Direct Drive Volume Control Research Articles

Research on Pressure Control of an Electro-Hydraulic Servo System Based on Sliding-Mode Variable-Structure Direct Torque Control

Taking a direct-drive volume control (DDVC) electro-hydraulic servo system as the research object and aiming at the problems of the servo motor torque fluctuation, high-precision system pressure control, and dynamic response of the system, based on traditional motor direct torque control (DTC), a motor direct torque control method based on a sliding-mode variable structure is proposed to control the system pressure. The motor torque loop is part of the inner control loop and has a rapid dynamic response speed, resulting in higher pressure control accuracy. A nonlinear mathematical model was established for the DDVC electro-hydraulic servo system. The switch meter hysteresis controller in the traditional DTC system was replaced with space vector pulse-width modulation technology. Then, the PID control module in space vector modulation technology was replaced with high-order sliding-mode variable-structure control. Through the coupling relationship between the electric machine and the constant-displacement pump, the pressure can be controlled with high precision using motor torque control. Finally, using the MATLAB/Simulink simulation platform and the DDVC electro-hydraulic servo system simulation model, the proposed theoretical approach to torque control was verified on the basis of simulations and experiments, and the performance with regard to pressure control in the hydraulic system was observed. The simulation and experimental results show that the designed torque control is able to effectively reduce the motor torque fluctuation and improve the dynamic response characteristics of the system. The system pressure control is superior to traditional pressure control methods based on speed regulation, and it has higher control accuracy and a better dynamic response.

Research on Feedback-Linearized Sliding Mode Control of Direct-Drive Volume Control Electro-Hydraulic Servo System

In this paper, a control strategy combining the feedback linearization theory and sliding mode variable structure theory is proposed to solve various nonlinear factors, uncertainty of external disturbance and high-precision pressure control problems in the Direct-Drive Volume Control (DDVC) electro-hydraulic servo system. The nonlinear mathematical model of the DDVC electro-hydraulic servo system is established, and the nonlinear factors in the system are accurately linearized by the feedback linearization theory. The uncertainty of external disturbance in the system is compensated by the sliding mode control variable structure theory. The feedback-linearized sliding mode control algorithm proposed in this paper is verified using the DDVC electro-hydraulic servo system experimental platform. The experimental results show that, compared with the classical PID control, the proposed control algorithm can effectively improve the pressure output precision, as well as the dynamic response characteristics, of the DDVC system.

Energy-Saving Nonlinear Friction Compensation Method for Direct Drive Volume Control Flange-Type Rotary Vane Steering Gear

In the research of various energy technologies, the direct-drive volume control flange-type rotary vane steering gear (DDVC-FRVSG) has become a promising component for controlling the course and posture of a vessel because of its superior energy-saving performance. However, nonlinear friction limits the ability of the DDVC-FRVSG to satisfy the efficient energy requirements of the vessel. This study proposes compensation methods to suppress nonlinear friction, such that the rudder can be efficiently controlled. Based on the principle of the DDVC-FRVSG, we establish a mathematical model and transfer function of the steering gear system along with a mathematical model of the impact of nonlinear friction on the rudder system. A friction model-based method using the integral back-stepping adaptive control strategy is proposed to suppress nonlinear friction, and both the models are studied theoretically and through simulation. Taking the no-compensation state as a benchmark, our measured results by prototype testing reveal that the method can compensate for nonlinear friction, achieving up to 73.08 % better performance on average and reducing the output power of the driving motor by 36.39 % on average. The findings of this research will contribute to the energy-saving performance and efficient energy requirement of the DDVC-FRVSG system.

The compensation for nonlinear friction of DDVC flange-type rotary vane steering gear.

This study reports on the direct drive volume control flange-type rotary vane steering gear (DDVC-FRVSG), a promising component with superior advantages of compact structure, powerful vibration absorption, and simple control for application in the controlling course and posture of a vessel. The ability of the DDVC-FRVSG to satisfy the accuracy requirement of the vessel is limited by nonlinear friction. This study proposes two compensation methods to compensate for the nonlinear friction. We establish the mathematical model and the transfer function of the steering gear system and the mathematical model of nonlinear friction on the DDVC-FRVSG system based on the principle of the DDVC-FRVSG. A high-gain proportional–integral–derivative control strategy and another method using the self-adaption robust control strategy is proposed and studied both theoretically and experimentally to suppress the nonlinear friction. With the “no-compensation state” as a benchmark, our measured results by prototype testing has proved that both methods can compensate for the nonlinear friction, with the second method showing a better performance of up to 78.85% increase compared to that of the 41.65% shown by the first one. The outcome of this research will contribute to the rapidity and stability of the DDVC-FRVSG.

