An Image-Processing-Based Gimbal System Using Fisheye Video

This paper presents a low-cost remote vision system for use in unmanned aircraft that provide a first person view （FPV） to vehicle operators in real-time. The system does not require a traditional electromechanical gimbal setup. Instead, the system uses a wide-angle （fisheye） lens and a video camera setup that is fixed on the vehicle and captures the full viewing area as seen from the cockpit in each video frame. Video is transmitted to a ground station wirelessly. On the ground, the pilot is outfitted with virtual reality goggles with integrated attitude and heading sensors. The received video is recertified and cropped by the ground station to provide the goggles with the appropriate view based on head orientation. Compared to traditional electromechanical setups, the presented system features reduced weight, reduced video lag, lower power consumption, and reduced drag on the airborne vehicle in addition to requiring only a unidirectional downlink. The video processing is preformed on the ground, further reducing computational resources and bandwidth requirements. These advantages, in conjunction with the advancement in miniature optical sensors and lenses, make the proposed approach a viable option for miniature remotely controlled vehicles. The system was successfully implemented and tested using an R/C airplane.

Application of Ultrasonic Motor to Control of Moment Gyroscope Gimbal Servo System

Attitude control system is one of the most important subsystems in a spacecraft.As a key actuator,the control moment gyroscope(CMG)mainly determines the performance of attitude control system.Whereas,the control accuracy and output torque smoothness of the CMG depends more on its gimbal servo system.Considering the constraints of size,mass and power consumption for a small satellite,here,a mini-CMG is designed,in which the gimbal servo system is driven by an ultrasonic motor.The good performances of the CMG are obtained by both the ultrasonic motor and the rotary inductosyn.The direct drive of gimbal improves its dynamic performance,with the output bandwidth above 20 Hz.The angular and speed closed-loop control obtains the 0.02°/s gimbal rate,and the output torque resolution better than 2×10^(-3) N·m.The ultrasonic motor provides 1.0N·m self-lock torque during power-off,with 12arc-second position accuracy.

基于扩张状态观测器的无人机云台系统控制算法

针对无人机(UAV)三轴云台增稳控制中变量耦合的问题,提出一种基于扩张状态观测器(ESO)的无人机云台系统控制算法。首先,建立了无人机机载云台期望角的姿态解算算法模型;其次,构建了无人机机载云台位置环和速度环的串级比例-积分-微分(PID)控制回路;最后,引入ESO对机载云台角速度项在线实时估计,解决角速度项由于高耦合、多外扰导致的难以直接测量的问题,并对各通道的控制输入进行补偿。实验结果表明,所提算法在无指令、有指令和综合任务场景下的角度均方根误差分别为0.2357°、0.6317°和0.9463°,与传统PID算法相比,所提算法的角度误差分别降低了69.43%、53.29%和50.43%。可见,所提算法对外界扰动的抗干扰能力更强,控制精度更高。

基于Gimbal的手机情境感知应用开发

解释了情景感知的定义,介绍了Gimbal开发平台能够高效、方便地帮助开发者实现手机情景感知应用的开发,给出了应用该平台开发一个校园位置感知的手机应用的细节。

Modeling and Simulation of Two Axes Gimbal Using Fuzzy Control

The application of the guided missile seeker is to provide stability to the sensor’s line of sight toward a target by isolating it from the missile motion and vibration.The main objective of this paper is not only to present the physical modeling of two axes gimbal system but also to improve its performance through using fuzzy logic controlling approach.The paper is started by deriving the mathematical model for gimbals motion using Newton’s second law,followed by designing the mechanical parts of model using SOLIDWORKS and converted to xml file to connect dc motors and sensors using MATLAB/SimMechanics.Then,a Mamdani-type fuzzy and a Proportional-Integral-Derivative(PID)controllers were designed using MATLAB software.The performance of both controllers was evaluated and tested for different types of input shapes.The simulation results showed that self-tuning fuzzy controller provides better performance,since no overshoot,small steady-state error and small settling time compared to PID controller.

