Analysis of thermal effects on the misaligned hydraulic servo cylinder

The hydraulic servo cylinders with conical–cylindrical hydrobearing can obtain a high normal load carrying capacity at the shoulder length ratio n_s=0.8, and also avoid cylinder rod in collision with the sharp edge of conical surface. However, the effects of eccentricity and misalignment must be considered since aligning the centers of the hydraulic servo actuator with the applied mechanical load is concerned. In this study, eccentricity ratio is varied between 0 and 0.6 with misalignment factor up to 0.6 and 0.05 along the horizontal and vertical directions, respectively. Thermal effects that include isothermal, adiabatic and thermohydrodynamic boundary conditions on the bearing performance, such as pressure distribution, normal load carrying capacity and the frictional coefficient, are all examined herein.     

基于CMAC与PID复合控制算法的液压缸装配专用设备电液伺服系统的研究

构建了液压缸装配专用设备电液伺服系统的数学模型,提出基于CMAC与PID复合控制算法的控制策略,克服传统PID控制存在的参数很难自整定、系统超调量过大、动态响应速度过慢等问题。仿真分析表明,采用CMAC与PID复合控制算法具有很好的控制效果,可以提高系统的动态特性,减小系统的超调量,增强系统的稳定性。     

阀控不对称液压缸系统改进控制策略研究

非对称液压缸具有占据空间小、制造简单且成本低廉等优点,在液压系统中应用极为广泛。但是,在液压伺服系统中,特别是在采用零开口伺服阀控制的阀控缸系统中,由于非对称液压缸活塞两侧的承压面积不同,当伺服阀阀芯在零开口附近做振荡时,液压缸两腔交替供油,活塞运动方向发生交替变化,此时液压缸两腔会产生压力突跳,产生系统振荡及爆振现象,严重时导致管道破裂等情况发生,不仅影响系统的稳定性,使系统无法正常工作,甚至导致液压系统及主机结构破坏。该问题在采用液压系统计算机仿真设计时很容易被忽略,造成设计失败。分析一个实际零开口对称伺服阀控不对称液压缸的液压系统设计案例,对对称阀控制不对称液压缸进行了不相容性分析,明确系统产生"爆振"的原因,以及提出该设计失败后的改进方案。     

Model-based nonlinear control of hydraulic servo systems: Challenges,developments and perspectives

Hydraulic servo system plays a significant role in industries, and usually acts as a core point in control and power transmission. Although linear theory-based control methods have been well established, advanced controller design methods for hydraulic servo system to achieve high performance is still an unending pursuit along with the development of modern industry. Essential nonlinearity is a unique feature and makes model-based nonlinear control more attractive, due to benefit from prior knowledge of the servo valve controlled hydraulic system. In this paper, a discussion for challenges in model-based nonlinear control, latest developments and brief perspectives of hydraulic servo systems are presented: Modelling uncertainty in hydraulic system is a major challenge, which includes parametric uncertainty and time-varying disturbance; some specific requirements also arise ad hoc difficulties such as nonlinear friction during low velocity tracking, severe disturbance, periodic disturbance, etc.; to handle various challenges, nonlinear solutions including parameter adaptation, nonlinear robust control, state and disturbance observation, backstepping design and so on, are proposed and integrated, theoretical analysis and lots of applications reveal their powerful capability to solve pertinent problems; and at the end, some perspectives and associated research topics (measurement noise, constraints, inner valve dynamics, input nonlinearity, etc.) in nonlinear hydraulic servo control are briefly explored and discussed.     

基于前馈控制的交流伺服系统高速定位控制

在要求高速、快响应的交流伺服定位系统中,采用传统PID控制很难实现高速定位.为解决此问题.在设计出包括位置环、速度环和电流环的三闭环PID伺服控制系统的基础上,引入电流环和速度环的前馈控制来提高定位控制的性能.通过仿真验证了前馈控制在指令信号跟踪方面的良好效果,然后设计出实验系统,进行了与普通PID伺服控制系统的对比实验.结果表明,引入前馈控制的PID伺服控制系统可以实现交流伺服系统的高速定位控制.     

