高精度风力摆控制系统设计

本系统设计制作一套由轴流风机为动力源的单片机精准控制系统。系统采用MC9S12XS128微控制器作为主控芯片,选用MPU6050六轴运动传感器及WDD35精密导电塑料电位器作为摆杆的角度检测模块,并采用四个空心杯电机作为系统的执行机构。该系统采用PID控制算法,控制摆杆做摆动方向和摆动幅度均可设定的平面单摆运动及摆动半径可设定的圆锥摆运动。实验结果表明,该风力摆控制系统摆动方向角度误差＜3°,摆动幅度误差＜5 mm,圆锥摆圆度误差＜5 mm。     

正弦平方势与晶体摆动场辐射的非线性特征

在经典力学框架内和偶极近似下,引入正弦平方势讨论了系统非线性对摆动场辐射的影响。首先,把粒子在弯晶中的运动方程化为具有周期外力作用的摆方程,用Jacobian椭圆函数和椭圆积分解析地描述了粒子运动行为;用多尺度度法和三角函数的广义Bessel展开,找到了受迫摆方程的近似解。而后,在超相对论情况下讨论了系统的瞬时辐射强度和平均辐射强度,并对两种辐射的强度比进行了讨论。结果表明,摆动场辐射强度与摆动场振幅平方成正比,振幅越大摆动场辐射强度越强。     

浅谈电磁智能控制运动装置的原理

电磁智能控制运动装置的设计受到单摆原理启发,通过调整单片机的占空比控制线圈的电流强度,产生不同的磁场强度控制磁摆来回摆动,并能够通过光电传感器控制磁摆的同步性达到控制装置的精确性。该系统能够控制磁摆在指定的摆角(10o~45o)范围内连续摆动,摆动摆角绝对误差≤5o。     

基于滑模预测的三维起重机防摆控制方法研究

为了使起重机安全、高效运行,同时为了减少附加设备,达到节能减排的目标,运用电子防摆控制方法的研究成了国内外学者广泛关注的课题。本文主要针对桥式起重机三维模型,利用滑模预测的方法来设计控制器,使用预测控制中的滚动优化和反馈校正方法来优化滑模轨迹的到达过程,以最终达到削弱抖振和增强鲁棒性的目的。仿真结果表明,该控制方法可以较好地对起重机系统的大、小车及负载的摆角进行控制,高效的消除起重机的摆动,达到了设计的预期目的。     

基于数字滤波的桥式起重机钢丝绳张力测量研究

桥式起重机工作在大载荷, 大冲击场合, 钢丝绳张力传感器测量吊重载荷瞬时冲击效应明显, 吊重载荷测量波动大, 给控制系统、故障诊断、安全作业提示带来了过多干扰数据。通过分析当前旁压式传感器的测量原理, 将其应用到容积卡尔曼数字滤波中, 实现了过滤冲击效应带来的瞬时波峰, 提升了桥式起重机控制系统的安全性。     

大跨度运动中肢体摆动幅度的视觉判断

针对大跨度运动中肢体摆动幅度视觉特征建模困难的问题,提出基于边缘区域轮廓特征检测的大跨度运动中肢体摆动幅度视觉判断方法。首先采用大跨度运动中肢体摆动视觉图像;然后对图像进行高频分量降噪,提高图像的信噪比,并采用边缘区域轮廓特征检测方法提取肢体摆动幅度特征,从而实现视觉检测和图像识别;最后进行仿真测试。结果表明,该方法能够准确进行大跨度运动中的肢体摆动幅度判断,具有较强的运动图像分析能力,并且提高了图像的输出信噪比和准确检测概率。     

基于电磁控制的周期运动装置设计

本系统以单摆为控制对象,通过电磁控制方式,设计电路实现对周期性运动装置的运动幅度(摆角)和周期(频度)的控制。控制核心采用ATMEL公司的ATmega16A,电磁线圈驱动器采用L298,角度检测采用MMA7455重力加速度传感器,显示采用LCD12864。通过PWM来控制线圈电流大小调节磁场强度,从而实现单摆摆动摆角和周期的控制。     

参数激励与大振幅近似下晶体摆动场的转动解

在经典力学框架内和偶极近似下,从势和场的观点出发,把晶体摆动场中的粒子运动方程化为了具有阻尼项和参数激励项的广义Mathieu方程,并对特殊情况下的Mathieu方程、摆方程和倒置摆方程进行了讨论.导出Mathieu方程的三种标准形式,分析了摆方程的三类轨道以及倒置摆的稳定区和不稳定区.用多尺度法找到了纯转动态的近似解和系统的临界曲线.指出了粒子的纯转动态就是准沟道态,准沟道粒子的电磁辐射就是准沟道辐射.     

