Multirotor Helicopters Research Articles

Autonomous Aerial Filming With Distributed Lighting by a Team of Unmanned Aerial Vehicles

This letter describes a method for autonomous aerial cinematography with distributed lighting by a team of unmanned aerial vehicles (UAVs). Although camera-carrying multi-rotor helicopters have become commonplace in cinematography, their usage is limited to scenarios with sufficient natural light or of lighting provided by static artificial lights. We propose to use a formation of unmanned aerial vehicles as a tool for filming a target under illumination from various directions, which is one of the fundamental techniques of traditional cinematography. We decompose the multi-UAV trajectory optimization problem to tackle non-linear cinematographic aspects and obstacle avoidance at separate stages, which allows us to re-plan in real time and react to changes in dynamic environments. The performance of our method has been evaluated in realistic simulation scenarios and field experiments, where we show how it increases the quality of the shots and that it is capable of planning safe trajectories even in cluttered environments.

Special Issue on Novel Technology of Autonomous Drone

In the past three years, there has been rapid progress in the use of drones in society. Drones, which were previously used only experimentally in various industrial fields, are now being used in earnest in everyday operations. Drones are becoming indispensable tools in several industrial fields, such as surveying, inspection, and agriculture. At the same time, there has also been dramatic progress in autonomous drone technology. With the advancement of image processing, simultaneous localization and mapping (SLAM), and artificial intelligence technologies, many intelligent drones that apply these technologies are being researched. At the same time, our knowledge of multi-rotor helicopters, the main type of drones, has continued to deepen. As the strengths and weaknesses of multi-rotor helicopters have gradually become clearer, drones with alternate structures, such as flapping-wing drones, have come to attract renewed attention. In addition, the range of applications for drones, including passenger drones, has expanded greatly, and research on unprecedented drone operations, as well as research on systems and controls to ensure operational safety, is actively being conducted. This special issue contains the latest review, research papers, and development reports on autonomous drones classified as follows from the abovementioned perspectives. · Research on drone airframes and structures · Research on drone navigation and recognition with a focus on image processing · Research on advanced drone controls · Research and development of drone applications We hope that the readers will actively promote the use of drones in their own research and work, based on the information obtained from this special issue.

Stability characteristics of multi-frequency parametrically-excited rotor-oscillator systems

The effect of multi-frequency parametric excitation on the stability of an oscillator is examined in the context of a rotating system where the rotor and the stator have comparable masses and hence the ‘stator’ cannot be considered to be mechanically fixed. The differential equations governing the dynamics of such systems have time-varying terms which are periodic in the rotor frequencies. Floquet theory is employed to numerically develop stability diagrams which distinguish stable from unstable parameter combinations. Reasons for the occurrence of instabilities are explained using the two time scale perturbation method. It was found that the most significant resonance in the single rotor case occurred when the rotor speed equaled the sum of two unforced natural frequencies. In addition, harmonic resonances were found to arise when the rotor speed matched the unforced natural frequencies. Furthermore, the excitation from a second rotor caused instabilities to arise around regimes where multiple combination resonances occurred together. The occurrence of certain experimentally-observed resonances and regimes of low amplitude oscillations were correlated with the model, and the corresponding rotor trajectories were explored. This investigation is useful for identifying operating regimes so as to avoid catastrophic failure in multi-frequency rotating machines such as multi-rotor helicopters and gas turbines with contra-rotating stages.

The Study on the Structural Optimization of Non-Planar Multi-rotor Helicopters Using the Force capacity

In recent years, multi-rotor helicopter has been used in various fields. However, it has the disadvantages. A general multi-rotor helicopter needs to change its attitude when moving horizontally. Therefore, fluctuations in the attitude of the aircraft to counter disturbances pose a risk of contact with structures when approaching a structure in infrastructure inspection. Furthermore, in contact work, it is required to independently control translational motion and rotational motion, such as maintaining the position of the aircraft while maintaining an arbitrary attitude. Based on the above background, the study is being conducted on a non-planar multi-rotor helicopter in which translational motion and rotational motion can be controlled independently. In this study, in order to establish the optimum design of the airframe specialized in the arbitrary axial direction, an evaluation index called ”Force capacity” is applied to the non-planar multi-rotor helicopter, and the attitude of each rotor is optimized.

Formation control of unmanned micro aerial vehicles for straitened environments

This paper presents a novel approach for control and motion planning of formations of multiple unmanned micro aerial vehicles (multi-rotor helicopters, in the literature also often called unmanned aerial vehicles—UAVs or unmanned aerial system—UAS) in cluttered GPS-denied on straitened environments. The proposed method enables us to autonomously design complex maneuvers of a compact Micro Aerial Vehicles (MAV) team in a virtual-leader-follower scheme. The results of the motion planning approach and the required stability of the formation are achieved by migrating the virtual leader along with the hull surrounding the formation. This enables us to suddenly change the formation motion in all directions, independently from the current orientation of the formation, and therefore to fully exploit the maneuverability of small multi-rotor helicopters. The proposed method was verified and its performance has been statistically evaluated in numerous simulations and experiments with a fleet of MAVs.

