Simulation Study on Dynamic Stiffness of Kick-reaction Link Actuator

Under the same aerodynamic load,the load transmitted by the kick-reaction link actuator to the aircraft structure is only 1/5 to 1/3 of that of the point-to-point actuator,which can significantly reduce the weight of the structure,and is widely used in the main flight control surface of large and medium-sized civil airliners.In order to restrain the flutter of aircraft rudder surface,it is necessary to design the servo stiffness of the kick-reaction link actuator in the development stage,so that it can meet the dynamic stiffness requirement within the frequency range.Taking the actuator of a civil airliner as the research object,the dynamic stiffness modeling of elevator actuator is carried out on MATLAB platform,and the dynamic stiffness test is carried out to verify the correctness of dynamic stiffness modeling.The simulation and test results show that the actuator can meet the dynamic stiffness design requirements.

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.

GIANT MAGNETOSTRICTIVE ACTUATOR IN SERVO VALVE AND MICRO PIPE ROBOT

Performance of giant magnetostrictive material (GMM) is introduced. Principleof work, basic structure and key techniques of giant magnetostrictive actuator (GMA) are analyzed.Its dynamic models of magneto-mechanical coupling are established. The structure and principle ofthe pneumatic servo valve and the micro pipe robot with new homemade GMM are presented. Theexperiment is carried out under typical working conditions. The experiment results show that the GMMpneumatic servo valve has wide pressure control characteristics, good linearity, and fast responsespeed. The movement principles of the GMM robot system are reliably feasible and its maximal movingspeed is about 8 mm/s. It is preferable to the driving frequency of the robot within 100 approx 300Hz.

Adaptive high precision position control of servo actuator with friction compensation using LuGre model

Adaptive control of servo actuator with nonlinear friction compensation is addressed. LuGre dynamic friction model is adopted to characterize the nonlinear friction and a new kind of slid ing mode observer is designed to estimate the internal immeasurable state of LuGre model. Based on the estimated friction state, adaptive laws are designed to identify the unknown model parameters and the external disturbances, and the system stability and asymptotic trajectory tracking perform ance are guaranteed by Lyapunov function. The position tracking performance is verified by the ex perimental results.

The Experimental Study of Micro-Tool Servo with Electrostrictive Actuator

An experimental study of micro-tool servo with electrostrictive actuator is presented.The design methods as well as the performance of the entire mechanism is given out.The results of the experiment show that the resolution of the micro-tool servo is 0.02μm and the frequency response is up to 200Hz,which satisfies the requirements of the ultra-precision machining.

INVESTIGATION ON FAULT DETECTION & DIAGNOSIS FOR POSITION SERVO SYSTEM OF AIRCRAFT ACTUATOR

A new approach to fault dignosis dealing with nonlinear system Hopfieldneural networks (HNN) is presented. The model parameters of the nonlinear systemtreated as functions of measured operating points and faults are estimated by HNN. Boththe nominal model of the healthy system and HNN training models corresponding to everyoperating point are recognized. In addition, the anticipated fault models corresponding toevery kind of fault and every operating point are obtaind in advance. The real systemmodel parameters of the system estimated by generalization process of HNN are matchedwith the nominal models of the healthy system and anticipated fault models. Consequent-ly, the final result of fault detection and diagnosis is acquired. The approach to fault diag-nosis is used in an aircraft actuating poisition servo system and the simulation resu1t is re-ported.

Design of a Servo Mechanical Press with Redundant Actuation

A servo press is a new type of mechanical press that is driven by programmable motors and offers superior performance such as low noise, excellent efficiency and high precision for metal forming operations. Similar to multi-link mechanical presses, a servo mechanical press tends to grow in size as the tonnage increases that calls for larger, heavy duty servo motors, which could be expensive and may not even be available. In this paper, a new concept of servo mechanical press with redundant actuation is proposed firstly using two servo motors driving one input shaft, i.e. one-point-two-motor mode that makes it possible to produce a larger press with available servomotors. Then the punching mechanism design is detailed. The performance indices are set up including mechanical advantage reciprocal and link force ratios. A bounded feasible solution space is constructed for dimensional synthesis based on non-dimensional link lengths and assembly conditions. The performance atlases are depicted over the bounded feasible solution space that lead to a visual solution of the punching mechanism with global optimization. Finally, case studies are given to illustrate the design method with visual global optimization, and a prototype with 200 t punching force is being developed in our laboratory to demonstrate efficacy of the new concept for servo mechanical press. The presented research provides a feasible solution to the development of heavy-duty servo mechanical presses and finds potential applications in the development of other types of heavy equipments with electric drive.

