Modeling and Simulation of the Dynamic Characteristics of a Hydraulic Power Limiting Valve with Two-Spring

2010 ◽  
Vol 44-47 ◽  
pp. 1387-1391
Author(s):  
Bi Zhong Xia ◽  
Ping Fa Feng ◽  
Hua Yong Yang
Keyword(s):  
Dynamic Characteristics ◽  
High Efficiency ◽  
Structural Parameters ◽  
Hydraulic Drive ◽  
Hydraulic Pump ◽  
Real Time Control ◽  
Hydraulic Power ◽  
Time Control ◽  
Pump Pressure ◽  
Discharge Pressure

A hydraulic power limiting valve, HPLV, is a key hydraulic element to realize power limiting control for hydraulic drive system in engineering machinery. By tracing with the discharge pressure of hydraulic pump, HPLVs are used to real-time control the pilot pressure that corresponds to the displacement of hydraulic pump, and match the output power of hydraulic pump with the power of its prime mover within high efficiency scope. So good dynamics is important for HPLVs to reflect the frequently change of pump pressure. Based on the description of a typical HPLV with two-spring structure, its principle and the working process are discussed, then the mathematical model is established and the effects of several main structural parameters on its dynamic characteristics are carried out.

Switchmode Hydraulic Power Supply Theory

2005 ◽  
Author(s):  
Jianwei Cao ◽  
Linyi Gu ◽  
Feng Wang ◽  
Minxiu Qiu
Keyword(s):  
Flow Rate ◽  
Dynamic Characteristics ◽  
Power Supply ◽  
Power Loss ◽  
High Speed ◽  
Hydraulic Pressure ◽  
Hydraulic Systems ◽  
Hydraulic Pump ◽  
Hydraulic Power ◽  
Supply Pressure

Switchmode hydraulic power supply is a new kind of energy-saving pressure converting system, which is originally proposed by the authors. It is mainly applied in multiple-actuator hydraulic systems, and installed between hydraulic pump and actuators (one switchmode hydraulic power supply for one actuator). It can provide pressure or flow rate that is adapted to the consumption of each actuator in the system by boosting or bucking the pressure, with low power loss, and conveniently, through high-speed switch valves, just like a hydraulic pressure transformer. There are two basic types of switchmode hydraulic power supply: pressure boost and pressure buck. Their structures and working principles are introduced. The dynamic characteristics of two typical types of switchmode hydraulic power supply, the pressure boost type and the pressure buck type, were analyzed through simulations and experiments. The performances were evaluated, and improvements on the efficiency of switchmode hydraulic power supply were proposed.

Damping Mechanisms in Cable-Harnessed Structures for Space Applications: Analytical Modeling

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Pranav Agrawal ◽  
Armaghan Salehian
Keyword(s):  
Structural Parameters ◽  
Analytical Models ◽  
Space Structures ◽  
Real Time Control ◽  
Space Applications ◽  
Time Control ◽  
Starting Point ◽  
Recent Developments ◽  
Damping Effects ◽  
Distributed Transfer Function

Abstract Recent developments in the aerospace industry have driven focus toward accurately modeling the effects of the cables and electronic cords on space structures. In the past, researchers have modeled the mass and stiffness effects of these cables but primarily overlooked their damping effects through careful analytical model developments. The objective of the current work is to present analytical models for cable-harnessed structures that also include the damping effects in their vibration response. Obtaining simple, low-order and high-fidelity models are highly advantageous in designing robust vibration real-time control algorithms for structures. Additionally, the analytical models are useful tools in providing insight into and better understanding of the dynamics of space structures as they are often difficult to be tested prior to launch due to their large size and at best only a few components may be tested. Motivated by the space applications, this work considers beam structures wrapped with cables which are modeled using beam and string theory assumptions. Two different damping models namely Kelvin–Voigt and hysteretic damping are considered. The homogenization approach is used as a starting point for structures of periodic wrapping patterns. Using the variational principle, the governing partial differential equation for the transverse coordinate of vibrations is found for three cable patterns and the results are compared to those from the distributed transfer function method (DTFM). Finally, the effects of several structural parameters are studied on the overall system damping.

Analyzing of Dynamic Characteristics of Special CNC Machine Tool

2010 ◽  
Vol 29-32 ◽  
pp. 2037-2041
Author(s):  
Ke Wang ◽  
Guang Lv ◽  
Xing Wei Sun
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Optimization Design ◽  
High Efficiency ◽  
Structural Parameters ◽  
Force Frequency ◽  
Cutting Method ◽  
Finite Element Software ◽  
Exciting Frequency ◽  
Motion Parameters

The dynamic characteristics of machine tool is an important factor, which make affect on the cutting stability of machine tool. The poor dynamic characteristics will seriously affect the stability of cutting, make the low cutting efficiency and low machining precision, and also accelerate the wear of tools and even reduce the machine’s service life. So it is necessary to analyze the dynamic characteristics of machine tool, and according to the results of analysis to optimize structural parameters and motion parameters of the machine tools. This paper analyses the dynamic characteristics of machine bed and machined work piece of the CNC special machine tool for Kelly with the finite element software, and analysis of excitation characteristics of cutting tool. It also makes optimization design to the machine bed, through the analysis and optimization, the natural frequency and stiffness will be obviously improved. According to the structure and calculation of the motion parameters we can get the exciting force frequency to workpiece when it is cut, using interlocking tooth cutting method to replace the initial symmetrical cutting method in order to avoid the resonance produced in the cutting process and improve stability. The exciting frequency when cutting can be improved and the probability of resonance when cutting is lowered. All these ensure high efficiency and high stability cutting.

