and enough torque to launch objects, heavier = harder Catapult... Pneumatics may work depending on objects and distance needed to fire... CHEESYPOOFS!

Sensors

Limit Switch Useful for making a limit on the arm's rotation, or for autonomous, determining if object is in claw

Potentiometer Measures the angle of the shaft Useful for autonomous or driver control for arms

Sources /2008/Videos/2008FRC_Mechanisms1_Collecti on_Ventimiglia.wmv