Cooperative path planning for leader – follower formation of Multi UAV based on the minimum energy consumption for load transportation

Today, unmanned aerial vehicles are highly considered for both military and commercial fields due to low cost, high maneuverability, and good survival. One of the most important design challenges of multi-UAV systems is mission planning. In the broad class of unmanned aerial vehicles (UAV), Quadrotor is an important member. The capabilities of this vehicle in load transportation has attracted the attention of many research groups around the world. In this paper, path planning based on the minimum energy consumption is studied for load transportation. The purpose of the present study is to investigate the effect of proposed cost function in order to obtain optimal path for transporting loads based on reducing the energy consumption of quadrotors. The results indicate the 35.29% energy consumption of multi UAV compared to the energy consumption of an individual quadrotor. This also leads to an increase in load carrying capacity. On the other hand, the leader- follower formation is preserved until the end of the path based on the defined relationships. The simulation results illustrate the power and efficiency of the method to overcome the high nonlinearity nature of the problem such as path optimization of multi-rotor helicopters.

Precise Formation Control of Multi-rotor Helicopters by Using Model Following Type Model Predictive Control

Precise Formation Control of Multi-rotor Helicopters by Using Model Following Type Model Predictive Control

Bandwidth Assessment for MultiRotor UAVs

AbstractThis paper is a technical note about the theoretical evaluation of the bandwidth of multirotor helicopters. Starting from a mathematical linear model of the dynamics of a multirotor aircraft, the transfer functions of the state variables that deeply affect the stability characteristics of the aircraft are obtained. From these transfer functions, the frequency response analysis of the system is effected. After this analysis, the bandwidth of the system is defined. This result is immediately utilized for the design of discrete PID controllers for hovering flight stabilization. Numeric simulations are shown to demonstrate that the knowledge of the bandwidth is a valid aid in the design of flight control systems of these machines.

Distributed Formation Flight Control of Multirotor Helicopters

This paper treats the problem of position formation flight control of a group of three multirotor aerial vehicles under obstacle and collision avoidance constraints. In order to solve the problem, a distributed architecture with model predictive controllers for each vehicle includes a set of convex constraints on the vehicles’s position to prevent collisions with other vehicles and obstacles. The resulting distributed scheme controls the formation based on a virtual structure approach where the computers of the architecture exchange position data through diagrams in Simulink. The performance of the method is assessed through simulations considering that the vehicles are subject to disturbance forces and the results show the effectiveness and the ability of the control architecture to handle the obstacle and collision avoidance constraints.

Evaluation of Microphone Array for Multirotor Helicopters

[abstFig src='/00290001/16.jpg' width='300' text='UAV with a microphone array whose performance is evaluated' ] High expectations are placed on the use of unmanned aerial vehicles (UAVs) in such tasks as rescue operations, which require a system that makes use of visual or auditory information to recognize the surrounding environment. As an example of such a system, this study examines the recognition of the environment using a helicopter mounted with a microphone array. Because the rotors of a helicopter generate high noise during operation, it is necessary to reduce the effects of this noise and those from other sources to record the audio signals coming from the ground with onboard microphones. In particular, because of helicopter body control, the rotor speed changes continuously and causes an unsteady rotor noise, which implies that it would be effective to arrange the microphones at a sufficient distance from the rotors. When a large microphone array is employed, however, the array weight may alter the helicopter’s flight characteristics and increase the noise, presenting a dilemma. This paper presents a model of rotor noise that takes into account the effect of the microphone array on the helicopter’s dynamic characteristics and proposes a method of evaluating the optimality of the array configuration, which is necessary for design. The validity of the proposed method is investigated using a multirotor helicopter mounted with a microphone array previously developed by the authors. In addition, an application example for locating sound sources on the ground using this helicopter is presented.

