A Study on Hovering Control of Small Aerial Robot by Sensing Existing Floor Features

Since precise self-position estimation is required for autonomous flight of aerial robots, there has been some studies on self-position estimation of indoor aerial robots. In this study, we tackle the self-position estimation problem by mounting a small downward-facing camera on the chassis of an aerial robot. We obtain robot position by sensing the features on the indoor floor.In this work, we used the vertex points(tile corners) where four tiles on a typical tiled floor connected, as an existing feature of the floor. Furthermore, a small lightweight microcontroller is mounted on the robot to perform image processing for the onboard camera. A lightweight image processing algorithm is developed. So, the real-time image processing could be performed by the microcontroller alone which leads to conduct on-board real time tile corner detection. Furthermore, same microcontroller performs control value calculation for flight commanding. The flight commands are implemented based on the detected tile corner information. The above mentioned all devices are mounted on an actual machine, and the effectiveness of the system was investigated.

Control for going from hovering to small speed flight of a model insect

The longitudinal steady-state control for going from hovering to small speed flight of a model insect is studied, using the method of computational fluid dynamics to compute the aerodynamic derivatives and the techniques based on the linear theories of stability and control for determining the non-zero equilibrium points. Morphological and certain kinematical data of droneflies are used for the model insect. A change in the mean stroke angle （δФ） results in a horizontal forward or backward flight; a change in the stroke amplitude （δФ） or a equal change in the down- and upstroke angles of attack （δα1） results in a vertical climb or decent; a proper combination of δФ and δФ controls （or δФ and δα1 controls） can give a flight of any （small） speed in any desired direction.

Stabilization control of a bumblebee in hovering and forward flight

Our previous study shows that the hovering and forward flight of a bumblebee do not have inherent stability （passive stability）. But the bumblebees are observed to fly stably. Stabilization control must have been applied. In this study, we investigate the longitudinal stabilization control of the bumblebee. The method of computational fluid dynamics is used to compute the control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion. Controllability analysis shows that at all flight speeds considered, although inherently unstable, the flight is controllable. By feedbacking the state variables, i.e. vertical and horizontal velocities, pitching rate and pitch angle （which can be measured by the sensory system of the insect）, to produce changes in stroke angle and angle of attack of the wings, the flight can be stabilized, explaining why the bumblebees can fly stably even if they are passively unstable.

Robust Near-Hovering Flight Controller for Model-Scale Helicopters Via Parametric Approach

This paper aims to provide a parametric design for robust flight controller of the model-scale helicopter. The main contributions lie in two aspects. Firstly,under near-hovering condition,a procedure is presented for simplification of the highly nonlinear and under-actuated model of the model-scale helicopter. This nonlinear system is linearized around the trim values of the chosen flight mode,followed by decomposing this high-order linear model into three lower-order subsystems according to the coupling properties among channels.After decomposition,the three subsystems are obtained which include the coupling subsystem between the roll( pitch) motion and the lateral( longitudinal) motion,the subsystem of the yaw motion and the subsystem of the vertical motion. Secondly,by using eigenstructure assignment,the problem of flight controller design can be converted into solving two optimization problems and the linear robust controllers of these subsystems are designed through solving these optimization problems. Besides, this paper contrasts and analyzed the performances of the LQR controller and the parametric controller. The results demonstrate the effectiveness and the robustness against the parametric perturbations of the parametric controller.

Stabilization control of a hovering model insect:lateral motion

Our previous study shows that the lateral disturbance motion of a model drone fly does not have inherent stability （passive stability）,because of the existence of an unstable divergence mode.But drone flies are observed to fly stably.Constantly active control must be applied to stabilize the flight.In this study,we investigate the lateral stabilization control of the model drone fly.The method of computational fluid dynamics is used to compute the lateral control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion.Controllability analysis shows that although inherently unstable,the lateral disturbance motion is controllable.By feeding back the state variables （i.e.lateral translation velocity,yaw rate,roll rate and roll angle,which can be measured by the sensory system of the insect） to produce anti-symmetrical changes in stroke amplitude and/or in angle of attack between the left and right wings,the motion can be stabilized,explaining why the drone flies can fly stably even if the flight is passively unstable.

