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Hydraulic servo actuator always suffers from various disturbance and uncertainties, which makes it difficult to design a higher performance controller. In this paper, an integral nonsingular terminal sliding mode controller based on extended state observer (ESO-INTSM) is proposed to improve the robust performance of hydraulic servo actuator. The ESO is designed to estimate not only the parametric uncertainties but also the model disturbance. Based on the observed states of ESO, the proposed controllers could enable hydraulic servo actuator to track the desired motion trajectories. The stability of the synthesized controller is proved via Lyapunov analysis, which is very important for high-accuracy tracking control of hydraulic servo actuator. Simulation and experimental results demonstrate that the proposed control strategy can effectively attenuate the adverse influence caused by the uncertainties and apparently improve the tracking accuracy.

An electrohydraulic servo actuator is used as an example to show how numerical data on the parameters of the components and assembly units supplied to the assembly section allow control of the assembly process, its qualitative transformation, and refinement of the characteristics of finished products. The described approach to the arrangement of the assembly process may be applied to any product both to ensure that nondefective items are assembled in manufacturing components with apparently extended parameter tolerance ranges and to enhance the characteristics and reduce labor input in the adjustment of products.

This paper proposes the use of the integral sliding mode control (ISMC) based on the barrier function to control the servo actuator system with friction. Based on the barrier function, the main features of the ISMC design were preserved, additionally, the proposed control design is done without the need to know the bound on the system model uncertainty, accordingly, the overestimation of the control gain doesn’t take place and the chattering is eliminated. Moreover, the steady-state error can be adjusted via selecting the barrier function parameter only. The simulation results demonstrate the performance of the proposed ISMC based on the barrier function where the system angle successfully follows the desired angular position with a small pre-adjusted steady-state error. Additionally, the obtained results clarify superior features compared with a traditional ISMC designed to the same actuator.

The technical, economic, and performance indicators of hydromechanical servo actuators with throttle control (HMSA/T) can be radically improved by structurally correcting the actuator initial configuration followed by parametrically optimizing the found solution. The conventional solution boils down to an analysis of partial correction problems. However, this adds difficulty to comparison of the results and entails a significant scope of refinement and adjustment works. The article presents a unified algorithm for settling matters concerned with structural and parametric correction of an HMSA/T as applied to the most efficient ways of changing the actuator initial structure: damping the hydraulic amplifier sliding valve and introducing additional feedbacks for the output section motion speed and derivative of pressure difference in the hydraulic amplifier outlet hydraulic lines. An integrated HMSA/T model is constructed on the basis of standard structural correction schemes and partial mathematical models of actuators, and the scheme of an algorithm for combined structural and parametric correction of the actuator is presented. It is shown that the algorithm can be implemented using limited computation resources with a quickly running application software.

A hydraulic servo actuator with passive compliance (HPCA) is designed for hydraulic actuated quadruped robots, aiming to solve the response discrepancy of the low-bandwidth servo valve to impact forces between robot's feet and the ground. This paper focuses on the performance of this passive compliance method combined with an active compliance control strategy when used on quadruped robots. First, the frequency-response characteristics of the HPCA are further discussed. Then, combined with the requirements of the quadruped robot, a compliant method characterized by incorporating dynamic feedforward control and joint angle feedback control items into the virtual model is proposed. Finally, both the new algorithm and the performance of the HPCA are verified by simulation and experiment. The results demonstrate that, compared with the original actuator, the frequency-response characteristics of the HPCA have better adaptability for the quadruped robot, while the efficiency of the active compliance control is also improved by this novel passive compliance strategy.

This paper designs and analyzes a drive module suitable for a certain integrated integrated design servo actuator. According to the limited installation space of the product, the combined miniaturization design is carried out, and relevant simulation analysis and experimental research are carried out to guide the The design of similar products has certain guiding significance.

Actuator performance is an important factor limiting the dynamic characteristics of the robot. In this paper, the energy transfer capability of the hydraulic servo actuator is improved by adding a miniature accumulator. We established the dynamic model of the system and obtained the optimal inflation pressure of the gas in the accumulator by numerical method. Both numerical analysis and virtual prototype simulation show this design can enlarge the work of the actuator to about 1.66 times the original. It allows the actuator to maintain high performance while reducing mass and volume.

This paper analyzes the vibration signals of aerospace servo actuator and studies their applications. In the signal pre-processing, an adaptive filter based on genetic algorithm is added to improve the signal-to-noise ratio. Time domain analysis is used to monitor the vibration signals and determine the main vibration directions. Frequency domain analysis is used to extract the main vibration frequencies and perform preliminary fault analysis. The WT method with optional window function is used for time-frequency analysis, which can describe the relationship between vibration signal frequency and time, and decompose the signal characteristics required for the analysis. In the research, LabVIEW and MATLAB are used for data processing and analysis. The research lays the foundation of aerospace servo actuator vibration signal analysis and processing system.

