一种改进的天棚半主动控制算法

针对传统天棚阻尼控制对参数可变的磁流变半主动悬挂系统不能进行有效控制的问题,设计了一种最小控制综合与天棚混合的控制算法;首先建立了理想天棚阻尼控制算法的模型,依据最小控制综合算法模型结构特点将理想天棚阻尼控制作为参考模型;然后依据磁流变阻尼器控制力特点,改进了最小控制综合算法的反馈控制方程,得到混合控制算法的控制律;最后对改进的算法进行了仿真分析;仿真结果表明,混合控制算法在悬挂系统参数发生变化的情况下能够有效降低车体加速度和车轮动载荷,具有较好的控制效果;所设计的改进的天棚半主动控制可以提高车辆的行驶平顺性,对被控系统参数的变化具有良好的适应性,具有较高的实用价值。     

冗余自由度工业机器人模糊自适应PID控制研究

为提高汽车生产中涂胶工序的工作效率和空间利用率,改善机器人避障性能,设计了一款具有7自由度的冗余度工业涂胶机器人,并对其控制方法开展研究。针对现有PID控制方法应用于非线性时变的多自由度多刚体串联式开链系统时,控制效果有限、难以达到系统精度要求等问题,基于传统PID控制和模糊自适应控制算法,提出了一种带有重力补偿的模糊自适应PID混合控制方法。该方法在对冗余度工业机器人进行动力学分析的基础上,基于牛顿-欧拉分析法建立了冗余度机器人动力学模型,基于动力学分析设计了带有重力补偿的模糊自适应参数整定PID控制策略,建立了控制器模型,通过Matlab仿真实验表明,具有模糊自适应参数整定PID控制较有重力补偿的传统PID控制具有更好的控制效果。     

倾转定翼无人机姿态控制系统设计

所研究对象为四旋翼倾转定翼无人机（Quad Tilt Wing-Unmanned Aerial Vehicle, QTW-UAV）,首先对QTW-UAV的直升机模式进行动力学特性分析,建立其滚转运动数学模型,然后设计了基于模型参考的PID自适应控制器,在传统PID控制方法的基础上融合自适应控制算法,给出PID参数自整定率,实现了QTW-UAV姿态角的自适应控制。仿真结果表明,设计的控制器具有良好的稳态和跟踪性能,实现了QTW-UAV姿态稳定控制。     

制浆废水厌氧处理过程中pH的控制算法研究

以山东某纸厂的制浆废水厌氧处理过程为背景,建立了pH调节系统的数学模型,组建了模糊PID控制系统,并用Matlab仿真软件对其进行了仿真;研究比较了PID控制、模糊控制和模糊PID控制的阶跃响应、抗干扰响应,对比分析了模型参数摄动时这3种控制算法的鲁棒性能;从仿真结果看,模糊PID的阶跃响应既具有模糊控制的快速性又具有PID控制的稳态无误差,在受到干扰后可以很快恢复到稳态值,达到比较好的控制效果;模型参数发生摄动后,模糊PID控制超调量相对较少,稳态误差为零,但要在200 s时才基本稳定;实验证明模糊PID控制算法的综合性能最好。     

基于滑模变结构的柔性倒立摆控制研究

针对柔性倒立摆稳摆控制比较困难且传统指数趋近率的滑模变结构控制易对系统造成抖振,基于机理建模方法建立柔性倒立摆数学模型,提出变指数趋近率的滑模变结构控制方法,设计了滑模变结构控制器,使系统具有较好的稳摆控制和鲁棒性。仿真结果表明,基于变指数趋近率的滑模变结构控制方法能够更好的实现倒立摆稳定控制,相比于传统指数趋近率的滑模控制器输出更加平滑,进而减小了控制器的负担。     

基于PLC的环境模拟系统温度控制算法的研究与实现

针对环境模拟试验温度控制系统中被控对象存在的非线性、时滞等特点,本文采用区间限幅PID控制算法和模糊PID控制算法对传统控制方法进行了改进。首先为了解决模拟量三通粗调阀调节缓慢的缺点,建立了区间限幅PID控制算法的控制规则表,并将其在PLC中实现。其次提出用模糊PID控制算法来解决电加热器的非线性、大时滞性问题,并结合实际控制经验建立了模糊控制规则表,然后将模糊PID控制算法在PLC中进行实现。最后将限幅PID和模糊PID控制算法应用于某大型环境模拟试验控制系统,实验结果表明利用改进算法对温度控制具有良好的稳定性及精确度。     

