Digital Hydraulic System Using Pumps and On/Off Valves Controlling the Actuator

2014 ◽  
Author(s):  
Cristiano Cardoso Locateli ◽  
Paulo Leonel Teixeira ◽  
Edson Roberto De Pieri ◽  
Petter Krus ◽  
Victor Juliano De Negri
Keyword(s):  
High Power ◽  
Power Dissipation ◽  
Hydraulic System ◽  
Control Method ◽  
Weight Ratio ◽  
Speed Control ◽  
High Energy ◽  
Hydraulic Systems ◽  
Low Efficiency ◽  
Smooth Transitions

Hydraulic systems employed in several industrial and mobile applications present significant advantages, such as a high power-to-weight ratio and fast dynamic response. However, these systems have low efficiency due to high power dissipation. A recent concept called “digital hydraulics” comprises particularities that create opportunities for a reduction in load loss. This paper proposes a configuration and control method for actuator speed control based on the principles of digital hydraulics. In this context, several fixed displacement units and on/off valves are connected directly to the actuators without throttling valves. The system studied here presents three operation methods (pump mode, motor mode and idle mode), which allows discrete valves to replace continuous or flow control valves in order to control the actuator. Furthermore, a fixed or variable displacement pump with large displacement is replaced by several small, fixed displacement units. Simulations are performed with a co-simulation technique using AMESim and MATLAB. The actuator speed, inlet and outlet pressures on the fixed displacement units and flow rate in the circuit lines are analysed. Preliminary simulation results exhibit smooth transitions between speed levels, adequate dynamic performance, low power dissipation and high energy-storage capacity. A specific limitation of this technology is the obtained actuator discrete speed. The main contributions of this research are the development of a digital hydraulic system configuration and its control strategy, which allows speed control of hydraulic actuators and provides the capacity to store energy.

Synchronous Control Characteristics Analysis of Shield Propulsion Hydraulic System Based on Tracking Differentiator and Self-Adaptive Nonlinear PID

2021 ◽  
Author(s):  
Sen Li ◽  
XiaoHua Cao
Keyword(s):  
Pid Control ◽  
Hydraulic System ◽  
Control Method ◽  
Hydraulic Systems ◽  
Fuzzy Pid Control ◽  
Synchronous Control ◽  
Tracking Differentiator ◽  
Characteristics Analysis ◽  
Servo Tracking ◽  
Self Adaptive

Aiming at the low precision problem of multi-cylinder cooperative propulsion control in different regions of shield propulsion hydraulic systems under conditions of large load changes, this paper proposes a tracking differentiator and self-adaptive nonlinear PID (TD-NPID) control method to improve the synchronous control characteristics of shield propulsion hydraulic systems. First, the working principles of shield propulsion hydraulic systems were analyzed, and a mathematical model and TD-NPID controller were developed. Then, a simulation model was developed in AMESim-MATLAB environment, and the synchronous dynamic performances of fuzzy PID control, conventional PID control, and TD-NPID control were compared and analyzed. The results demonstrated that the shield propulsion hydraulic system with TD-NPID control had better servo tracking ability and steady-state performance than the systems with fuzzy or conventional PID control, which verified the feasibility of the application of TD-NPID control for the synchronous control of shield propulsion hydraulic systems.

scholarly journals The Influence of Valve-Pump Weight Ratios on the Dynamic Response of Leaking Valve-Pump Parallel Control Hydraulic Systems

2018 ◽  
Vol 8 (7) ◽  
pp. 1201 ◽  
Author(s):  
Haigang Ding ◽  
Jiyun Zhao ◽  
Gang Cheng ◽  
Steve Wright ◽  
Yufeng Yao
Keyword(s):  
Dynamic Response ◽  
Hydraulic System ◽  
Weight Ratio ◽  
Open Loop ◽  
Hydraulic Systems ◽  
Variable Speed ◽  
Weight Factors ◽  
Wide Range ◽  
Parallel Control ◽  
Valve Control

A new leaking valve-pump parallel control (LVPC) oil hydraulic system is proposed to improve the performance of dynamic response of present variable speed pump control (VSPC) system, which is an oil hydraulic control system with saving energy. In the LVPC, a control valve is operating at leaking status, together with a variable speed pump, to regulate the system flow of hydraulic oil simultaneously. Therefore, the degree of valve control and pump control can be adjusted by regulating the valve-pump weight ratio. The LVPC system design, mathematical model development, system parameter and control performance analysis are carried out systematically followed by an experimental for validation process. Results have shown that after introducing the valve control, the total leakage coefficient increases significantly over a wide range with the operating point and this further increases damping ratios and reduces the velocity stiffness. As the valve-pump weight ratio determines the flow distribution between the valve and the pump and the weight factors of the valve and/or the pump controls determines the response speed of the LVPC system, thus if the weight factors are constrained properly, the LVPC system will eventually have a large synthetic open-loop gain and it will respond faster than the VSPC system. The LVPC will enrich the control schemes of oil hydraulic system and has potential value in application requiring of fast response.

