• International Journal of Aeronautical and Space Sciences
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• v.11 no.3
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• pp.167-174
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• 2010

The design, dynamics, and control allocation of tri-rotor unmanned aerial vehicles (UAVs) are introduced in this paper. A trirotor UAV has three rotor axes that are equidistant from its center of gravity. Two designs of tri-rotor UAV are introduced in this paper. The single tri-rotor UAV has a servo-motor that is installed on one of the three rotors, which enables rapid control of its motion and its various attitude changes-unlike a quad-rotor UAV that depends only on the angular velocities of four rotors for control. The other design is called 'coaxial tri-rotor UAV,' which has two rotors installed on each rotor axis. Since the tri-rotor type of UAV has the yawing problem induced from an unpaired rotor's reaction torque, it is necessary to derive accurate dynamic and design control logic for both single and coaxial tri-rotors. For that reason, a control strategy is proposed for each type of tri-rotor, and nonlinear simulations of the altitude, Euler angle, and angular velocity responses are conducted by using a classical proportional-integral-derivative controller. Simulation results show that the proposed control strategies are appropriate for the control of single and coaxial tri-rotor UAVs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.539-540
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• 2012

최근까지 무인 항공기는 군사적인 목적으로 활용하기 위해 활발하게 연구 되어 왔다. 근래에 들어 레저용, 또는 상업용으로 활용도가 급격히 증대되고 있다. 이에 국내외의 대학 및 연구기간에서 무인항공기의 자동비행 제어시스템을 위한 연구를 활발히 진행되고 있다. 최근 들어 무인항공기로 제어하기가 쉽고 활용도가 높은 쿼드로터 비행체가 각광을 받고 있는데 이미 많은 연구가 진행되어 왔다. 이러한 쿼드로터는 4개의 로터의 속도 제어로 비행체의 위치제어가 가능하다. 쿼드로터의 구조적인 이점으로 제어가 쉬운 반면 바람과 같은 외란에 매우 취약하다는 단점이 있어 실제 위치 제어가 쉽지가 않다. 본 논문에서는 외란(disturbance)에 취약한 쿼드로터의 위치제어를 안정하게 제어하기 위해 비행체의 자세 측정 센서인 관성측정장치(Inertial Measurement Unit)를 만들어 비행체의 자세를 측정 할 수 있도록 하였다. IMU는 자이로(Gyro)와 가속도(Accelerometer) 센서를 융합하여 비행체의 Roll, Pitch, Yaw 자세를 계측할 수 있도록 하였다. 본 논문에서는 일반적인 PID 제어기법을 적용하여 기존의 쿼드로터의 비행체에 대한 제어 성능을 실험을 제시하고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.580-585
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• 2005

A QRT(Quad-Rotor Type) hovering robot system is developed for quick detection and observation of the circumstances under calamity environment such as indoor fire spots. The UAV(Unmanned Aerial Vehicle) is equipped with four propellers driven by each electric motor, an embedded controller using a DSP, INS(Inertial Navigation System) using 3-axis rate gyros, a CCD camera with wireless communication transmitter for observation, and an ultrasonic range sensor for height control. The developed hovering robot shows stable flying performances under the adoption of RIC(Robust Internal-loop Compensator) based disturbance compensation and the vision based localization method. The UAV can also avoid obstacles using eight IR and four ultrasonic range sensors. The VTOL(Vertical Take-Off and Landing) flying object flies into indoor fire spots and sends the images captured by the CCD camera to the operator. This kind of small-sized UAV can be widely used in various calamity observation fields without danger of human beings under harmful environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.1
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• pp.37-46
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• 2014

This paper describes the conceptual design and development test procedure of a unmanned scaled-down personal air vehicle(PAV) with drive and flight dual mode capability. Trade studies on operational requirements led to the suggestion of a quad tilt prop platform which has nacelle tilt capability with multi rotor configuration. Motors for propeller propulsion and driving mechanism were integrated into a single nacelle, then they were implemented by nacelle tilt mechanism for conversion between the drive and the flight modes. Primary design parameters and initial specifications were confirmed through conceptual design, then functional tests were performed with the test platforms for the drive and the flight modes.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.1
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• pp.1-8
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• 2017