В статье показана важность реализации законов движения, основные требования, которые необходимо выполнить для стабильной работы мехатронного устройства, а также частые проблемы, возникающие при программировании движения ведущего звена. Рассмотрены вопросы, связанные с прохождением отдельных звеньев механической системы, особых положений их движения, в которых происходят скачки или резкие изменения скорости. Предложена методика написания программ для реализации законов движения с указанием основных этапов, которые необходимо сделать для реализации законов движения, таких как расчет математической модели, определение структуры программы и определение необходимых элементов программного кода. Реализован закон движения на универсальном программируемом логическом контроллере, представлен программный код, написанный на языке МЭК, и представлен графический результат работы программы управления., The article demonstrates the importance of implementing the laws of motion, the basic requirements that should be met to guarantee stable performance of the mechatronic device, and frequently encountered problems involved in the process of programming the driving link motion. Issues related to the transit of separate links of the mechanical system and their specific driving positions, in which velocity jumps and sudden velocity changes appear, are considered. The programming technique for implementing the laws of motion is suggested: it includes the main stages necessary for implementing the laws of motion, such as calculation of the mathematical model, establishment of the programme structure, and identification of the necessary programme code elements. Results include the realization of a law of motion on the universal programmable logic controller, the programme code written on the IEC language, and the graphically depict performance of the management programme., №8 (2019)

In order to solve the seal problem both the cylinder chamber of the servo actuator in a severe environment, a new hydraulic lock was designed by applying new composite material PEEK and valve injection technology in this paper. The life test and the seal effect of that were carried out. The results implied that the cylinder chamber of the servo actuator was locked in any position. And the hydraulic lock has been applied on the launch vehicle successfully.

A new motor-driven lever-based servo actuator is proposed for automatic manipulation of dry clutches. The dynamic model considering the negative stiffness of the diaphragm spring is built. The characteristics of torque-saving and power-saving are analyzed. Moreover, the stability addressing the negative stiffness is analyzed. The simulation results are verified by the experimental results. The results from quasi-steady experiments show the proposed actuator reduces the motor torque up to 23.9%, the motor power loss up to 38.7%, and the motor output power up to 21.9% compared to the ordinary lever-based actuator. As a whole, the energy consumption during a usual clutch engagement is reduced by 30.1%. In addition, the proposed actuator can track the desired displacement well under the negative stiffness case, and thus overcomes the weakness of the “Luk-like” actuator.

점적률 Key Words: Servo Actuator(서보 액추에이터), Response Characteristic(응답 특성), Design Parameter(설계 파라미터), FEM Analysis(유한요소 해석), Performance Test(성능 시험) 초록: 유압밸브 구동용 서보 액추에이터는 항공기, 자동차의 유압시스템 그리고 산업용 유압시스템의 정밀한 작동에 중요한 장치이다. 서보 액추에이터의 신뢰성 있는 동작은 전체 유압시스템의 정밀한 제어에 큰 영향을 미친다. 서보 액추에이터의 주파수 응답특성, 스텝 응답특성과 같은 응답특성은 액추에이터의 성능을 판단하는 중요한 기준이 된다. 본 논문에서는 신뢰성해석을 통해 신뢰성 있는 동작과 응답특성을 만족시키기 위한 구성 부품에 대한 분석을 실시하였다. 또한 신뢰성 있는 동작과 빠른 응답성을 구현하기 위해 현장의 경험적 지식과 문헌 및 전문가의 전자기 이론을 통해 유압밸브 구동용 서보 액추에이터의 설계 파라미터를 도출하였다. 보빈, 요크, 플런저의 설계값, 그리고 코일의 감긴 수와 같은 서보 액추에이터의 설계값들을 결정하는 설계 파라미터를 제안하고, 설계방정식을 통해 산출한 설계값을 유한요소해석을 통해 타당성을 검증하였다. 또한 서보 액추에이터가 장착된 유압밸브의 성능시험을 통해 제안한 설계 방안의 타당성을 검증하였다. Abstract: The precision hydraulic valve is widely used in various industrial field like aircraft, automobile, and general machinery. Servo actuator is the most important device for driving the precise hydraulic valve. The reliable operation of servo actuator effects on the overall hydraulic system. The performance of servo actuator relies on frequency response and step response according to arbitrary input signal. In this paper, we performed the analysis for the components of servo actuator to satisfy the reliable operation and response characteristics through the reliability analysis, and also induced the design parameters to realize the reliable operation and fast response characteristics of servo actuator for hydraulic valve operation through the empirical knowledge of experts and electromagnetic theories. We suggested the design equations to determine the values of design parameters of servo actuator as like bobbin size, length of yoke and plunger and turn number of coil, and verified the achieved design values through FEM analysis and performance tests using some prototypes of servo actuators adapted in hydraulic valve.