基于摆扫反射镜的大视场成像像移模型

为实现大视场技术指标,建立了一种基于摆镜转动的摆扫成像模型。通过对摆扫成像与推扫成像模式的比较,分析得出当横滚角等于摆镜转角的2倍时,摆扫成像能够实现与推扫成像小姿态时相同的视场;经过实验验证,在横滚角为2°、4°、6°、8°、10°时,本文的方法与推扫成像模型像移相对误差在1%以内,偏流角大小相对误差在0.001%以内,两种方法保持了较好的一致性,保证了模型的合理性与正确性。此外,该模型还可以通过实时地控制摆镜的转动来实现穿航方向上的对地的扫描成像,进而实现大视场、宽幅盖对地成像,减小回访周期,提高空间相机对地成像的工作效率。     

近程巡飞弹姿态控制优化仿真研究

近程巡飞弹姿态控制系统是一个非线性、时变性及耦合性的复杂控制系统,是近程巡飞弹武器系统型号研制的关键技术之一;传统的PID控制在不同巡飞状态下调节稳定性较差、响应时间慢、影响姿态控制的稳定性和机动性;针对近程巡飞弹姿态控制系统中PID控制参数不可调,自适应、抗干扰性能较差等问题,引入了自适应模糊PID控制方法,使系统在不同巡飞姿态和干扰条件下能够实时整定PID的三个控制参数,提高系统的控制性能;在此基础上设计了近程巡飞弹的姿态角控制回路,并以俯仰角为例,在Matlab/Simulink平台下建立仿真模型,进行仿真实验;仿真结果显示,采用自适应模糊PID的控制方法,系统控制性能更好,抗干扰能力和自适应能力优于传统PID控制,减小了巡飞过程中姿态角的波动情况。     

基于自适应单神经元PID的四旋翼飞行控制研究

针对传统增量式PID控制算法在四旋翼飞行器的姿态控制中自整定参数不足的缺点,提出了一种改进的自适应单神经元PID控制算法,该算法在单神经元加权系数调整的基础上引入PSD自适应控制方法,增加了对比例系数的自适应调整;通过建立四旋翼飞行器的动力学模型和飞行试验平台对该改进算法进行仿真验证;仿真结果表明,采用自适应单神经元PID算法的控制器结构简单且响应速度快,精度高,具有更高的鲁棒性和自适应能力,能有效的实现四旋翼飞行器姿态的稳定控制。     

自适应模糊PID前馈补偿在机载挂飞摆扫转台控制中的应用

针对机载挂飞转台的摆扫速度控制问题,提出了一种利用模糊自适应PID技术进行前馈补偿的复合控制策略。首先根据实际应用提出摆扫转台的期望摆扫速度曲线,并对直流力矩电机驱动的摆扫转台进行了建模;然后根据扰动前馈补偿的控制原理,提出了模糊自适应PID前馈补偿方法,为摆扫转台的速度环设计了模糊PID控制器,并在此基础上设计了与之相适应的的自适应前馈补偿函数;最后进行了仿真结果验证。通过Matlab仿真结果表明,相对于模糊PID控制,所设计的模糊自适应PID前馈补偿控制器能有效的跟踪期望的转台摆扫速度,大幅地提高了在有稳定干扰和摆扫速度越变情况下的跟踪精度。     

An inverse model of MR damper using optimal neural network and system identification

Magnetorheological (MR) damper is one of the more promising new devices for vibration control of structures. External energy required by the adjustable fluid damper is minuscule while speed of its response is in the order of milliseconds. The MR damper is a semi-active control device and has been characterized by a set of non-linear differential equations which represent a forward model of the MR damper, i.e., the model can generate a force to a given displacement and applied voltage.This paper presents an inverse model of the MR damper, i.e., the model can predict the required voltage so that the MR damper can produce the desired force for the requirement of vibration control of structures. The inverse model has been constructed by using a multi-layer perceptron optimal neural network and system identification, which are Gauss-Newton-based Levenberg-Marquardt training algorithm, optimal brain surgeon strategy and autoregressive with exogenous variables (ARX) model. Based on the data from numerical simulation of the MR damper, the trained optimal neural networks can accurately predict voltage. If the inverse model is used in a control system, the semi-active vibration control can be implemented easily by using the semi-active MR damper.     