基于OpenMV摄像头的运动目标控制与自动追踪系统设计与实现

针对运动目标自动追踪系统复杂且成本较高等问题,文中旨在设计一种成本低廉且易于部署的基于STM32F103C8T6、OpenMV摄像头和二维舵机云台的运动目标自动追踪系统,以解决传统自动追踪系统设备昂贵、算法复杂难于推广的问题,并为OpenMV摄像头在安防监控等领域的应用提供新的思路。该系统主要由主控模块、OpenMV摄像头模块、二维舵机云台模块、电源模块、OLED显示模块组成,通过OpenMV摄像头模块识别特定阈值的色块或矩形图形,并处理色块与矩形角点位置信息,将处理后的数据通过串口通信发送给主控模块,再由主控模块通过PID算法与运动算法控制二维舵机云台模块运动,从而实现运动控制与自动追踪。最后通过激光笔测试装置实际追踪效果,整合数据进行分析验证,该运动目标控制与自动追踪系统的理论研究与设计能够达到目标效果。

Error analysis and a new steering law design for spacecraft control system using SGCMGs

Based on the singular value decomposition theory,this paper analyzed the mechanism of escaping/avoiding singularity using generalized and weighted singularity-robust steering laws for a spacecraft that uses single gimbal control moment gyros （SGCMGs） as the actuator for the attitude control system.The expression of output-torque error is given at the point of singularity,proving the incompatible relationship between the gimbal rate and the output-torque error.The method of establishing a balance between the gimbal rate and the output-torque error is discussed,and a new steering law is designed.Simulation results show that the proposed steering law can effectively drive SGCMGs to escape away from singularities.

Design and implementation of model test installation of heave compensation system of deepsea mining

In order to validate the simulation model and develop heave compensation control strategy,heave compensation model tests were performed.The model test installation includes themining ship motion simulator,the heave compensation system,the lifting pipe simulator,the buffer simulator and the water pool.The tests ofmining ship motion simulator show that it is able to perform under the predetermined attitude path smoothly and can meet the requirements of themining ship motions.The heave compensation effect is more than 60% under random wave and the goal is set to be 50%.The model test results indicate that this heave compensation system is effective and feasible.

Underactuated spacecraft angular velocity stabilization and three-axis attitude stabilization using two single gimbal control moment gyros

Angular velocity stabilization control and attitude stabilization control for an underactuated spacecraft using only two single gimbal control moment gyros （SGCMGs） as actuators is investigated. First of all, the dynamic model of the underactuated spacecraft is established and the singularity of different configurations with the two SGCMGs is analyzed. Under the assumption that the gimbal axes of the two SGCMGs are installed in any direction, and that the total system angular momentum is not zero, a state feedback control law via Lyapunov method is designed to globally asymptotically stabilize the angular velocity of spacecraft. Under the assumption that the gimbal axes of the two SGCMGs are coaxially installed along anyone of the three principal axes of spacecraft inertia, and that the total system angular momentum is zero, a discontinuous state feedback control law is designed to stabilize three-axis attitude of spacecraft with respect to the inertial frame. Furthermore, the singularity escape of SGCMGs for the above two control problems is also studied. Simulation results demonstrate the validity of the control laws.

机载光电跟踪系统的自抗扰与快速非奇异终端滑模组合控制方法

机载目标跟踪系统由于受到外部干扰、内部参数摄动和未建模动态等扰动的影响,使跟踪控制分系统设计面临巨大的挑战。以两轴四框架的光电稳定平台为对象研究抗扰动控制方法,针对自抗扰控制的扰动补偿一般留有扰动残差和滑模控制会引入较大抖振的问题,设计一种自抗扰与快速非奇异终端滑模组合控制的方法。利用线性扩张状态观测器来估计总扰动量并在控制端进行补偿,从而允许设计滑模控制的控制率时采用较小的滑模切换增益,并通过设计快速非奇异终端滑模面得到控制率,加快系统收敛的同时避免非奇异现象。数值仿真结果表明,该组合控制方法在外部扰动和模型不确定性的影响下,可以实现快速收敛与高跟踪精度的同时引入较小的抖振,并且实现了机载目标跟踪系统需求的快速响应性能,验证了这个组合控制方法的有效性。

