Study of Control Method Based on Hydromechanics for Hydraulic Impact of Open Hydraulic System in Concrete Pump

2014 ◽  
Vol 908 ◽  
pp. 320-325
Author(s):  
Wan Rong Wu ◽  
Zhen Wen Mao
Keyword(s):  
Hydraulic System ◽  
Control Method ◽  
Process Time ◽  
Displacement Control ◽  
Hydraulic Impact ◽  
Variable Displacement ◽  
Time Parameters ◽  
Concrete Pump ◽  
The Impact ◽  
Changing Process

According to the working principle of open hydraulic system in concrete pump, and though the theoretical analysis on the phenomenon of hydraulic impact in direction changing process, it concluded that the impact pressure has a linear relation with the displacement of the main oil pump .To solve the hydraulic impact problem ,a variable displacement method was proposed .Under the requirement of piston not striking the bottom of cylinder and piston stroke control accuracy ,the authors optimized the pumping direction changing process time parameters and the displacement control time parameters . Though the AMESim modeling simulation and experimental study , the variable displacement control method is proved feasible on reducing the hydraulic impact in direction changing process.

A Control Algorithm for Active/Passive Hydraulic Winches Used in Active Heave Compensation

2019 ◽  
Author(s):  
Geir-Arne Moslått ◽  
Damiano Padovani ◽  
Michael R. Hansen
Keyword(s):  
Hydraulic System ◽  
Control Algorithm ◽  
Closed Loop ◽  
Peak Pressure ◽  
Control Method ◽  
High Fidelity Simulation ◽  
Speed Performance ◽  
Variable Displacement ◽  
Active Motor ◽  
Classical Control

Abstract The most common active heave compensated offshore cranes have hydraulic winch systems. This paper investigates an active/passive hydraulic winch system with variable-displacement motors and variable-displacement pumps. The paper addresses the challenges when the active motors are set with a low displacement. The active motor displacement is shown to have significant impact on the dynamics of the closed loop hydraulic system. The classical control strategy for this type of system do not address these challenges and will in certain situations have significantly reduced performance. Therefor, a new control method is presented that utilize the variable displacement of the pumps and motors for speed control and to improve dynamics characteristics. The new winch controller is tested in a high-fidelity simulation model and is shown to improve low speed performance, reduce winch speed limitations by up to 30%, reduce system peak pressure by approximately 20%, and reduce control error by approximately 30%.

Dynamic Response of Pressure Compensated Variable Displacement Linkage Pump

2018 ◽  
Author(s):  
Nathaniel J. Fulbright ◽  
James D. Van de Ven
Keyword(s):  
Dynamic Model ◽  
Control Method ◽  
Response Times ◽  
Control Line ◽  
Displacement Control ◽  
Mechanical Pressure ◽  
Control Valves ◽  
Variable Displacement ◽  
Simulation Results ◽  
Displacement Control Method

The Variable Displacement Linkage Pump (VDLP) uses an adjustable planar linkage to vary the displacement of the piston. Previous work focused on dynamic modeling of the pump at fixed displacements and therefore did not account for the displacement control method or the dynamics of changing displacement. One key application of the VDLP is in pressure compensated, high-pressure water hydraulics. This paper expands on previous modeling work to include the behavior of the hydro-mechanical pressure compensation valves and the displacement control linkage. The multi-domain dynamic model captures the fluid dynamics in the pumping chambers and poppet-style control valves; the dynamics of the control valves; and the kinematics and kinetics of the two degree-of-freedom nine-bar pump linkage. The dynamic model was exercised in a simulation of the pump responding to changing demands in the output flow rate. Simulation results showed that quick response times of 100 milliseconds to a step in the load were achieved. Overshoot of the displacement is damped using an orifice in the control line. A physical prototype of the VDLP was used to validate the simulation results.

