The mechanical design of robots has no major change since 2012 and just some part of kicking system and dribbling system optimized for better performance. The main chassis consists of a 5mm hard anodized 7075 aluminum alloy plate on which motors, batteries, encoders, capacitors, and kicker systems are mounted. Robots are covered by a carbon-fiber compound that is light as it is solid. In order to mechanically stabilize the robot movement and kicking, the altitude of the center of mass is lowered by arranging rather heavy parts on the plate, that level first in the whole robot structure. The overall height of the robot is 148mm and its diameter is 178mm.
Robots are designed omni-directional by using four omni-wheels. Each wheel is 61mm in diameters and has 18 rollers covered by double seal O-rings for better grip. Both wheels and rollers are made of 7075 aluminum alloy. As the field size has been increased, higher speeds are inevitable; so the gear ratio is optimized to 45:12 and 50 Watts Maxon EC-45 brushless motors are used to overcome the max-speed/max-acceleration trade off. The gearbox is merged into wheels to minimize the volume occupied by driving system. Its design is unique so that the gear used for transition is carved into the wheel itself.
One of the major issues in the robots was inaccurate low-level navigation. After many experiments, measurements and inspections on the control system, it came out that non-identical mechanical properties of each gear are the biggest issue, which was caused by manufacturing inaccuracies. To have smoother and more accurate movement, gear module is redesigned with smaller module size this year. Also there are a little change in sub wheels design and tolerance to reduce unsteadiness and to stick better to the field during fast accelerations.
Although safe navigation has been a must for years in the league, highly dynamic nature of the SSL causes unavoidable collisions that lead to damages ranging from minor to severe. To avoid damages to internal parts, especially electronics which are fragile, making a robust, solid casing that can efficiently damp impacts is a necessity. Thus, a case made up of 2mm thick carbon-fiber compound is made which is as solid as it is light to cover the whole body but kicking devices and the dribbler.
Kicking & Dribbling System
To account for the increase in field size, the kicking system is redesigned and to have more power and accuracy in booth chip and direct shoots. Also because of some high voltage short circuit caused by magnet solenoids, in our new version whole kick system is isolated from body and there isn't any direct metal to metal contact by using resin as an isolator material.