Space range estimate for battery-powered vertical take-off and landing aircraft

A novel method for estimating the space range of battery-powered vertical take-off and landing(VTOL) aircraft is presented. The method is based on flight parameter optimization and numerical iteration. Subsystem models including required thrust, required power and battery discharge models are presented. The problem to be optimized is formulated, and then case study simulation is conducted using the established method for quantitative analysis. Simulation results show that the space range of battery-powered VTOL aircraft in a vertical plane is an oblate curve, which appears horizontally long but vertically short, and the peak point is not located on the vertical climb path. The method and results are confirmed by parameter analysis and validations.

基于仿生技术的尾座式VTOL无人机起降稳定控制及轨迹优化

尾座式垂直起降(Vertical takeoff/landing,VTOL)无人机(Unmanned aerial vehicle,UAV)稳定性差,与传统起落架的适配性低。针对上述问题,提出了一种采用自由尾翼技术的新型起落架。该起落架采用串联多级结构,在降低机身高度的同时,保证了巡航状态下尾翼力臂的长度,并通过虚拟中心点力分布技术对动态着陆过程进行调控,简化了控制过程,有利于模式转换过程中的无缝轨迹优化。随后基于猫中心点单点数据集,利用神经网络对起落架控制进行训练,有效提高了起落架自适应起落速度和精度。最后,结合无人机不同模式的参数要求,进行多目标优化和相似性转换,有效提高了尾座式垂直起降无人机的着陆适应性和稳定性。

Prognostics for Lithium-ion batteries for electric Vertical Take-off andLanding aircraft using data-driven machine learning

The health management of batteries is a key enabler for the adoption of Electric Vertical Take-off and Landingvehicles (eVTOLs). Currently, few studies consider the health management of eVTOL batteries. One distinctcharacteristic of batteries for eVTOLs is that the discharge rates are significantly larger during take-off andlanding, compared with the battery discharge rates needed for automotives. Such discharge protocols areexpected to impact the long-run health of batteries. This paper proposes a data-driven machine learningframework to estimate the state-of-health and remaining-useful-lifetime of eVTOL batteries under varying flightconditions and taking into account the entire flight profile of the eVTOLs. Three main features are consideredfor the assessment of the health of the batteries: charge, discharge and temperature. The importance of thesefeatures is also quantified. Considering battery charging before flight, a selection of missions for state-ofhealth and remaining-useful-lifetime prediction is performed. The results show that indeed, discharge-relatedfeatures have the highest importance when predicting battery state-of-health and remaining-useful-lifetime.Using several machine learning algorithms, it is shown that the battery state-of-health and remaining-useful-lifeare well estimated using Random Forest regression and Extreme Gradient Boosting, respectively.

基于有限时间观测器的VTOL飞行器跟踪控制

针对垂直起降(VTOL)飞行器的轨迹跟踪控制问题,本文提出了一种基于有限时间控制的输出反馈控制方案。采用系统分解技术将原系统解耦成2个子系统,将原系统的输出轨迹跟踪问题转化为2个子系统的镇定问题。对解耦后的系统,利用滑模控制方法设计了一种状态反馈控制律,所设计的控制器能够保证闭环系统有限时间稳定。考虑部分状态不可测量情况下的VTOL飞行器轨迹跟踪控制问题,提出了一个有限时间快速收敛观测器,基于有限时间快速收敛观测器提出了有限时间输出反馈控制律。仿真结果表明,所提出的控制方法具有良好的跟踪性能,能够实现飞行器对给定参考轨迹的快速、准确跟踪。

A multi-strategy pigeon-inspired optimization approach to active disturbance rejection control parameters tuning for vertical take-off and landing fixed-wing UAV

In this paper.Active Disturbance Rejection Control(ADRC)is utilized in the pitch control of a vertical take-off and landing fixed-wing Unmanned Aerial Vehicle(UAV)to address the problem of height fluctuation during the transition from hover to level flight.Considering the difficulty of parameter tuning of ADRC as well as the requirement of accuracy and rapidity of the controller,a Multi-Strategy Pigeon-Inspired Optimization(MSPIO)algorithm is employed.Particle Swarm Optimization(PSO),Genetic Algorithm(GA),the basic Pigeon-Inspired Optimization(PIO),and an improved PIO algorithm CMPIO are compared.In addition,the optimized ADRC control system is compared with the pure Proportional-Integral-Derivative(PID)control system and the non-optimized ADRC control system.The effectiveness of the designed control strategy for forward transition is verified and the faster convergence speed and better exploitation ability of the proposed MSPIO algorithm are confirmed by simulation results.

