Trajectory Tracking Control for Parafoil Systems Based on the Model-Free Adaptive Control Method

Linggong Zhao,Wang Xiaoguang,Weiliang He,Feikai Lv

doi:10.1109/access.2020.3017539

Abstract

Parafoil systems are unique steerable decelerator systems. However, due to the strong nonlinearity caused by the flexibility of the canopy and the suspension lines, the existing dynamic models of parafoil systems are not sufficiently accurate enough; and hence, existing model-dependent control methods are not suitable for practical applications. To effectively eliminate the influence of inaccurate models on trajectory tracking, this paper introduces a novel real-time model-independent control method named the model-free adaptive control (MFAC) method. The stability of the MFAC method is theoretically deduced, and the robustness of this approach is analyzed and demonstrated by the Monte Carlo method. To assess the performance of the MFAC method, a six-degree-of-freedom (DOF) dynamic model is built, and then a series of simulations are performed under different conditions. The simulation results demonstrate the effectiveness of the proposed MFAC method in trajectory tracking. Compared with the proportional/integral/derivative (PID) control method and the active disturbance rejection control (ADRC) method, the MFAC method has higher precision and lower energy consumption, especially under complex disturbance conditions.

Highlights

To further evaluate the control performance, a six-DOF model of the parafoil system is built, and a series of simulation tests are performed under various conditions: no disturbances, gusty wind disturbances, and random disturbances
This proposed method can eliminate the influences of inaccurate models and external disturbances and enables the parafoil system to track desired trajectories
The simulation results for the model-free adaptive control (MFAC) controller are compared with those of the PID and active disturbance rejection control (ADRC) controllers commonly used in parafoil systems

Summary

Introduction

The canopy provides lift and drag for the vehicle, and the suspension lines connect the canopy to the payload. The lateral and longitudinal control of the parafoil system is achieved through the deflection of the steering lines attached to the left and right trailing edge (TE) of the canopy [1]. Asymmetric deflection leads to a turning maneuver, and symmetric deflection provides speed control of impact on the ground. These controls allow the parafoil systems to steer in a horizontal direction during descent [2]

Methods

Results

Conclusion