DRAKOS

Drivetrain

Holonomic precision — compact modules maximize interior space

Materials

6061 aluminum chassis · Swyft Drive V2 mecanum modules · 86mm 40A TPE wheels

Motors

4× 550 Motor · 12.7:1 gearbox · ~475 RPM wheel speed

Design rationale

Compact Swyft Drive V2 modules keep the drivetrain footprint minimal, freeing interior space for the intake and shooter. Holonomic drive enables full-field repositioning without turning — critical for aligning to the goal quickly between cycles. Metal-plated sides protect internal components while keeping pit access fast.

Tradeoffs considered

Lower pushing force than tank drive, but the game rewards positioning speed and cycle rate over defense. Mecanum strafing (~3.5 ft/s) is slower than forward speed, but the compact module size justified it.

Intake

Overdrive acquisition — ~2227 RPM with auto-staging

Materials

Custom 30A cast silicone center wheels · 3D printed vector wheels with surgical tubing · mechanical rack-and-pinion feed stop · REV color/distance sensor

Motors

goBILDA Yellow Jacket 1620 RPM · 22T→16T overdrive (1.375:1) → ~2227 RPM at intake wheels

Design rationale

Overdrive on the forward intake increases artifact acquisition speed beyond motor RPM. 30A cast silicone maximizes grip. A mechanical rack-and-pinion feed stop prevents collecting a 4th artifact — a hard rules-compliance safety net that eliminates penalty risk. A REV color sensor detects artifacts and automates staging, so drivers focus on driving rather than button timing.

Tradeoffs considered

The angled compression path adds length to the robot footprint, but the consistent feed rate, automatic penalty prevention, and driver workload reduction justified the design.

Flywheel Shooter

3 shots in under 0.5 sec — 80% accuracy at full field

Materials

96mm 30A Gobilda Rhino rubber wheel · ~700g custom steel inertia inserts · GT2 belt drive · Axon Max Mk2 servo hood (26° range)

Motors

2× goBILDA 5000 Series 6000 RPM · 1:1 GT2 belt

Design rationale

Soft 30A rubber maximizes energy transfer to artifacts. ~700g steel inserts increase rotational inertia, stabilizing flywheel RPM between rapid shots. Hood angle is set via a lookup table keyed to Limelight distance — 48° standard, up to 74° for close shots. PID only allows firing when RPM stabilizes at the correct setpoint (2000 RPM close · 2300 RPM mid · 2900 RPM far), eliminating wasted cycles from premature shots.

Tradeoffs considered

Two-motor shooter adds weight and wiring complexity vs. a single-motor design, but the inertia stability and burst rate (3 shots / 0.5s) were critical to the cycle strategy.

End Game / Park

Full park via kickstand — minimal space, maximum points

Materials

3D printed kickstands driven by Axon Max servos

Motors

Axon Max Servos

Design rationale

Kickstands tilt the robot body, reducing the footprint needed to achieve full park scoring. This frees space for the alliance partner to also park, enabling double-park when conditions allow.

Tradeoffs considered

Allows more room for the alliance robot to obtain a partial park, which can score more total points than one full park alone.

Electronics & Control

State machine automation — one button fires the entire shot cycle

Materials

REV Control Hub · REV Expansion Hub · Limelight 3A · goBILDA Pinpoint odometry · REV color/distance sensor · custom wire harness

Motors

N/A

Design rationale

A Shot Controller state machine sequences the entire cycle: IDLE → STAGED → PREP → READY → SHOOT → RECOVERY. Limelight 3A provides vision-based pose updates; Pinpoint odometry calculates distance and alignment. The system only fires when flywheel RPM has stabilized and alignment is confirmed — the driver triggers with one button, the robot handles the rest. Color sensors monitor artifact flow through the serpent channel.

Tradeoffs considered

State machine complexity requires thorough testing across all field positions, but the reduction in driver button complexity and gain in shooting consistency justified the investment.