Scheduling PID Attitude and Position Control Frequencies for Time-Optimal Quadrotor Waypoint Tracking under Unknown External Disturbances

Cheongwoong Kang,Bumjin Park,Jaesik Choi

doi:10.3390/s22010150

Cheongwoong Kang, Bumjin Park + Show 1 more

Open Access

https://doi.org/10.3390/s22010150

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Journal: Sensors	Publication Date: Dec 27, 2021
Citations: 8	License type: CC BY 4.0

Affiliation: Korea Advanced Institute of Science and Technology

Abstract

Recently, the use of quadrotors has increased in numerous applications, such as agriculture, rescue, transportation, inspection, and localization. Time-optimal quadrotor waypoint tracking is defined as controlling quadrotors to follow the given waypoints as quickly as possible. Although PID control is widely used for quadrotor control, it is not adaptable to environmental changes, such as various trajectories and dynamic external disturbances. In this work, we discover that adjusting PID control frequencies is necessary for adapting to environmental changes by showing that the optimal control frequencies can be different for different environments. Therefore, we suggest a method to schedule the PID position and attitude control frequencies for time-optimal quadrotor waypoint tracking. The method includes (1) a Control Frequency Agent (CFA) that finds the best control frequencies in various environments, (2) a Quadrotor Future Predictor (QFP) that predicts the next state of a quadrotor, and (3) combining the CFA and QFP for time-optimal quadrotor waypoint tracking under unknown external disturbances. The experimental results prove the effectiveness of the proposed method by showing that it reduces the travel time of a quadrotor for waypoint tracking.

Highlights

In recent years, the use of quadrotor has rapidly increased in various fields, including agriculture [1,2], rescue [3,4], delivery [5], inspection [6], and map construction [7].A quadrotor, or drone, shows a versatile ability for various kinds of missions because of the simple structure, the simple use of control, and useful properties, such as VTOL.Quadrotor waypoint tracking is defined as controlling quadrotors to follow the given waypoints
PID control [8] is widely used for controlling robots, including quadrotors [9,10,11], it is hardly generalizable to various environments, such as various trajectories and dynamic external disturbances, which cannot be precisely modeled due to the uncertainties [12]
We observe that the Quadrotor Future Predictor (QFP) model perfectly predicts the direction of the position, whereas there are some errors in the magnitude

Summary

Introduction

The use of quadrotor has rapidly increased in various fields, including agriculture [1,2], rescue [3,4], delivery [5], inspection [6], and map construction [7].A quadrotor, or drone, shows a versatile ability for various kinds of missions because of the simple structure, the simple use of control, and useful properties, such as VTOL (vertical take-off and landing).Quadrotor waypoint tracking is defined as controlling quadrotors to follow the given waypoints. To complete time-critical missions, such as rescue and delivery, time-optimal quadrotor waypoint tracking is essential. In this work, we discover that different trajectories require different control frequencies to achieve time-optimal tracking control. The orientation η = [φ, θ, ψ], where ξ is the position of the body frame with respect to Sensors 2022, 22, 150 the inertial frame A and η is the rotation coordinates of the body frame with respect to the inertial frame. These values are denoted as roll, pitch, and yaw [29]

Methods

Results

Conclusion