Human simulated intelligent control of vehicle suspension system with MR dampers

This paper presents vibration control responses of a controllable magnetorheological (MR) suspension system of a passenger car. The MR damper is designed and manufactured on the basis of the mixed-mode operation, and its time response is experimentally evaluated to integrate with the suspension model. After formulating the dynamic model of a half-car MR suspension system, a human simulated intelligent control (HSIC) scheme is developed to attenuate unwanted vibrations such as pitch angle acceleration. After verifying the effectiveness of the HSIC via computer simulation, the road test of the passenger car installed with four MR dampers is undertaken. The power spectrum densities of dynamic motions such as body acceleration and pitch angle acceleration are measured and analyzed. In addition, the control results obtained from the proposed HSIC are compared with those obtained from a conventional linear quadratic Gaussian (LQG) control method.     

EVALUATION OF VIBRATION AND SHOCK ATTENUATION PERFORMANCE OF A SUSPENSION SEAT WITH A SEMI-ACTIVE MAGNETORHEOLOGICAL FLUID DAMPER

The potential benefits of a semi-active magnetorheological (MR) damper in reducing the incidence and severity of end-stop impacts of a low natural frequency suspension seat are investigated. The MR damper considered is a commercially developed product, referred to as “Motion Master semi-active damping system” and manufactured by Lord Corporation. The end-stop impact and vibration attenuation performance of a seat equipped with such a damper are evaluated and compared with those of the same seat incorporating a conventional damper. The evaluation is performed on a servo-hydraulic vibration exciter by subjecting the seat-damper combinations to a transient excitation with dominant frequency close to that of the seat and continuous random excitation class EM1 applicable to earth-moving machinery, and a more severe excitation realized by amplifying the EM1 excitation by 150%. Tests are performed for medium and firm settings of the MR damper and for seat height positions corresponding to mid-ride and ±2·54 and ±5·08 cm relative to mid-ride. The results indicate that significantly higher levels of transient excitation are necessary to induce end-stop impacts for the seat equipped with the MR damper, particularly when set for firm damping, the difference with the conventional damper being more pronounced for seat positions closer to the end-stops. Under the EM1 excitation, the results indicate that under conditions which would otherwise favour the occurrence of end-stop impacts for a seat equipped with a conventional damper, the use of the MR damper can result in considerably less severe impacts and correspondingly lower vibration exposure levels, particularly when positioned closer to its compression or rebound limit stop.     

A STOCHASTIC OPTIMAL SEMI-ACTIVE CONTROL STRATEGY FOR ER/MR DAMPERS

A stochastic optimal semi-active control strategy for randomly excited systems using electrorheological/magnetorheological (ER/MR) dampers is proposed. A system excited by random loading and controlled by using ER/MR dampers is modelled as a controlled, stochastically excited and dissipated Hamiltonian system with n degrees of freedom. The control forces produced by ER/MR dampers are split into a passive part and an active part. The passive control force is further split into a conservative part and a dissipative part, which are combined with the conservative force and dissipative force of the uncontrolled system, respectively, to form a new Hamiltonian and an overall passive dissipative force. The stochastic averaging method for quasi-Hamiltonian systems is applied to the modified system to obtain partially completed averaged Itô stochastic differential equations. Then, the stochastic dynamical programming principle is applied to the partially averaged Itô equations to establish a dynamical programming equation. The optimal control law is obtained from minimizing the dynamical programming equation subject to the constraints of ER/MR damping forces, and the fully completed averaged Itô equations are obtained from the partially completed averaged Itô equations by replacing the control forces with the optimal control forces and by averaging the terms involving the control forces. Finally, the response of semi-actively controlled system is obtained from solving the final dynamical programming equation and the Fokker-Planck-Kolmogorov equation associated with the fully completed averaged Itô equations of the system. Two examples are given to illustrate the application and effectiveness of the proposed stochastic optimal semi-active control strategy.     