Reinforcement Learning for Active Noise Control in a Hydraulic System

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Eric R. Anderson ◽  
Brian L. Steward
Keyword(s):  
Reinforcement Learning ◽  
Hydraulic System ◽  
Noise Control ◽  
Control Method ◽  
Active Noise Control ◽  
Operating Point ◽  
Hydraulic Pressure ◽  
Hydraulic Systems ◽  
Active Noise ◽  
Pressure Ripple

Abstract Hydraulic pressure ripple in a pump, as a result of converting rotational power to fluid power, continues to be a problem faced when developing hydraulic systems due to the resulting noise generated. In this paper, we present simulation results from leveraging an actor-critic reinforcement learning method as the control method for active noise control in a hydraulic system. The results demonstrate greater than 96%, 81%, and 61% pressure ripple reduction for the first, second, and third harmonics, respectively, in a single operating point test, along with the advantage of feed forward like control for high bandwidth response during dynamic changes in the operating point. It also demonstrates the disadvantage of long convergence times while the controller is effectively learning the optimal control policy. Additionally, this work demonstrates the ancillary benefit of the elimination of the injection of white noise for the purpose of system identification in the current state of the art.

Analysis of Aircraft Hydraulic System Failures

2014 ◽  
Vol 989-994 ◽  
pp. 2947-2950 ◽  
Author(s):  
Wen Guang Zhang ◽  
Guo Min Lin
Keyword(s):  
Fault Diagnosis ◽  
Hydraulic System ◽  
Economic Losses ◽  
Aircraft Maintenance ◽  
Hydraulic Systems ◽  
System Failures ◽  
Common Causes ◽  
Maintenance Cycle ◽  
The Common ◽  
Low Efficiency

The hydraulic system of Aircraft is an important power organization and plays an important role in the process of airplane operation. The failures of the airplane have the character of concealment, complexity and uncertainty. So if the hydraulic system ran out of order it not only cause huge casualties and economic losses, but also has a long and low efficiency maintenance cycle. This text analyzes the common causes of the failures and the failures that newly appeared of the aircraft hydraulic systems in detailed. Some of effective solutions have been proposed which quicken accelerate the speed of fault diagnosis and improve the efficiency of aircraft maintenance.

Energy Consumption Model of the Force Application Hydraulic System for Friction Welding Machine

2014 ◽  
Vol 536-537 ◽  
pp. 1361-1364
Author(s):  
Zheng Qiang Yang ◽  
Sui Geng Du
Keyword(s):  
Energy Consumption ◽  
Friction Welding ◽  
Hydraulic System ◽  
System Efficiency ◽  
Hydraulic Systems ◽  
Operating Characteristics ◽  
Force Application ◽  
Welding Machine ◽  
Output Flow ◽  
Low Efficiency

For the problem of low efficiency of the ordinary hydraulic systems of the friction welding machine, operating characteristics and efficiency model of the force application hydraulic system of friction welding machine are studied. The energy consumption characteristics of traditional welding machine are simulated, the efficiency characteristics of the force application hydraulic system of friction welding machine is studied, and the energy consumption and efficiency model are deduced. According to theoretical analysis, the system efficiency can be improved by changing pump output flow and relief output flow. The simulation results show that the working efficiency of the new system can be enhanced to 24%. The new friction welding hydraulic system was used in actual production and the system efficiency can be improved to 22%.

scholarly journals An experimental analysis of Lithium battery use for high power application

2021 ◽  
Vol 238 ◽  
pp. 09004
Author(s):  
Gabriele Bandini ◽  
Gianluca Caposciutti ◽  
Mirko Marracci ◽  
Alice Buffi ◽  
Bernardo Tellini
Keyword(s):  
High Power ◽  
Energy Demand ◽  
Control Method ◽  
High Energy ◽  
Market Demand ◽  
Li Ion Batteries ◽  
Experimental Conditions ◽  
Energy Devices ◽  
Industrial Sectors ◽  
Li Ion