A Nonlinear Optimal Control Approach for the Vertical Take-off and Landing Aircraft

The paper proposes a nonlinear optimal control approach for the model of the vertical take off and landing(VTOL)aircraft.This aerial drone receives as control input a directed thrust,as well as forces acting on its wing tips.The latter forces are not perpendicular to the body axis of the drone but are tilted by a small angle.The dynamic model of the VTOL undergoes ap-proximate linearization with the use of Taylor series expansion around a temporary operating point which is recomputed at each iteration of the control method.For the approximately linearized model,an H-infinity feedback controller is designed.The linearization procedure relies on the computation of the Jacobian matrices of the state-space model of the VTOL aircraft.The proposed control method stands for the solution of the optimal control problem for the nonlinear and multivariable dynamics of the aerial drone,under model uncertainties and external per-turbations.For the computation of the contollr's feedback gains,an algebraic Riccati equation is solved at each time-step of the control method.The new nonlinear optimal control approach achieves fast and accurate tracking for all state variables of the VTOL aircnaft,under moderate variations of the control inputs.The stability properties of the control scheme are proven through Lyapunov analysis.

New stabilization design for planar vertical take-off and landing aircrafts

This paper presents a new stabilizing control law for a planar vertical take-off and landing aircraft.The model is first transformed into an equivalent form,and then a control law consisting of a linear term and a saturated term is given for a related subsystem,with the saturation levels being assigned as large as possible.Compared to the existing saturation scheme in which all states are restricted by saturations,the design brings about a relatively fast convergence.The effectiveness and advantage of the design are validated by numerical simulations.

有输入饱和的欠驱动VTOL飞行器滑模控制

垂直起降飞行器(vertical take-off and landing,VTOL)是典型的非线性、欠驱动系统,实际工程中VTOL飞行器的执行机构通常有饱和特性,针对这种模型的特点,对原始数学模型进行了解耦坐标变换,通过可逆坐标变换化成一个最小相位系统和一个非最小相位系统,之后采用滑模设计方法设计控制器。为了解决执行机构的饱和问题,将超出饱和受限的部分回馈到控制器中,构造一个赫尔伍兹稳定的辅助线性系统,然后把它加入到滑模控制器之中,在控制器中做补偿。利用李雅普诺夫函数证明了系统的稳定性。仿真结果表明,此方法可有效地解决输入受限的VTOL飞行器的镇定和轨迹跟踪问题。

欠驱动VTOL飞行器的位置反馈动态面控制

针对非最小相位欠驱动垂直起降飞行器系统,提出一种位置反馈动态面控制算法。首先设计高增益观测器,估计系统未知状态;然后采用动态面控制方法避免Backstepping设计存在的"微分爆炸"现象,同时简化控制律设计过程;最后采用Lyapunov直接法证明闭环系统所有信号一致有界,且跟踪误差通过调节控制器参数可以达到任意小。理论分析和仿真表明,所提方法能减轻计算负担,降低对系统状态的测量要求,实现飞行器位置准确跟踪,并对非线性建模的参数不确定性具有鲁棒性。

基于自适应浸入与不变的VTOL飞行器跟踪控制

针对输入存在不确定干扰的垂直起降(VTOL)飞行器的跟踪控制问题,提出了一种基于自适应系统浸入与不变(I&I)的控制方案:对于不确定性输入干扰,采用自适应I&I方法对于扰进行实时估计补偿;为便于控制器设计,采用系统分解技术将原系统解耦成一个最小相位误差子系统和一个非最小相位子系统,将原系统的输出跟踪问题转换为两个误差子系统的镇定问题。基于自适应I&I估计律和滑模变结构控制方法分别设计了两个子系统的控制器,所设计的控制器能够保证两个闭环子系统指数稳定。仿真结果表明,上述控制方案在干扰估计精度和收敛速度方面明显优于传统自适应估计方法,能够实现飞行器对给定轨迹的准确跟踪,同时抑制输入干扰对系统性能的不良影响。