Robust controller design of the integrated direct drive volume control architecture for steering systems

Recently, much effort has been directed toward the large throttling loss and low efficiency of the valve control system widely applied in steering system of ships. This paper presents an Integrated Direct-Drive Volume Control (IDDVC) electro-hydraulic servo system with the advantages of high efficiency and energy conservation. Firstly, the simulation model of IDDVC is improved by software AMESim, including the nonlinear interaction of the motor-pump and the oil supply ignored by traditional transfer function model. Then, by establishing discrete state equations, a controller based on robust sliding control strategy has been designed to enhance the practicality and real-time performance. Finally, the accuracy of the model and the effectiveness of the controller are proved through the experiments which are conducted after constructing the IDDVC prototype.

S1150303 回転数制御油圧アクチュエータによる船舶用燃料噴射率制御

This paper proposes a new control technique of fuel injection quantity for marine diesel engine using a direct drive volume control (DDVC). The DDVC is a kind of displacement control system which consists of a cylinder and a fixed-displacement oil-hydraulic pump driven by an AC servo motor. Feedback control system of the fuel injection quantity for marine diesel engine is studied by simulation. The fuel injection quantity is compared with desired value. The crank angle to stop injection is updated according to proportional control at each engine cycle. Simulation study shows a good performance of the proposed system to control the fuel injection quantity.

Optimization of the Dynamic Performance of the Direct Drive Volume Control System Based on Orthogonal Experiment

Direct drive volume control (DDVC) electro-hydraulic servo system has many advantages compared to the valve control system. However, its application scopes were restricted by its poor dynamic performance. To study the reason for the low dynamic response, mechanical model of DDVC electro-hydraulic servo system is established. Structure parameters influencing the dynamic performance are analyzed. To optimize the structure parameters, the methodology of orthogonal experiment is presented. The selection of factors and levels of the experiment and the choice of the evaluation index are also revealed. The proposed methodology is carried out by simulation software and an optimal configuration is obtained. The dynamic response of the DDVC system with the optimal parameters is simulated. The results show that the dynamic performances are improved. The cross-over frequencyincreases from 0.0046 rad/s to 0.0442 rad/s, and the rise time Tr decreases from 488.6s to 47.90s.

Simulation Research on Effects of Low Velocity Characteristics to Direct Drive Volume Control Systems

The Direct Drive Volume Control (DDVC) Electro-hydraulic Servo System is a new Electro-hydraulic Servo System. It has the advantages of flexibility of AC servo motor control and high power of hydraulic servo system. Compared with the traditional electro-hydraulic servo system, the DDVC system is efficient, miniaturized integrated, convenient operated and economical. It has been used in many domains, and made great economic benefits. So it is widely considered to be one of the most important developing directions of the hydraulic control system. It will be widely used in more and more areas in the future. With the development of its application, how to improve the trajectory tracking precision of the DDVC system in low velocity motions becomes more important in the field. So that, the level of the low velocity characteristic impacted the system become to an important subject. In this paper, the mathematical mode of AC asynchronism motor Direct Torque Control was established, and the simulation mode was built. In addition, the idealized model of the DDVC system which based on united simulation of AMEsim/Simulink was established, simulation was executed. In order to make the research available, the low velocity characteristic of the DDVC system was also analyzed, and the low velocity characteristic simulation model was built. Computer simulation validated that the friction, the leakage and the mechanical losses are seriously influenced the system performance when the system working on the low velocity mode.

Direct-Drive Differential Volume Control Electro-Hydraulic Servo Control System

Direct-drive volume control electro-hydraulic servo control system, derivation model of single-rod hydraulic cylinder system, pointed out that when the reciprocating motion characteristics are inconsistent. In order to solve this problem, proposed direct-drive differential volume control electro-hydraulic servo system design of its control system and analysis of system models. Through theoretical analysis, validate this proposed direct-drive bad dynamic volume control system, symmetric dynamic performance, improving control system reliability.