Nowadays many articles describe the controlling models for four rotor flying vehicle. Basic approaches to the problem of these articles are mathematical expressions describing dynamics of the models of the vehicle and PID control for manipulating the object in 3 dimensional space. Design of control systems is usually started by careful consideration of its mathematical model description. We present a detailed mathematical model for a quad rotor. This paper first considers simulation of quadcopter control based on full state feedback technique with linearization in MATLAB environment and shows the results of the simulations. Finally will be shown experimental results of the state feedback control implemented in real model.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.9
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• pp.752-761
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• 2014

With increasing of interest in quad-rotor which has excellent maneuverability recently, a various types of multi-rotor aircraft was developed and commercialized, and there are many kinds of leisure products to be easily operated. In these products, the AR.Drone manufactured by Parrot has an advantage that it is easily operated by user due to the its internal stabilization loop in the on-board computer. Thus it is possible to design the unmanned UAV system easily by using this AR.Drone and its inner loop for the stabilization. For this advantage, KARI(Korea Aerospace Research Institute) has been developing the indoor swarming flight system by using multiple AR.Drones. For this indoor swarming flight, it is necessary that not only the position controller for each AR.Drone, but also the collision avoidance algorithm. Therefore, in this paper, the collision avoidance controller is provided for the swarm flight by using these AR.Drones.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.12
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• pp.819-828
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• 2022

Sensitivity of aircraft sizing depending on battery performance was studied for a generic quad tilt rotor type electric vertical takeoff and landing vehicle. The mission requirements proposed by Uber Elevate and NASA were used for initial sizing, and the calculated gross weight is ranged between 5,000lb and 11,000lb for battery specific energy range of 200-400Wh/kg in pack level and continuous discharge rate range of 4-5C. For the assumed gross weight of 7,000lb, the required battery performance was calculated with two different criteria: available power and energy, and the effects of battery specific energy and discharge rate are analyzed. The maximum discharge rate is also recommended considering failure cases such as one battery pack inoperative and one prop rotor inoperative.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.3
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• pp.274-282
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• 2011

This paper is focused on dynamic modeling and control system design as well as vision based collision avoidance for multi-rotor unmanned aerial vehicles (UAVs). Multi-rotor UAVs are defined as rotary-winged UAVs with multiple rotors. These multi-rotor UAVs can be utilized in various military situations such as surveillance and reconnaissance. They can also be used for obtaining visual information from steep terrains or disaster sites. In this paper, a quad-rotor model is introduced as well as its control system, which is designed based on a proportional-integral-derivative controller and vision-based collision avoidance control system. Additionally, in order for a UAV to navigate safely in areas such as buildings and offices with a number of obstacles, there must be a collision avoidance algorithm installed in the UAV's hardware, which should include the detection of obstacles, avoidance maneuvering, etc. In this paper, the optical flow method, one of the vision-based collision avoidance techniques, is introduced, and multi-rotor UAV's collision avoidance simulations are described in various virtual environments in order to demonstrate its avoidance performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.5
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• pp.517-526
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• 2015

This paper presents the results of study for improving the reliability of quadrotor attitude control by applying a multi-sensor along with a data fusion algorithm. First, a mathematical model of the quadrotor dynamics was developed. Then, using the quadrotor mathematical model, simulations were performed using the improved reliability multi-sensor data as the inputs. From the simulation results, we designed a Gimbal-equipped quadrotor system. With the quadrotor in a hover state, we performed experiments according to the angle change of the user's specifications. We then calculated the attitude control data from the actual experimental data. Furthermore, with additional simulations, we verified the performance of the designed quadrotor attitude control system with multiple sensors.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.153-165
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• 2014

Multi-rotor UAVs are utilized in various fields because of the advantages such that a hovering capability such as helicopters, a simple structure and a relatively high thrust. Recently, AR.Drone manufactured by Parrot is easily operated by beginner due to its internal stabilization loop in the on-board computer and it can be easily applied on various researches for the multi-rotor UAVs by providing an SDK(Software Development Kit). Further this platform can be suitably used for application to swarm flight since it is low cost and relatively small. Therefore, in this paper, we introduce the development process of the controller for indoor swarm flight by using the AR.Drone.