A compound control strategy combining velocity compensation with ADRC of electro-hydraulic position servo control system

In order to enhance the anti-jamming ability of electro-hydraulic position servo control system at the same time improve the control precision of the system, a compound control strategy that combines velocity compensation with Active Disturbance Rejection Controller (ADRC) is proposed, and the working principle of the compound control strategy is given. ADRC controller is designed, and the extended state observer is used for observing internal parameters uncertainties and external disturbances, so that the disturbances of the system are suppressed effectively. Velocity compensation controller is designed and the compensation model is derived to further improve the positioning accuracy of the system and to achieve the velocity compensation without disturbance. The compound control strategy is verified by the simulation and experiment respectively, and the simulation and experimental results show that the electro-hydraulic position servo control system with ADRC controller can effectively inhibit the external disturbances, the precise positioning control is realized after introducing the velocity compensation controller, and verify that the compound control strategy is effective.     

电液位置伺服系统神经滑模控制仿真

分析了电液位置伺服控制系统的数学模型,提出利用线性化反馈技术构建滑模控制率,并应用神经网络进行参数逼近,实现了自适应神经滑模控制器的设计.仿真结果表明所设计的滑模控制器能进行有效的参数估计,有效的克服系统抖振,取得较为满意的控制品质.     

Sliding mode control with varying boundary layers for an electro-hydraulic position servo system

In this study, a new sliding mode control with varying boundary layers is proposed to improve the tracking performance of a nonlinear electro-hydraulic position servo system, which can be found in many manufacturing devices. The key feature of the proposed control scheme is the use of varying boundary layers instead of fixed boundary layers, which are usually employed in conventional sliding mode control. The validity of the proposed control scheme is verified through practical testing on an experimental electro-hydraulic positioning device. In the cases of step and sinusoidal command inputs, the experimental results strongly suggest that the proposed control scheme is capable of improving the tracking precision without causing any chattering. In addition, the new control scheme seems to be very robust against various set point conditions .     

Model-based position tracking control of a hose-connected hydraulic lifting system

High-pressure rubber hose is normally used to connect the control valves and actuators of hydraulic systems and thus lower their natural frequency. PID control is preferred in industrial hydraulic systems as it has many advantages over other controls. However, the low natural frequency of hose-connected systems limits the performance of PID control. In this paper, a hose-connected hydraulic lifting test rig is presented and the mathematical model of the system is proposed. Valve compensation strategy and hose compensation strategy are designed based respectively on the flow characteristic of the proportional valve and the mathematical model of the hose. Comparative experiments with typical desired trajectories are carried out in the test rig. Results show that both the compensation strategies are effective in improving the tracking accuracy.     

Matlab在电液速度控制系统设计中的应用

在液速度控制系统设计中引入M atlab的编程计算方法,可以实现高精度设计,容易求出不同开环增益K值下,Bode图中系统相对稳定性的幅值裕度和相位裕度及对应的穿越频率,从而简单精确地选择合理的参数,而且可以利用M atlab/S imu link对系统进行仿真,对设计结果进行检验。     

An energy-saving nonlinear position control strategy for electro-hydraulic servo systems

The electro-hydraulic servo system (EHSS) demonstrates numerous advantages in size and performance compared to other actuation methods. Oftentimes, its utilization in industrial and machinery settings is limited by its inferior efficiency. In this paper, a nonlinear backstepping control algorithm with an energy-saving approach is proposed for position control in the EHSS. To achieve improved efficiency, two control valves including a proportional directional valve (PDV) and a proportional relief valve (PRV) are used to achieve the control objectives. To design the control algorithm, the state space model equations of the system are transformed to their normal form and the control law through the PDV is designed using a backstepping approach for position tracking. Then, another nonlinear set of laws is derived to achieve energy-saving through the PRV input. This control design method, based on the normal form representation, imposes internal dynamics on the closed-loop system. The stability of the internal dynamics is analyzed in special cases of operation. Experimental results verify that both tracking and energy-saving objectives are satisfied for the closed-loop system.     