变频器在立井提升机的应用研究

为解决传统立井提升机所采用的PI控制策略在频繁启停、加速、减速过程中对电网造成较大冲击,稳定性较差的问题,在对立井提升机工况分析的基础上,为其匹配设计立井提升机的驱动电机,为后续变频器选型奠定基础;针对性地提出了零速悬停控制策略,并与传统控制策略的零速悬停控制策略的控制效果进行对比;对变频器在立井提升机的应用效果进行现场验证。

基于自耦PD的四旋翼无人机轨迹跟踪控制

针对输入受限的四旋翼无人机,为了使其能够快速稳定地跟踪期望轨迹,使用了一种基于自耦PD(SCPD)的轨迹跟踪控制方法。该方法将四旋翼无人机系统不确定性和内外扰动等复杂因素定义为总和扰动,进而将非线性不确定系统映射为未知线性系统。根据自耦PID控制理论,为四旋翼无人机位置环和姿态环各控制通道设计了独立的SCPD控制器,并设计了一种基于误差的速度因子模型。以定点悬停、轨迹跟踪等方式,与基于传统PID和滑模控制的飞行控制系统进行了动态响应性能测试和抗干扰性能对比。仿真结果表明:基于SCPD控制的四旋翼飞行控制系统具有较优的动态响应性能和较强的抗干扰能力,验证了SCPD控制旋翼无人机轨迹跟踪的有效性。

矿井提升机调速系统优化

针对矿井提升机调速系统存在调速能力差、抗干扰能力不足的问题,通过建立大功率电励磁同步电机调速模型,设计交-直-交变频控制策略、设计双绕组串联容错控制策略、基于自抗扰控制策略设计提升机零速悬停方案进行优化,并进行了现场应用。结果表明,优化后的矿井提升机调速系统可满足煤矿安全规程及设计要求,达到提升调速及抗干扰能力、安全可靠运行的目的。

Control of flight forces and moments by flapping wings of model bumblebee

The control of flight forces and moments by flapping wings of a model bumblebee is studied using the method of computational fluid dynamics. Hovering flight is taken as the reference flight： Wing kinematic parameters are varied with respect to their values at hovering flight. Moments about （and forces along） x, y, z axes that pass the center of mass are computed. Changing stroke amplitude （or wingbeat frequency） mainly produces a vertical force. Changing mean stroke angle mainly produces a pitch moment. Changing wing angle of attack, when down- and upstrokes have equal change, mainly produces a vertical force, while when down- and upstrokes have opposite changes, mainly produces a horizontal force and a pitch moment. Changing wing rotation timing, when dorsal and ventral rotations have the same timing, mainly produces a vertical force, while when dorsal and ventral rotations have opposite timings, mainly produces a pitch moment and a horizontal force. Changing rotation duration has very small effect on forces and moments. Anti-symmetrically changing stroke amplitude （or wingbeat frequency） of the contralateral wings mainly produces a roll moment. Anti-symmetrically changing angles of attack of the contralateral wings, when down- and upstrokes have equal change, mainly produces a roll moment, while when down- and upstrokes have opposite changes, mainly produces a yaw moment. Anti-symmetrically changing wing rotation timing of the contralateral wings, when dorsal and ventral rotations have the same timing, mainly produces a roll moment and a side force, while when dorsal and ventral rotations have opposite timings, mainly produces a yaw moment. Vertical force and moments about the three axes can be separately controlled by separate kinematic variables. A very fast rotation can be achieved with moderate changes in wing kinematics.

