起重机变幅运动吊重防摆控制研究

针对起重机变幅运动过程中吊重摆动造成的就位精度差、工作效率低和作业不安全等问题,提出了一种误差渐进补偿控制方法,以减小吊重摆动。在分析误差渐进补偿控制原理的基础上,设计了误差渐进补偿控制器。采用变补偿系数控制方法,在实现吊绳摆角渐进减小的同时满足了变幅加速度和液压泵排量的要求。运用MATLAB软件对系统进行仿真,仿真结果表明,对于不同的绳长和臂架长度,误差渐进补偿控制具有良好的鲁棒性和控制精度,在起重机开始制动后,吊绳摆角在10s内减小到了0.003rad以下。     

科里奥利加速度对机械摆的影响

起重机这类起重运输设备的吊钩缆绳可以看作受大车、小车运动驱动的机械摆,会产生摆振。其垂直方向的起吊运动也在摆振方向上产生科里奥利力,影响载荷摆动的规律。为此建立了机械摆三维驱动的模型,定量地研究了不同的垂直运动速度在初始摆角和水平运动加速度的共同作用下对机械摆摆振的影响。     

回转起重机吊重摆振的动力学模型与控制

为研究回转起重机回转作业中吊重的摆振特性,寻求抑制吊重摆振的控制方法,将回转起重机工作装置等效为开链机械手的形式,采用机器人动力学方法建立吊重摆振的动力学模型,提出了基于最优调节器理论的控制方案用以抑制回转作业中的吊重摆振.该方案通过1个切换开关将2个最优调节器结合起来分别控制吊重在回转运动中的切向摆振和到达目标位置后的摆振.研究结果表明,该控制方案可以实现吊重在回转运动中摆振最小,在到达目标位置后迅速静止的控制目的,具有良好的摆振抑制效果.     

船式起重机的建模与消摆控制研究

针对海上平台船式起重机在运行过程中负载摆动过大、运输效率低下等问题,将辨识与最优化技术应用到船式起重机中,对船式起重机各部分动力学关系进行了分析,建立了船式起重机的数学模型。考虑了负载与船体运动的相互耦合,在FLOW-3D(计算流体动力学软件)中建立了仿真平台,对船摇模型进行了参数辨识,从而建立了完整的系统模型。应用最优化方法设计了一种消摆控制器,该控制器由PI控制器、低通滤波器、陷波滤波器串联而成。最后在Matlab/Simulink上进行了控制模型的仿真试验,比较了负载摆角在控制前、后的差别,发现消摆控制器可以将负载的残余摆动控制在消摆前的10%左右。研究结果表明,通过使用FLOW-3D来辅助建模,效率高且准确;采用最优化方法设计的控制器能较大幅度抑制负载摆动,可以提高船式起重机的运输效率与安全系数。     

Anti-sway system with image sensor for container cranes

High speed and efficiency are highly important factors in handling cargo at ports. The ability to handle cargo at high speed strongly depends on the anti-sway system employed. However, it is not easy to realize a high-performance anti-sway control system due to a number of problems. High-speed operation of container cranes is continuously required for crane operators who work as cargo handlers at ports. Undesirable motion can lower the work efficiency due to the prolonged strain to which operators are subjected. To overcome this problem, we propose an anti-sway system with an image sensor for container cranes. In this system, the image sensor is used for measuring the motion of the spreader, and the measured data are fed back to the controller in real time. The applied image processing technique is a kind of robust template matching method referred to as vector code correlation (VCC), which was devised in order to consider real environmental conditions. The anti-sway system proposed in this paper is a mass damper type system in which a movable mass is installed on the spreader. The actuator acting on the movable mass applies inertial force to the spreader, which results in suppressing undesirable sway motion. The system is simple and can be easily applied to any crane system. In this regard, the useful features and the performance of the proposed anti-sway system are experimentally verified.     

Adaptive control of an axially moving system

The objective of this paper is to move a load hanging under a very long rope from one place to another and to suppress the transverse vibrations of the load at the end of movement by adaptive control. The disturbance affecting the gantry motion is estimated and is incorporated into the control law design. The control command is given as a function of the position and velocity of the trolley, the hoisting speed, the sway angle of the rope at the gantry side, and the estimated disturbance force. The Lyapunov function taking the form of the total mechanical energy of the system is adopted to ensure the uniform stability of the closed-loop system. Through experiments, the effectiveness of the proposed control law is demonstrated.     

Rolling Element Skew in Tapered Roller Bearings

This paper reports on the roller skew in tapered roller bearings monitored by contact potential difference probes. The effect of the load, rotational speed, and viscosity of lubricant on roller skew angle, along with the variation of bearing torque with the running conditions, were measured on a LM501300 bearing. Two greases (SHC15 and SHC460) were used to lubricate the bearing. The skew angles were found to vary from 0.15° to 0.6°. The results indicate that the skew angle depends on the friction force at the roller-rib interface. An empirical equation is derived which relates the skew angle to the bearing operational parameters.     

