Pseudo Derivative Feedback Control of Electro Hydraulic Speed Servos

The Pseudo-Derivative Feedback (PDF) algorithm is introduced into design of electro-hydraulic speed servos. With limited extra complexity in implementation of controller's electronic circuits, the PDF control enables the electro-hydraulic speed servo to respond to a step command without steady-state error, and also to follow successfully a sinusoidal command at the frequency higher than that the system resulted from traditional design can reach. The numerical example-based comparison in dynamic and static behavior shows also the PDF system is superior to the traditional system in terms of both the capability of handling loads applied to the system and the robustness to ignore variation and uncertainty of the parameters of the hydraulic valve-actuator unit in operation.

无人飞行器在不确定扰动下的动态目标跟踪

This study proposes an image-based visual servoing(IBVS)method based on a velocity observer for an unmanned aerial vehicle(UAV)for tracking a dynamic target in Global Positioning System(GPS)-denied environments.The proposed method derives the simplified and decoupled image dynamics of underactuated UAVs using a constructed virtual camera and then considers the uncertainties caused by the unpredictable rotations and velocities of the dynamic target.A novel image depth model that extends the IBVS method to track a rotating target with arbitrary orientations is proposed.The depth model ensures image feature accuracy and image trajectory smoothness in rotating target tracking.The relative velocities of the UAV and the dynamic target are estimated using the proposed velocity observer.Thanks to the velocity observer,translational velocity measurements are not required,and the control chatter caused by noise-containing measurements is mitigated.An integral-based filter is proposed to compensate for unpredictable environmental disturbances in order to improve the antidisturbance ability.The stability of the velocity observer and IBVS controller is analyzed using the Lyapunov method.Comparative simulations and multistage experiments are conducted to illustrate the tracking stability,anti-disturbance ability,and tracking robustness of the proposed method with a dynamic rotating target.

Adaptive Robust Servo Control for Vertical Electric Stabilization System of Tank and Experimental Validation

A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevarying but bounded uncertainty within the vertical electric stabilization system:model parameter uncertainty and uncertain nonlinearity.First,the vertical electric stabilization system is constructed as an uncertain nonlinear dynamic system that can reflect the practical mechanics transfer process of the system.Second,the dynamical equation in the form of state space is established by designing the angular tracking error.Third,the comprehensive parameter of system uncertainty is designed to estimate the most conservative effects of uncertainty.Finally,an adaptive robust servo control which can effectively handle the combined effects of complex nonlinearity and uncertainty is proposed.The feasibility of the proposed control strategy under the practical physical condition is validated through the tests on the experimental platform.This paper pioneers the introduction of the internal nonlinearity and uncertainty of the vertical electric stabilization system into the settlement of the tracking stability control problem,and validates the advanced servo control strategy through experiment for the first time.

Manipulator tracking technology based on FSRUKF

Aiming at the shortcoming that the traditional industrial manipulator using off-line programming cannot change along with the change of external environment,the key technologies such as machine vision and manipulator control are studied,and a complete manipulator vision tracking system is designed.Firstly,Denavit-Hartenberg(D-H)parameters method is used to construct the model of the manipulator and analyze the forward and inverse kinematics equations of the manipulator.At the same time,a binocular camera is used to obtain the threedimensional position of the target.Secondly,in order to make the manipulator track the target more accurately,the fuzzy adaptive square root unscented Kalman filter(FSRUKF)is proposed to estimate the target state.Finally,the manipulator tracking system is built by using the position-based visual servo.The simulation experiments show that FSRUKF converges faster and with less error than the square root unscented Kalman filter(SRUKF),which meets the application requirements of the manipulator tracking system,and basically meets the application requirements of the manipulator tracking system in the practical experiments.

Research and Application of"Soft"Devices for Realizing Servo Amplification

This article analyzes and discusses the working principle and problems encountered by various servo amplification devices used in the on-site continuous adjustment system,analyzes and discusses the application of the servo mechanism,and analyzes the mechanism of the servo device's implementation of the"positioning"func-tion on the control device.Intended to guide the continuous adjustment process in controlling the function/accuracy of actuator equipment and application debugging,ensuring the safe and stable operation of production equipment and facilities.

Backstepping Sliding Mode Control Based on Extended State Observer for Hydraulic Servo System

Hydraulic servo system plays an important role in industrial fields due to the advantages of high response,small size-to-power ratio and large driving force.However,inherent nonlinear behaviors and modeling uncertainties are the main obstacles for hydraulic servo system to achieve high tracking perfor-mance.To deal with these difficulties,this paper presents a backstepping sliding mode controller to improve the dynamic tracking performance and anti-interfer-ence ability.For this purpose,the nonlinear dynamic model is firstly established,where the nonlinear behaviors and modeling uncertainties are lumped as one term.Then,the extended state observer is introduced to estimate the lumped distur-bance.The system stability is proved by using the Lyapunov stability theorem.Finally,comparative simulation and experimental are conducted on a hydraulic servo system platform to verify the efficiency of the proposed control scheme.

