直升机大球铰摆动和滑动磨损试验机测控系统设计

直升机大球铰摆动、滑动磨损试验机可以真实地模拟大球铰在直升机上的运转和受载荷状态.试验机测控系统主要解决运动模式和力加载的协调运动,设计关键算法解决了任意更换滑动行程、滑动频率和摆动角、摆动频率的4个参数对运动曲线的拟合问题,生成3个缸的位置时域序列,解决了任意方向力加载的难点,模拟大球铰受力情况,实现了大球铰在不同飞行状态下运动和受载荷的自动运行.通过合理的硬件设计和软件开发,其自动化程序高、界面友好、运行稳定,为直升机大球铰疲劳磨损试验数据的准确性和可靠性提供了保证.     

基于能量分析的桥式起重机防摆控制方法

针对欠驱动桥式起重机在自动化驾驶研究中负载升/落吊运动与台车水平位移联动时,负载摆动抑制效果和控制性能不能满足实际工程需要,易造成安全事故的问题,提出一种基于能量分析的桥式起重机联动系统非线性耦合防摆控制器.采用非线性耦合控制方法,构造新型储能函数,设计出非线性耦合防摆控制器.利用LaSalle不变性原理和Lyapunov方法对该闭环反馈系统稳定性进行严格的数学分析.理论推导、仿真与实验结果表明:相比于非线性跟踪控制器和局部反馈线性化控制器,所提非线性耦合防摆控制器具有更佳的控制性能,不仅提高了负载的吊运效率,而且能够有效抑制和快速消除负载摆角;在添加外部扰动的情况下,仍能取得良好的控制效果,具有较强的鲁棒性,为桥式起重机联动系统提供了一种新的防摆控制方法.     

Vibration control of load for rotary crane system using neural network with GA-based training

A neuro-controller for vibration control of load in a rotary crane system is proposed involving the rotation about the vertical axis only. As in a nonholonomic system, the vibration control method using a static continuous state feedback cannot stabilize the load swing. It is necessary to design a time-varying feedback controller or a discontinuous feedback controller. We propose a simple three-layered neural network as a controller (NC) with genetic algorithm-based (GA-based) training in order to control load swing suppression for the rotary crane system. The NC is trained by a real-coded GA, which substantially simplifies the design of the controller. It appeared that a control scheme with performance comparable to conventional methods can be obtained by a relatively simple approach. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Nonlinear Anti-swing Control of Underactuated Tower Crane Based on Improved Energy Function

The control system of tower crane exhibits strong nonlinearity in the process of control execution, which is prone to the problems of inaccurate positioning control of the payload and difficult anti-swing control. Aiming at the problems, this paper proposes a control law based on improved energy coupling analysis for suppressing the payload swing in the tower cranes. A three-dimensional dynamic model of tower crane system with considering friction is established, and an improved energy coupling signal is designed. The coupling relationship of trolley movement and payload swing, jib rotation and payload swing are considered, then a nonlinear anti-swing controller is established in order to reduce the swing. The closed-loop stability of the system with the controller is verified by the Lyapunov method and LaSalle invariance principle, simulations and experimental analyses are performed to verify the controller performance. The control performance of the controller is compared with other classic and typical current control methods, and the proposed controller outperformed other controllers. The anti-swing controller proposed in this paper has accurate positioning, and can achieve precise control when the payload is transported, reaching the set target position in a little time and eliminating residual swing angle. Meanwhile the proposed controller has a good control robustness, which can restore stability in around a very short time when the rope length and payload mass of the system’s inherent property are changed and external interference is added. In addition, when different target position parameters are uncertain, the proposed control law has good robust performance.

     

A practical fuzzy controllers scheme of overhead crane

This paper presents fuzzy-based design for the control of overhead crane.Instead of analyzing the complex nonlinear crane system,the proposed approach uses simple but effective way to control the crane.There are twin fuzzy controllers which deal with the feedback information,the position of trolley crane and the swing angle of load,to suppress the sway and accelerate the speed when the crane transports the heavy load.This approach simplifies the designing procedure of crane controller;besides,the twin controller method reduces the rule number when fulfilling the fuzzy system.Finally,experimental results through the crane model demonstrate the effectiveness of the scheme.     

无人机吊挂飞行的非线性控制方法设计

针对四旋翼无人机吊挂飞行系统,本文设计了一种新型控制策略.本文首先建立了四旋翼无人机吊挂系统的数学模型.其中负载被看作由刚性绳悬挂在四旋翼无人机重心位置的质点.之后本文通过能量分析的方法设计了针对此系统的非线性控制器.本文提出的控制方法可以在抑制吊挂负载摆动的同时将四旋翼无人机移动到目标位置.本文运用李雅普诺夫稳定性分析和拉塞尔不变性原理对闭环系统的稳定性进行了证明.最后,通过数值仿真,分别将本控制器镇定控制和调节控制的控制效果与线性二次调节器(linear-quadratic regulator,LQR)控制器进行了对比.     