天线共形飞艇的盘旋飞行控制设计

天线共形飞艇携带雷达在空中抵近侦察时,在指定空域进行盘旋飞行,其盘旋飞行性能直接影响搭载的雷达性能,为实现控制飞艇在盘旋飞行时的航线位置跟踪、姿态稳定,建立了含风场特性的通用六自由度非线性模型,并利用小扰动线性化方法将运动模型线性化。在此基础上,本文针对该飞行场景设计一种外环基于自适应PID+内环线性自抗扰法的双闭环盘旋飞行控制方法,并经过实际飞行验证,证明了控制方法的有效性,给出飞艇实际空中盘旋飞行姿态波动范围,为后续天线共形飞艇搭载雷达提供设计参考。

Research on the attitude regulation of 3-DOF hover system

Quadrotor helicopter is emerging as a popular platform for unmanned aerial vehicle re- search, due to its simplicity of structure and maintenance as well as the capability of hovering and vertical take-off and landing. The attitude controller is an important feature of quadrotor helicopter since it allows the vehicle to keep balance and perform the desired maneuver. In this paper, nonlin- ear control strategies including active disturbance rejection control （ADRC）, sliding mode control （SMC） and backstepping method are studied and implemented to stabilize the attitude of a 3-DOF hover system. ADRC is an error-driven control law, with extended state observer （ESO） estimating the unmodeled inner dynamics and external disturbance to dynamically compensate their impacts. Meanwhile; both backstepping technique and SMC are developed based on the mathematical model, whose stability is ensured by Lyapunov global stability theorem. Furthermore, the performance of each control algorithm is evaluated by experiments. The results validate effectiveness of the strate- gies for attitude regulation. Finally, the respective characteristics of the three controllers are high- lighted by-comparison, and conclusions are drawn on the basis of the theoretical and experimental a- nalysis.

喷杆喷雾机旋翼悬浮式喷杆自动收放控制系统研究

旋翼悬浮式喷杆分别融合了地面机械和空中无人机的优点,可简化复杂的桁架结构并通过旋翼下压风场能减小雾滴飘移造成的二次污染,具有较好的应用前景。传统的收放方式难以收放旋翼悬浮式喷杆,为此提出了一种以正四边形滚筒为主体的喷杆自动收放装置,建立了喷杆收放过程的D-H坐标系和正运动学模型,通过牛顿-欧拉法构建了动力学模型,并采用三次均匀B样条曲线轨迹规划获取了喷杆收放最优轨迹。以喷杆收放的运动时间、关节冲击和能量消耗为多目标函数,通过NSGA-Ⅱ算法求解Pareto解集,选取解集中喷杆展开时间为56、61、66、71、76、81 s,喷杆收卷时间为54、59、64、69、74、79 s轨迹进行喷杆收放试验。试验结果表明:喷杆运动时间与喷杆角度标准差存在显著性关系,运动时间越短,喷杆稳定性越差、关节冲击越大、能量消耗越多。取喷杆收放时间59、61 s对应轨迹为喷杆收放最优轨迹时,滚筒转速与规划转速的平均跟踪误差不超过0.201(°)/s,关节3、4、5实际运动角度与规划角度的平均跟踪误差不超过6.201°,喷杆能较好地跟踪最优轨迹完成收放。该研究验证了喷杆自动收放装置的有效性和喷杆收放最优轨迹的准确性。

基于模拟退火法的悬停飞艇载货控制分配研究

大型重载飞艇悬停装卸货物时重心、转动惯量的变化会影响飞艇稳定性,为了解决飞艇载货时质量变化带来的安全问题,提出了基于水箱补水排水的动态补偿策略,并针对多推力矢量特殊布局大型重载飞艇的控制问题,采取控制分配策略,引入基于模拟退火思想的遗传算法,对广义逆控制分配算法进行优化,大大提高了控制分配效率,提升了飞艇货物装载的安全性和稳定性,仿真结果验证了控制分配策略及水箱质量补偿策略在飞艇悬停装卸货物中的有效性。

基于悬停驻留的大口径鱼雷水下引爆定位控制

大口径鱼雷用在深海反潜作战中,为了提高鱼雷对敌攻击的威慑能力,提出基于悬停驻留的大口径鱼雷水下引爆定位控制技术。建立大口径鱼雷的水下动力学和运动学模型,以大口径鱼雷航行的偏航角、俯仰角和横滚等信息为约束参量,采用鱼雷运动状态试验参数数据辨识水下流体动力参数和系统性能参数,结合参数辨识法建立鱼雷动力学输入输出响应模型,采用有限元分析方法建立鱼雷水下悬停驻留的湍流模型,通过调整鱼雷的位置和姿态,结合回波探测技术,采用定位扫描和悬停驻留技术实现鱼雷因定位引爆控制。仿真结果表明,采用该方法进行大口径鱼雷水下引爆定位控制的定位精度较高,输出鲁棒性和稳定性较好,收敛误差较低。