红外成象系统中摆镜扫描电机的控制

在红外成象系统中,其帧扫常常采用摆镜扫描来实现。在摆镜扫描中存在着三个技术难点:(1)摆动平衡位置的稳定;(2)摆动终端位置的稳定;(3)摆动特性的高线性。同样,这三个问题也是人们应用摆动电机时所遇到的技术难点,如何解决这些技术问题呢?本文对此进行了详细的分析和讨论,提出了解决这些问题的方法,设计了一个结构简单、性能稳定的摆动电机控制回路,实验结果表明,该控制回路很好地实现了摆动平衡位置的稳定和摆动终端位置的稳定.     

运动阻尼对晶体摆动场辐射稳定性的影响

从势和场的观点出发,考虑电子多重散射和晶格热振动的影响,在经典力学框架内,把粒子的运动方程化为广义摆方程;在线性近似下,把摆方程化为带有阻尼项的Mathieu方程。用变形参数方法求出了Mathieu方程的过渡曲线,讨论系统阻尼对稳定性的影响。结果表明,系统的稳定性与阻尼有关,阻尼越大稳定性越好。为晶体摆动场辐射的获得提供了较为宽松的物理条件。     

Robust control of rotary crane by partial-state feedback with integrator

This paper deals with a simple design of robust control systems for rotary cranes. After deriving a simple linear model of crane dynamics, a constant gain partial state feedback controller is presented. Using information on the nominal natural frequencies of a load–rope system, the control system can be designed easily to be robustly stable for any rope length, without iterative computations. In addition, a method of including an integrator in the robust control system is proposed for reducing the positional error of the crane boom. The effectiveness of the proposed method is confirmed experimentally.     

Simple rotary crane dynamics modeling and open-loop control for residual load sway suppression by only horizontal boom motion

To suppress two-dimensional load sway caused by the horizontal boom motion of a rotary crane, both horizontal and vertical boom motions are generally used. However, it would be more energy efficient and safer if a control scheme using only horizontal boom motion could be developed, eliminating the need for any boom vertical motion. In addition, if we can suppress load sway without the need to measure it, cost reduction of sensors can be achieved. Furthermore, the use of simple velocity trajectory patterns such as a trapezoidal velocity pattern and an S-curve acceleration/deceleration pattern, which are widely used in industrial automation systems, may provide cost-effective implementation of controllers. This paper presents a simple model of rotary crane dynamics that includes only significant centrifugal and Coriolis force terms. This simple model allows analytical solutions of the differential equations of the model to be derived. Thus, S-curve trajectory that considers residual vibration suppression without sensing it, using only horizontal boom motion, can be generated by solving only algebraic equations numerically. The effectiveness of the proposed method is demonstrated by numerical simulations and experimental results.     

Design and implementation of robust visual servoing control of an inverted pendulum with an FPGA-based image co-processor

This paper presents the design and implementation of robust real-time visual servoing control with an FPGA-based image co-processor for a rotary inverted pendulum. The position of the pendulum is measured with a machine vision system. The pendulum used in the proposed system is much shorter than those used in published vision-based pendulum control system studies, which makes the system more difficult to control. The image processing algorithms of the machine vision system are pipelined and implemented on a field programmable gate array (FPGA) device to meet real-time constraints. To enhance robustness to model uncertainty and to attenuate disturbance and sensor noise, the design of the stabilizing controller is formulated as a problem of the mixed H₂/H_∞ control, which is then solved using the linear matrix inequality (LMI) approach. The designed control law is implemented on a digital signal processor (DSP). The effectiveness of the controller and the FPGA-based image co-processor is verified through simulation and experimental studies. The experimental results show that the designed system can robustly control an inverted pendulum in real-time.     

Model-Based Adaptive Predictive Control with Visual Servo of a Rotary Crane System

This paper investigated the implementation of an adaptive predictive controller using nonlinear dynamic echo state neural (ESN) model for a rotary crane system by the visual servo method. The control sequences within the control horizon were described using cubic spline interpolation to enlarge the predictive horizon. Verification of the proposed scheme in the face of exogenous disturbances and modeling error with inaccurate string length was demonstrated by both simulations and experiments.     