A practical fuzzy controllers scheme of overhead crane

1IntroductionThe overhead crane systemis widely usedinindustryformoving heavy cargos .Thus anti_sway and position controlhave become the requirements as a core technology forautomated crane systemthat are capable of flexible spatialautomatic conveyance .The purpose of crane control is to reduce the swing ofthe load while movingthe trolleyto the desired position asfast as possible .However ,the overhead crane has seriousproblems :the crane acceleration,required for motion,always induces undesir…     

塔吊防摆LQR最优控制器研究

针对塔吊工作系统中出现的摆动现象,设计一种高效而快速的防摆控制器来对摆动进行抑制。系统利用拉格朗日方程建立三维力学数学模型,设计LQR控制器对摆动进行控制,采用Matlab进行仿真,通过改变加权矩阵Q得到LQR最优控制器;分别改变荷载重量和摆线长度,与PID控制进行比较,结果表明LQR最优控制对摆角的抑制更加明显,稳定时间也明显减少,是一种更加优化的控制方法。     

Nonlinear coupling tracking control for underactuated construction lifting robots with load hoisting/lowering under initial input saturations

Underactuated construction lifting robots, which have been widely concerned by erudite researchers, always contain load hoisting/lowering motion. When the cable length is utilized as a variable, construction lifting robots produce violent load swing, which affects the construction safety undoubtedly and brings great challenges to the development of the controller. Moreover, most existing controllers may not take into account issues, such as initial input saturations and poor ability to suppress load swing, and they may utilize linearization or approximation. Inspired by these phenomena, a nonlinear coupling tracking controller for underactuated construction lifting robots with load hoisting/lowering under initial input saturations is proposed. With reference to expected trajectories to ensure the smooth operation of the construction lifting robot system, the initial input saturations are considered to make the trolley and cable start stably, respectively; a coupling signal, which contains actuated variables and underactuated variables, is constructed to improve the transient control performance of construction lifting robots. Combined with theoretical derivation, simulation, and experimental verification, the proposed controller achieves superior control performance, which ensures the accurate positionings of the system, and suppresses and eliminates the load swing effectively, so as to ensure the safe construction; the proposed controller admits outstanding robustness with respect to the changes of system parameters and the adverse effects of external disturbances. The proposed controller provides a novel antiswing strategy for construction lifting robots with load hoisting/lowering, which possesses excellent practical significance.     

Image-Based Visual PID Control of a Micro Helicopter Using a Stationary Camera

This paper proposes an image-based visual servo control method for a micro helicopter. The helicopter does not have any sensors to measure its position or posture on the body. A stationary camera is placed on the ground and it obtains image features of the helicopter. The differences between current features and given reference features are computed. PID controllers then make control input voltages for helicopter control and they drive the helicopter. The proposed controller can avoid some major difficulties in computer vision such as numerical instability due to image noise or model uncertainties, since the reference is defined in the image frames. An experimental result demonstrates that the proposed controller can keep the helicopter in a stable hover.     

Combined control with sliding mode and partial feedback linearization for 3D overhead cranes

A 3D overhead crane is an underactuated system consisting of five outputs: trolley position, bridge translation, cable length, and two cargo swings. These outputs are controlled by three actuators for cargo hoisting, trolley motion, and bridge traveling. This study proposes the use of a nonlinear controller that performs five tasks concurrently: cargo hoisting, trolley tracking, bridge motion, payload vibration suppression during transport, and cargo swing elimination at the destination. The proposed algorithm is combined with two control components: (i) partial feedback linearization, which is a precursor to controller design, to suppress cargo vibration; and (ii) sliding mode method, which provides robust control in lifting the payload and driving trolley and bridge motions against model imprecision and uncertainty. These two control mechanisms are successfully merged into a combined controller because the kinematic relationships between the state variables are made apparent in the system dynamics. Simulation and experimental results show that the proposed controller asymptotically stabilizes all system responses.Copyright © 2013 John Wiley & Sons, Ltd.     

Fuzzy Logic Controller for a Mini Coaxial Indoor?Helicopter

In this paper the design process of a fuzzy logic based controller for a coaxial micro helicopter is presented. The developed controller for altitude, attitude, and position control is tested through simulations on an identified non-linear model of the helicopter. The robustness properties of the controller to parameter variations of the model is assessed, as well as, its ability to accommodate or absorb external disturbances.     

无人机吊挂飞行系统的减摆控制设计

主要考虑了四旋翼无人机（Unmanned aerial vehicle,UAV）吊挂飞行系统的位置控制及负载摆动抑制的设计问题.在存在欠驱动特性以及未知系统参数的约束下,本文基于能量法设计了一种非线性控制策略,实现了对无人机位置的精确控制和飞行过程中负载摆动的快速抑制.基于Lyapunov方法的稳定性分析证明了闭环系统的稳定性,位置误差的收敛及摆动的抑制.实验结果表明本文提出的控制策略取得了较好的控制效果.     