In the recent years, the sustainable energy demand is growing among the civil and industrial sectors. However, the renewable sources present an aleatory behaviour, and the improvement of their reliable and secure employment have received great interest. In this framework, the energy storage devices can be used to smooth the market demand and to increase the control on the energy fluxes over transmission lines. To this aim, devices such as Li-ion batteries are widely used in several application scenarios, such as the transportation sector. Generally speaking, batteries are often classified as high-energy devices and their use for high-power applications is limited. Indeed, for the latter applications, other devices, such as supercapacitors or ultracapacitors, are usually employed. In the present work, the use of 3Ah 18650 Li-Ion batteries is investigated for high-power applications, and a performance analysis during pulsed discharge with current up to 50C is carried out. These experimental conditions are significantly beyond the manufacturer specifications; therefore, an accurate ageing estimation of the cell is required, and a novel internal resistance control method is proposed to monitor the state of health of the device.

scholarly journals The General Structure Of The Microprocessor

2020 ◽  
Vol 02 (11) ◽  
pp. 25-30
Author(s):  
Oybek Bakhtiyorjon ogli Parpiev ◽  
Keyword(s):  
Automatic Control ◽  
High Voltage ◽  
High Power ◽  
Control Method ◽  
General Structure ◽  
High Energy ◽  
Excitation Current ◽  
Synchronous Motors ◽  
Industrial Enterprises ◽  
Master's Thesis

Synchronous motors used by the technological process in the production of industrial enterprises are considered to be the organ of mechanical drives of pipe compressors. When high-voltage, high-power motors are excited by the automatic control method, the setting nominal excitation current is maintained, and when such equipment is operated, a high energy saving is achieved. Such problems are the problems of the quarry and the demand for production. When solving these problems, the replacement of inefficient tristor excitatory devices with effective microprocessor exciters is set forth in the report of the master's thesis.

Actuator Speed Control Using Digital Hydraulics

2014 ◽  
Author(s):  
Cristiano Cardoso Locateli ◽  
Henri Carlo Belan ◽  
Edson Roberto De Pieri ◽  
Petter Krus ◽  
Victor Juliano De Negri
Keyword(s):  
Hydraulic System ◽  
Power Loss ◽  
Speed Control ◽  
Energetic Efficiency ◽  
Hydraulic Systems ◽  
Small Oscillations ◽  
Small Power ◽  
Delay Times ◽  
Motor Mode ◽  
Circuit Configuration

In the last few years, the energetic efficiency of hydraulic systems has been widely discussed. One approach that has a particular potential is digital hydraulics. According to recent research, digital hydraulics has several potential advantages when compared with traditional technology, such as improved energy efficiency and the simplicity and robustness of its components. In this context, the main objective of this paper is to discuss the speed control of symmetrical actuators using digital hydraulic principles. It is proposed a hydraulic circuit configuration based on use of several fixed displacement units instead of one pump, on/off directional valves replacing flow control valves, and a specific control strategy. An energy management device is also proposed. This device allows the digital hydraulic system to operate in motor mode as well as store energy, therefore, improving the efficiency. The modelling of the hydraulic system is carried out by AMESim software and the control is implemented in the MATLAB software. The simulations were carried out using a co-simulation technique. Initially, the speed behaviour of the digital hydraulic system, using different delay times applied to on/off valves, is analyzed. The cases where the smallest power loss and the best dynamic behaviour take place are identified. Based on this, the actuator speed behavior, flow rate on the on/off valves and actuators and the pressure in the fixed displacement units for different speed steps are studied. The preliminary results showed a small power loss in the digital hydraulic system when compared with the average efficiency of other hydraulic systems. The speed transitions had small oscillations and adequate dynamic behavior.

HAYNES Ti-3Al-2.5V

Alloy Digest ◽  
2008 ◽  
Vol 57 (1) ◽  
Keyword(s):  
Stainless Steel ◽  
Physical Properties ◽  
Tensile Properties ◽  
Weight Ratio ◽  
Heat Treating ◽  
Hydraulic Systems ◽  
Seamless Tubing

Abstract Haynes Ti-3Al-2.5V alloy is used where the strength/weight ratio is of prime importance; the alloy is 43% lighter than 21-6-9 stainless steel. It is most often used in the form of seamless tubing for aircraft hydraulic systems. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on forming, heat treating, and joining. Filing Code: TI-145. Producer or source: Haynes International Inc.

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