Electric Mayhem is a reactive, command-based robot behavior control system designed specifically for the FIRST Tech Challenge (FTC). The project aims to build upon the approach taken in FTCLib, incorporating Kotlin flows and coroutines to decouple various robot components like sensors and subsystems. This makes the overall system more reactive and easier to manage. The project features two main reactive BehaviorControllers: a FiniteStateMachine and a BehaviorTree.
Note: The project initially focused on a reactive version of a FiniteStateMachine but has since shifted its main focus to BehaviorTrees.
- 100% Kotlin: The entire codebase is written in Kotlin, leveraging its modern syntax and features.
- Optimized for FTC: Designed with FIRST Tech Challenge teams in mind.
- Modular Design: Inspired by ROS and other modular approaches to robot software.
To integrate Electric Mayhem into your project, click 
For usage examples, refer to the sample opModes in the app module. Additionally, unit tests provide further insights into the library's capabilities.
The BehaviorTree class serves as the main controller for the behavior tree. It takes a CoroutineDispatcher and a root node as parameters and manages the execution of the tree.
The Node class is the basic building block of the behavior tree. It defines the behavior that the tree should execute.
The ConditionNode class represents conditions in the behavior tree. It extends the Node class and adds additional functionality specific to conditions.
The 'ActionNode' class represents an actiont that will be taken (a leaf node in the behavior tree). This will typically amount to issuing a Command to a particular subsystem to change its target control state. e.g. turret.MoveToPosition(120.0)
The ControlNode class is a type of node that can have child nodes. It is used to build complex behaviors by combining simpler nodes.
The FallbackNode class executes its children from left to right and returns a status code of SUCCESS if any of its children return SUCCESS. If none of the children return SUCCESS, it returns FAILURE.
The ParallelNode class executes all of its children in parallel. It returns SUCCESS if all children return SUCCESS, CANCELLED if any child is cancelled, and FAILURE otherwise.
The SequenceNode class executes its children from left to right and returns immediately with a status code of FAILURE if any of its children return FAILURE. If all children return SUCCESS, it returns SUCCESS.
The DecoratorNode class is used to modify the behavior of its child node. It wraps around another node and changes its behavior based on certain conditions.
The NodeStatus enum defines the possible statuses a node can have. The statuses are Idle, Success, and Failure.
- For an introduction to Finite State Machines in the context of FTC, refer to Game Manual Zero.
- To learn more about BehaviorTrees, check out this YouTube playlist.
- For an academic perspective on BehaviorTrees, read this paper.
- Here is another good survey of Behavior Trees.
- Here is a really good overview of kotlin flows.
If you're interested in contributing, feel free to fork the repository and submit a pull request. All contributions are welcome!
- FTCLib for the foundational approach to FTC robot behavior control.
- The Kotlin community for providing the language and tools that make this project possible.