In order to connect electro-hydraulic servo actuator to CAN network, one interface is designed for connecting electro-hydraulic servo actuator to CAN network. In this article, the author expounds design thinking and realization method for interface hardware and software. The card is applied in practice, and the practice proves the feasibility of the design method.

Velocity and position are the most important signals used in industrial controllers such as proportional–integral–derivative controllers. While in some real-time applications like structural control, acceleration measurements are easily accessible via accelerometers. The velocity and position have to be estimated from the measured acceleration. In this paper, offset cancellation and high-pass filtering techniques are combined effectively to solve common problems in numerical integration of acceleration signals in real-time applications. The integration accuracy is improved compared with other numerical integrators. Experimental results on a linear servo actuator and a shake table illustrate the effectiveness of the proposed method.

The paper submitted presents a new-generation mobile platform specially designed for the service robot destined for motion on vertical oriented walls, e.g. on glass façade systems of tower buildings. The platform has been developed goal-directly as a motive system allowing special technological extensions to be installed with a view to inspecting, assembling or washing. It uses a stepping principle alternating step by step the motion of legs and body. A holding system was created based on the vacuum principle with greater number of parallel suction cups associated with the smart vacuum technique. Component rotational motive units are fitted with servo-actuators with electro motors being controlled on the level of modular systems based on an embedded PC.

To resolve the complexity and uncertainty between the fault portent and the causes of electric and hydraulic actuator, a fault diagnosis model base on neural network arithmetic for actuator is designed. The genetic optimization arithmetic is used to initialize the value of weight and bias to improve the search efficiency and global convergence of the network. The simulation result indicate the feasibility and validity of the method based on genetic neural network model to diagnose the faults of electric and hydraulic servo actuator.

In this paper, a particle swarm optimization (PSO) method is proposed to design Quantitative Feedback Theory (QFT) control. This method minimizes a proposed cost function subject to appropriate robust stability and performance QFT constraints. The PSO algorithm is simple and easy to implement, and can be used to automate the loop shaping procedures of the standard QFT. The proposed method is applied to the high uncertainty pneumatic servo actuator system as an example to illustrate the design procedure of the proposed algorithm. The proposed method is compared with the standard QFT control. The results show that the superiority of the proposed method in that it can achieve the same robustness requirements of standard QFT control with simple structure and low order controller.

This paper addresses the experimental identification of a servo actuator which is used in many industrial applications. Because the system consisted of electrical and mechanical components, the behavior of the system was nonlinear. In addition, the under load behavior of this servo was different. The load torque was considered as the input and a two input-one output model was presented for this servo actuator. Special focus was given in order to present a simple model for this servo actuator. The comparison between simulation and experimental results showed the effectiveness of the propose model. The model can be applied as a reference for characterizing different designs and future control strategies.

This paper is dedicated to investigate the static and dynamic behavior of a pilot operated pressure reducing valve (PRV). The valve is the main component in an Anti-skid braking system of a vehicle. This system is fed by the hydraulic power from a constant pressure source. A mathematical model is deduced for the valve. A simulation program is developed usingthe MATLAB-SIMULINK where the mathematical model is implemented in the program. The developed program is used to study the dynamic valve response due to different input displacement values and effect of varying different design parameters on the overall performance of valve. A conclusion is made to evaluate the valve response and recommendations are suggested to improve valve performance.

In model based fault detection is very important to analyze how the effect of model uncertainty is considered when determining the optimal threshold to be used in residual evaluation. In case of model uncertainty is located in parameters (interval model), an interval observer has been shown to be a suitable strategy to generate this adaptive threshold. However, interval observers can be affected by the wrapping effect when low computational algorithms, such as region-based approaches coming from the interval community, are used to determine the predicted output interval. This paper shows that the wrapping effect might be avoided forcing the observer gain to satisfy the isotonicity condition. Then, the effect of this observer condition on the time evolution of the residual sensitivity to a fault and the minimum detectable fault is analyzed in order to see whether the fault detection performance is enhanced or not. Finally, an example based on an industrial servo actuator will be used to illustrate the derived results.