PLC 在叉车液压缸检测系统中的应用

介绍了叉车液压缸检测系统的基本结构、主要特性、检测方法、KOYO公司SZ-4型PLC的特点以及采用了KOYO公司SZ-4型PLC控制系统的软、硬件设计。     

Adaptive backstepping slide mode control of pneumatic position servo system

With the price decreasing of the pneumatic proportional valve and the high performance micro controller, the simple structure and high tracking performance pneumatic servo system demonstrates more application potential in many fields. However, most existing control methods with high tracking performance need to know the model information and to use pressure sensor. This limits the application of the pneumatic servo system. An adaptive backstepping slide mode control method is proposed for pneumatic position servo system. The proposed method designs adaptive slide mode controller using backstepping design technique. The controller parameter adaptive law is derived from Lyapunov analysis to guarantee the stability of the system. A theorem is testified to show that the state of closed-loop system is uniformly bounded, and the closed-loop system is stable. The advantages of the proposed method include that system dynamic model parameters are not required for the controller design, uncertain parameters bounds are not need, and the bulk and expensive pressure sensor is not needed as well. Experimental results show that the designed controller can achieve better tracking performance, as compared with some existing methods.     

闭环控制数字液压缸及其控制系统

本文介绍了一种新型闭环控制数字液压缸的结构、工作原理及其控制系统。     

基于DSP的泵控液压缸变频调速系统

变频泵控调速系统通过改变输入供电频率来改变电机的转速,从而改变定量泵的排量,实现对液压缸的速度调节.相比于传统的阀控调速系统,无节流损失,效率高,结构简单,精度高,适用于对精度要求高的大惯量液压提升机械.本文利用智能IPM模块及DSP控制器搭建1套基于DSP的泵控液压缸调速系统平台,通过DSP输出SVPWM波控制IPM...     

Real-time tracking control of electro-hydraulic force servo systems using offline feedback control and adaptive control

This paper focuses on an application of an electro-hydraulic force tracking controller combined with an offline designed feedback controller (ODFC) and an online adaptive compensator in order to improve force tracking performance of an electro-hydraulic force servo system (EHFS). A proportional-integral controller has been employed and a parameter-based force closed-loop transfer function of the EHFS is identified by a continuous system identification algorithm. By taking the identified system model as a nominal plant model, an H_∞ offline design method is employed to establish an optimized feedback controller with consideration of the performance, control efforts, and robustness of the EHFS. In order to overcome the disadvantage of the offline designed controller and cope with the varying dynamics of the EHFS, an online adaptive compensator with a normalized least-mean-square algorithm is cascaded to the force closed-loop system of the EHFS compensated by the ODFC. Some comparative experiments are carried out on a real-time EHFS using an xPC rapid prototype technology, and the proposed controller yields a better force tracking performance improvement.     

伺服飞锯机的控制系统和运动分析

伺服飞锯机是一种最新型的飞锯机,介绍了该飞锯机的控制系统,并对其进行了运动分析。     

基于伺服电动缸驱动的铣削头主轴位置控制结构设计

针对组合机床通用部件滑套式铣削头主轴伸出缩回运动的不足,设计了一种采用伺服电动缸驱动的主轴伸出缩回运动的结构方案。将铣削头主轴伸出缩回直线往复运动由液压缸驱动转换成伺服电动缸推杆驱动,主轴伸出位置实现无级精确控制,具备自动粗铣、半精铣、精铣、让刀功能。在数控组合铣床上实现柔性化加工,得到广泛应用。     

基于PLC的油缸自动焊控制系统设计

针对液压油缸自动焊的控制要求,介绍了以PLC为核心的液压油缸自动焊接设备的控制系统,采用三菱FX2N-32MR-D对油缸的焊接过程进行逻辑控制和运动控制,给出了自动焊控制系统的PLC输入输出接线图和梯形图程序.最后通过现场调试及生产运行,证明该系统具有可靠性高、操作简便,极大提高了生产效率,油缸焊接质量好.     

