# Controller Design
An agnostic PID controller class is used so It can be applied to a variety of 
inputs and outputs. This controller is primarily used to set effort values for 
each motor based on error. This error is either positional error dictated by the 
offset from the IR sensor centroid, or angular position error based on IMU 
heading angles.  

The documented low-level controller class can be found [here](controller.md). 

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![PID Controller diagram](./image/MotorControlBlockDiagram.png)

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Our motor controller task in [main](main.md) implements a cascading control 
scheme, where the IR sensor position is regulated by the outer loop, which in 
turn adjusts the motor effort through the inner loop. This design enhances 
stability by ensuring that more accurate setpoints lead to less sensitivity to 
variations in system dynamics.

To achieve this, we first tuned the inner motor controllers to reliably track 
the line position. Once the inner loop was stable, we tuned the outer IR sensor 
controller to further refine and smooth the system’s response.

![Cascading control diagram](./image/IR_Control_diagram.png)