共查询到20条相似文献,搜索用时 46 毫秒
1.
为了提高水力发电机组过渡动态性能,利用模糊控制理论设计了基于分数阶的模糊分数阶控制器,并将其应用于水轮机调速系统,利用PSO优化算法对控制器的参数进行优化.与常规PID控制器进行对比实验,实验结果表明,模糊分数阶控制比传统PID控制具有更好的动态性能,对于水轮机转速调节是一种有效的控制手段. 相似文献
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EPS用机械转向器是实现汽车转向的主要部件之一,为保证车辆的安全性,需要了解其耐冲击性能。机械转向器冲击试验台主要用于对机械转向器的冲击试验。文中针对试验台的阀控非对称缸电液力控制系统进行了研究。通过对控制系统的各个环节的分析,建立各环节的数学模型。进而得到以力为控制量的电液伺服系统数学模型,并利用Simulink仿真平台对系统进行频域和时域分析。分析结果表明,试验台液压系统闭环稳定,满足性能要求。 相似文献
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《Mechatronics》2015
In this paper, an analytical method for tuning the parameters of the set-point weighted fractional order PID (SWFOPID) controller is proposed. The studied control scheme is the filtered fractional set-point weighted (FFSW) structure. Also to achieve a desired closed-loop performance, a fractional order pre-filter is employed. The proposed method is applicable to stable plants describable by a simple three-parameter fractional order model. Such a model can be considered as the fractional order counterpart of a first order transfer function without time delay. Finally, the proposed method is implemented on a laboratory scale CE 150 helicopter platform and the results are compared with those of applying a filtered fractional order PI (FFOPI) controller in a similar structure. The practical results show the effectiveness of the proposed method. 相似文献
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Swapnil Khubalkar Amit Chopade Anjali Junghare Mohan Aware Shantanu Das 《Circuits, Systems, and Signal Processing》2016,35(6):2189-2211
The aim of paper is to employ digital fractional order proportional integral derivative (FO-PID) controller for speed control of buck converter fed DC motor. Optimal pole-zero approximation method in discrete form is proposed for realization of digital fractional order controller. The stand-alone controller is implemented on embedded platform using digital signal processor TMS320F28027. The five tuning parameters of controller enhance the performance of control scheme. For tuning of the controller parameters, dynamic particle swarm optimization technique is employed. The proposed control scheme is simulated on MATLAB and verified by experimental results. Performance comparison shows better speed control of separately excited DC motor with the realized digital FO-PID controller than that of the integer order PID controller. 相似文献
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This paper studies the identification and the real-time control of an electrohydraulic servo system. The control strategy is based on the nonlinear backstepping approach. Emphasis is essentially on the tuning parameters effect and on how it influences the dynamic behavior of the errors. While the backstepping control ensures the global asymptotic stability of the system, the tuning parameters of the controller, nonetheless, do greatly affect the saturation and chattering in the control signal, and consequently, the dynamic errors. In fact, electrohydraulic systems are known to be highly nonlinear and non-differentiable due to many factors, such as leakage, friction, and especially, the fluid flow expression through the servo valve. These nonlinear terms appear in the closed loop dynamic errors. Their values are so large that in the presence of a poor design, they can easily overwhelm the effect of the controller parameters. Backstepping is used here because it is a powerful and robust nonlinear strategy. The experimental results are compared to those obtained with a real-time proportional-integral-derivative (PID) controller, to prove that classic linear controllers fail to achieve a good tracking of the desired output, especially, when the hydraulic actuator operates at the maximum load. Before going through the controller design, the system parameters are identified. Despite the nonlinearity of the system, identification is based on the recursive least squares method. This is done by rewriting the mathematical model of the system in a linear in parameters (LP) form. Finally, the experimental results will show the effectiveness of the proposed approach in terms of guaranteed stability and zero tracking error 相似文献
6.