Kinematics optimization and static analysis of a modular continuum robot used for minimally invasive surgery

2017 ◽  
Vol 232 (2) ◽  
pp. 135-148 ◽  
Author(s):  
Fei Qi ◽  
Feng Ju ◽  
Dong Ming Bai ◽  
Bai Chen
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Invasive Surgery ◽  
Virtual Work ◽  
Structural Parameters ◽  
Real Time Control ◽  
Time Control ◽  
Payload Capacity ◽  
Continuum Robot ◽  
The Relationship

For the outstanding compliance and dexterity of continuum robot, it is increasingly used in minimally invasive surgery. The wide workspace, high dexterity and strong payload capacity are essential to the continuum robot. In this article, we investigate the workspace of a cable-driven continuum robot that we proposed. The influence of section number on the workspace is discussed when robot is operated in narrow environment. Meanwhile, the structural parameters of this continuum robot are optimized to achieve better kinematic performance. Moreover, an indicator based on the dexterous solid angle for evaluating the dexterity of robot is introduced and the distal end dexterity is compared for the three-section continuum robot with different range of variables. Results imply that the wider range of variables achieve the better dexterity. Finally, the static model of robot based on the principle of virtual work is derived to analyze the relationship between the bending shape deformation and the driven force. The simulations and experiments for plane and spatial motions are conducted to validate the feasibility of model, respectively. Results of this article can contribute to the real-time control and movement and can be a design reference for cable-driven continuum robot.

Optimal Pole Assignment of Self-Balancing Robot System

2012 ◽  
Vol 538-541 ◽  
pp. 2649-2653
Author(s):  
Yan Hua Zhao ◽  
Guo Zhang ◽  
Chun Xia Duan
Keyword(s):  
Optimal Design ◽  
Dynamic System ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic System ◽  
Pole Assignment ◽  
Real Time Control ◽  
Robot System ◽  
Time Control ◽  
Balancing Robot

Self-balancing robot is a multivariable, coupled, nonlinear dynamic system, using the optimal pole assignment which can give attention to both good dynamic characteristics and LQ optimal design technology robustness and other advantages. Emulation and real-time control are given to show the effectiveness of the presented method.

Optimal Efficiency Shift Schedule of Automatic Transmission for Construction Vehicle

2012 ◽  
Vol 468-471 ◽  
pp. 2403-2408
Author(s):  
Huai Liang Kang ◽  
Jie Gong ◽  
Ding Xuan Zhao ◽  
Tian Yu Li
Keyword(s):  
Working Conditions ◽  
High Efficiency ◽  
Automatic Transmission ◽  
Vehicle Speed ◽  
Hydraulic Pump ◽  
Wheel Loader ◽  
Dynamic Simulation Model ◽  
Simulation Results ◽  
Optimal Efficiency ◽  
Pump Pressure

The working conditions for construction vehicles (wheel loader, bulldozer, etc.) are very complicated and the operating loads change frequently and sharply. This result will lead to lower powertrain efficiency. In order to maintain the high efficiency of construction vehicles equipped with automatic transmission, an optimal efficiency shift (OES) schedule with 3-parameter (vehicle speed, throttle opening, and hydraulic pump pressure) is proposed and designed by creating and analyzing the powertrain model. A dynamic simulation model using the OES schedule for the construction vehicle has been established by MATLAB/Simulink. The simulation results show that the 3-parameter shift (3PS) schedule is superior to the 2-parameter (vehicle speed and throttle opening) shift (2PS) schedule in energy saving.

scholarly journals Studies related to the calculation of the noise. The study of pumping hydraulic systems and the study of the use of an unloading valve in a hydraulic system

2020 ◽  
Vol 175 ◽  
pp. 05037 ◽  
Author(s):  
Kirill Kobzev ◽  
Sergey Vyalov ◽  
Alexander Rybak
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Numerical Experiment ◽  
Dynamic Properties ◽  
Structural Parameters ◽  
Power Source ◽  
Hydraulic Systems ◽  
Hydraulic Pump ◽  
Original Design ◽  
Hydraulic Power

In order to identify the main functional capabilities of the control system of the pump-accumulator hydraulic power source equipped with a pump unloading machine of the proposed design, a numerical experiment was carried out. The experiment was a numerical solution of the above mathematical model of a power source. During the experiment, the influence of various structural parameters of the hydraulic pump unloading machine and the functional parameters of the power supply system as a whole on its dynamic properties was revealed. The article discusses the control system of a hydraulic power source of constant pressure, which is a pump-storage power source, equipped with the original design of the automatic unloading of the hydraulic pump, which provides relay switching of its operation mode. A mathematical model is proposed, obtained using a modeling technique based on the application of the theory of volumetric rigidity of hydraulic systems and their elements. The results of a numerical experiment carried out by numerically solving the equations that make up the mathematical model of a power source are also presented.

The Oil Temperature Controlling of Hydraulic Pump Performance Test-System

2013 ◽  
Vol 561 ◽  
pp. 478-482
Author(s):  
Bei Sun ◽  
Xue Man Zhang ◽  
Kai Ge Sun
Keyword(s):  
Performance Test ◽  
Minimum Variance ◽  
Test System ◽  
Test Bed ◽  
Hydraulic Pump ◽  
Real Time Control ◽  
Pump Performance ◽  
Time Control ◽  
Computer Device ◽  
Testing Accuracy

In the testing of the oil temperature controlling of hydraulic pump performance test-system, the changing of oil temperature bring the testing accuracy decrease, so it can influence nicety and contrast of test-bed. A computer device of oil temperature real time control are designed. The result of control achieve B level accuracy of international and guild. The software of computer is minimum variance correcting by oneself.

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