屋外環境下におけるマルチローターヘリコプターの編隊飛行制御システム

屋外環境下におけるマルチローターヘリコプターの編隊飛行制御システム

産業用マルチロータヘリコプタのオンラインシステム同定機構を有する自動チューニング適応I-PD制御

産業用マルチロータヘリコプタのオンラインシステム同定機構を有する自動チューニング適応I-PD制御

Coastal and Environmental Remote Sensing from Unmanned Aerial Vehicles: An Overview

Klemas, V.V., 2015. Coastal and environmental remote sensing from unmanned aerial vehicles: An overview.Unmanned aerial vehicles (UAVs) offer a viable alternative to conventional platforms for acquiring high-resolution remote-sensing data at lower cost and increased operational flexibility. UAVs include various configurations of unmanned aircraft, multirotor helicopters (e.g., quadcopters), and balloons/blimps of different sizes and shapes. Quadcopters and balloons fill a gap between satellites and aircraft when a stationary monitoring platform is needed for relatively long-term observation of an area. UAVs have advanced designs to carry small payloads and integrated flight control systems, giving them semiautonomous or fully autonomous flight capabilities. Miniaturized sensors are being developed/adapted for UAV payloads, including hyperspectral imagers, LIDAR, synthetic aperture radar, and thermal infrared sensors. UAVs are now used for a wide range of environmental applications, such as coastal wetland mapping, LIDAR bathymetry, flood and wildfire surveillance, tracking oil spills, urban studies, and Arctic ice investigations.

Stability and performance analysis of unmanned aerial vehicles: Quadrotor against Hexrotor

Multirotor helicopters are very powerful flying robots used in many applications, but their lack is robustness. A fail in any of their rotors can drive the helicopter to fall. In this study two different micro-helicopter structures are analysed, a standard Quadrotor and a Hexrotor. An uncertainty model is generated and a robust controller is designed. The structured singular value μ Δ is used to test the robust stability and performance of these two plants, obtaining better results for Hex than Quadrotor. At the end of the study, a set of flight tests, where some of the motors are partially damaged, is presented confirming the analysis of μ Δ. Results of this study show Hexrotor as a very interesting structure for unmanned aerial vehiclesbecause of its stability and performance characteristics compared with Quadrotor.

Disturbance Observer Based Control of Multirotor Helicopters Based on a Universal Model with Unstructured Uncertainties

To handle different perspectives of unstructured uncertainties, two robust control techniques on the basis of a universal model are studied in this paper. Rather than building a model only applicable to a specific small-scale multirotor helicopter (MHeli), the paper proposes a modeling technique to develop a universal model-framework. Particularly, it is straightforward to apply the universal model to a certain MHeli because the contribution and allocation matrix is proposed in the model-framework. Based on the model uncertainties, the load perturbation of the rotor is the primary focus due to its indispensable importance in the tracking performance. In contrast to the common methods, it is proposed to take this unstructured uncertainty in that external disturbance and designs disturbance observer (DOB). In addition, a class of lead-compensator is specifically designed as for compensating phase lag induced by DOB. Compared withH∞loop-shaping, greater robust tracking performance on rejecting load perturbation could be achieved as a tradeoff between robust stability and tracking performance which is successfully avoided with DOB-based control strategy.

A205 産業用マルチロータヘリコプタの自動チューニング適応制御(OS11 自律知能無人ビークルの運動と制御1)

A205 産業用マルチロータヘリコプタの自動チューニング適応制御(OS11 自律知能無人ビークルの運動と制御1)

2A1-G03 脳波計によるマルチローターヘリコプター用操縦デバイスの開発(飛行ロボット・メカトロニクス(1))

In this paper, we consider a remote control system for multi-rotor helicopters developed in our previous researches. Multi-rotor helicopters are used in aerial photography such as disaster information collection, group photograph, and structural deterioration investigation. When human operates such a multi-rotor helicopter, there is a risk of falling and contacting because of human errors. Therefore, we have proposed a remote control system with an electroencephalograph. Remote control in only expressions and head motions and operation support system by alerting in case of an abnormal condition become enable.

2A2-B02 フォーメーション制御を利用したマルチローターヘリコプターによる観測システムの開発(飛行ロボット・メカトロニクス(2))

2A2-B02 フォーメーション制御を利用したマルチローターヘリコプターによる観測システムの開発(飛行ロボット・メカトロニクス(2))

2103 強化学習を用いたマルチロータヘリコプタの行動学習(OS10-1 ビークルオートメーション,OS10 アドバンティシンポジウム,オーガナイズド・セッション(OS))

We tried to control quadrotor helicopter which is one of the multirotor helicopters by reinforcement learning. Quadrotor helicopter is a very simple machine which consists of four rotor blades and rigid cross airframe. However, the nonlinear dynamic behavior of quadrotor helicopter requires a more advanced stabilizing control. On the other hand, reinforcement learning agent acquires optimal action by itself for a purpose of maximizing reward through trial and error. In this paper, we try to apply Q-learning to quadrotor helicopter in order to easily control. We verified that quadrotor helicopter with Q-learning could acquire optimal action by itself to keep target altitude in flight experiment.

2A1-G02 マルチローターヘリコプターのミニチュア模型型遠隔操縦システムの開発(飛行ロボット・メカトロニクス(1))

2A1-G02 マルチローターヘリコプターのミニチュア模型型遠隔操縦システムの開発(飛行ロボット・メカトロニクス(1))