STUDY ON THE CONTROL OF SINGLE PNEUMATIC MUSCLE ACTUATOR

The control of single pneumatic muscle actuator is studied, as one basic partof research on the parallel-robot arthrosis actuated by pneumatic muscle actuators. Experimentsshow that a self-modified fuzzy-PID controller is obviously effective for its position servo and asimple PID controller is good for its force track.

Performance analysis of a pneumatic to servo converted system for electrode actuation in resistance spot welding using 304L austenitic stainless steel

A high current, AC waveform controller with C-type body frame of spot welder(75 k VA), was examined for the electrode actuating system whose pneumatically driven system has been redesigned and refitted for the servo based system without any vertical spring assistance in the 50 mm movable distance. Moreover, the pressing mechanism was carefully handled during the entire pressing tasks as to ensure that no catastrophic reaction happens for the electrodes' caps, electrodes' holders as well as the other part of mechanical assembly. With the mechanically originated-pneumatic and also the converted-servo systems, the stainless steels are welded for both systems to characterize the improvements. While the welding processes were carried out, the electrical signals have been captured to compute the signals' representation of entire sequences. Later, the welded samples were underwent the tensile shear test, metallurgical observation and hardness test. The analytical results show distinct changes in the force profiles which has led to profound changes in mechanical properties of welded specimens.

A New Approach to Improve the Matched Responses of High-Speed PWM Mode Electropneumatic Actuators

A new approach to improve the matched responses of high-speed PWM mode electro pneumatic actuators is introduced. By modifying the control signal, the matched responses are highly improved. For testing this new approach, an instrument is designed and developed. And the effectiveness of the approch is proved by experiment. The block diagram of the instrument is also presented.

Modeling and fuzzy adaptive proportion-integration-differentiation control of X-Y position servo system actuated by oscillating pneumatic cylinder

The servo system actuated by oscillating pneumatic cylinder for X-Y plate is a multi-variable nonlinear control system. Its mathematical model is established, and nonlinear factors are analyzed. Due to the existence of deadlock zone and the small damp of the pneumatic oscillating cylinder, it is likely to result in overshoot, and there is also certain steady-state error, so online modifying of proportion-integration-differentiation （PID） parameters is needed so as to achieve better control performance. Meanwhile considering the stability demand for long-term run, a fuzzy adaptive PID controller is designed. The result of hardware-inloop （HIL） test and real-time control experiment shows that the adaptive PID controller has desirable serfadaptability and robustness to external disturbance and to change of system parameters, and its control per- fonnance is better than that of traditional PID controllers.

Solenoid Actuator Design for Improvement of Response Speed

The main design factors which effect on operating speed of solenoid actuator for valve operation are mass of plunger, electromagnetic motive force, inductance and return spring, and these factors are not independent but related with each other in view point of design and electromagnetic theory. It is impossible to increase the operating speed by only change the value of any one design factor. The change of any one value results in change of any value related it in various design factors. Permanent magnets are as assistant materials which make higher flux density in air gap. Electromagnetic motive force in controlled only by current. This paper presents a speed increasing design method of solenoid actuator using a solenoid, by some governing equations which are composed of electromagnetic theory and empirical knowledge, and proved the propriety by experiments.

基于严格反馈模型的电液伺服作动器控制策略研究

主动悬架可根据车辆实时状态调节悬架参数,显著提高应急救援车辆救援效率,电液伺服作动器是电液伺服主动悬架系统实施主动控制的核心部件。对电液伺服作动器控制策略展开了研究,建立了主动悬架液压伺服作动器模型;基于该模型提出了基于严格反馈模型的自适应位置跟踪控制策略,并证明了该策略在Lyapunov意义下的稳定性。仿真和单缸实验验证表明,与传统控制方法相比,所提出的位置跟踪算法可有效提高电液伺服作动器的位置跟踪性能。

A Kind of PWM Pneumatic Servo Control System——Modulation Methods and Dynamic Responses

Vibrations or dither's are features of the PWM servo control system in their steady outputs. On the grounds of analyses and experiments of a PWM pneumatic servo control system, the paper puts forward four varieties of PWM modulation methods, and concludes on the relationship between dithers and the different methods, and then discusses the influence of friction to the dithers. Results from experiments regarding the dynamic and static responses on the given system support the theories presented.

