四旋翼无人机飞行过程孪生仿真研究

为了满足无人机在实际飞行过程中的虚实交互、实时响应和精确控制等要求,以四旋翼无人机的飞行过程作为任务需求,提出基于数字孪生技术的四旋翼无人机飞行过程仿真研究。搭建了四旋翼无人机飞行数字孪生系统架构,分析了数字孪生体仿真数据的流向及其作用,并对四旋翼无人机飞行数字孪生系统的功能和意义进行了介绍。从几何、物理、行为和规则等四个方面融合构建了四旋翼无人机的数字孪生体模型。最后进行了四旋翼无人机巡航过程的案例研究,通过仿真案例中的各项参数分析,考察了虚实无人机之间的交互性,证明了数字孪生体模型的精确性,验证了四旋翼无人机飞行数字孪生系统的可行性。     

基于浸入—不变集的三旋翼无人机高度系统自适应控制器设计

针对三旋翼无人机的研究集中于数学模型分析、简单的控制算法设计等起步阶段,且高度系统空气阻尼系数未知的情况,研究了三旋翼无人机高度系统的控制问题。基于浸入—不变集方法设计了一种控制三旋翼无人机跟踪目标高度的自适应控制器,根据三旋翼无人机飞行运动特点,推导了三旋翼无人机运动数学模型,完成了控制器参数设计和气动参数选择,采用Lyapunov分析方法对所设计控制器的渐近稳定性进行了理论证明,并对未知空气阻尼系数进行了在线估计,最终在三旋翼无人机实验平台上在环仿真实验验证。实验结果表明,高度跟踪误差在0-6秒可较好地趋于收敛,控制阻尼系数估计值也较好地收敛于合理的范围,表明该算法稳态误差小,收敛速度快,具有较好的控制性能和较强的实用性。     

小型旋翼无人机巡线模拟降雨系统

为了改善现阶段巡线小型旋翼无人机在降雨环境下巡检性能参差不齐的现状,根据无人机在降雨环境下的巡检功能要求,在分析降雨对飞行性能影响的基础上,有针对性地确定系统参数,采用西门子S7-200控制器构建了适用于小型旋翼无人机巡线的模拟降雨系统,阐述了系统的硬件组成、控制算法及软件实现,该系统可自动调节降雨强度、实时显示并存储试验数据.试验测试结果表明,系统稳定可靠,可检测小型旋翼无人机在降雨环境下的巡检性能,对于大、中型旋翼以及固翼等无人机的巡检性能试验开发具有重要意义.     

智能型四旋翼无人机飞控系统的设计与实现

通过数学建模进行动力学系统分析,设计实现智能型四旋翼无人机飞控系统。构建四旋翼无人机动力学模型并进行理论分析;设计无人机机架,对各组成模块进行测试、分析和实验;实现无人机飞控系统的自主避障和智能飞行;实现旋转机臂,使无人机具有新型的加速机制和变向模式。飞行实验结果表明,该无人机飞控系统取得较好的效果,灵敏性强、稳定性高,总体性能良好。     

四旋翼无人机参数预测和抗扰动自适应轨迹跟踪控制

为了降低外界环境对四旋翼无人机飞行轨迹的扰动性,提高无人机的控制精度,提出1种基于滑模控制的四旋翼无人机参数预测和抗扰动的自适应轨迹跟踪控制器。这种控制器对四旋翼无人机系统的不确定状态参数、气流、风阻和执行器故障等外界扰动进行预测,实现了对系统输入的状态补偿和扰动补偿,提高了无人机的轨迹跟踪效率和抗扰动能力,消除了机体在飞行过程中的抖振现象,提高了无人机系统对环境的适应性和控制器的稳定性。通过仿真实验,分析了四旋翼无人机在不同控制器作用下的轨迹跟踪性能曲线,验证了所提出的控制器的优越性和有效性。     

