3D inverted pendulum stabilization on a quadrotor via bilinear system approximations

This paper tackles a 3D inverted pendulum stabilization problem, where the pendulum is attached on a quadrotor. We first derive the mathematical model of the quadrotor-pendulum system based on the Euler-Lagrange equation. Then, with hope for better control performance than traditional linear quadratic optimal control by efficiently using the vertical input, the bilinear approximation model is built by the second order Taylor expansion. We then propose an inverse optimal stabilization law for the bilinear system, conduct the convergence analysis and give the interpretation of the optimality. Finally, the validity of the present approach is demonstrated via simulations, where we explicitly show the effectiveness of the vertical input by comparing with the linear quadratic control case.