Robust control for a biaxial servo with time delay system based on adaptive tuning technique

A robust control method for synchronizing a biaxial servo system motion is proposed in this paper. A new network based cross-coupled control and adaptive tuning techniques are used together to cancel out the skew error. The conventional fixed gain PID cross-coupled controller (CCC) is replaced with the adaptive cross-coupled controller (ACCC) in the proposed control scheme to maintain biaxial servo system synchronization motion. Adaptive-tuning PID (APID) position and velocity controllers provide the necessary control actions to maintain synchronization while following a variable command trajectory. A delay-time compensator (DTC) with an adaptive controller was augmented to set the time delay element, effectively moving it outside the closed loop, enhancing the stability of the robust controlled system. This scheme provides strong robustness with respect to uncertain dynamics and disturbances. The simulation and experimental results reveal that the proposed control structure adapts to a wide range of operating conditions and provides promising results under parameter variations and load changes.     

机电一体化技术在控摇系统中的应用与研究

起重机的摆动会降低装卸效率,影响运输安全。传统的电子控摇系统采用力控制方式,推导繁琐,计算量大。采用速度控制方式,通过控制小车的加速度来控制吊重摆动,所建立的模型不损害系统的非线性特性,且计算相对简单。具体实施过程中,建立闭环控摇系统,对系统输入、传输和外界作用等引起的误差进行修正。系统输入由编制的PLC程序实现。实验证明,这种方法直接、简单,可以有效控制吊重摆动,达到理想的控摇效果。     

Anti-sway position control of an automated transfer crane based on neural network predictive PID controller

In this paper, we develop an anti-sway control in proposed techniques for an ATC system The developed algorithm is to build the optimal path of container motion and to calculate an anti-collision path for collision avoidance in its movement to the finial coordinate Moreover, in order to show the effectiveness in this research, we compared NNP PID controller to be tuning parameters of controller using NN with 2 DOF PID controller The simulation and experimental results show that the proposed control scheme guarantees performances, trolley position, sway angle and settling time in NNP PID controller than other controller As the results in this paper, the application of NNP PID controller is analyzed to have robustness about disturbance which is wind of fixed pattern in the yard. Accordingly, the proposed algorithm in this study can be readily used for industrial applications     

基于MEMS微加速度计的无视觉传感器防摇控制系统研究

通过建立起重机吊重摆动的数学模型,明确吊重摆角与小车运行加减速之间的关系,并将MEMS微加速度计应用到起重机的防摇控制中,建立闭环控制系统,适时根据吊重摆角大小修正小车速度指令,实现防摇控制。实验证明,这种方法简单、经济,不需要安装视觉传感器测量吊重摆角,可以有效地消除载荷的摇动。     

Note: Design of a novel ultraprecision in-plane XYθ positioning stage

This paper presents the design, fabrication, and experimental results of a novel ultraprecision in-plane XYθ positioning stage with kinematic decoupling between translational motion and rotational motion components. Two translational motions are guided by four cymbal mechanisms that have both motion guide and motion amplifier. Four leaf springs guide a rotational motion amplified by a Scott-Russell linkage mechanism. The proposed stage has advantages such as an in-plane symmetrical configuration as well as ease of design and control by serial kinematics. The experimental results demonstrate that the stage has a translational full motion range of 58 μm and a rotational full motion range of 1.05 mrad. The crosstalk experimental results show good agreement with the theoretical prediction of the decoupling between translational motion and rotational motion.     

Nonlinear dynamic analysis of coupled gear-rotor-bearing system with the effect of internal and external excitations

Extensive studies on nonlinear dynamics of gear systems with internal excitation or external excitation respectively have been carried out. However, the nonlinear characteristics of gear systems under combined internal and external excitations are scarcely investigated. An eight-degree-of-freedom(8-DOF) nonlinear spur gear-rotor-bearing model, which contains backlash, transmission error, eccentricity, gravity and input/output torque, is established, and the coupled lateral-torsional vibration characteristics are studied. Based on the equations of motion, the coupled spur gear-rotor-bearing system(SGRBS) is investigated using the Runge-Kutta numerical method, and the effects of rotational speed, error fluctuation and load fluctuation on the dynamic responses are explored. The results show that a diverse range of nonlinear dynamic characteristics such as periodic motion, quasi-periodic motion, chaotic behaviors and impacts exhibited in the system are strongly attributed to the interaction between internal and external excitations. Significantly, the changing rotational speed could effectively control the vibration of the system. Vibration level increases with the increasing error fluctuation. Whereas the load fluctuation has an influence on the nonlinear dynamic characteristics and the increasing excitation force amplitude makes the vibration amplitude increase, the chaotic motion may be restricted. The proposed model and numerical results can be used for diagnosis of faults and vibration control of practical SGRBS.     

