Cortisol Spike

Overview

Cortisol Spike is a Plastic Antweight combat robot originally built for Aggie Combat Robotics by Kirill Lutsenko in 2026. The robot features a 4 wheel drive setup, small vertical spinner with a 2600 kV Palm Beach Bots^[3] motor, configurable front armor, and a PLA build. The first version of the robot attended the 2026 Red Dirt Rumble event at LeTourneau University^[1], losing 2 fights, and getting one bye. The limitations of the first version are to be addressed in version 2.

Version 1

Development was started in February of 2026, with the initial version of the robot being known as Mildred. After many technical issues, the robot got a complete redesign to its first competition version.

Drive

The four wheel drive was decided on due to its improved performance over 2 wheel drive on rough floors, also providing larger pushing power in combat scenarios. The initially sourced 2S LiPo battery was found to not be powerful enough to drive the robot, and was switched out for a 3S instead. The initially larger drive base on Mildred, paired with the smaller wheels made driving impossible, so the final version was reduced in footprint significantly, also allowing for better fitting into the 1lb weight budget. Wheels were cast using 2 part polyurethane in a custom designed mold with 3D printed polycarbonate wheel cores. The rear set of wheels was powered by 2 Repeat Robotics Mini Mk2^[2] motors, which are connected with polybelt to the front wheels. The initial drive design was found to be highly performant in maneuvering, however speed was lacking. This is to be remedied with the implementation of a 4S LiPo and Repeat Robotics Mini Mk4 motors.

Weapon

The weapon was chosen to be a small vertical spinner at a high RPM. Higher RPM spinners win engagements, and vertical spinners are better at launching. The size was limited by available weight. The profile of the spinner is single tooth, with an optimal 15 degree rake angle and a large root to improve durability. The weapon spins at over 20000 RPM, ensuring good contact during engagements. The motor utilizes a 2800 kV Palm Beach Bots^[3] purchased motor.

Durability

The first version was built entirely from Polysonic PLA Pro^[4]. This was a mistake as later pointed out by other builders, as this material is prone to cracking and shattering on impact, specially noticeable in the weak front forks of this version of the robot, as well as the side armor. The appropriate material choice is Bambu PLA Tough+^[5]. All fasteners were m2 screws into heated inserts, which was also a mistake, as the appropriate choice of screw are larger m3 plastites with threadlocker red applied in order to ensure security. These issues are taken into account in version 2.

Competition History

2026 Red Dirt Rumble

Cortisol spike competed in Red Dirt Rumble 2026 at LeTourneau University^[1] on April 11, losing its fights against Sidewinder and PLA TIme, and recieving one bye. The PLA Pro^[4] body proved prone to shattering, and needs to be replaced. The lack of threadlocker and use of heatsets lead to the detachment of the weapon uprights in the fight against Sidewinder (mainly the threadlock missing really), and was later remedied with Loctite Red supplied by another builder. The robot did not compete in playoffs due to its disappointing qualifying run. Lessons were learned and will be applied in the future.