Common Mechanisms

Flywheel Shooter

Construction

• Two counter-rotating wheels (often with compliant covers) mounted on motor shafts, spaced to pinch a round projectile.

• Motors may include encoders for closed-loop speed control.

Use Cases

• Rapid-fire launch of small, spherical game pieces (e.g., Power Cells, foam balls).

Advantages

• Continuous, high-rate firing-no reload cycle time needed.

• Velocity (and thus range) can be tuned on the fly by adjusting wheel speed.

Disadvantages

• Only handles round objects reliably-non-spherical items slip or jam. 2

• Motor speed (and shot consistency) falls off as battery voltage drops unless actively regulated by encoders. 2

Striker (“Impact”) Shooter

Construction

• Rigid striker arm or plate driven by a geared motor or spring, which impacts the projectile to launch it.

• Includes a pull-back mechanism (e.g., a torque motor with gear train) to reset the striker.

Use Cases

• Launching flat or irregular objects (pucks, square blocks) that cannot be gripped by wheels.

Advantages

• Compatible with a wide variety of shapes and sizes. 2

• Range adjustable by tuning spring tension or motor torque. 2

Disadvantages

• Energy loss to friction when the object slides against a surface reduces distance. 2

• High impact loads cause wear on linkages and mounting hardware. 2

• Reset mechanism adds cycle time and mechanical complexity. 2

Catapult/Popper Shooter

Construction

• Elastic element (rubber band or spring) attached to an arm linkage, latched by a servo or pin.

• Release mechanism discharges stored energy to fling the projectile.

Use Cases

• Single-shot loops at moderate rate for uniform, repeatable distance (e.g., tennis-ball poppers, small foam ring launchers).

Advantages

• Very consistent shot energy and accuracy thanks to fixed spring tension. 6
• Simple control: prime once, trigger, then re-prime.

Disadvantages

• Fixed launch distance unless spring tension is manually adjusted between shots. 6
• Mechanical linkage must absorb high forces, leading to potential fatigue and breakage.

Linear Motion Guides

Linear Travel Guide using Stepper motor and Timing belt

Whit Worth Mechanism

Construction: Aluminum extrusion or steel rail profiles with rolling or plain bearings (linear slides, drawer slides, profile rails). 2 Use Cases

• Robot lifts, elevators, extendable arms, precise slide mechanisms Advantages

• Recirculating bearings: smooth, low friction under load

• Profile rails: tight tolerances, long life Disadvantages

• Adds weight and cost

• Requires precise alignment and mounting

Arms & Elevators

Continuous Elevator Mechanism

Retractable Elevator Arm

Construction: Pivoting bars or telescoping frames driven by motors, winches, or actuators; may include cascade or continuous-loop rigging. 2 Use Cases

• Scoring at various heights, reaching over obstacles

• Gripper positioning and manipulator extension Advantages

• Pivot arms: simple kinematics, compact stowage

• Telescopes: extendable range, rigid at full height Disadvantages

• Pivot: limited vertical reach without long links

• Telescopes: mechanical complexity, potential binding

Linkages

4-Bar Linkage Gripper

Simple Linkage Mechanism

Rotary Linkage (Joint)

HInge

Construction: Rigid links connected by revolute (pin) joints, forming Four-Bar, Parallel (pantograph), Scissor, Corner, or Cross linkages. 2 Use Cases

• Converting rotary motor motion into complex planar or vertical motion

• Lifts, level platforms, bilateral extension Advantages

• Four-Bar: predictable motion path, adjustable leverage

• Scissor: large vertical extension in compact footprint

• Pantograph: maintain parallel output motion Disadvantages

• Multiple joints: cumulative backlash and wear

• Scissor: linkage binding without precise fabrication

Passive Intakes & Claws

Servo Powered Gripper

Adaptive Claw

Construction: Fixed mounting plates with compliant materials (rubber bands, foam), passive rollers or fingers. 2 Use Cases

• Gripping variable-shape game pieces without active actuation

• Centering objects against a backplate for further processing Advantages

• Low complexity, minimal actuators required

• Gentle on game pieces, self-centering behavior Disadvantages

• Limited gripping force, shape dependence

• No active release control

Active Intakes

Active Intake with Gripper

Active Intake

Construction: Powered rollers, wheels, or pneumatic fingers mounted on pivoting arms or frames. 2 Use Cases

• High-speed collection of balls, cubes, rings, or custom game pieces

• Feeding objects into indexers or shooters Advantages

• Controlled grasping and ejection, high throughput

• Adjustable speed and torque for different materials Disadvantages

• Additional motors or pneumatics add weight and draw current

• Complex timing and synchronization with downstream subsystems

Transfers & Indexers

Construction: Belt or roller conveyors, pneumatic gates, channel guides, and staging shelves. 2 Use Cases

