Haitao Qi

Optimization of the control strategy for EHA-VPVM system

Aiming at the problem that different sections of the flight profile have different requirements on dynamic response and energy loss, by adjusting the rotating speed in steady state and the matrix R to make the system meet the requirement is put forward. The EHA-VPVM is modeled and simulated in the Matlab/Simulink and AMESim software. The simulation results show that the dynamic response and energy loss of system are determined by rotating speed in steady-state and the weighting coefficients of the displacement and the rotating speed of pump in the matrix R. The dynamic response becomes faster as the steady-state rotating speed increases, but the energy loss becomes more. It would improve the dynamic response when reducing the weighting coefficient of displacement in matrix R appropriately.

Active disturbance rejection control for the airborne pmsm in direct drive ema application

Compared with the general ball screw electromechanical actuators (EMAs), direct drive EMAs have several attractive advantages such as more reliable, efficient, accurate, and integrated due to the elimination of the intermediate gear boxes. However, the direct drive structure brings challenges to the servo control of the permanent magnetic synchronous motors (PMSMs) which are widely used in EMAs. Aiming at improving the performance of the PMSM servo system, such as wide speed range and outstanding load disturbance-rejection ability, a novel active disturbance rejection control (ADRC) is presented in this paper. To begin with, as a technique for estimating and compensating uncertainties, characteristics, and principles of the ADRC strategy are introduced in detail by comparing with PID and several advanced control strategies. Then, based on the PMSM model in d-q frame, an ADRC controller for the d-axis current is designed to implement the rotor flux linkage oriented vector control. Finally, ADRC controllers for the position and q-axis current are designed to complete the position servo control. Simulation results verify that the ADRC-based PMSM servo system is fast, precise, of no overshoot and strongly robust to load disturbance. Therefore, the ADRC strategy is feasible in the PMSM servo control and this provides necessary technical support to the direct drive EMA, which is one of the enabling technologies for the all-electric aircraft (AEA).

The application of co-simulation based on AMESim and Matlab in electro-hydraulic servo system

The structure and operating principle of Electro-hydraulic servo system were described, and the Co-Simulation based on AMESim and Matlab was performed. Furthermore, aiming at the problem that construction of an accurate model of an Electro-hydraulic servo system based on traditional linear methods remains a difficult task due to its nonlinear characteristics including flow/pressure relation, etc, the paper proposed a data-driven control method based on the model-free adaptive control. The simulation results show that the model-free adaptive control method satisfies the performance of servo control system, and provides the electro-hydraulic servo control system with new ideas and new methods.

Application of heat pipe technology in the design of hydraulic motor pump

The hydraulic motor pump is a kind of new integrated hydraulic power unit, but it has a serious problem of heat dissipation when its used in closed hydraulic system and other special applications. Firstly this paper introduces the heat pipe technology into the design of the hydraulic motor pump to solve the heat dissipation problem. Afterwards we design a heat pipe radiator integrated with the back cover according to the new internal gear hydraulic pump motor. Finally we simulate the temperature field through ANSYS. The simulation results show that the heat pipe radiator can take the heat generated by the hydraulic motor pump effectively. It can greatly reduce the temperature of the oil in hydraulic motor pump and make the oil in the hydraulic motor pump at a low level. In addition it also helps reducing the temperature gradient. In conclusion, this paper demonstrates the feasibility and efficiency of heat pipe technology for heat dissipation of hydraulic motor pump.

Investigation in hybrid actuation for duplex actuators operating in active/no-load modes

This communication deals with the key issues of a hybrid actuation system operating in active/no-load mode. The hybrid actuation system under study is made of a servo valve controlled hydraulic actuator (SHA) and an electro-mechanical actuator (EMA). In active/no-load mode, both actuators are actively controlled; the SHA is in position control while the EMA is controlled to generate null force. Virtual prototype of the hybrid actuation system is firstly built in the AMESim simulation environment and validated through experiments. Then, three operating modes of the hybrid actuation system are analyzed and simulated using the validated virtual prototype. Finally, the control strategies in active/no-load modes are discussed. The active/no-load mode is proved to be a promising operating mode with high dynamics, low failure transient, reduced wear and power consumption.

