Module 4: Control Physics & Voltage Models

Welcome to Module 4: Control Physics & Voltage Models. In this module, we bridge physical dynamics with modern autonomous control systems—showing why physics-based feedforward models (kS, kV, kA, kG) eliminate lag and how closed-loop PID controllers achieve tight, stable trajectory tracking.

Concepts in this Module

• Concept 01: Physics Feedforward: kS, kV, kA, and kG Models
  • The Everyday Problem: Why does a pure feedback PID controller lag behind fast motion profiles or droop under gravity? The physics of predicting required motor voltage from desired velocity and acceleration.
  • Code & WPILib: SimpleMotorFeedforward, ElevatorFeedforward, ArmFeedforward, and V = kS · sgn(v) + kV · v + kA · a + kG.
• Concept 02: Closed-Loop PID Tuning & Step-Response Stability
  • The Everyday Problem: How do you tune a flywheel RPM velocity loop or an arm position servo without sluggish settling, violent overshoot, or dangerous oscillations?
  • Code & WPILib: Proportional stiffness (kP), Integral error accumulation (kI), Derivative damping (kD), and edu.wpi.first.math.controller.PIDController.