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.     

电液比例位置控制系统的仿真分析

以采煤机滚筒调高液压系统为对象,建立电液比例位置控制系统的数学模型,并通过Simulink仿真软件对PID控制器校正前、后系统的性能进行分析,结果表明校正后的系统响应速度和稳态精度得到了很大改善,在绝大部分场合可以用电液比例控制系统代替电液伺服控制系统。     

电液伺服系统的智能控制及其仿真研究

为提高电液伺服系统的控制性能。设计了一种神经网络自组织模糊控制器。即NNSOC。通过仿真实验表明,与传统的模糊控制器相比,该控制器可有效的抑制参数扰动及外力干扰,具有很强的鲁棒性。     

Acceleration tracking control combining adaptive control and off-line compensators for six-degree-of-freedom electro-hydraulic shaking tables

An electro-hydraulic shaking table (EHST) is an essential experimental facility to simulate in real-time actual vibration situations. An adaptive controller combined with off-line compensators is proposed to improve the acceleration frequency bandwidth and tracking accuracy of a six-degree-of-freedom (6-DOF) EHST. A servo controller has been employed to implement acceleration closed-loop and coordinate control of the 6-DOF EHST. A recursive extended least-squares algorithm is employed to identify acceleration closed-loop transfer functions and a zero-phase-error tracking controller is used to design off-line inverse model compensators using the identified transfer functions. However, the off-line compensators cannot compensate in real-time varying dynamics of the 6-DOF EHST; so an online adaptive controller with a least-mean-squares (LMS) algorithm based on a delay compensator is employed. The proposed controller combines advantages of the off-line compensators and the online adaptive controller, which guarantees both a fast rate of convergence of the LMS algorithm and high-fidelity acceleration tracking accuracy of the 6-DOF EHST. Some experimental studies have been conducted on a 6-DOF EHST and experimental results show that acceleration tracking control performances, including the rate of convergence of the LMS algorithm and acceleration tracking accuracy, have been improved compared to a conventional three-variable controller and adaptive controllers.     

电液位置伺服系统的计算机辅助设计

利用面向对象编程的思想对电液位置伺服系统CAD软件进行开发.该软件以中文WindowsXP为操作平台,用MicrosoftAccess建立的数据库为基础,以Autodesk公司的AutoCAD2005和MathWorks公司的Matlab7.0为支撑软件,利用VisualBasic6.0开发语言,将系统原理图绘制、参数计算、元件选取、动态仿真集成于一体.使用该软件进行电液位置伺服系统的设计,可获得工程上直接可用的系统原理图.     

光电跟踪系统自抗扰伺服控制器的设计

考虑系统扰动对光电跟踪伺服系统精度的影响,提出了采用自抗扰的控制方案,并分析了实现自抗扰的工作原理。对某型光电跟踪系统进行了结构分析,将目标运动速度视为外部扰动,系统内部参数摄动视为内部扰动,采用扩张状态观测器从系统响应的输入、输出信号中估计出扰动,并进一步用跟踪微分器提取扰动的一阶导数来提高对扰动的估计精度,以最大程度地补偿扰动。实验结果表明,在载体扰动下,跟踪最大角速度为40mrad/s,最大角加速度为8mrad/s2,机动目标的误差0.1mrad,且响应速度快,超调10%。该方案结构简单,控制鲁棒性强;无需额外的传感器对目标运动进行测量、滤波和预测,即可有效提高系统高精度捕获、跟踪快速机动目标的能力。     

Adaptive super-twisting observer for fault reconstruction in electro-hydraulic systems

An adaptive-gain super-twisting sliding mode observer is proposed for fault reconstruction in electro-hydraulic servo systems (EHSS) receiving bounded perturbations with unknown bounds. The objective is to address challenging problems in classic sliding mode observers: chattering effect, conservatism of observer gains, strong condition on the distribution of faults and uncertainties. In this paper, the proposed super-twisting sliding mode observer relaxes the condition on the distribution of uncertainties and faults, and the gain adaptation law leads to eliminate observer gain overestimation and attenuate chattering effects. After using the equivalent output-error-injection feature of sliding mode techniques, a fault reconstruction strategy is proposed. The experimental results are presented, confirming the effectiveness of the proposed adaptive super-twisting observer for precise fault reconstruction in electro-hydraulic servo systems.     

