The Actobotics kit from ServoCity is another fixed-pitch, channel-based building system. Its 1.5” c-channel and ball-bearing based motion system allows teams to iterate and build mechanisms entirely from kit parts. One advantage of Actobotics is that their channel hole pattern has many more mounting holes than a Tetrix channel, so it is less restrictive in terms of mounting. Actobotics uses imperial units across the board, allowing for clean spacing and fitting. A variety of mounts and brackets make strong, compact joints between channels. Actobotics also sells mini-channel in addition to the standard size channel. In addition to the channel, the main structural component in Actobotics kits, the X-rail extrusion system offers immense adjustability. To complement the structural offerings, Actobotics uses a series of clamping hubs and a robust 1/4” steel D-shaft. Finally, Actobotics has a Linear Motion Kit which uses X-rail extrusion to build extending mechanisms. The ServoBlock, which prolongs the life of a servo, is recommended for all teams, regardless of kit; however, ServoBlocks seamlessly interface with the Actobotics ecosystem. Actobotics furthermore offers options such as bevel gears and Linear Actuator kits (using lead screws) for specific use cases. Actobotics can interface with other kits such as REV through a variety of Pattern Adapters. ServoCity offers a 25% off discount for all FIRST teams, making pricing competitive. Actobotics is a solid choice for new teams, offering a reliable base kit with many options to expand upon.
Aluminum c-channel and mini channel, various lengths
X-rail (a special type of extruded rail similar to 8020)
Assorted plates and brackets, flat and 90 degree
Clamping hubs, spacers
Gears and sprockets
HS-488 HB servo (4x), assorted accessories
5201 Series, 53:1 Ratio, 105 RPM Spur Gear Motor
5201 Series, 26.9:1 Ratio, 210 RPM Spur Gear Motor
Bars and angles
Omni and traction wheels
Nuts, screws, fasteners
Tools (screwdrivers, etc.)
Actobotics provides a great value fixed pitch build system that is generally easier to assemble than extrusion-based systems which require cutting extrusion to length.
Actobotics has the patented ServoBlock, which helps drastically increase servo life by protecting it from shock loads. More information may be found in the glossary.
Actobotics is easily compatible with other build systems such as REV’s kit using adapters which can be found on the Servocity website.
Actobotics is more sturdy than TETRIX in terms of drivetrain flex and has more support options to prevent structural bending.
The clamping hubs offered are more reliable than set screws, as clamping engages the shaft in more places than a set screw (one face). As discussed in the TETRIX section, set screws in particular are vulnerable to loosening, especially without application of Loctite.
Actobotics’ motion system is very robust and relies on ball bearings, which have a lower coefficient of friction than bushings. Actobotics is compatible with the 5mm hex used by REV with their adaptable hubs.
Actobotics also allows for face mounting of motors as opposed to clamp mounting. This is explained in the glossary section.
Actobotics is not very cheap, so its cost may be prohibitive for some teams with a low budget. Note that with the 25% off FTC team discount, Actobotics can be cheaper than TETRIX. The only cheaper build system is REV.
The belts from ServoCity are not great. It is recommended that belts are purchased from vendors other than ServoCity. This may necessitate 3D printed belt pulleys and other parts, which is more difficult for newer teams. There also isn’t a large amount of space inside the channel for a belt or chain run, vastly limiting the size of the pulleys.
Channel takes up more space than extrusion, so mechanisms can be a bit larger with the Actobotics kit. To remediate this issue, ServoCity sells mini-channel which is a similar size as extrusion.