Output feedback control and parameters influence analysis of active suspension electro-hydraulic servo actuator

The hydraulic servo actuator of heavy vehicle active suspension is investigated to clarify the correlation between system parameters and the control characteristics of active suspension hydraulic servo system.Accordingly, a nonlinear physical model of electro-hydraulic servo active suspension system is built.Compared with the conventional nonlinear modeling, the model in this study considers the asymmetry of working areas caused by single rod hydraulic cylinder in the suspension system.In accordance with the model, a nonlinear output feedback controller based on backstepping is designed, and the effectiveness of the controller is proved based on the experimental platform.The dynamic response curve of the electro-hydraulic servo control system under the change of parameters is generated based on the simulation model.The sensitivity of electro-hydraulic servo control performance to the change of system physical parameters is investigated, and two evaluation indexes are proposed to quantify and compare the effect of all physical parameter changes on position control system.As revealed by the results, the position control characteristics of suspension actuator are more sensitive to the changes of flow gain of the servo valve, system supply oil pressure and effective working areas of cylinder, and the two evaluation indexes are over 10 times higher than other physical parameters.

Design and Implementation of Paired Pectoral Fins Locomotion of Labriform Fish Applied to a Fish Robot

In present,there are increasing interests in the research on mechanical and control system of underwater vehicles.These ongoing research efforts are motivated by more pervasive applications of such vehicles including seabed oil and gas explorations, scientific deep ocean surveys,military purposes,ecological and water environmental studies,and also entertainments. However,the performance of underwater vehicles with screw type propellers is not prospective in terms of its efficiency and maneuverability.The main weaknesses of this kind of propellers are the production of vortices and sudden generation of thrust forces which make the control of the position and motion difficult. On the other hand,fishes and other aquatic animals are efficient swimmers,posses high maneuverability,are able to follow trajectories,can efficiently stabilize themselves in currents and surges,create less wakes than currently used underwater vehicle, and also have a noiseless propulsion.The fish's locomotion mechanism is mainly controlled by its caudal fin and paired pectoral fins.They are classified into Body and/or Caudal Fin(BCF)and Median and/or paired Pectoral Fins(MPF).The study of highly efficient swimming mechanisms of fish can inspire a better underwater vehicles thruster design and its mechanism. There are few studies on underwater vehicles or fish robots using paired pectoral fins as thruster.The work presented in this paper represents a contribution in this area covering study,design and implementation of locomotion mechanisms of paired pectoral fins in a fish robot.The performance and viability of the biomimetic method for underwater vehicles are highlighted through in-water experiment of a robotic fish.

基于VB6.0&ServoWorks SDK的全软型四轴联动数控系统研究与开发

ServoWorks是一种基于PC解决方案的全软件开放式CNC系统,它所有的功能均由软件实现。通过对ServoWorks CNC系统硬件结构和软件结构的分析,依据Soft Servo System公司提供的SDK开发包在VB6.0上进行软件的二次开发,开发出了全软型四轴联动数控系统,并在实验平台上进行了软件的调试运行试验,实现了预期的目标。

Servo^i/Servo^s呼吸机的维护及常见故障处理

随着社会的发展,智能化呼吸机的应用范围也越来越广泛,而Servo^i/Servo^s呼吸机作为西门子公司研发的最新一代中的高端呼吸机,在临床各科室的医疗实践活动中,发挥着重要的作用。本文主要从Servo^i/Servo^s呼吸机的日常维护和常见故障的处理,两个方面进行分析,希望能对实际操作提供帮助。

一种伺服优化方法在模具曲面加工中的应用

为了解决模具零件曲面加工中因机床振动引起的零件加工表面过切,表面质量不佳的问题,文中在不改变机床机械性能和零件加工工艺的基础上,提出一种基于FANUC SERVO GUIDE的伺服优化方法。该方法通过对机床机械性能测试,针对测试结果从伺服系统电流环、速度环和位置环控制参数进行逐级优化与反复调试,实现机床机电系统高度匹配,有效降低机床振动。应用优化结果对某模具零件的曲面加工进行试验验证,达到产品的技术指标要求。