线性自抗扰的增稳云台控制系统研究与实现

增稳云台是维持摄像头稳定并获得清晰图像的重要装置。文中提出一种LADRC线性自抗扰控制算法与FOC矢量控制算法相结合的方法,并将其应用于增稳云台系统中,提高增稳云台的控制精度、稳定性与抗干扰能力。其次,对无人系统增稳云台的硬件和软件进行设计,搭建测试实验平台。测试结果表明,所设计的控制系统运行良好,对阶跃控制命令的上升时间在0.3 s以内,在17.5 m/s的风速环境下,三轴角度的变化范围在0.15°以内,可达到预期目标。

基于RBF神经网络的三轴云台自适应滑模控制

针对云台系统在日常运转过程中,易受到外界非线性干扰、参数时变等不确定因素影响的问题,提出了一种基于径向基函数神经网络(RBFNN)的自适应滑模控制方法。根据对云台系统工作时性能状态进行分析,建立了动力学模型;利用扩张状态观测器实现对内外部环境扰动量的实时预测,从而获取到神经网络自学习的信息;通过Lyapunov分析法推导出云台系统的滑模控制率,并采用一种新型饱和函数消除了滑模抖振对系统带来的影响,也使得控制量切换时更加具有连续性。仿真结果表明,所提三轴云台控制策略与普通滑模控制方法相比,控制精度更高且抗干扰能力更强。

影像稳定系统发展和趋势解析

画面不稳定往往是在移动拍摄时,肩扛或手持设备使镜头不稳定导致的,而频繁晃动的画面会给观看者带来疲劳、烦躁及反感的情绪。在图片摄影和影视创作中,为了能获得更稳定的拍摄效果,拍摄者往往需要运用影像稳定系统。因此,众多设备厂商研制了3种类型,4种不同方式的稳定系统。其中,斯坦尼康和三轴云台稳定器属于物理稳定;镜头防抖、机身五轴防抖系统属于光学稳定;图像数字稳定系统属于电子稳定。这几类稳定系统各有特色,在众多的纪录片、影视剧中发挥着各自的特点,在未来的影视创作中,影像稳定系统将会发挥举足轻重的作用。

控制力矩陀螺框架系统的谐振抑制与精度控制

控制力矩陀螺(CMG)框架系统的速率控制精度是影响其输出力矩精度的重要因素,系统中谐波减速器提高了框架系统的动态响应能力,但其产生的机械谐振大幅降低了系统的控制精度。为抑制框架系统的谐振并满足系统的控制精度,本文建立了框架系统的动力学模型,根据系统动态性能要求选取合适的阻尼系数来设计系统主导极点,使控制器产生的零点与机械谐振对应的极点重合形成偶极子,从而抑制系统的机械谐振。仿真和实验结果显示:提出的方法有效地抑制了控制力矩陀螺框架系统的谐振,0.175rad/s恒速控制精度为0.002,0.175sin(2πt)rad/s正弦随动控制的幅值相对误差为3.28%,相位差为0.13rad。结果很好地满足了控制力矩陀螺的高精度输出力矩需求。

控制力矩陀螺框架伺服系统的超低速测速方法

在超低转速下,有限的转速测量分辨率是影响控制力矩陀螺框架伺服系统控制性能的一个重要因素。在分析转速分辨率对超低速控制性能影响的基础上,提出了一种基于多周期后向差分的转速计算方法,可提高测速分辨率并保证测速带宽。针对后向差分带来的相位延迟会限制测速分辨率进一步提高的问题,在选取合适的差分周期基础上,采用Kalman预估器对框架转速进行预估,进一步提高了框架转速的测速分辨率及测速带宽。通过仿真表明,所提出的测速方法将转速分辨率提高了两个数量级,解决了框架伺服系统在超低转速下由于有限的转速测量分辨率造成的爬行现象。

