Linear Quadratic Regulator (LQR)

Optimal state feedback control for an inverted pendulum on a cart

Uncontrolled
LQR Controlled
Cart position
θ = 0.00 rad  |  x = 0.00 m  |  Cost J = 0.00

LQR Weights

Initial Conditions

LQR minimizes J = ∫(xᵀQx + uᵀRu)dt

Higher Q angle → more aggressive stabilization.
Higher R → gentler control effort.

Uses linearized pendulum dynamics:
mẍ = u − ml θ̈ cos θ
(m+M)l θ̈ = (m+M)gθ − u cos θ