基于STC89C52的简易倒立摆控制装置设计

以全国大学生电子设计竞赛为背景,通过分析简易旋转倒立摆及控制装置系统的任务和基本要求,设计制作了基于单片机为主控芯片的倒立摆控制系统,利用光电编码器传回来的反馈信号采用PID控制调节,并发出控制信号驱动直流电机,实现调速控制。该装置可以使旋转臂适时适当的摆动,准确地让摆杆在短时间内达到题目所需的要求。     

基于AVR单片机的旋转倒立摆设计

对简易旋转倒立摆的各个模块做了相关介绍,对系统的实现方案和设计步骤进行描述。采用ATmega16单片机作为主控元件,以BTS7960模块作为驱动器,使用直流伺服电机作为驱动电机。采用增量式PID算法控制摆杆达到稳定,对摆杆所处位置的角度进行分段,然后采用分段PID算法进行控制,以使摆杆快速趋于稳定状态,得到良好的控制效果。     

Trajectory generation of rotary cranes based on A* algorithm and time-optimization for obstacle avoidance and load-sway suppression

Rotary cranes are widely utilized for cargo handling of heavy objects in various construction sites by synchronizing two-dimensional boom rotations and rope motion. The crane’s motion is accompanied by undesirable load-sway and constrained by obstacles, which influence the crane motion and may cause collisions and accidents. Therefore, safe and fast motion for rotary cranes are a main demand for reducing operation time and suppressing residual load-sway. Moreover, avoiding collisions is highly required to guarantee safety during load transportation, while sudden acceleration/deceleration motions are basically prohibited. This paper proposes an optimal trajectory generation method for a large crane using a simple nonlinear dynamics to enhance load-sway suppression without collisions. The three-dimensional crane trajectory is generated by two different algorithms; the first one is the A* algorithm, which is used to generate a short-distance load path from a starting position to the destination with avoiding collision with not only the loads but also the crane body and the rope. Using the inverse kinematics of the crane, the shortest-distance paths for boom rotations and rope motion can be determined. The second algorithm is applied to obtain a time-optimal trajectory for the paths generated by the A* algorithm under crane dynamics and load-sway constraints. The proposed trajectory is represented by a polynomial function, which provides practical and smooth motion for the crane. Computational and experimental results confirm the effectiveness of the proposed approach for suppressing residual load-sway and obstacle avoidance.     

Data-based error compensation for georeferenced payload path tracking of automated tower cranes

In order to increase the productivity on construction sites, a current topic of research is the automation of the payload transport by tower cranes. Thereby, a key requirement is to ensure that the tower crane precisely tracks the planned paths and positions the payload at the specified target location. Most of the state-of-the-art tower crane controllers damp load sway while moving each driving system to its desired position. However, the path error also consists of bending displacements of the tower crane’s mechanical structure, observer errors, or sensor offsets once the crane hook position is considered in a fixed georeferenced construction site system. These errors have not been addressed in literature on tower cranes so far. This paper introduces an approach to reduce the path error of automated tower cranes without permanently integrating additional sensors. A regression model is derived for predicting the path error and a least absolute shrinkage and selection operator (LASSO) is used to select the most important features. The predicted error is then used to compute a compensating hook path such that the measured hook path matches the desired hook path. The effectiveness of the approach is experimentally validated utilizing a real large-scale tower crane showing a reduction of the path error of more than 50% and a position accuracy of less than 16 cm.     

Robust adaptive sliding-mode control using fuzzy modeling for aninverted-pendulum system

In this paper, a new robust adaptive control architecture is proposed for operation of an inverted-pendulum mechanical system. The architecture employs a fuzzy system to adaptively compensate for the plant nonlinearities and forces the inverted pendulum to track a prescribed reference model. When matching with the model occurs, the pendulum will be stabilized at an upright position and the cart should return to its zero position. The control scheme has a sliding control input to compensate for the modeling errors of the fuzzy system. The gain of the sliding input is automatically adjusted to a necessary level to ensure the stability of the overall system. Global asymptotic stability of the algorithm is established via Lyapunov's stability theorem. Experiments on an inverted-pendulum system are given to show the effectiveness of the proposed control structure     

A dynamic neuromuscular model for describing the pendulum test ofspasticity

Both dynamic and static thresholds, as well as the gain in the stretch reflex loop, affect the sensitivity of motoneurons to muscle stretch. How the variation in each parameter will influence the mechanical behavior of patients with spasticity is not well understood because of the difficulty in experimentally isolating individual parameters. A neuromuscular dynamic model, based on the pendulum test of spasticity, has been developed to study the specific contribution of individual parameter abnormalities in stretch reflex loops to the observed mechanical abnormalities. The model contains detailed nonlinear dynamics of muscle force generation and stretch reflexes. A computer simulation of the model indicates that the stretch reflex thresholds and the gain have different influences on the leg swing in the pendulum test of spasticity. Individual changes in the static stretch reflex threshold, in the dynamic threshold, or in the gain can not stimulate the whole spectrum of spasticity severity. When simultaneous changes in all three parameters of the stretch reflex loop occur, a small variation of the gain coupled with changes in both static and dynamic thresholds can produce increasing severity of spasticity as the thresholds further decrease. The model is also successful in simulating the effect of posture changes on spasticity