A Non-Time Based Controller for Load Swing Damping and Path-Tracking in Robotic Cranes

This paper proposes the use of the non-time based control strategy named Delayed Reference Control (DRC) to the control of industrial robotic cranes. Such a control scheme has been developed to achieve two relevant objectives in the control of autonomous operated cranes: the active damping of undesired load swing, and the accurate tracking of the planned path through space, with the preservation of the coordinated Cartesian motion of the crane. A paramount advantage of the proposed scheme over traditional ones is its ease of implementation on industrial devices: it can be implemented by just adding an outer control loop (incorporating path planning) to standard position controllers. Experimental performance assessment of the proposed control strategy is provided by applying the DRC to the control of the oscillation of a cable-suspended load moved by a parallel robot mimicking a robotic crane. In order to implement the DRC scheme on such an industrial robot it has been just necessary to manage path planning and the DRC algorithm on a separate real-time hardware computing the delay in the execution of the desired trajectory suitable to reduce load swing. Load swing has been detected by processing the images from two off-the-shelf cameras with a dedicated vision system. No customization of the robot industrial controller has been necessary.     

Second-order sliding-mode control of container cranes

Moving a suspended load along a pre-specified path is not an easy task when strict specifications on the swing angle and on the transfer time need to be satisfied. Intuitively, minimizing the cycle time and the load swing are conflicting requirements, and their satisfaction requires proper control actions, especially if some uncertainties in the system dynamics are present. In this paper we propose a simple control scheme, based on second-order sliding modes, which guarantees a fast and precise load transfer and the swing suppression during the load movement, despite of model uncertainties and unmodeled dynamic actuators. Such controller has been tested on a laboratory-size model of the crane, and some experimental results are reported.     

A HIL Testbed for Initial Controller Gain Tuning of a Small Unmanned Helicopter

A Hardware-In-The-Loop (HIL) testbed design for small unmanned helicopters which provides a safe and low-cost platform to implement control algorithms and tune the control gains in a controlled environment is described. Specifically, it allows for testing the robustness of the controller to external disturbances by emulating the hover condition. A 6-DOF nonlinear mathematical model of the helicopter has been validated in real flight tests. This model is implemented in real-time to estimate the states of the helicopter which are then used to determine the actual control signals on the testbed. Experiments of the longitudinal, lateral and heading control tests are performed. To minimize the structural stress on the fuselage in case of controller failure or a subsystem malfunction, a damping system with a negligible parasitic effect on the dynamics of the helicopter around hover is incorporated. The HIL testbed is capable of testing the helicopter in hover, as well as on any smooth trajectories such as cruise flight, figure-8, etc. Experimentally tuning the controller on the HIL testbed is described and results in a controller which is robust to the external disturbances, and achieves an accuracy of ±2.5 cm in the position control on the longitudinal and lateral trajectory tracking, and ±5 deg accuracy around the yaw axis on the heading trajectory tracking.     

非匹配扰动干扰下的无人直升机轨迹跟踪控制

针对小型无人直升机在飞行过程中容易受到非匹配扰动影响的特点,本文设计了一种基于新型滑模控制方法的轨迹跟踪控制器.首先,建立了无人直升机系统的非线性数学模型,并对该模型进行近似反馈线性化处理,同时将模型分为位置和偏航两个子系统;然后,利用扩展扰动观测器对复合扰动以及非匹配扰动的各阶导数的估计值,设计新型时变滑模面,得到滑模控制律,并给出了控制系统的稳定性分析;最后,仿真结果验证了控制方法的有效性和优越性.该新型滑模控制方法的优越性主要体现在:对非匹配扰动具有较强的鲁棒性,以及能有效地抑制抖振现象.     

无人直升机的姿态增强学习控制设计与验证

针对小型无人直升机的姿态控制问题,考虑到现有基于模型的控制方法对直升机动力学模型的先验信息依赖较大,以及未建模动态系统的影响等问题,设计了一种基于增强学习(RL)的飞行控制算法.仅利用直升机的在线飞行数据,补偿了未建模不确定性的影响.同时为了抑制外界扰动,提高系统的鲁棒性,设计了一种基于误差符号函数积分的鲁棒(RISE)控制算法.将两种算法结合,并利用基于Lyapunov分析的方法,证明了无人机姿态控制误差的半全局渐近收敛.最后在无人直升机飞行控制实验平台上,进行了姿态控制的实时实验验证.实验结果表明,本文提出的控制方法具有良好的控制效果,对系统不确定性和外界风扰具有良好鲁棒性.     

非线性优化PID控制在桥式起重机防摆中的应用

控制或消除吊重摇摆对提高起重机工作效率、减少装卸作业安全隐患具有重要意义。以桥式起重机为例,建立其非线性模型,对负载摆动的动态过程进行动力学分析,研究负载摆动过程对系统的影响。以此为基础在Simulink环境下设计双闭环机构的PID控制器,通过非线性优化NCD模块对其进行参数优化。实验结果证明:该方法可快速准确确定PID控制器优化参数,5 s内可消除摆动,达到满意的控制效果;即使在吊重和绳长发生改变时系统仍具有一定鲁棒性。