控制力矩陀螺框架系统高精度复合控制研究

控制力矩陀螺(CMG)是大型航天器姿态控制的关键执行机构,控制力矩陀螺框架系统的控制精度是影响其输出力矩精度的重要因素。为满足框架系统的恒速控制精度和随动控制精度,采用反馈控制与前馈控制相结合的复合控制方法;建立了采用永磁同步电机的框架系统动力学模型,采用矢量控制方法及高精度的角位置和角速度反馈控制有效地提高了恒速控制精度,根据系统传递函数设计了前馈控制器,有效地提高了随动控制精度。实验结果显示:10°/s恒速控制精度为0.0012,10sin(6π)t°/s正弦随动控制的幅值相对误差为0.18dB,相位差为8°,很好地满足了控制力矩陀螺的高精度输出力矩需求。

SGCMG框架伺服系统动力学建模与低速控制

单框架控制力矩陀螺(SGCMG)框架伺服系统内部存在的各种干扰会严重影响陀螺的力矩输出精度。为了实现力矩输出的高精度控制,需要对框架伺服系统进行精确动力学建模与控制。通过对作用于航天器上SGCMG的详细动力学分析,建立了框架伺服系统动力学模型,其中考虑了动静不平衡干扰力矩以及摩擦力矩。基于正弦永磁同步电机,利用自抗扰理论设计了框架伺服系统内外环控制器。仿真结果表明,在忽略转子不平衡所引起的高频干扰力矩的前提下,此控制器能对内外环存在的所有建模及未建模干扰进行准确估计和补偿,保证了框架的高精度控制。通过仿真还得到了转子不平衡对框架控制精度的影响量级,将为进一步研究如何抑制不平衡振动提供参考依据。

双框架磁悬浮控制力矩陀螺框架系统的扰动抑制

内外框架之间的耦合力矩和谐波减速器的非线性传输力矩是影响双框架磁悬浮控制力矩陀螺(DGMSCMG)框架系统精确角速度控制的主要因素,为了解决以上干扰问题,实现框架系统高精度角速率伺服控制提出了一种基于扰动观测器和自适应反步的框架系统复合解耦控制方法。通过扰动观测器来估计框架系统中的扰动,并结合自适应反步法获得控制律,其间将扰动估计误差当作未知参数设计了其自适应律,对扰动的两次处理使得框架系统干扰估计更加精确,同时可以保证估计参数的收敛性和整个框架系统的稳定性。仿真和实验结果表明,采用此复合控制方法,DGMSCMG框架系统扰动估计误差不超过框架系统实际扰动的3%,实际框架角速率跟踪参考指令角速率的精度达到99.2%。此复合解耦控制方法可以满足DGMSCMG框架系统抗干扰能力强、高精度角速率伺服控制的要求。

悬臂式SGCMG的高速转子的径向振动特性研究

悬臂式单框架控制力矩陀螺(SGCMG)的高速转子在运行过程中将会激发复杂的微幅高频振动,迄今对SGCMG的这种振动特性的认识既不准确也不完整。首先,在线性假设的基础上分析了径向振动的来源——静动不平衡量所产生的离心力和力偶以及预紧轴承滚动面的几何误差产生的预紧力的波动;其次,在结构的基础上利用分析力学的方法得到了悬臂式高速转子的径向振动模型——相互耦合的二阶常微分方程组;最后,通过数值仿真和测试结果的对比验证了分析的合理性和模型的有效性。

多环架光电稳定系统及分析

提出一种多环架高精度光电稳定系统方案。通过对其进行运动学分析，并结合伺服控制原理，证明该方案优于常规的二环架光电稳定系统。