基于STM32的多传感器四旋翼姿态控制系统设计

针对四旋翼无人机姿态传感器易受干扰,导致姿态输出误差大的问题,设计了一种基于STM32的多传感器四旋翼姿态控制系统。系统使用MPU6050等传感器实时采集四旋翼姿态数据,通过四元数互补滤波算法进行姿态解算,利用串级PID控制,以PWM方式驱动电机。在设计控制系统的软硬件基础上,完成了四旋翼的实物制作与飞行测试。结果表明:该系统能够灵活地控制四旋翼无人机的姿态,实现四旋翼无人机稳定飞行。     

无人机数据采集EKF滤波悬停稳定的研究与应用

许多国内外的研究机构致力于四旋翼无人机飞行控制姿态和高度悬停稳定的研究,以实现四旋翼无人机的自主飞行。四旋翼无人机是一种多输入、强耦合、多变量、欠驱动的系统,其稳定性、数据传输的可靠性、精确度、实时性对飞机性能起着决定性的作用。针对四轴无人机悬停运动测试环节中不稳定的影响,基于已有的无人机平台,最新科研前沿的文献,以ARM嵌入式系统作为上位机,设计了一个无人机数据采集的扩展卡尔曼滤波器(EKF),结合二次型最优控制预估气压计最优初始矩阵值进行开源编程。从扩展卡尔曼滤波器的建立与优化,原程序气压计程序严谨的探讨、衔接和写入飞控,最终在软件匿名科创地面站上,通过无人机对气压计大量实时悬停数据采集,实验仿真进行滤波图形对比验证和无人机实际运行的稳定性分析表明,提出的无人机数据采集扩展卡尔曼滤波方法效果良好,具有良好的应用和推广价值。     

基于Unity物理引擎的多旋翼无人机仿真模型

本文主要基于Unity物理引擎,以四旋翼无人机作为研究对象,通过建立无人机运行模式的数学模型,进行仿真模型研究.一方面,通过将无人机受力模型直接应用在电机对应位置,来仿真现实物体的受力状态,从而免去了对模型的刚体数学建模,简化了仿真建模过程;另一方面,通过分析无人机运动原理,对无人机进行动力系统和控制系统建模,其中控制系统采用串级PID控制算法进行姿态控制;本文最后,通过飞行实验和测试验证了无人机模型的稳定性、有效性,满足了四旋翼无人机的仿真要求.     

四旋翼无人机飞控系统的研究与实现

本文通过数学建模进行动力学系统分析,研究实现了基于硬件和软件的四旋翼无人机飞控系统。首先、构建了四旋翼无人机动力学模型并进行理论分析;其次、设计了无人机机架,对各组成模块进行测试、分析和试验;再次、通过集成软硬件实现了无人机飞控系统并进行飞行测试;最后、实验结果表明,实现的无人机飞控系统取得了较好的飞控效果,具有灵敏性强、稳定性高,总体性能优良等优点。     

四旋翼无人机飞控系统仿真平台研究

为了便于对四旋翼无人机的飞行控制系统进行开发,设计了一个用于验证飞行控制系统的全数字仿真平台;建立了四旋翼无人机的数学模型,利用Simulink下的RTW(Real-Time Workshop)工具箱将数学模型转化为C++代码添加到仿真平台中;设计了可视化平台,可将仿真过程直观的进行显示;仿真平台采用C++语言实现,具有良好的外部接口,可方便的将设计好的飞行控制算法添加到仿真平台中,以进行验证和参数整定,还具有数据存储和仿真过程回放等功能;经实际运行表明,仿真平台直观可视,运行良好,能较好地对飞控系统进行仿真验证。     

基于TMS320F28335的小型无人旋翼机数据采集系统

大气数据的采集对于小型无人旋翼机飞行的控制具有关键性的作用,针对小型无人旋翼机的飞行控制需求,利用数字式MEMS传感器和TMS320F28335芯片设计了一种装载于小型无人旋翼机上双采集装置的大气数据采集系统.通过传感器采集数据,实时解算出控制无人旋翼机飞行所需要的空速等数值,同时采用线性插值等算法来提高计算性能.该系统体积小,功耗低,抗干扰能力强等优点,能够满足小型无人旋翼机的需求,为小型无人旋翼机数据采集系统在实际中的应用做了一定的理论工作.     