Research on the Low Velocity Accuracy Control of the Direct Drive Volume Control Electro-Hydraulic Servo System

The Direct Drive Volume Control (DDVC) Electro-hydraulic Servo System is a new Electro-hydraulic Servo System. With the development of its application, how to improve the trajectory tracking precision of the DDVC system in low velocity motions becomes more important in the field. So that, the level of the low velocity characteristic impacted the system become to an important subject. In this paper, the mathematical mode of AC asynchronism motor Direct Torque Control was established, and the simulation mode was built. In addition, the idealized model of the DDVC system which based on united simulation of AMEsim/Simulink was established, simulation was executed. In order to make the research available, the low velocity characteristic of the DDVC system was also analyzed, and the low velocity characteristic simulation model was built. Computer simulation validated that the friction is seriously influenced the system performance when the system working on the low velocity mode. An integral back stepping adaptive control law is designed to realize the friction compensation and load disturbance estimation. From the Lyapunov theory, the stability of the closed-loop system is proved. Simulation results show that LuGre friction in servo systems will lead to the effect of limit cycles and stick-slip. Moreover, the proposed compensation method can greatly reduce the effect and improve the system tacking accuracy and robustness.

Pressure Control Technology of DDVC Gas Regulating System for Butterfly Valve

For the problem needed to solve during the process of steel cycle power generation, a set of pressure regulating system driven by step motor was designed based on direct-drive volume control (DDVC). An incremental fuzzy PID controller was developed for this system. Then the dynamic characteristics were simulated in Matlab/simulink. The results show that: compared with the simulation curve controlled by traditional PID, this regulating system can achieve better performance by fuzzy PID.

Research on High Power Direct Drive Differential Volume Control Electro-Hydraulic Servo System

For traditional direct drive volume control electro-hydraulic servo system, the servo motors rotary inertia is limited strictly, the speed of response is slow and the actuators reciprocating motion characteristics are not consistent. In order to solve these problems, this paper designs a kind of high power direct drive differential volume control electro-hydraulic servo system. It is instructive for design of hydraulic system which demands high output power, changes direction of motion frequently, needs high response frequency and requires the speed of reciprocating motion keep consistent.

Model and Simulation of Six-DOF Parallel Platform Based on Direct Drive Volume Control

The fuel system experimental platform based on Stewart manipulator is used to test the performance and reliability of airplane’s fuel system. Synthesizing efficiency and safety, direct drive method is used as actuator of the experimental platform. Kinematic and dynamic model of the parallel manipulator platform is established. Servo motor and hydraulic cylinder of pump control are modeled for deducing the mathematical model of the experimental platform. Simulation results of the experimental platform show the platform of direct drive method can satisfy the requirements of operation. In addition, data from the simulation can be used as the basis for the design and optimization of the experimental platform for fuel system.

Design and Simulation of Direct Drive Volume Control Actuator

The electro-hydraulic actuator which was designed based on the technology of the direct drive volume control, has the advantages of small volume, high reliability, energy saving and so on, and can effectively overcome the deficiency of traditional valve control electro-hydraulic actuator. This paper realizes co-simulation of direct drive volume control actuator (DDVCA) by using AMESim and Matlab/Simulink. The simulation results show that DDVCA has the characteristics of smooth operation, fast response speed, high control accuracy. Therefore, DDVCA can replace traditional servo valve electro-hydraulic actuator in the case of low frequency response requirement.

Direct Drive Volume Control Electro-Hydraulic Servo Ship Rudder

Direct drive volume control（DDVC）electro-hydraulic servo system has synthesized the advantages of high power of hydraulic system and flexible control of the motor. It also has other features such as energy saving, high efficiency, small bulk and high reliability. On the background for application to the ship steering system, DDVC electro-hydraulic servo system for the control actuator of ship is designed and the mathematic model is made and simulated with Matlab/Simulink. The steering gears closed-loop system’s simulation obtained the perfect dynamic performances; verify the correctness of the design with its control strategy. It can satisfy the ships request of boat to steering gears system and the DDVC electro-hydraulic servo system will be a extensive prospective power equipment of the control actuator of ship in future.