飞机襟翼阀控伺服作动系统动态性能分析

由于阀控伺服作动系统存在的非线性因素,传统的建模方法所建立的数学模型无法准确地反映系统实际情况。为提升液压系统的控制精度及动态响应性能,解决在实际系统试验中出现的动态特性超差问题,对可能引起的因素及关键参数进行研究,重点分析引起系统静态误差的主要因素,同时分析系统各关键元件的固有频率和阻尼比对系统动态性能的影响。利用Matlab/Simulink软件对系统进行非线性建模,理论推导计算及仿真结果分析表明,较高的系统各关键元件固有频率和阻尼比有利于提高系统动态性能。

弹载永磁同步电机模糊滑模控制器设计

针对弹载永磁同步电机伺服控制系统,建立了表贴式弹载永磁同步电机矢量控制模型,设计了基于变指数趋近率的模糊滑模控制器。该方法将模糊控制思想引入滑模控制策略,通过模糊控制器动态调整滑模趋近律的相关参数,显著提升了系统的响应速度,同时有效削弱了滑模控制引起的抖振。最后,在MATLAB/Simulink平台对该方法进行了仿真。由实验结果可知,与传统的PI控制器相比,所提模糊滑模控制算法在提升系统响应速度方面具有显著优势,且展现出了较强的鲁棒性,完全能够满足系统对控制精度的严苛要求。

非最小相位法向电磁应力驱动快速刀具伺服系统轨迹跟踪控制

基于快速刀具伺服(FTS)的金刚石车削是复杂光学表面超精密制造的一种高效手段。为进一步提高具有非最小相位特征的电磁法应力驱动FTS的控制性能,将系统逆动力学补偿嵌入主控制回路中以改善被控对象动力学特征。对改善后的被控系统以比例微分积分(PID)和前馈补偿作为主控制器,并以基于内模原理的并联谐振控制器实现周期性轨迹的超高精度跟踪。考虑系统非最小相位特征,结合因子分解和镜像极点配置方法获得了系统稳定逆动力学模型。实验测试结果表明:该文所设计的控制方法,获得了1070 Hz(-3 dB)闭环带宽;100 Hz正弦轨迹实际跟踪误差小于±0.375%,并可对5 nm台阶轨迹进行稳定闭环跟踪,证明所设计的FTS控制系统可有效实现nm精度切削。

一种水压驱动机器人关节动态特性分析及优化

为减小水压机器人关节尺寸,提出了一种体积小、输出力矩大的水压驱动的转角伺服机器人关节执行器。首先根据水压转角伺服机器人关节作动器的结构和工作原理,建立了关节作动器的数学模型,推导了关节作动器的控制方程并进行了线性化处理,并建立了机器人关节执行器的AMESim模型,验证了线性化控制方程的可靠性,在此基础上根据输入角幅值、外部负载扭矩和水压对关节执行器进行优化,优化后的水压驱动机器人关节执行器具有位置跟踪精度高,动态响应快等优点。

基于非线性状态空间控制的伺服液压执行器跟踪误差仿真研究

目前,伺服液压执行器控制系统不仅响应速度慢,而且执行器运动位移跟踪精度也相对较低。对此,本文设计了非线性状态空间控制方法,并对伺服液压执行器响应速度和跟踪误差进行仿真。建立了伺服液压执行器平面简图,推导出液压执行器运动方程式。针对传统线性控制方法进行改进,利用系统的非线性状态空间模型,通过非线性反馈和坐标变换转化为线性可控系统,给出了非线性状态空间控制流程。针对不同环境条件下的信号波形,采用Matlab软件对伺服液压执行器响应速度和跟踪误差进行仿真,并且与线性控制效果进行比较。仿真结果表明:采用线性控制的伺服液压执行器,执行器响应速度慢、运动位移跟踪误差大,容易受到外界波形的干扰。采用非线性状态空间控制的伺服液压执行器,执行器响应速度快、运动位移跟踪误差较小,能够抑制外界波形的干扰。该执行器能够有效地抑制外界波形的干扰,不仅可以提高伺服液压执行器的响应速度,而且还能降低位移跟踪误差。

飞机舵面作动系统动压反馈特性分析

电液伺服作动系统是飞控系统的关键子系统,在实际工作中,存在作动系统与飞机舵面结构谐振的问题。为了研究飞机电液伺服作动系统稳定性的问题,建立了完整准确的伺服系统数学模型。在不降低系统性能的前提下,提出利用高通滤波即动压反馈的控制算法来提高伺服系统稳定性的方法。对动压反馈的补偿作用和原理进行介绍,对加入动压反馈后的系统进行数学建模,并对系统阶跃特性和频率特性进行仿真验证,结果证明动压反馈的引入没有降低系统性能,且在综合谐振处提高了系统阻尼,较好地解决了谐振问题,起到了增稳效果。电液伺服作动系统动压反馈技术的初步研究,对后续型号设计有较大应用价值。