四旋翼飞行器控制系统设计

四旋翼飞行器姿态控制是四旋翼飞行器控制系统的核心. 通过分析四旋翼飞行器的飞行原理,模型建立,设计了四旋翼飞行器的姿态控制系统;在该系统中采用STM32系列处理器作为主控芯片,MPU6050三轴加速度集和三轴陀螺仪惯性测量单元、磁力计等传感器用于姿态信息检测. 本文中传感器使用结构简单的数字接口对数据进行交换,运用模块化的思想对系统进行设计. 使用PID控制算法进行姿态角的闭环控制,最终实验结果表明,在实验平台上四旋翼飞行器飞行效果稳定,系统满足四旋翼飞行器飞行姿态控制的要求.     

Vision-based obstacle detection for rotorcraft flight

The ability of rotorcraft to fly at low altitude is hindered by the high pilot workload required to avoid obstacles. The development of automation tools that can detect obstacles in the rotorcraft flight path, warn the crew, and interact with the guidance system to avoid detected obstacles would significantly reduce pilot workload and increase safety. This article describes an obstacle detection approach based on feature tracking and recursive range estimation that takes into account the characteristics of rotorcraft flight. The merits and weaknesses of the approach are discussed using image sequences from the laboratory and from flight. © 1992 John Wiley & Sons, Inc.     

Modeling and Global Control of the Longitudinal Dynamics of a Coaxial Convertible Mini-UAV in Hover Mode

The aim of this paper is to present a configuration for a Convertible Unmanned Aerial Vehicle, which incorporates the advantages of the coaxial rotorcraft for hover flight and the efficiencies of a fixed-wing for forward flight. A detailed dynamical model, including the aerodynamics, is obtained via the Newton-Euler formulation. It is proposed a nonlinear control law that achieves global stability for the longitudinal vertical-mode motion. Indeed, we have performed a simulation study to test the proposed controller in presence of external perturbations, obtaining satisfactory results. We have developed an embedded autopilot to validate the proposed prototype and the control law in hover-mode flight.     

An adaptive vision-based autopilot for mini flying machines guidance,navigation and control

The design of reliable navigation and control systems for Unmanned Aerial Vehicles (UAVs) based only on visual cues and inertial data has many unsolved challenging problems, ranging from hardware and software development to pure control-theoretical issues. This paper addresses these issues by developing and implementing an adaptive vision-based autopilot for navigation and control of small and mini rotorcraft UAVs. The proposed autopilot includes a Visual Odometer (VO) for navigation in GPS-denied environments and a nonlinear control system for flight control and target tracking. The VO estimates the rotorcraft ego-motion by identifying and tracking visual features in the environment, using a single camera mounted on-board the vehicle. The VO has been augmented by an adaptive mechanism that fuses optic flow and inertial measurements to determine the range and to recover the 3D position and velocity of the vehicle. The adaptive VO pose estimates are then exploited by a nonlinear hierarchical controller for achieving various navigational tasks such as take-off, landing, hovering, trajectory tracking, target tracking, etc. Furthermore, the asymptotic stability of the entire closed-loop system has been established using systems in cascade and adaptive control theories. Experimental flight test data over various ranges of the flight envelope illustrate that the proposed vision-based autopilot performs well and allows a mini rotorcraft UAV to achieve autonomously advanced flight behaviours by using vision.     