转向缸系统反馈线性化分析与系统解耦

为解决汽车转向缸加载控制中出现的诸如强位置干扰、多通道耦合、非线性等问题,将线性系统和非线性系统理论引入系统控制器的设计中,对各通道耦合问题开展了以前馈补偿为基础的解耦控制,所设计的前馈补偿结构简单,解耦网络阶次低;针对非线性问题提出了将非线性系统精确反馈线性化与最优控制相结合的方法,设计了基于精确反馈线性化的最优控制器,该方法将复杂的非线性系统问题转化为线性系统的综合问题,采用渐近输出跟踪方法实现系统控制。仿真结果表明:采用前馈补偿解耦控制器可以有效消除耦合,但当系统存在高度非线性时,仅采用前馈补偿解耦控制不能达到高品质的性能要求,而进一步设计的基于精确反馈线性化的最优控制器考虑系统非线性时,系统能快速、准确达到预置设定。     

基于卡尔曼滤波器的交流伺服系统自适应滑模控制

为了减小负载转矩扰动和系统参数摄动对永磁同步电机控制系统的影响,提出了一种基于卡尔曼滤波器的自适应滑模速度控制器。该控制器由自适应律估计参数摄动项,用卡尔曼滤波器估计外部扰动项。设计了含积分作用的滑模面,以保证电机转速的无静差跟踪;采用了指数趋近律,以提高趋近速度并削弱抖振。卡尔曼滤波器估计得到的系统外部扰动前馈补偿至控制器的输出,用于有效降低滑模控制器的不连续切换项造成的系统抖振。实验结果显示:跟踪设定的600r/min转速时,控制器稳态转速精度达到±1r/min。电机在以600r/min稳速运行时,设计的控制器在1.6N·m的外部转矩扰动下的最大转速波动比传统PI控制器的转速波动减小了2%。仿真分析和实验数据表明基于卡尔曼滤波器的自适应滑模控制器对交流伺服控制系统具有较强的抗扰动性、鲁棒性以及良好的稳态性能。     

电动助力转向系统随动特性仿真

电动助力转向系统（Electric Power Steering,EPS）必须随时根据驾驶员的操作,提供渐进随动的转向助力动作,所以系统必须有很高的跟踪性和很好的稳定性．在对EPS的工作原理和力学模型分析的基础上,建立EPS系统仿真模型,设计出一种模糊自适应PID（Proportion—Integral—Derivative）控制器,有效地改善了传统PID控制器的不足．通过仿真表明,这种模糊自适应PID控制器与传统PID控制器相比,具有更好的跟踪性和稳定性．     

基于Matlab的液压伺服系统二次型最优控制器设计

分析泵控液压马达传递函数,给出液压伺服系统通用数学模型;运用二次型最优控制理论,将最优控制的性能泛函与液压伺服系统的动态误差指标相结合,在matlab环境下编程仿真求解最优意义下的控制器。对系统响应曲线及频谱图进行分析,提出了最佳加权矩阵的一般形式,并指出了提高系统频宽的途径,为电液伺服系统提供了一种有效的优化设计方法。     

气动伺服系统同步控制实验台的研究

气动同步控制是同步控制研究领域的关键问题。本文主要以气动同步控制试验台为研究对象，对该气动系统的基本特性和气动伺服系统的双缸位置同步控制问题进行研究，提出双层滑模变结构控制同步控制策略，进行双缸位置跟踪控制的实验研究。实验结果表明，提出的新型控制方法在双缸跟踪控制精度和抗干扰能力方面都十分有效。     

应用于起重机稳钩控制的自适应神经模糊推理系统

提出一种基于自适应神经模糊推理系统（ANFIS）的控制方法应用于起重机的稳钩控制,该方法采用反向传播算法（BP）和最小二乘算法（LS）的混合算法对小车—吊重系统样本数据进行学习,调整各变量的隶属度函数,自动产生模糊规则。仿真结果表明,这种控制方法对小车—吊重系统的摇摆角度和小车位置的控制过程具有良好的动态性能和较强的鲁棒性能,说明了自适应神经模糊推理系统在起重机稳钩控制中的有效性。