Model Predictive Control of a Tandem-Rotor Helicopter With a Nonuniformly Spaced Prediction Horizon

TL;DR

This paper presents a model predictive control approach for a tandem-rotor helicopter using a nonuniform prediction horizon, combining trajectory refinement with robustness to uncertainties and disturbances.

Contribution

It introduces a novel nonuniformly spaced prediction horizon in MPC for complex helicopter dynamics, utilizing Lie group error formulation and trajectory refinement techniques.

Findings

Demonstrates robustness to initial conditions and disturbances

Effective handling of multi-timescale dynamics

Maintains tractability with nonuniform prediction horizon

Abstract

This letter considers model predictive control of a tandem-rotor helicopter. The error is formulated using the matrix Lie group $SE_2(3)$. A reference trajectory to a target is calculated using a quartic guidance law, leveraging the differentially flat properties of the system, and refined using a finite-horizon linear quadratic regulator. The nonlinear system is linearized about the reference trajectory enabling the formulation of a quadratic program with control input, attitude keep-in zone, and attitude error constraints. A non-uniformly spaced prediction horizon is leveraged to capture the multi-timescale dynamics while keeping the problem size tractable. Monte-Carlo simulations demonstrate robustness of the proposed control structure to initial conditions, model uncertainty, and environmental disturbances.