Development of a Rotorcraft Micro air Vehicle for Indoor Flight Research

Autonomous flight of micro air vehicles (MAVs) in hostile indoor environments poses significant challenges in terms of control and navigation. In order to support navigation and control research for indoor micro air vehicles, a four-wing tail-sitter type rotorcraft MAV weighing less than 350g has been designed in this paper. In an effort to achieve autonomous indoor flight, an embedded integrated avionic system has been developed. The modeling process has been conducted to obtain accurate six degrees of freedom dynamical model for the designed rotorcraft MAV. In addition, aerodynamic coefficients are evaluated from the results of Computational Fluid Dynamics A PI-ADRC double loop controller with inner-loop outer-loop control scheme has been proposed which takes into account the system’s nonlinearities and uncertainties. The proposed flight controller was implemented on the designed rotorcraft MAV that has undergone various simulation and indoor flight tests. Experimental results that demonstrate robustness of the proposed controller with respect to external disturbances and the capabilities of the designed rotorcraft MAV are presented.     

六轴旋翼碟形飞行器控制系统软件设计及仿真研究

采用了控制不同电机转速组合的方法,对六轴旋翼碟形飞行器进行姿态控制,使六轴旋翼碟形飞行器在不同姿态下飞行时具有较好的性能;为了实现六轴旋翼碟形飞行器的飞行控制,对飞行器的控制系统进行了初步的设计,并且给出了控制系统软件设计流程图;同时以ProtuesISIS软件为基础建立了六轴旋翼碟形飞行器控制系统的仿真模型,并进行了仿真,仿真结果显示该控制系统能够满足六轴旋翼碟形飞行器起飞、悬停及降落等控制姿态的要求。     

四旋翼微型飞行器控制系统设计

四旋翼微型飞行器是一种以4个电机作为动力装置,通过调节电机转速来控制飞行的欠驱动系统;为了实现四旋翼微型飞行器的自主飞行控制,对飞行控制系统进行了初步设计,并且以C8051F020单片机为计算控制单元,给出了飞行控制系统的硬件设计,研究了设计中的关键技术;由于采用贴片封装和低功耗的元器件,使飞行器具有重量轻、体积小、功耗低的优点;经过多次室内试验,该硬件设计性能可靠,能满足飞行器起飞、悬停、降落等飞行模态的控制要求。     

An acceleration measurements-based approach for helicopter nonlinear flight control using Incremental Nonlinear Dynamic Inversion

Due to the inherent instabilities and nonlinearities of rotorcraft dynamics, its changing properties during flight and the engineering difficulties to predict its aerodynamics with high levels of fidelity, helicopter flight control requires the application of special strategies. These strategies must allow to cope with the nonlinearities of the system and assure robustness in the presence of inaccuracies and changes in configuration.In this paper, a novel approach based on an Incremental Nonlinear Dynamic Inversion is applied to simplify the design of helicopter flight controllers. With this strategy, by employing the feedback of acceleration measurements to avoid the need for information relative to any aerodynamic change, the control system does not need any model data that depends exclusively on its states, thus enhancing its robustness to model uncertainties.The overall control system is tested by simulating two tasks with distinct agility levels as described in the ADS-33 helicopter handling qualities standard. The analysis shows that the controller provides an efficient tracking of the commanded references. Furthermore, with the robustness properties verified within the range of inaccuracies expected to be found in reality, this novel method seems to be eligible for a potential practical implementation to helicopter vehicles.     

Comparative Results on Stabilization of the Quad-rotor Rotorcraft Using Bounded Feedback Controllers

In the recent years autonomous flying vehicles are being increasingly used in both civil and military areas. With the advancement of the technology it has become possible to test efficiently and cost-effectively different autonomous flight control concepts and design variations using small-scale aerial vehicles. In this paper the stabilization problem of the quad-rotor rotorcraft using bounded feedback controllers is investigated. Five different types of nonlinear feedback laws with saturation elements, previously proposed for global control of systems with multiple integrators, are applied and tested to control the quad-rotor rotorcraft roll and pitch angles. The results obtained from autonomous flight simulations and real time experiments with the Draganflyer V Ti four-rotor mini-rotorcraft are analyzed with respect to the structural simplicity of the control schemes and the transient performance of the closed-loop system.