Lian-min Cao Shi-jiao Sun Ya-zhu Zhang Hui Guo Zhen Zhang 《Wireless Personal Communications》2018,102(4):2667-2680
This paper researches the electro hydraulic control system of two-column shield hydraulic supports, takes the hydraulic support base advancing loop as the position servo control system, and studies its dynamic characteristics. It establishes the power amplifier, position sensor, hydraulic cylinder and loading mathematical model of the position servo control system, determines the model parameters of the advancing control system according to the shield hydraulic support used in the 1315 working face of GuoTun coal mine, and derives the opening loop transfer function of the valve controlled advancing cylinder. This paper also analyzes the stability of the control system of the advancing loop with the modern design method, and verifies the stability of the electro-hydraulic control system loop according to the simulation curve and the stability. By comparing with the valve core displacement and system flow curve while the system opening or closing, this paper explains the application effect of servo control system. It provides a new research idea and method for the study of the overall stability and effectively reduces the failure rate of electro-hydraulic control system of the hydraulic support. It also plays practical significance and value to improve the mining efficiency of the coal mining face. 相似文献
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Hydraulic systems play an important role in modern industry for the reason that hydraulic actuator systems have many advantages over other technologies with electric motors, as they possess high durability and the ability to produce large forces at high speeds. Therefore, the hydraulic actuator has a wide range of application fields such as hydraulic punching, riveting, pressing machines, and molding technology, where controlled forces or pressures with high accuracy and fast response are the most significant demands. Consequently, many hybrid actuator models have been developed for studying how to control forces or pressures with best results.This paper presents a kind of hydraulic load simulator for conducting performance and stability testing related to the force control problem of hydraulic hybrid systems. In the dynamic loading process, perturbation decreases control performance such as stability, frequency response, and loading sensitivity decreasing or bad. In order to improve the control quality of the loading system while eliminating or reducing the disturbance, a grey prediction model combined with a fuzzy PID controller is suggested. Furthermore, fuzzy controllers and a tuning algorithm are used to change the grey step size in order to improve the control quality. The grey prediction compensator can improve the system settle time and overshoot problems. Simulations and experiments on the hydraulic load simulator are carried out to evaluate the effectiveness of the proposed control method when applied to hydraulic systems with various external disturbances encountered in real working conditions. 相似文献
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Eva-Henrietta Dulf Cristina-Ioana Pop Francisc-Vasile Dulf 《Signal, Image and Video Processing》2012,6(3):479-485
Controller design for an isotope separation column is recognized as a difficult and challenging problem. The dynamics of the isotope separation process is difficult to model precisely using integer order transfer functions; thus, a fractional order approach is preferred. The objective of this work is to design two different PI controllers??a classical one and a fractional order one??and test their closed loop performance under nominal conditions as well as gain uncertainties. Since the process is represented by a fractional order mathematical model, the simplest approach to design both controllers is based on a frequency specification. For the fractional order of the PI controller and its parameters, the authors solve a system of equations that includes a robust performance specification to gain uncertainties. For the classical PI controller, a traditional tuning algorithm based on phase margin specification is implemented. The simulation results show that both controllers meet the design specifications, with the fractional order PI controller behaving more robustly to plant gain variations. 相似文献
11.
《Mechatronics》2021
To solve the problem of the control accuracy in electrohydraulic loading systems caused by load increment, this paper proposes a multi-cylinder electrohydraulic digital loading (MEDL) technology for accurate reproduction of large load. A traditionally used single cylinder loading (SCL) is replaced by a new hydraulic cylinders group that includes N hydraulic cylinders at each point, in which one is controlled by the electrohydraulic servo valve and the others (N-1) are controlled by the on-off valve. The areas of the on-off valve controlled (OVC) cylinders form an increasing geometric sequence with a common ratio of 2. In addition, the force of the servo valve controlled (SVC) cylinder can be regulated continuously, and the OVC cylinders have only two states of no force or maximum force. There should be no force tracking error caused by nonlinear factors for the OVC cylinders. Thus, a continuous accurate large loading can be achieved by changing the working area of the cylinders group. Moreover, an improved full closed-loop (FCL) control strategy is proposed to solve the load reverse sudden change caused by the asynchronous opening and closing of the servo valve and on-off valve. With a case of N = 4 for MEDL, AMESim simulation results illustrated that the tracking error of the 4-cylinder group was about 1/6 of the single cylinder under a case of 40 kN. Furthermore, extensive experiments conducted on a real full loading bench under the FCL control method indicated that compared with SCL, the tracking error of the 4-cylinder group with a multi-step signal and various-frequency sinusoidal signals were reduced by 73% and 46%, respectively. Both simulation and experimental results proved that the proposed MEDL technology improved the loading accuracy and optimized the dynamic performance of the system. 相似文献
12.
Automated onboard modeling of cartridge valve flow mapping 总被引:1,自引:0,他引:1
Song Liu Bin Yao 《Mechatronics, IEEE/ASME Transactions on》2006,11(4):381-388
Proportional poppet-type cartridge valves are the key elements of the energy-saving programmable valves, which have been shown to be able to achieve good motion control performance while significantly saving energy usage in our previous studies. Unlike costly conventional four-way valves, the cartridge valve has a simple structure and is easy to manufacture, but the complicated mathematical model of its flow mapping makes the controller design and implementation rather difficult. Although off-line individually calibrated or manufacturer supplied flow mappings of the cartridge valves can be used, neither method is ideal for wide industrial applications. The former method is time-consuming and needs additional flow sensors while the latter may lead to significantly degraded control performance due to the inaccuracy of the manufacturer supplied flow mappings. Furthermore, due to inevitable system worn out and/or changing working conditions, actual cartridge valve flow mapping may change significantly over the life span of the system and need to be updated periodically in order to maintain the same level of control performance. Sometime, it may be even impractical to do off-line calibrations once the valve leaves the manufacturing plant. To solve this practically significant problem, this paper focuses on the automated onboard modeling of the cartridge valve flow mappings without using any extra sensors and removing the valves from the system. The estimation of flow mappings is based on the pressure dynamics of the hydraulic cylinder with the consideration of effects of some unknown system parameters such as the effective bulk modulus of the working fluid. Localized orthogonal basis functions are proposed to bypass the lack of persistent exciting identification data over the entire domain of the flow mapping during onboard experiments. Experimental results are obtained to illustrate the effectiveness and practicality of the proposed novel automated modeling method. 相似文献
13.
