Model-Free Adaptive Control for Parafoil Systems Based on the Iterative Feedback Tuning Method

Linggong Zhao,Feikai Lv,Weiliang He

doi:10.1109/access.2021.3050275

Abstract

Parafoil systems are strongly nonlinear due to the flexibility of the canopy and suspension lines, and this characteristic cannot be simulated accurately by existing dynamic models. Hence, model-independent control methods are necessary for parafoil systems. This paper introduces a model-free adaptive control method based on the iterative feedback tuning (IFT-MFAC) method for parafoil systems that is a data-driven control method in which only input/output (I/O) data are needed during construction. In this paper, the MFAC construction process and stability analysis are explained, and then the IFT method is used to tune the two stepping factors of the MFAC method. A six-degree-of-freedom (DOF) dynamic parafoil system model is built to assess the performance of the method in a simulation with disturbances added to imitate real flights. A series of simulations and hardware-in-loop (HIL) tests are designed to verify the performance of the IFT-MFAC controller, and it is compared with the PID control method, the active disturbance rejection control (ADRC) method, and the MFAC method.

Highlights

A parafoil system consists of a canopy, suspension lines, a payload, and an airborne guidance unit
iterative feedback tuning (IFT)-MFAC is a solution for the nonlinear problems of parafoil systems; its effectiveness and performance are discussed in this paper through both simulations and hardwarein-loop (HIL) tests
This paper introduced a model-free adaptive control method for parafoil systems based on the iterative feedback tuning method (IFC MFAC)

Summary

INTRODUCTION

A parafoil system consists of a canopy, suspension lines, a payload, and an airborne guidance unit. Zhao et al employed a model-free adaptive control method (MFAC) for parafoil systems and verified it through a series of simulations that considered wind environment and flight data disturbances [9]. IFT-MFAC is a solution for the nonlinear problems of parafoil systems; its effectiveness and performance are discussed in this paper through both simulations and hardwarein-loop (HIL) tests. The MFAC method is a type of data-driven control method that was proposed in the 1990s by Hou for discrete-time nonlinear systems [20], and its effectiveness and applicability have been verified by rigorous mathematical derivation and corresponding simulations [21]. Based on the control method, simulations are carried out to verify the IFT-MFAC controller’s performance in parafoil systems. A six-degree-of-freedom (six-DOF) dynamics model of parafoil systems is established here to verify the control performance of IFT-MFAC in simulations. Where Cxx represents a series of aerodynamic parameters, and δs and δa are the symmetric trailing edge (TE) deflection and the asymmetric TE deflection of parafoil systems, respectively

MODEL-FREE ADAPTIVE CONTROLLER

SIMULATION CONDITION

Findings

CONCLUSION