Every team faces this decision after building their robot: what type of attachment should I use?
Introduction
After building a robot, attachments are the most important next step. FIRST only allows a total of four motors, and with teams already using two of them for the drivebase, it might be hard to think of non-passive alternatives and not just using many active attachments. However, here are some advantages and disadvantages of both and why a mix of both is most likely the best way forward.
Passive Attachments
Sometimes a stick or a slope is the best way to complete a simple mission. When you need to push a simple lever like the Salvage Operation mission in the Unearthed season, a simple slope to help lift is good enough. They are easy to build, help save resources for more complicated attachments or robot enhancements, and they have relatively high success rates…except when they don’t. Sometimes passive attachments will get stuck and are less flexible than active attachments. An active lever to raise an object might be used for multiple missions, but a passive attachment is usually hardcoded around a specific mission. This leads to a higher number of attachments, leading to a higher required changing time, eventually resulting in missed points. Passive attachments can also degrade your robot’s accuracy. When a passive attachment interacts with a mission, it can push back on the robot and change its alignment, resulting in possible failed missions afterwards.
Active Attachments
Active attachments are attachments that are powered by one of your remaining 2 motors. Many teams use this type of attachment because they allow for more power, allowing your robot to complete tasks that require more heavy lifting. They also allow for more accuracy and control, and you are able to direct exactly how much the motor turns and how much speed it uses. However, these attachments also have some drawbacks. They use up motor slots, allowing for only 2 active attachments at once. They require a lot more resources to build than passive attachments, and they offset your robot’s center of gravity, A.K.A. its COG, and its weight (see more info about your robot’s COG here: Center of Balance – And Why It’s Important).
The Solution
The solution here is to use passive attachments for tasks that require less accuracy. It is also better if the tasks can be aligned to a wall to reduce any misalignment that may occur. You can attach passive attachments to the side of active attachments, allowing for more flexibility. Active attachments should be used in tight spaces where the robot cannot turn accurately and where the robot has to lift a heavy object (similar to Mineshaft Explorer or Statue Rebuild). All in all, passive and active attachments should not be ditched for each other, but rather used together.