A Novel Sliding Mode Control Framework for Electrohydrostatic Position Actuation System

A novel sliding mode control (SMC) design framework is devoted to providing a favorable SMC design solution for the position tracking control of electrohydrostatic actuation system (EHSAS). This framework is composed of three submodules as follows: a reduced-order model of EHSAS, a disturbance sliding mode observer (DSMO), and a new adaptive reaching law (NARL). First, a reduced-order model is obtained by analyzing the flow rate continuation equation of EHSAS to avoid the use of a state observer. Second, DSMO is proposed to estimate and compensate mismatched disturbances existing in the reduced-order model. In addition, a NARL is developed to tackle the inherent chattering problem of SMC. Extensive simulations are conducted compared with the wide adoption of three-loop PID method on the cosimulation platform of EHSAS, which is built by combining AMESim with MATLAB/Simulink, to verify the feasibility and superiority of the proposed scheme. Results demonstrate that the chattering can be effectively attenuated, and the mismatched disturbance can be satisfyingly compensated. Moreover, the transient performance, steady-state accuracy, and robustness of position control are all improved.

Symmetrical valve controlled asymmetrical cylinder based on wavelet neural network

Purpose The symmetrical valve is usually used in the hydraulic servo control system to control the asymmetrical cylinder, but this system’s structure involves asymmetry, and so its dynamic characteristics are asymmetrical, which causes issues in the control system of symmetric response. The purpose of this paper is to achieve the aim of symmetric control. Design/methodology/approach In this paper, the authors proposed a method that combined wavelet neural network (WNN) and model reference adaptive control. The reference model determined the dynamic response that the system was expected to achieve, and the WNN adaptive control made the system follow the reference model to achieve the purpose of symmetric control. Findings The experimental results show that the method can achieve a more accurate symmetric control and position control compared with the solutions via the classical PID control. Originality/value The proposed combination of the WNN and the reference model can effectively compensate for the asymmetry of dynamic response of the asymmetric cylinder in forward and return directions, which can be extended to deal with other classes of applications.

Modelling and simulation of a novel dual-redundancy electro-hydrostatic actuator

The proposed paper deals with the problem of modelling and simulation of a dual-redundancy Electro-Hydrostatic Actuator (DREHA) by the way of co-simulation based on AMESim and MATLAB. With the development of More Electric Aircraft (MEA) technology, integrated Power-by-Wire (PBW) actuator will be used in the airborne actuation system. As an important PBW actuation system, EHA has virtues of high efficiency, little heat generation, easy structure integration design, effortless parallel redundancy design, convenient power distribution and management, few installation restriction, control-configured layout, and expediently implementing lock and isolation, which are more suitable to the actual technology development level and airborne requirements. The research of DREHA has a vital significance to improve the reliability of its use in aircraft. The schematic of a novel DREHA are firstly given based on the existing fault tolerant EHA architectures, and its principle is analyzed in detail. Then, build the model of control and motor part in MATLAB, and the model of hydraulic part in AMESim. Analyze the operating modes of DREHA, including active/active and active/passive mode. Finally, co-simulate the dynamic response and operating modes of DREHA based on AMESim and MATLAB. The simulation results show that this new DREHA has the ability of no performance degradation after the first failure and safe after the second failure.

The Simulation of Six Phase PMSM Taking Iron Loss into Account

This paper studies the mathematical model considering iron loss in the d-q axis of six phase permanent magnetic synchronous motor (PMSM), through the expansion of Field-Oriented Control (FOC) based on three phase PMSM, the simulation model of six phase PMSM under environment of simulink7.0 is set up, which has fast dynamic response, high steady-state precision, and has no problems about current balance compared to dual three phase PMSM. In order to get an accurate simulation results, this mathematical model takes iron loss into account. The simulation results show that iron loss have bad effects on the performance of PMSM especially affect the dynamic response, and to reduce the bad effects, the resistance of the motor core should be increased.