Bionic visual navigation control system and method thereof for autonomous aerial refueling docking

Patent metadata

Field	Value
Publication number	US-11427316-B2
Application number	US-201816147240-A
Country	US
Kind code	B2
Filing date	Sep 28, 2018
Priority date	Jul 31, 2018
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A bionic visual navigation control system for autonomous aerial refueling docking includes: a tanker/receiver bottom layer control module, a multi-wind disturbances hose-drogue stable control module, an enable and select module, a close-range bionic vision relative navigation module, and a receiver relative position precise control module. A bionic visual navigation control method for autonomous aerial refueling docking is also provided. The present invention aims at improving the reliability, anti-interference and accuracy of the close-range relative navigation in the autonomous air refueling docking stage, and designs a matching relative position accurate control method with control switch, thereby improving the accuracy of close-range navigation and control, thereby promoting the successful realization of probe-and-drogue autonomous aerial refueling and improving the autonomy of UAVs.

First claim

What is claimed is:

1. A bionic visual navigation control system for autonomous aerial refueling docking, comprising: a tanker/receiver bottom layer control module, a multi-wind disturbances hose-drogue stable control module, an enable and select module, a close-range bionic vision relative navigation module, and a receiver relative position control module; wherein
1) the tanker/receiver bottom layer control module comprises tanker/receiver pitch angle, roll angle, yaw angle and speed controllers; the pitch angle controller controls an elevator, wherein an inner ring of the pitch angle controller is pitch angle speed PI (Proportional Integral) controller, and a proportional feedback of attack angle is used to stabilize the receiver; an outer ring of the pitch angle controller is a pitch angle PI controller, and an inner ring pitch angle speed command is calculated by the outer ring for pitch angle stability and control; the roll angle controller controls an aileron, wherein an inner ring of the roll angle controller is roll angle speed PI controller; an outer ring of the roll angle controller is roll angle PI control, and an inner ring roll angle speed command is calculated by the outer ring for roll angle stability and control; the yaw angle controller controls a rudder, wherein a proportional feedback of yaw angle speed is used to stabilize the receiver, and yaw angle PI controller is used for yaw angle stability and control; the speed controller controls a throttle thrust, wherein speed PI control is used to calculate a desired engine thrust for speed stability and control; in an autonomous aerial refueling docking stage, the receiver obtains a pitch angle command, a roll angle command and a speed command through the receiver relative position precise control module as inputs of the tanker/receiver bottom layer control module; since a straightened sideslip deviation control is adopted to eliminate lateral position differences, a yaw angle remains at zero; assume that the tanker makes fixed straight level flight, a pitch angle thereof maintains at a trim state value, and roll and yaw angles remain at zero;
2) the multi-wind disturbances hose-drogue stable control module comprises a hose-drogue model, multi-wind disturbances models and drogue position stability controller; wherein, the hose-drogue model comprises hose multi-rigid dynamics and kinematics, as well as drogue dynamics and kinematics; a hose-drogue assembly is fixed with the tanker; the hose-drogue model established is formed by a plurality of mass-concentrated links and a drogue; the multi-wind disturbances models comprises an atmospheric turbulence model, a tanker trailing vortex model and a receiver bow wave model which establish a wind disturbance environment for probe-and-drogue autonomous aerial refueling docking stage, so as to enhance authenticity of a simulation system; wind speed components of three atmospheric disturbances in three directions are obtained by simulation, and wind speed is superimposed; a composite wind speed acts on a mass center of the hose and the drogue, thus affecting aerodynamic forces of the hose and the drogue, leading to a swing of the stable position of the hose and the drogue and difficulties in autonomous docking; the drogue position stability control comprises a drogue lateral position PID (Proportional Integral Derivative) controller, a vertical position PID controller, and a drogue actuator distribution, wherein for reducing difficulties of the autonomous docking, the drogue lateral position PID controller and the vertical position PID controller are designed according to the stable position of the drogue to obtain desired active control forces along lateral and vertical directions; according to drogue aerodynamics, corresponding actuators of the drogue are used to generate actual active control forces, thereby reducing a swinging range of the drogue and reducing the difficulties of the autonomous docking;
3) the enable and select module comprises visual enablement, visual navigation method selection, and control selection, wherein the visual enablement activates the bionic visual navigation system, obtains images in virtual reality (VR) simulation and performs visual navigation processing; the visual navigation method selection is firstly provided, comprising VR visual simulation, marker detection, and judging whether all markers are detected, wherein drogue markers in an VR image are processed with the eagle-eye marker detection, according to whether all designed markers on the drogue are detected, different close-range vision relative navigation methods are selected; the control selection determines whether to use a visual navigation signal according to calculated visual position differences between a probe and the drogue;
4) the close-range bionic vision relative navigation module comprises two situations of the drogue is completely detected, and the drogue is at a distance or partially blocked; according to a visual navigation method selection result, if the drogue is completely detected, then marker matching is performed, so as to perform accurate pose estimation; if the drogue is at a distance or partially blocked, thus the marker are not completely detected, then ellipse fitting is performed according to color information of the drogue, so as to perform pose estimation; and
5) the receiver relative position control module comprises a receiver altitude controller, a lateral deviation controller and a forward deviation controller; wherein the altitude controller uses the pitch angle control as an inner ring of the altitude controller, and the forward deviation controller uses the speed control as an inner ring of the forward deviation controller; the lateral deviation control adopts a receiver straightened sideslip method, and uses the rolling angle as an inner ring; relative position control is achieved by feeding back relative positions between the tanker and the receiver.

2. A bionic visual navigation control method for autonomous aerial refueling docking, comprising steps of:
step 1 : establishing a receiver model, a hose-drogue model and multi-wind disturbances models, and setting initial states, comprising specific steps of:
establishing a six-degree-of-freedom nonlinear tanker/receiver model:

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Assignees

• Univ Beihang

Inventors

• Duan Haibin
• Sun Yongbin
• Deng Yimin
• Xin Long
• Li Han
• Xu Xiaobin
• Fei Lun
• Huo Mengzhen
• Chen Lin
• Qiu Huaxin
• Zhang Daifeng
• Shen Yankai
• Xian Ning
• Wei Chen
• Zhou Rui

Classifications

• B64U2201/102

  adapted for flying in formations · CPC title

• G05B17/02

  electric · CPC title

• G06T2207/30204

  Marker · CPC title

• G06T2207/10024

  Color image · CPC title

• G06T7/11

  Region-based segmentation · CPC title