基于卡尔曼滤波的四旋翼飞行器姿态估计和控制算法研究(英文)

四旋翼飞行器作为无人机的一种,由于其简单气动布局和复杂的动力学模型,在控制领域获得了越来越多的学术关注;本文首先分析了微机电系统惯性测量单元(MEMS IMU)传感器的误差,给出了基于自回归(autoregressive,AR)噪声模型的卡尔曼滤波算法设计;然后根据加速度计和陀螺仪长短周期测量的不同特性,进一步对姿态数据做互补融合,实验表明此算法可以实现良好的滤波效果;基于上面的姿态估计,本文又提出了一种双增益的PD控制算法对飞行器进行姿态控制;最后将姿态估计算法和控制算法应用到实验平台中,可以实现四旋翼在支架上的自主悬停等功能.

基于自适应遗传算法的小型无人旋翼机系统辨识方法

提出一种基于自适应遗传算法的小型无人旋翼飞行器系统辨识方法.通过机载传感器设备,系统采集小型无人旋翼机的输入信号(舵机的控制信号)和输出信号(飞行器的姿态及速度等信息);经过数据预处理后,利用自适应遗传算法构建小型无人旋翼飞行器高精度动力学模型,并通过仿真和实验对模型的有效性进行验证.实验表明,基于本文提出的动态模型,小型无人旋翼机可以精确完成悬停和前飞任务.

无人直升机悬停姿态控制系统设计

显模型跟踪控制技术以特有的优点,在直升机控制中得到了成功应用。以样例无人直升机为控制对象,为其设计了基于显模型跟踪法的悬停姿态控制器,对显模型跟踪控制系统中的显模型模块、逆模型模块及反馈补偿模块作了详细的论述,并以俯仰通道和滚转通道为例,进行了悬停与小速度前飞的数字仿真和非线性仿真验证,取得了满意的控制效果。

四旋翼飞行器悬停状态姿态控制建模与仿真

对四旋翼飞行器悬停状态下建立合理动力学模型,为实现四旋翼机悬停飞行时可靠姿态优化控制,提出采用四旋翼机悬停状态建模从单个旋翼受力方法,以四个旋翼转速作为控制量,认为悬停飞行时飞行器自身重力与竖直方向升力完全平衡,在竖直方向上施加一个约束方程,结合其它三个姿态角约束方程,建立起四旋翼机悬停状态下姿态角到旋翼转速的对应方程。利用上述模型,在Matlab软件上对四旋翼机进行悬停时的PID控制联合仿真。仿真结果表明,所建立动力学模型正确有效,更有助于实现四旋翼机悬停状态的姿态优化控制。

固定时间稳定航天器相对轨道悬停控制

针对航天器相对空间目标的定点悬停控制需求,基于非线性反馈固定时间稳定算法设计了一种闭环悬停控制律.阐述了固定时间稳定的原理,以C-W方程为相对运动模型设计了悬停控制律,可以通过改变相关控制参数来消除初始悬停误差和干扰的影响,实现对控制效果的调节.结果分析表明,提出的控制律对初始悬停误差收敛速率较快,能够保持长时间、高精度定点悬停,仿真结果验证了方法的有效性.

基于LQR的直升机悬停控制律设计与仿真

建立了某型直升机数学模型,并将该模型分解为纵向模型和横侧向模型两部分,提出了悬停控制律应该达到的稳态指标;以该型直升机为被控对象,采用输出反馈线性二次型调节器(LQR)技术设计了由纵向控制律和横侧向控制律组成的悬停控制律,使得直升机能取得满意的悬停性能指标;以该型直升机模型、执行器模型以及设计的悬停控制器构成全数字闭环仿真系统进行控制律仿真验证;仿真结果表明,文中设计的悬停控制律正确有效,能够较好地实现直升机的悬停功能,另外,由于该悬停控制律是基于输出反馈的,在工程上也比较容易实现。