Long Di

Low-cost Multi-UAV Technologies for Contour Mapping of Nuclear Radiation Field

Low cost UAVs are becoming more and more popular in both research and practical applications, and it leads to a new, potentially significant service product known as UAV-based personal remote sensing (PRS). Multi-UAV system with advanced cooperative control algorithms has advantages over single UAV system, especially in time urgent tasks such as detecting nuclear radiation before deploying the salvage. This paper considers two scenarios for nuclear radiation detection using multiple UAVs, of which contour mapping of the nuclear radiation is simulated. Then, for real applications, this paper presents a low-cost UAV platform with built-in formation flight control architecture together with a formulated standard flight test routine. Three experimental formation flight scenarios that imitate the nuclear detection missions are prepared for contour mapping of nuclear radiation field in 3D space.

A comparative evaluation of low-cost IMUs for unmanned autonomous systems

Inertial measurement units (IMUs) are widely used for navigation and calibration purposes on unmanned autonomous vehicles. This paper provides a comparative survey and evaluation of the low-cost IMUs focusing on both the possible sensor packages and the available software solutions. Several example IMUs are compared in detail including inertial only IMUs, GPS-coupled IMUs, and hobbyist-level IMUs. The future direction of low-cost IMUs are discussed including optical-flow-based solutions and collaborative IMUs.

A Data Fusion System for Attitude Estimation of Low-cost Miniature UAVs

Miniature unmanned aerial vehicles (UAVs) have attracted wide interest from researchers and developers because of their broad applications. In order to make a miniature UAV platform popular for civilian applications, one critical concern is the overall cost. However, lower cost generally means lower navigational accuracy and insufficient flight control performance, mainly due to the low graded avionics on the UAV. This paper introduces a data fusion system based on several low-priced sensors to improve the attitude estimation of a low-cost miniature fixed-wing UAV platform. The characteristics of each sensor and the calculation of attitude angles are carefully studied. The algorithms and implementation of the fusion system are described and explained in details. Ground test results with three sensor fusions are compared and analyzed, and flight test comparison results with two sensor fusions are also presented.

Cognitive Multi-UAV Formation Flight: Principle, Low-Cost UAV Testbed, Controller Tuning and Experiments

Cooperative UAV systems can have great advantages over isolated UAV systems, regarding application, safety, efficiency and many other perspectives. Motivated by challenges from practical multiple UAV formation flight, this paper presents our approaches towards cognitive formation flight. It introduces the principle ofmulti-UAV cognitive formation flight and the control structure utilized in our development, describes a low-cost UAV testbed developed by ourselves, and details the tuning procedures of the implemented multi-agent flight controller for stable and consistent formation flights. Different formation flight scenarios are also discussed and the experimental setup is presented including real-time issues and the formation flight test protocol. Routinized comprehensive flight test results are also shown at the end.Copyright

Pitch Loop Control of a VTOL UAV Using Fractional Order Controller

Pitch loop control is the fundamental tuning step for vertical takeoff and landing (VTOL) unmanned aerial vehicles (UAVs), and has significant impact on the flight. In this paper, a fractional order strategy is designed to control the pitch loop of a VTOL UAV. First, an auto-regressive with exogenous input (ARX) model is acquired and converted to a first-order plus time delay (FOPTD) model. Next, based on the FOPTD model, a fractional order [proportional integral] (FO[PI]) controller is designed. Then, an integer order PI controller based on the modified Ziegler-Nichols (MZNs) tuning rule and a general integer order proportional integral derivative (PID) controller are also designed for comparison following three design specifications. Simulation results have shown that the proposed fractional order controller outperforms both the MZNs PI controller and the integer order PID controller in terms of robustness and disturbance rejection. At last, ARX model based system identification of AggieAir VTOL platform is achieved with experimental flight data.

FRACTIONAL ORDER FLIGHT CONTROL OF A SMALL FIXED-WING UAV: CONTROLLER DESIGN AND SIMULATION STUDY

This paper focuses on designing and implementation of fractional order proportional integral (PI a ) flight controller on a small fixed-wing unmanned aerial vehicle (UAV). It describes mainly the controller design and simulation studies. The basics of UAV flight control are introduced first with a special emphasis on small UAV platforms. Time domain system identification methods are tried on the UAV roll channel. A new fractional order PI controller design method is then provided based on the identified first order model. The fractional order PI a controller can outperform the traditional integer order PID controller because it has a larger memory and more candidate solutions to choose. The simulation results show the effectiveness of the proposed controller design strategy and the robustness of fractional order controller under conditions of wind gusts and various payloads.

Improved architecture designs for a low cost personal remote sensing platform: flight control and safety

Remote sensing is a field traditionally dominated by expensive, large-scale operations. This paper presents our efforts to improve our unmanned aircraft (UA) platforms for low-cost personal remote sensing purposes. Safety concerns are first emphasized regarding the local airspace and multiple fail-safe features are shown in the current system. Then the AggieAir unmanned system architecture is briefly described including the Paparazzi UA autopilot, AggieAir JAUS implementation, AggieNav navigation unit and payload integration. Some preliminary flight test results and images acquired using an example thermal IR payload system are also shown. Finally Multi-UAV and heterogeneous platform capabilities are discussed with respect to their applications. Based on our approaches on the new architecture design, personal remote sensing on smaller-scale operations can be more beneficial and common.Copyright

Autonomous Flying Under 500 USD Based on RC Aircraft

Radio control (RC) aircrafts have been favorite toys of aviation hobbyists for years. Because of their simple configurations and low expense, they can also be used for reconnaissance and surveillance with information-gathering devices under commands of a skillful human pilot. However, control with human in the loop not only degrades the reliability of the flight performance, but also bring restrictions in endurance and accuracy. In order to resolve these issues and extend the usage of RC aircrafts, getting them capable of autonomous navigation is a preferred solution. This paper reports our approach by designing and integrating an autonomous system on a regular RC aircraft to achieve full autonomy while keeping the additional costs almost equivalent to the cheap RC platform. The current platform will be briefly presented, the system architecture and major components will be introduced, and detailed autonomous demonstration flight results will be provided at the end.Copyright

Fractional order controller for pitch loop control of a VTOL UAV

As the fundamental tuning step for vertical takeoff and landing (VTOL) unmanned aerial vehicles (UAVs), pitch loop control has significant impact on the flight. In this paper, an auto-regressive with exogenous input (ARX) model is acquired and converted to a first-order plus time delay (FOPTD) model for the pitch loop of a VTOL UAV. Based on the FOPTD model, a fractional order [proportional integral] (FO[PI]) controller is designed. An integer order PI controller based on the modified Ziegler-Nichols (MZNs) tuning rule and a general integer order proportional integral derivative (PID) controller are also designed for comparison following three design specifications. Simulation results have shown that the proposed fractional order controller outperforms both the MZNs PI controller and the integer order PID controller in terms of robustness and disturbance rejection.

A two-stage calibration method for low-cost UAV attitude estimation using infrared sensor

Infrared (IR) sensors are widely used on robotics platforms for measurement purposes. Low-cost small unmanned aerial vehicles (UAVs) have drawn broad interests during recent years for their various uses in many applications. This paper introduces a two-stage IR sensor calibration method for the attitude estimation of low-cost UAVs. The first stage is based on ground and flight tuning procedures, which are concluded from experience; the second stage is to use the calibration algorithm with inertial measurement unit (IMU) as the baseline reference. The implementation and optimization of the proposed algorithm is described and explained in detail. The experimental flight results are compared and discussed in the end.