基于非线性干扰观测器的VTOL飞行器跟踪控制

研究了输入存在不确定干扰的垂直起降(VTOL)飞行器的跟踪控制问题,提出了一种基于非线性干扰观测器对干扰进行实时估计的控制方案。为便于控制器设计,采用坐标变换和输入变换将原系统解耦成一个最小相位误差子系统和一个非最小相位误差子系统,将原系统的输出跟踪问题转换为两个子系统的镇定问题。为使所设计的控制器能够保证两个闭环子系统指数稳定,基于非线性干扰观测器,采用滑模变结构控制和最优控制,对两个子系统分别设计了控制器。仿真结果表明,所设计的控制器在输入干扰作用下能保证跟踪控制的稳定性,对干扰具有良好的鲁棒性。

VTOL飞行器有限时间轨迹跟踪控制

针对VTOL飞行器的轨迹跟踪控制问题,提出一种基于有限时间控制的控制方案。鉴于VTOL飞行器系统是强耦合的非线性系统,首先采用系统分解技术将原系统解耦成两个子系统,将原系统的输出跟踪问题转化为两个子系统的镇定问题。对于解耦后的系统,设计了有限时间控制律,所设计的控制器能够保证闭环系统有限时间稳定,克服了传统有限时间控制的弊端。仿真结果表明了所提出的控制方法具有良好的跟踪性能,能够实现飞行器对给定参考轨迹的快速、准确跟踪。

VTOL飞行器有限时间输出反馈跟踪控制

针对垂直起降(VTOL)飞行器的轨迹跟踪控制问题,提出了一种基于有限时间控制的输出反馈控制方案。首先,采用系统分解技术将原系统解耦成两个子系统,将原系统的输迹跟踪问题转化为两个子系统的镇定问题。对解耦后的系统,设计了有限时间状态反馈控制律,所设计的控制器能够保证闭环系统有限时间稳定。然后,考虑部分状态不可测量情况下的VTOL飞行器轨迹跟踪控制问题,设计了一个有限时间快速收敛观测器,基于有限时间快速收敛观测器提出了有限时间输出反馈控制律。仿真结果表明,所提出的控制方法具有良好的跟踪性能,能够实现飞行器对给定参考轨迹的快速、准确跟踪。

基于图像的VTOL飞行器视觉伺服控制

针对垂直起降(VTOL)飞行器的定点降落控制问题,本文提出一种基于图像的视觉伺服控制方法。对于VTOL飞行器视觉伺服控制系统,利用机载摄像头采集图像信息,将反步法与滑模控制技术相结合,设计了视觉伺服控制器。由于该方法采用的视觉模型中包含与深度无关的图像雅克比矩阵,从而避免了特征点深度的测量与估计。利用李雅普诺夫理论证明了在控制器的作用下,VTOL飞行器视觉伺服系统渐近稳定;同时保证图像误差渐近收敛为零,飞行器最终到达期望降落位置。最后的仿真结果表明了所提出的控制方法实际有效。

Analysis of VTOL UAV Propellant Technology

Recently, the surge in the interests in unmanned aerial vehicles has soared dra-matically worldwide due to many potential benefits foreseen by this technology. The most widespread use of the commercial drones is a multi-copter form of unmanned aerial vehicle, because of its vertical takeoff and landing (VTOL) capability. However, due to the structural characteristics, it has a disadvantage that the flight time is quite short, which is typically ranging between 15 to 30 minutes. The fixed wing type of unmanned aerial vehicles has a longer flight time and duration, but it is not easy to secure a safe landing space, especially in the city areas. For this reason, demand for vertical fixed take-off and landing aircraft is rapidly increasing throughout the world. This study analyzes the trends and recent development of global VTOL technology and provides a direction into which the current state of the technology should be heading. By comparing the advantage and disadvantage of various VTOP propulsion types, we can clearly identify the most effective form of VTOL propulsion types. Such analysis will be highly beneficial to the drone researchers and scientists in terms of future development.