火箭炮电液伺服系统的滑模控制研究

针对在不同射角和带弹量下,火箭炮方向机以及托架的转动惯量是不断变化的问题,以及外部干扰(如冲击力矩等)也会时变的情况,将滑模型控制策略引入该电液伺服控制系统中。首先,对其电液伺服控制系统原理进行了阐述,得出了其状态方程;其次,设计了伺服控制系统的滑模控制器,克服了系统模型不精确和扰动的影响,以提高系统的抗干扰能力;最后,进行了系统的仿真。研究结果表明,与常规PID控制器相比,该控制器可以减小动态误差,增强系统的鲁棒性,而且抗扰性改善明显,满足了系统的要求。     

Hybrid finite-time trajectory tracking control of a quadrotor

In this paper, accurate trajectory tracking control problem of a quadrotor with unknown dynamics and disturbances is addressed by devising a hybrid finite-time control (HFTC) approach. An adaptive integral sliding mode (AISM) control law is proposed for altitude subsystem of the quadrotor, whereby underactuated characteristics can decoupled. Backstepping technique is further deployed to control the horizontal position subsystem. To exactly attenuate external disturbances, a finite-time disturbance observer (FDO) combining with nonsingular terminal sliding mode (NTSM) control strategy is constructed for attitude subsystem, and thereby achieve finite-time stability. Using the compounded control scheme, trajectory tracking errors can be stabilized rapidly. Simulation results and comprehensive comparisons show that the proposed HFTC scheme has remarkably superior performance.     

电液伺服控制摩托车随机疲劳试验台的研究

分析了摩托车随机疲劳试验台的基本原理与结构特点,并针对其电液伺服系统建立了一种新的疲劳模拟时域控制方法,设计了多级递阶模糊控制器来控制试验台跟踪期望输入信号,以最终实现对电液伺服系统的实时控制.最后在试验台上进行了多种规格摩托车的振动试验,试验结果证明该试验台完全满足摩托车可靠性试验要求,为摩托车零部件及整车疲劳试验提供了新的方法.     

双框架控制力矩陀螺框架系统的扰动观测及抑制

内外框架间的耦合力矩、非线性摩擦和未建模动态是影响双框架控制力矩陀螺框架系统高精度角速率伺服控制的主要因素。为提高框架系统的干扰抑制能力,保证框架系统输出角速率精度,本文提出了一种基于非线性级联扩张状态观测器和滑模控制的复合扰动抑制方法。框架系统中的所有干扰都被认为是集总干扰并由设计的NCESO估计,通过滑模控制可从系统输出通道中消除集总干扰的影响。最后,将本文提出的控制方法与线性级联扩张状态观测器和状态反馈结合的复合控制方法进行了对比仿真实验。仿真和实验结果表明,本文提出的方法具有更好的干扰抑制和动态响应性能,内框架角速度波动从0.5(°)/s减小到0.2(°)/s,外框架角速度波动从0.45(°)/s减小到0.15(°)/s;跟踪正弦参考信号时,速度跟踪误差从1.8(°)/s减小到1.2(°)/s,相位滞后从8°减小到1.3°。     

Task-space position/attitude tracking control of FAST fine tuning system

This paper addresses the task-space position/attitude tracking control of a suspended parallel robot, which is being developed in the framework of a five-hundred meter aperture spherical radio telescope (FAST) project. Based on the quaternion algebra, a novel modelindependent task-space PD controller that ensures endeffector position and attitude tracking is presented. The simulation and experimental results show that the new controller has better control effects than the traditional joint-space controller.