Zongxia Jiao

The Nonlinear Accuracy Model of Electro-Hydrostatic Actuator

The electro-hydrostatic actuator (EHA) is a kind of power-by-wire (PBW) actuator. In this paper, a typical architecture of EHA is described and the block diagram model of EHA is established directly from the mathematic equations without transfer functions, which is a nonlinear accuracy model. The influence of refeeding circuit on the EHA system is discussed based on the comparison with conventional linear model. A gain-variable PID controller is introduced to this model to compensate the friction.

Preliminary Design and Optimization of Toroidally Wound Limited Angle Servo Motor Based on a Generalized Magnetic Circuit Model

This paper proposes a new generalized equivalent magnetic circuit model for the preliminary design of a toroidally wound limited angle servo motor. In the model, the magnetic networks are formulated as a function of the pole number and geometric dimensions. Nonlinear saturation effect of the ferromagnetic material is also taken into consideration. A multi-objective optimization function involving the torque requirement, the mass, the time constant, and the magnetic saturations of ferromagnetic material is introduced. Based on the proposed model, six design cases with different objectives have been carried by the particle swarm optimization method. The comparisons of different optimization cases demonstrate the effectiveness and computation efficiency of the proposed method, and hence its suitability in preliminary design. Moreover, the generalized model can be readily applied in the other electromagnetic modeling.

Dynamic robust compensation control to inherent high-frequency motion disturbance on the electro-hydraulic load simulator

This paper focuses on a robust control method applied to an electro-Hydraulic Load Simulator (HLS) acting on a special aerodynamic load. Owing to the high-speed on-off valve, some pneumatic aircraft actuators have inherent high-frequency motion disturbance that reduces the dynamic tracking performance. Through combining velocity synchronising decoupling compensation and equivalent disturbance observers, this paper presents a Dynamic Robust Compensation (DRC) to achieve high precision load simulation. The experiments indicate that the velocity synchronising decoupling is used to restrain strong disturbance, whereas the robust compensator is adopted to reduce the remaining extraneous torque from motion flutter efficiently further.

On-line identification based optimal control method

This paper presents an On-line Identification based Optimal Control (OIOC) method that composed of two layers: the control layer is used to realize the close-loop control while the optimization layer is used to search the optimal control parameters. This control strategy can ensure the robustness of a servo system. The nonlinear PID controller, Elman network based identifier and Particle Swarm Optimization (PSO) algorithm are designed and applied to OIOC. The simulation results with respect to a typical electro-hydraulic servo system are presented.

Dual linear motors synchronous control for horizontal axis of far-field target motion simulators

This paper proposes a simple synchronous control scheme for a linear servo system applied to driving the horizontal axis of far-field target motion simulators(TMS). The investigated horizontal axis is driven by two parallel linear motors, which are arranged at both ends of the vertical axis. This layout, which can improve the system dynamics, overall thrust and structural stiffness, requires accurate synchronous control. To meet this requirement, the velocity difference compensation scheme is proposed to reduce the synchronous errors. Prior to this, the parallel synchronous control model of dual linear motors is established, and a stiffness coefficient is introduced to consider the impact of the mechanical connection coupling between these two linear motors. The performance of the proposed method is verified by a S-curve motion profile, and the simulation results substantiate the effectiveness of the control method.

Rotate-Vector Optimization and its Application to PID Controller Tuning

This paper first presents theoretical research on direct optimization using the Rotate-Vector (RV) Algorithm which is suitable for the complex objects and valuable in engineering applications with global optimization ability. The derivation of the RV algorithm is illustrated in three-dimensional space and subsequently extended into multi-dimensional space. The numerical simulation utilizes this RV algorithm to optimize the parameters of a Proportional-Integral-Differential (PID) controller for an electro-hydraulic system. Simulation results show that the RV algorithm can solve optimization problems without calculating the function gradient.

High bandwidth adaptive robust control for hydraulic rotary actuator

This paper studies on improving the bandwidth of electro-hydraulic rotary actuator. Electro-hydraulic servo system is a typical nonlinear system, and also usually disturbed by internal and external uncertain factors. The nonlinear and uncertainty characteristics make the conventional controller not yield to the system high bandwidth requirement. In this paper, an adaptive robust controller based on varying boundary discontinuous projection is proposed. Online parameter estimation based its empirical varying trail is given to adapt the proposed controller due to the system nonlinear characteristics. A simulation case study and comparative results are shown that the tracking performance and the bandwidth of the hydraulic rotary actuator are greatly enhanced.

An Information Integration Framework Based on XML to Support Mechatronics Multi-disciplinary Design

To implement the information integration of multi-disciplinary applications, an information integration framework of mechatronics system multi-disciplinary design is developed. This developed integration framework adopts a XML Web service based architecture which facilitates the seamless information integration in Internet environments. MSCIM (mechatronics system common information model) is defined as well as the standard data access interfaces are specified. MSCIM includes all the major objects and the relationships of objects in the process of mechatronics systems design. As a neutral and Web-friendly industry standard, the XML schema is used as the formal definition language of the MSCIM. DAF (data access facility) is adopted as the standard data access interface and the accurate definition is given via WSDL. Standard data access interfaces are implemented through SOAP (simple object access protocol) over HTTP which provides the multi-disciplinary design application with a generic way to exchange information and access public data. Furthermore, this information integration framework provides the multi-disciplinary engineers with an integrated logical view of mechatronics systems and realizes cooperation of multi-disciplinary teams which shortens the development cycle and saves the cost at the same time in mechatronics multi-disciplinary design.

Investigation of an Electromagnetic Wearable Resonance Kinetic Energy Harvester With Ferrofluid

Human motion energy harvester can offer clean and continuous power, and therefore plays an important role in powering mobile devices, which suffer from short standby time because of the limited capability of the battery. In this paper, we investigate an electromagnetic resonance wearable kinetic energy harvester, which is comprised of an oscillator and a carbon fiber tube with two coils wound on its surface. The oscillator is comprised of a columnar PM connected to the two end covers with two elastic strings. The designed resonant frequency is 8–10 Hz, which is higher than the major frequency range of human motion (2–4 Hz), but it can absorb high frequency energy of impulse, such as footfall. Thus, the harvester can wear on legs to absorb the kinetic energy of footfall by resonance. The ferrofluid is adopted to decrease friction, which is one of the main challenges for improving efficiency of this type of energy harvester. The ferrofluid prevents the PM from touching the wall of the tube resulting in significant friction reduction. The FEM simulation results indicate that the ferrofluid can keep the vibrator (a permanent magnet) contactless even subjecting to ten times gravity acceleration. The maximum average output power of 9.5 mW is obtained with a total weight of 80.5 g when running at a speed of 10 km/h. A energy harvest circuit is carried out and an average power of 0.28 s can be stored.

Preliminary design and simulation of electro-hydrostatic actuator with modelica

This article presents a methodology for preliminary design of the electro-hydrostatic actuator. This methodology based on the modeling library of components of EHA. The modeling library of components are built with Modelica language. These model libraries are advantage of reuseability and non-causality and object orientedness and then the model of EHA can be fully integrated by these components. A demo of a new design EHA simulation illustrates the feasibility of the proposed method.