• Sequencing multiple game pieces, buffering under shooters or scoring mechanisms

• Automated stacking or batch delivery Advantages

• Precise object positioning, continuous feeding

• Scalable to multiple game-piece types Disadvantages

• Added length and mass on the robot

• Requires control logic to avoid jams

Dead (Idle) Wheels

Construction: Free-spinning omni or traction wheels mounted on bearings, used as load-bearing supports. 2 Use Cases

• Reducing friction on non-driving corners

• Stabilizing mechanisms or gantry plates Advantages

• Simple, passive way to carry loads without consuming motor power

• Minimal wear on drive motors Disadvantages

• Adds drag if misaligned

• Does not contribute to motion

Turrets

Turret Actuation

Turret

Construction: Rotating subplate on thrust bearings or lazy-Susans, driven by motors or servos. 2 Use Cases

• Aiming shooters or sensors independently of chassis orientation

• Multi-directional intake or scoring without turning the robot Advantages

• Decouples turret and chassis control, rapid targeting

• Enables continuous rotation and precise angular positioning Disadvantages

• Complex wiring management (slip rings or cable chains)

• Increased mass and higher center of gravity

Forklift Mechanisms

One of the implementations for lesser load, for higher loads a tension string is also reccomended

Above shown Screw and Belt Driven Linear Guides can also be used

Construction

• A rigid rectangular frame built from metal tubing or plates supports four drive motors with reduction gearing and a single H-bridge controller for traction and steering6.
• A vertical lift assembly uses profile rails or linear slide tracks on each side to guide motion, with a rack-and-pinion driven by a DC motor to raise and lower forks or a carriage2.

• Ultrasonic distance sensors mounted near the base detect shelf or object positions and trigger lift actions, all wired through a microcontroller (e.g., Arduino Uno) and soldered onto a breadboard for flexible I/O expansion2.

Use Cases

• Warehouse and warehouse-style competition challenges requiring precise fork positioning under pallets or blocks.

• Educational projects demonstrating pick-and-place automation, obstacle avoidance, and sensor integration.

Advantages

• High load capacity and stable vertical motion when properly counterbalanced.

• Precise height control via gear reduction and encoder feedback.

• Modular design allows easy adjustment of fork width and lift height.

Disadvantages

• Heavy lift assemblies can unbalance the drive base, requiring careful weight distribution or repositioning of components2.

• Increased mechanical complexity and part count raise build time and maintenance.

• Rack-and-pinion systems can bind if rails are misaligned or not lubricated.

Robotic Grippers

Mechanical Grippers

• Construction: Two or more rigid fingers actuated by servos, motors, or linkages; often include compliant pads for better friction3.
• Use Cases: General-purpose part handling, from small rigid game pieces to irregular objects in warehouses.

• Advantages: High grip force, adaptability to varied geometries, straightforward control.

• Disadvantages: Complex designs for large workpieces, increased weight, limited softness for fragile items3.

Vacuum Grippers

Vacuum Gripper

• Construction: Suction cups linked to a vacuum pump or venturi generator, often with integrated pressure sensors4.
• Use Cases: Handling flat, smooth panels, sheet goods, glass, and light game elements.

• Advantages: Simple design, fast pick-and-place cycles, low profile for tight spaces.

• Disadvantages: Only works on non-porous surfaces; rubber cups wear and require frequent replacement3.

Magnetic Grippers

Magnetic Gripper

• Construction: Electromagnets, permanent magnets, or electro-permanent magnets embedded in a flat contact pad35.
• Use Cases: Lifting ferrous parts, sheet metal handling, assembly tasks with metallic game pieces.

• Advantages: Single contact surface, rapid gripping, minimal structural components, energy-efficient (permanent/electro-permanent)35.
• Disadvantages: Limited to ferrous materials, reduced holding force if surfaces are oily or covered in debris, parts may retain magnetism35.

Pneumatic Grippers

• Construction: Parallel or angular jaw fingers driven by air cylinders, with flow control valves for speed and force tuning4.
• Use Cases: High-speed pick-and-place, automated packaging, fluid-tight sealing in assembly.

• Advantages: High force-to-weight ratio, fast actuation, built-in compliance.

• Disadvantages: Requires compressed air infrastructure, noisy operation, potential air leaks.

Servo-Electric Grippers

• Construction: Brushless or stepper motors with gearboxes driving finger linkages, often with integrated position and force sensors4.
• Use Cases: Precision handling in electronics assembly, variable-force tasks in competition robots.

• Advantages: Precise position and force control, easy integration with digital controllers, low maintenance.

• Disadvantages: Higher cost, more complex control algorithms, potential heat generation in continuous use.