基于ServoWorks CNC的全软型PLC系统研究

ServoWorks CNC中采用了软PLC控制机床的运动。通过对ServoWorks CNC中软PLC系统功能的分析,结合编制的宏程序,开发出了旋转刀库的自动换刀系统,并在实验平台上进行了程序的调试运行试验,实现了预期的目标。

医科达Precise医用直线加速器故障检修

本文介绍了Precise医用直线加速器出束系统中AFC、GUNSERVO具体设置方法 ,以及如何根据联锁指示检修故障 ,快速排除故障。

FANUC数控铣床的参数调试

FANUC SERVO GUIDE是伺服和主轴的调整工具,其具有参数窗口、程序窗口和图形窗口,很容易检测出机床的误差和伺服调试的状态。以一台机床为例,介绍利用SERVO GUIDE进行机床参数调试的过程,并与手工调试进行比较,说明自动调试更有利于实现机床性能的最优化。

交流永磁伺服系统技术讲座 第一讲 伺服技术的基本概念

一'伺服'的由来 '伺服'一词系英语单词'servo'的音译和意译的结合,它来源于拉丁语 servus,意为奴隶、仆人;汉语中的'伺' 有侍奉、'服'为服从之意,合起来'伺服'一词的汉语与英语的意义也是相同的。

PID Controller Optimization by GA and Its Performances on the Electro-hydraulic Servo Control System

A proportional integral derivative （PID） controller is designed and attached to electro-hydraulic servo actuator system （EHSAS） to control the angular position of the rotary actuator which control the movable surface of space vehicles. The PID gain parameters are optimized by the genetic algorithm （GA）. The controller is verified on the new state-space model of servo-valves attached to the physical rotary actuator by SIMULINK program. The controller and the state-space model are verified experimentally. Simulation and experimental results verify the effectiveness of the PID controller adaptive by GA to control the angular position of the rotary actuator as compared with the classical PID controller and the compensator controller.

Development of PLC-based Tension Control System

Fiber winding tension is an important factor in the molding techniques of composite material which influences the quality of winding product directly, and the tension control is a key technique in fiber winding techniques. This paper introduces a closed-loop tension control system with the programmable logic controller （PLC） with function modules as its control kernel, the alternating current （AC） servo motor as execute element and the radius-following device to accomplish the real-time radius compensation. The mechanism of the tension control system is analyzed and the numerical model is set up. The compensation technique of the radius of the scroll is analyzed. Experimental results show that the system is well qualified with high control precision and high reaction speed.

Numerical Simulation and Experimental Study of Heat-fluid-solid Coupling of Double Flapper-nozzle Servo Valve

The double flapper-nozzle servo valve is widely used to launch and guide the equipment. Due to the large instantaneous flow rate of servo valve working under specific operating conditions, the temperature of servo valve would reach 120℃ and the valve core and valve sleeve deform in a short amount of time. So the control precision of servo valve significantly decreases and the clamping stagnation phenomenon of valve core appears. In order to solve the problem of degraded control accuracy and clamping stagnation of servo valve under large temperature difference circumstance, the numerical simulation of heat-fluid-solid coupling by using finite element method is done. The simulation result shows that zero position leakage of servo valve is basically impacted by oil temperature and change of fit clearance. The clamping stagnation is caused by warpage-deformation and fit clearance reduction of the valve core and valve sleeve. The distribution roles of the temperature and thermal-deformation of shell, valve core and valve sleeve and the pressure, velocity and temperature field of flow channel are also analyzed. Zero position leakage and electromagnet＇s current when valve core moves in full-stroke are tested using Electro-hydraulic Servo-valve Characteristic Test-bed of an aerospace sciences and technology corporation. The experimental results show that the change law of experimental current at different oil temperatures is roughly identical to simulation current. The current curve of the electromagnet is smooth when oil temperature is below 80℃, but the amplitude of current significantly increases and the hairy appears when oil temperature is above 80℃. The current becomes smooth again after the warped valve core and valve sleeve are reground. It indicates that clamping stagnation is caused by warpage-deformation and fit clearance reduction of valve core and valve sleeve. This paper simulates and tests the heat-fluid-solid coupling of double flapper-nozzle servo valve, and the obtained results provide the reference value for the design of double flapper-nozzle force feedback servo valve.

Sliding Mode Controller Design for Position and Speed Control of Flight Simulator Servo System with Large Friction

Flight simulator is an important device and a typical high-performance position and speed servo system used in the hardware-in-the-loop simulation of flight control system. Friction is the main nonlinear resistance in the flight simulator servo system, especially in a low-speed state. Based on the description of dynamic and static models of a nonlinear Stribeck friction model, this paper puts forward sliding mode controller to overcome the friction, whose stability is

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 performance, as compared with some existing methods. results show that the designed controller can achieve better tracking