Fuzzy iterative learning control of electro-hydraulic servo system for SRM direct-drive volume control hydraulic press

A new kind of volume control hydraulic press that combines the advantages of both hydraulic and SRM (switched reluctance motor) driving technology is developed. Considering that the serious dead zone and time-variant nonlinearity exist in the volume control electro-hydraulic servo system, the ILC (iterative learning control) method is applied to tracking the displacement curve of the hydraulic press slider. In order to improve the convergence speed and precision of ILC, a fuzzy ILC algorithm that utilizes the fuzzy strategy to adaptively adjust the iterative learning gains is put forward. The simulation and experimental researches are carried out to investigate the convergence speed and precision of the fuzzy ILC for hydraulic press slider position tracking. The results show that the fuzzy ILC can raise the iterative learning speed enormously, and realize the tracking control of slider displacement curve with rapid response speed and high control precision. In experiment, the maximum tracking error 0.02 V is achieved through 12 iterations only.

Application of self-tuning fuzzy PID controller for a SRM direct drive volume control hydraulic press

A new kind of volume control servo hydraulic press driven directly by Switched Reluctance Motor (SRM) is presented in this paper. In considering the saturation and dead zone nonlinearity as well as the time-variability and the time lag existed in SRM direct drive volume control system, a fuzzy PID control method is introduced to improve the overall performance of the electro-hydraulic position servo system. The relationships between the PID parameters and the response characteristics of electro-hydraulic position servo system are investigated. The fuzzy inference rules which enable adaptive adjustment of PID parameters are established based on the error and change in error. The simulations and experiments of step response and cosine tracking are carried out on the SRM direct drive hydraulic press. The results indicate that the fuzzy self-tuning PID method has great ability of restraining external disturbance, and it can effectively raise the position tracking ability of the volume control electro-hydraulic servo system.

Ｄｉｒｅｃｔ Ｄｒｉｖｅ Ｖｏｌｕｍｅ Ｃｏｎｔｒｏｌ Ｅｎｇｉｎｅ Ｇｏｖｅｒｎｏｒの開発と燃費節減

Revolution control in the marine diesel engine is accomplished with a governor, and an electro-hydraulic type has become conventional these days. Thus performance of the governor has improved so much, but it is complex, and some trouble can be expected. We are developing a new type of electro-hydraulic governor, one using a direct drive volume control hydraulic system. It has been installed aboard the training ship of TUMSAT "Shioji-Maru." By this paper we introduce our newly developed "Electro-Hydraulic engine Governor" which has the direct drive volume control hydraulic system. We continue to study the effects, for the reeducation of fuel consumption in Marine Diesel Engines.

舵減揺オートパイロットシステムの転舵速度影響に関する研究

This study treats with the effect of rudder speed to the Batch Adaptive Roll Reducible Autopilot System (BARRAS) which was developed by the authors. The onboard experiments are carried out using a newly developed oil pressure steering gear called Direct Drive Volume Control System (DDVC) which has high performances on rudder speed, fuel assumption and so on. The effects of the rudder speed are examined by changing the weight of performance index and analyzed from view points of power spectra, noise contribution and impulse response functions.

DIRECT DRIVE VOLUME CONTROL OF HYDRAULIC SYSTEM AND ITS APPLICATION TO THE SHIP

Direct Drive Volume Control Hydraulic Servo System (DDV System) is the system which can control the position of actuator with controlling the revolution of hydraulic pump directly.This system is known that it can decrease energy consumption because the pump is driven only when the motion of actuator is required. It does not has a transient phenomena such as surging because the change of actuator motion is carried out with changing the direction of pump revolution. It can make the size of system very small, because heat loss of the system is small and it does not require a large size of oil tank for cooling. Many kinds of hydraulic system are used in a ship. One of the most important system is steering system and we adopted the DDV system to “Shioji-maru” which is the training ship of Tokyo Univ. of Mercantile Marine. The results of this study was excellent ; the size of hydraulic source system become less than 1/10, energy consumption become under 1/20 and surging is eliminated.Considering those results, the authors are trying to apply this system to anti-rolling system with rudder or fin stabilizer.