In case of model uncertainty is located in parameters (interval model), an interval observer has been shown to be a suitable strategy to generate an adaptive threshold to be used in residual evaluation. In interval observer-based fault detection methods, the observer gain plays an important role. First, it determines the minimum detectable fault for a given type of fault. Second, it allows avoiding the wrapping effect when low computational algorithms such as region-based approaches coming from the interval community are used to determine the predicted output interval. In this paper, the effect of the observer gain on the time evolution of the residual sensitivity to a fault and the minimum detectable fault while avoiding the wrapping effect is analyzed. Finally, an example based on an industrial servo actuator will be used to illustrate the derived results.

Billet spraying is one of the most commonly used applications for spray forming. An optimised as-sprayed geometry of the billets head reduces post-processing steps in terms of the shape of the endproduct. It also generates desired thermal conditions inside the billet, which are responsible for the development of a homogenous microstructure. This work shows the influence of different scanning kinematics on the head contours of billets. Usually, the atomiser is scanning mechanically with a prescribed kinematics. Here a programmable servo actuator is used to control the movement of the scanning atomiser, which makes it possible to change the movement profile during a spray run. Billets are sprayed using different atomiser velocity profiles. The different contours generated are described and compared.

One major difficulty in nursing the bedridden is moving their body. This includes lifting and carrying them from one place to another, as well as changing their body posture. Because they are lifting a heavy solid weight while in an unstable posture, the caregiver usually suffers hack pain due to this work. We propose a solution by replacing this labor with robotics technology to lift and/or carry a person. The robot is designed with the smooth, high torque hydraulic actuation, and the bilateral servo system for the control to meet the necessity of the service. The superiority of this robotic device is in its interface and output torque. The bilateral servo system allows the robot to he directly operated (holding the end of the arm) and to control an average weight of a Japanese adult (e.g. 60 kgf) with little effort (e.g. 1 kgf).

In this paper, we propose a new prototype model of the active guide wire microcatheter whose bending has two degrees of freedom. The design and fabrication methods of this active microcatheter are described. It is 3Fr, 4Fr, 6Fr (1Fr=1/3mm)in diameter and consists of catheter tube and active guide wire with ICPF on its front end as the servo actuator. The bending motion and bending angle of the active guide wire microcatheter have been measured by application of electricity in water and in physiological saline solution. We also modeled this active microcatheter. Experimental results show that the model of the active catheter is reasonable for practical applications. By using simulators (conditions similar to those of a body cavity), we also carried out simulation experiments in vitro. The experimental results indicate that the proposed active guide wire catheter is applicable to intracavity operations.

This paper mainly focuses on the design of a novel type of intelligent DDV actuator system for aeroplane. The function, structure principle and redundancy management of the intelligent DDV (Direct-Drive-Valve) servo actuator system for aeroplane is described in detail. The intelligent DDV servo actuator which is the important part of the system is also described in the paper, including the structure and performance characteristic, the key technique, and so on. An experiment is conducted to verify the dynamic performance and fault monitoring function of the new system. The hardware-in-loop experimental results prove that the design and application of the intelligent DDV servo actuator system on some aeroplane could solve the technical problems in real world. Also, the control precision, stability, and fault monitoring of the system can perfectly satisfy the aeroplane control system design requirements.

Servo actuator is one most important section of flying control system, and faults also often happen to it. The fault detection and diagnosis technology is seriously important to improve the reliability of servo actuator. The paper proposes a method of fault diagnosis based on Elman neural network, using its non-linear distributed processing and dynamic feature reflecting ability to detect servo actuator fault. Then, neural network algorithm is applied to simulation. The result indicated that the method could accurately identify the servo actuator fault. Meanwhile, compared with BP neural network, the advantage of Elman neural network in fault diagnosis is confirmed.

The servo writer is known as the most accurate and sensitive tool on an HDD (harddisk drive) manufacturing line. ESPER-2 is designed as a product-independent common servo writer which incorporates major advances in equipment cost, reduction of clean-room requirements, and writing accuracy. The servo writing process consists of two stages. The first stage writes the master servo pattern on as many as ten disks at once with little need for contaminant protection facilities. One such master disk is then assembled with other, raw, disks in a file, and the second stage writes the proper servo pattern on all disk surfaces by referring to the master. The effects of off-center discursions in the mechanical disk assembly and random runout (NRRO, or nonrepeatable runout) in the product spindle components are eliminated by table-lookup servo actuator control, so that writing accuracy is improved. Neither an exceptionally clean environment nor fine mechanical parts are required for the second-stage operation.

The aims of this paper, are to obtain for an electro-hydrostatic servo-actuator, good performances, (time response and frequency characteristics), making it usable on aircraft, and a more simple configuration of the regulator, with a short computing time and a more simple program, in order to obtain a cheaper and more simple implementation. The strategy is to reduce the membership functions number of the fuzzy regulator keeping in the same time the requested performances of the servo-actuator.