“火流星”的动力分析设计及控制

以“火流星”为分析对象 ,运用多体动力学理论 ,借助拉格朗日第二方程 ,对支承运动下的多体系统进行了动力分析、动力设计及其控制研究。数字仿真表明 :文中的分析及结论是正确的     

旋转运动模糊的实时恢复

提出了一种旋转运动模糊恢复算法,用来解决航空成像时旋转运动模糊的实时恢复问题.对旋转运动模糊这种具有异速像移的空间变化模糊进行了分析,并推导出旋转运动模糊的数学模型.用基于Bresenham画圆法的坐标转换方法将旋转圆弧上的空间变化模糊转变为常见的线性空间不变模糊,并使用一维维纳滤波对圆弧轨迹上的像素点进行模糊恢复.实验结果显示:本文算法在GPU处理平台下用3.31 ms即能恢复一帧1 024×1 024,8 bit旋转运动模糊图像,且极好地恢复了图像上的细节信息,恢复图像的峰值信噪比(PSNR)为28.76.算法的速度及效果表明本文所提出的算法具有较大的实用价值.     

Feedforward compensation of back electromotive force for suppressing rotational motion errors in a magnetically levitated system

The magnetically levitated system, so called maglev system, has been researched and developed with the purpose of vacuum compatibility in the semiconductor industry. In the maglev system, the back electromotive force is inevitably generated when the system moves. The back electromotive force causes force/moment disturbances. Especially, the moment disturbances have negative effect on controlling the rotational motions (θ _x , θ _y , θ _z ) whose control bandwidth is low. Therefore, the back electromotive force causes rotational motion errors. The rotational motion errors should be suppressed since they prevent high speed motion of the maglev system due to the rotational motion allowance of sensors. The rotational motion errors are suppressed by compensating the back electromotive force. In this paper, the back electromotive force, the cause of the rotational motion errors, is mathematically found in terms of the mover velocity and element of force-current matrix. A maglev system without the compensation was simulated and the rotational motion errors due to back electromotive force were found. Then, a feedforward compensated system using a mathematically modeled back electromotive force was simulated. It was verified that the feedforward compensation method with the modeled equation could be useful for suppressing rotational motion errors.     

防摇控制系统在集装箱起重设备中的研究与应用

对集装箱起重设备中小车定位及负载摇晃问题进行了研究。通过拉格朗日分析法,建立了小车负载的动态模型,提出了采用2段加速及叠加防摇速度分量驱动小车从而抑制负载摆动的方法,并在Simulink环境中对以上分析进行了仿真验证。在此基础上,实际开发了1套防摇控制系统并进行PLC编程,实现了小车手动和自动防摇运行功能。该系统已成功应用于集装箱场桥和岸边集装箱装卸桥,应用结果表明系统具有良好的定位性能和防摇效果。     

基于质量传感器系统的 岸边集装箱起重机挂舱保护系统

岸边集装箱起重机挂舱保护系统能检测并避免挂舱事故,保障其作业安全。基于质量传感器的挂舱保护设定,通过分析挂舱过程中钢丝绳的受力变化,优化合适的挂舱保护程序阈值,利用已有的质量传感器系统及主程序控制系统,增设逻辑保护程序,达到挂舱保护的目的。     

船体横荡运动对转子-浮筏气囊耦合系统非线性动力学特性的影响*

为研究横荡作用下船用转子-浮筏气囊耦合系统的非线性动力学特性,基于短轴承理论建立系统的数学模型,并用数值方法分析系统的动力学行为,探究转子转速、横荡幅值和频率变化对系统非线性动力学特性的影响。结果表明：与无横荡作用时相比,系统的动力学特性更为复杂;在转子转速较低时,系统在船体横荡作用下处于拟周期运动状态,随着转子转速的增加,系统出现分岔现象然后又合为一支直至混沌;随着横荡幅值的增大,转子的振动幅值也会随之增大,然而频率比的增加会使转子的振幅变小。     

旋转运动模糊的实时恢复算法

提出一种旋转运动模糊恢复算法,解决航空成像时旋转运动模糊的实时恢复问题。对旋转运动模糊这种具有异速像移的空间变化模糊进行分析,推导出旋转运动模糊的数学模型。用基于Bresenham画圆法的坐标转换方法将旋转圆弧上的空间变化模糊转变为常见的线性空间不变模糊,并使用一维维纳滤波对原圆弧轨迹上的像素点进行模糊恢复。实验结果显示：本文算法在GPU处理平台下用3.31ms即能完成一帧1024x1024 8bit旋转运动模糊图像的恢复,实现图像的实时恢复处理;同时图像上的细节信息均能得到很好的恢复,恢复图像的PSNR为28.76。算法的效率及效果表明本文算法具有一定的实用价值。