基于双闭环PD控制的VTOL飞行器轨迹跟踪控制方法

为解决垂直起降VTOL飞行器的轨迹跟踪控制问题,提出一种基于双闭环PD控制的轨迹跟踪控制方法。建立了VTOL飞行器的简化动力学模型,将轨迹跟踪系统分解为位置跟踪系统和姿态跟踪系统;构建了基于位置外环和姿态内环的双闭环PD控制结构,设计了基于前馈补偿的PD控制器;通过快速内环的控制算法保证了系统的稳定性。仿真结果表明,该方法简化控制系统的设计过程,保证VTOL飞行器能够快速准确跟踪给定轨迹,满足欠驱动VTOL飞行器的轨迹跟踪需求。

Retarded Harrier Maneuver as a New and Efficient Approach for Fixed-Wing Aircraft to Achieve S/VTOL

Modern day VTOL fixed-wing aircraft based on quadplane design is relatively simple and reliable due to lack of complex mechanical components compared to tilt-wings or tilt-rotors in the pre-80’s era. Radio-controlled aerobatic airplanes have thrust-to-weight ratio of greater than unity and are capable of performing a range of impressive maneuvers including the so-called harrier maneuver. We hereby present a new maneuver known as the retarded harrier that is applicable to un/manned fixed-wing aircraft for achieving VTOL flight with a better forward flight performance than a quadplane in terms of weight, speed and esthetics. An airplane with tandem roto-stabilizers is also presented as an efficient airframe to achieve VTOL via retarded harrier maneuver, and detailed analysis is given for hovering at 45° and 60° and comparison is made against the widely adopted quadplane. This work also includes experimental demonstration of retarded harrier maneuver using a small remotely pilot airplane of wingspan 650 mm.

Flight Transient Estimation of VTOL Aircraft with Propellers

Methodological issues associated with the determination of the vertical take-off and landing aerodynamic parameters equipped with two rotary propellers during take-off and hovering, descent and landing are studied in the proposed article. During the computer simulation process, kinematics parameters diagrams were made, aerodynamic coefficients and propellers thrust components at all stages of aircraft take-off were estimated. That numerical data can be used in a preliminary stage of aerodynamic design for the vertical take-off and landing aircraft and electric drones at the determination of control and equalization elements geometric and kinematic parameters.

改进的TECS在VTOL倾转翼无人机中的应用

以垂直起降(VTOL)倾转翼无人机为研究对象,优化了总能量控制系统(TECS)的核心算法,实现了固定翼模式下的大包线纵向解耦控制,同时设计了垂向速度限幅调节策略和失速保护策略,提高了无人机的飞行安全,降低了工程应用中参数适配的复杂性。经过仿真验证、平原试飞和高原试飞验证,解决了高度控制和速度控制的超调,高度轨迹跟踪误差减小了19.9%,垂向速度限幅调节策略有效。失速保护策略只进行仿真测试,通过强突风干扰诱发失速保护,无人机迅速增大空速,保证了飞行安全。

复合翼垂直起降无人机直驱混合动力系统验证设计与试验建模方法

针对传统复合翼垂直起降(vertical take-off and landing,VTOL)无人机(unmanned aerial vehicle,UAV)垂直机动时间短的固有缺陷,提出了一种应用油电混动技术的直驱混合动力系统拓扑结构。面向起飞质量约15~20 kg的复合翼垂直起降无人机对直驱混合动力系统的软硬件进行开发与选型,设计出了满足上述起飞质量下功率需求的直驱混合动力系统。为对动力系统的设计方法进行验证并在探究其特性规律的基础上建立简化的直驱混合动力系统数学仿真模型,搭建了能够在地面模拟搭载直驱混合动力的复合翼垂起无人机飞行工况与工作模式的直驱混合动力系统地面一体化验证平台。基于此验证平台,设计了直驱混合动力系统特性一体化探究试验方案,采用试验建模法建立了简化的直驱混合动力系统的稳态与动态数学仿真模型,通过仿真与实物对比试验分析法,验证了试验方案的可行性与模型准确性。直驱混合动力系统配装复合翼垂直起降无人机搭建飞行验证平台并完成垂直机动飞行试验,试验过程中,全系统工作正常,飞行验证平台垂直机动时间超过预期指标。飞行试验结果表明,直驱混合动力系统设计方法是正确且有效的,动力系统具有良好的功率输出表现,能够改善复合翼垂起无人机垂直机动时间短的固有缺陷。