磁流变液阻尼器在转子振动控制中的应用

设计了一种转子振动控制用的剪切式磁流变液阻尼器,建立了磁流变液阻尼器－悬臂转子系统的分析模型,理论和实验研究了转子系统的不平衡响应特性。研究表明,随着施加磁场强度的增加,磁流变液阻尼和刚度增大,转子系统的临界振幅明显下降,系统的临界转速也明显提高。通过简单的开关控制,可抑止转子通过临界转速过程中的振动。     

Quasi-active suspension design using magnetorheological dampers

Quasi-active damping is a method of coupled mechanical and control system design using multiple semi-active dampers. By designing the systems such that the desired control force may always be achieved using a combination of the dampers, quasi-active damping seeks to approach levels of vibration isolation achievable through active damping, whilst retaining the desirable attributes of semi-active systems. In this article a design is proposed for a quasi-active, base-isolating suspension system.Control laws are firstly defined in a generalised form, where semi-active dampers are considered as idealised variable viscous dampers. This system is used to demonstrate in detail the principles of quasi-active damping, in particular the necessary interaction between mechanical and control systems. It is shown how such a system can produce a tunable, quasi-active region in the frequency response of very low displacement transmissibility.Quasi-active control laws are then proposed which are specific for use with magnetorheological dampers. These are validated in simulation using a realistic model of the damper dynamics, again producing a quasi-active region in the frequency response. Finally, the robustness of the magnetorheological, quasi-active suspension system is demonstrated.     

Analytical and experimental validation of a nondimensional Bingham model for mixed-mode magnetorheological dampers

In this paper an experimental validation of a nondimensional analysis for a mixed-mode magnetorheological (MR) damper is described. Based on the Bingham constitutive equation of an MR fluid, a nondimensional model describing damping capacity of the MR damper is formulated using nondimensional parameters including the Bingham number, nondimensional plug thickness, hydraulic amplification ratio, and equivalent viscous damping coefficient. The effects of the Bingham number and the hydraulic amplification ratio on the nondimensional plug thickness and equivalent viscous damping coefficient are analyzed. A mixed-mode MR damper is designed and fabricated to validate the relationships between nondimensional parameters. The damper is tested under various loading conditions and current (applied magnetic field intensity) levels. The nondimensional parameters and variables are measured experimentally, and the effectiveness of the nondimensional analysis model for mixed-mode MR dampers is demonstrated. In addition, comparisons between mixed and flow mode dampers are undertaken using this nondimensional analysis.     

Energy harvesting using semi-active control

This paper presents the application of semi-active control for optimising the power harvested by an electro-mechanical energy harvester. A time-periodic damper, defined by a Fourier series, is introduced for energy harvesting in order to increase the performance of the device. An analytical solution for the transmissibility and the average absorbed power is derived based on the method of harmonic balance. The coefficients of the semi-active model are optimised to maximise the harvested power. The harvested power from the optimum periodic time-varying damper at a particular frequency is compared and is shown to be greater than that from an optimum passive damper and a semi-active on–off damper not only at that particular frequency but also at other frequencies. In addition, the performance of the optimised periodic time-varying damper is also compared with an arbitrary semi-active time-periodic damper, which has the same transmissibility at resonance. An optimisation is carried out to maximise the power in a frequency range and the optimum damper is derived as a function of the excitation frequency. The numerical results are validated with the analytical approach.     

Optimal control of structures with semiactive-tuned mass dampers

In this paper, the optimal performance of a magnetorheological (MR) damper which is used in a tuned mass damper in reducing the peak responses of a single-degree-of-freedom structure subjected to a broad class of seismic inputs including the harmonic, pulse, artificially generated and recorded earthquake excitations are studied. The optimal semiactive control strategy minimizes an integral norm of the main structure squared absolute accelerations subject to the constraint that the non-linear equations of motion are satisfied and is determined through a numerical solution to the Euler-Lagrange equations. The optimal performance evaluated for an MR damper is compared to an equivalent passive-tuned mass damper with optimized stiffness and damping coefficients. It is shown numerically that the optimal performance of the MR damper is always better than the equivalent passive-tuned mass damper for all the investigated cases and the MR damper has a great potential in suppressing structural vibrations over a wide range of seismic inputs.     

用含苯甲酸甲氧基苯酯的聚硅氧烷组成均相电流变液及其智能阻尼特性的研究

在合成并表征含苯甲酸甲氧基苯酯的侧链液晶聚硅氧烷高分子的基础上,制备了均相电流变(ER)液及其智能阻尼器.测试了ER液及其智能阻尼器在室温下的性能.结果表明,用含苯甲酸甲氧基苯酯的侧链液晶聚硅氧烷能组成在室温下表现出较强ER活性的均相ER液,它在外加电场E=2.2kV/mm,剪切速率为300s-1时,剪切应力达到1550Pa;增加E和振动频率,均相ER液智能阻尼器的阻尼力均增加,阻尼效果提高.