This paper proposes a relay-based performance-improving method for servo mechanism systems. The method first utilizes a relay-based feedback technique to identify the model parameters and the Coulomb friction value. Then, based on the identified results, a control algorithm, which consists of a feedforward controller, a time-delay compensator and a sliding mode controller, is designed. The feedforward controller and the time-delay compensator are used to compensate the system dynamics and the external disturbances respectively. Their parameters are decided directly according to the identified values. The sliding mode controller is to stabilize the system, two of whose parameters are one-to-one mapping to the closed-loop characteristic roots. Thus, this method avoids the complicated parameters tuning process, which is attractive in practice to the control engineers. Experimental studies on a linear-motor-driven table illustrate that the proposed method is capable of improving the servo performance greatly and canceling the external disturbances effectively. 相似文献
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Khoshzaban Zavarehi M. Lawrence P.D. Sassani F. 《Mechatronics, IEEE/ASME Transactions on》1999,4(3):324-334
Solenoid-controlled pilot-operated servovalves are flow control devices widely used to drive high-flow hydraulic actuators in heavy-duty off-highway machinery. In these applications, a spool-operated pilot stage is required to account for large flow force in the main hydraulic valve. Design optimization, performance improvement, and fault diagnosis of such complex two-stage servovalves often require sophisticated analytical models with accurate physical parameters. The paper presents a step-by-step methodology for nonlinear modeling, parameter determination, model validation, and performance evaluation of solenoid-controlled pilot-operated spool valves. The proposed model takes into account such nonlinearities as pilot spool dead band, spool friction, flow coefficient variability, and leakage. This new model is complete in the sense that all nonlinear interactions between various electromechanical elements have been incorporated in a compact yet comprehensive model. The simulation model accepts a command voltage to the solenoids as input and gives the second stage spool displacement as output. To obtain the physical parameters used in the valve model, a systematic approach is proposed based on state measurement and curve-fitting techniques. The identified parameters of an example valve were used in simulations both to validate the nonlinear valve model and also to assess the valve's performance when certain valve parameters change 相似文献
15.
The batching system of the integrated mixing and spreading equipment for MOH material is a nonlinear system with large uncertainty. It is difficult for conventional control strategies to meet the requirements for system performance. This research combines generalized predictive control and active disturbance rejection technique to propose a new generalized predictive active disturbance rejection controller (GPADRC) used in the batching system of MOH material. For the nonlinearity and uncertainty of the batching system, the extended state observer in the active disturbance rejection technique is used for estimation and compensation. The batching system model is converted into an integrator form, based on which the use of generalized predictive control can greatly reduce the impact of nonlinear models and uncertainties on the controller. Aiming at the problem that the parameters of the proposed new controller are numerous and difficult to tune, the adaptive genetic algorithm is used to realize the automatic tuning of the parameters. The simulation experiment shows that the designed GPADRC can well adapt to the working conditions of the batching system and can meet the requirements for various control indicators. At the same time, the adaptive genetic algorithm can realize the rapid tuning of the controller parameters, which reduce the difficulty and time consumption of the tuning process, and improve the applicability and achievability of the designed controller. 相似文献
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基于ATmega16L的电液伺服控制系统设计 总被引:2,自引:2,他引:0
针对电液伺服闭环控制过程中,设定信号不断发生变化,电液阀门位置定位精确度较低的难题.采用AT-mega16L作为核心控制器,并配有高精度A/D、D/A转换器,通过对阀门开度控制信号和位置反馈信号进行采集、转换、计算和比较,发出控制信号决定并执行换向阀的换向、交流伺服电动机的起停运转,推动液压缸推杆的伸缩,进而对阀门转角大小、开度百分比进行精确定位. 相似文献
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结合变结构控制、自适应控制和模糊技术等特点,提出一种自适应模糊变结构控制方法.首先,设计一个带积分开关平面函数的变结构控制器,并构造一个二维模糊边界层宽度调节器以削弱抖振.其次,基于Lyapunov稳定性理论,引入一自适应算法,自适应调节变结构控制参数.应用于液压伺服系统的控制实验结果表明,所提出的控制方法能削弱抖振,改善液压伺服系统稳态控制精度,具有较强的鲁棒自适应综合性能. 相似文献
20.
Mohammad Saleh Tavazoei Mohammad Haeri Saeid Jafari 《Circuits, Systems, and Signal Processing》2009,28(5):625-647
A simple fractional differentiator-based controller is proposed to suppress chaos in a 3D single input chaotic system by stabilizing
some of the fixed points. The tuning procedure for the proposed controller is based on the stability concepts in the incommensurate
fractional order systems. To show the efficiency of the controller, some numerical simulations are given. Also, to evaluate
the practical capability of the proposed controller, we experimentally apply it to control chaos in a chaotic circuit. Moreover,
some mathematical analyses are presented to show the applicability of the proposed controller, when its structure is not exactly
implementable. 相似文献