Skim

GENERAL

After sitting in a box for 10 years, Skim is currently going through a general refurbishment to get him back in the arena sooner rather than later. Skim will receive minor upgrades throughout the 2023 season, and possibly be redesigned from the bottom-up during the 2024 Club season. 

Skim was originally designed in 2011 with the same concept of Vitamin D: a simple box with a horizontal beater weapon in the front to cause damage to the opponent. Early designs revolved around a square frame with all the internal structure supported by carbon fiber top and bottom plates. This design was quickly phased out for a more simplistic design. After multiple competitions demonstrated the benefits and shortcomings of Skim, the design evolved into what we have today: a uni-body frame, angled wedge to guide opponents into our weapon, and beater weapon with large teeth.

BODY

The body was machined by wire electrical discharge machining (EDM) from a solid block of 7075-T6 aluminum for strength and rigidity. The frame has six separate cavities each housing different robot components (e.g., battery, weapon motor, drive motors, wheels). All of the external walls are 0.125" thick, except for the front supports for the weapon which are 0.25" thick and the internal battery wall which is is 0.0625" thick. The top and bottom plates to protect the internal components are made of 0.05" thick Grade 2 titanium.

At the front of the body is a wedge of 0.125" thick Grade 2 titanium with a cutout to allow the weapon to protrude. The thickness, material, and angle of the wedge allows Skim to absorb and deflect weapon impacts from opponents' weapons, while also providing a convenient path to direct our opponents into Skim's weapon. And it makes pretty, bright-white sparks. 

WEAPON

Skim's weapon was machined out of a solid piece of S7 tool steel, and the profiles were machined by wire EDM on two planes. This kept machining to a minimum, and made for a very awesome looking blade. The weapon is powered by a HXT 2835 2700kv brushless motor. We have a 1:1 ratio from the motor to the blade, with a measured RPM of XYZ RPM. The motor electronic speed controllers (ESCs) is an Otter 40A brushless ESC, which also supplies the 5V to our control system through its onboard battery eliminator circuit (BEC).

DRIVE

Skim's drive system consists of two Rectified Robotics 1806 2300kv brushless motors with 22:1 planetary gearboxes in a tank drive configuration. The speed obtained from these motors is ridiculously fast. We basically bounce around the arena like a pin ball. The motors are each driven by a 35A BLheli-32 ESCs. Power is transferred to the arena floor using AndyMark 2in. compliant wheels. All internal systems are powered by a single 11.1V 3S 1500mAh LiPo battery.

DOWNLOADS