Optimization on Control Time Sequence of Double-Pump Hydraulic System of Concrete Pump

2013 ◽  
Vol 437 ◽  
pp. 728-733
Author(s):  
Hai Bo Xie ◽  
Jian Chen ◽  
Hua Yong Yang ◽  
Zhi Bin Liu ◽  
Yu Zhen ◽  
...  
Keyword(s):  
Simulation Model ◽  
Hydraulic System ◽  
Simulation Models ◽  
Open Circuit ◽  
Time Sequence ◽  
Integrated Simulation ◽  
Control Time ◽  
Save Energy ◽  
Concrete Pump ◽  
The Impact

This research mainly investigates the control time sequence in the open circuit double-pump hydraulic system of the concrete pump. The control time sequence is the electrical signals given to the two pumps and the pilot valves of the two main valves. Under the signals’ control, the valves are switched and the flowrate of the two pumps becomes low during the valve switch in order to save energy and reduce the impact pressure. According to the actual hydraulic components, the simulation models about two main hydraulic circuits which are pumping circuit and distributing circuit including directional valves, the pump with the function of constant power control with pressure cut-off and electrical stroke limiter, the two pumping cylinders with cushion structure and distributing structure are developed with software AMESim. On the basis of the two circuits model, an integrated simulation model is developed. Having been validated by the pumping water experiment, the simulation model is used to simulate different control time sequence. Based on the analysis of these simulation results, a proper control time sequence which ensures the pumping system has higher pumping efficiency and longer cylinder stroke is achieved.

scholarly journals EVALUATION OF PARAMETERS OF HYDRAULIC IMPACT DEVICES OF ACTIVE BUCKET WITH DIRECT CONNECTION TO THE HYDRAULIC SYSTEM OF II GRADE EXCAVATOR

2020 ◽  
Vol 2 ◽  
pp. 45-51
Author(s):  
Leonid V. Gorodilov ◽  
Nikolai A. Maslov ◽  
Alexander N. Korovin
Keyword(s):  
Compressive Strength ◽  
Hydraulic System ◽  
Direct Connection ◽  
Frozen Soils ◽  
Impact Power ◽  
Percussion System ◽  
Hydraulic Impact ◽  
Evaluation Of Parameters ◽  
The Impact ◽  
Active Bucket

The impact power of hydraulic percussion system of active bucket of Belarus EO-2628 excavator with a capacity of 0.25 m required for the effective mining of rocks with ultimate compressive strength of 60-80 MPa and frozen soils of V-VIII category is determined. The diagram of direct connection of hydraulic impact devices to excavator hydraulic system is presented. Using the HPS software, the parameters and characteristics of impact devices are selected.

Applying Synthetic Control Method to Estimate the Impact of the Lava Jato Operation on the Worldwide Governance Indicators in Brazil

2021 ◽  
pp. 2631309X2110178
Author(s):  
Eduardo Carvalho Nepomuceno Alencar ◽  
Bryant Jackson-Green
Keyword(s):  
Rule Of Law ◽  
Control Method ◽  
Synthetic Control ◽  
Synthetic Control Method ◽  
The Rule Of Law ◽  
Governance Indicators ◽  
Regulatory Quality ◽  
Legal Judgments ◽  
The Impact ◽  
Control Of Corruption

In 2014, the most prominent anti-corruption investigation in Latin America called Lava Jato, exposed a Brazilian corruption scheme with reverberations in 61 countries, resulting in legal judgments for nearly 5 billion USD in reimbursements thus far. This article applies the synthetic control method on data from 135 countries (2002–2018) to test the hypothesis that Lava Jato impacts the Worldwide Governance Indicators in Brazil. The findings reveal that Lava Jato negatively affects control of corruption, the rule of law, and regulatory quality. There are signs of possible improvement in at least the corruption and the rule of law measures. This paper brings value to the criminological body of literature, notably lacking in the Global South.

scholarly journals When is a Match Sufficient? A Score-based Balance Metric for the Synthetic Control Method

2020 ◽  
Vol 8 (1) ◽  
pp. 209-228
Author(s):  
Layla Parast ◽  
Priscillia Hunt ◽  
Beth Ann Griffin ◽  
David Powell
Keyword(s):  
Los Angeles ◽  
Control Method ◽  
Control Unit ◽  
Treated Group ◽  
Control Group ◽  
Synthetic Control ◽  
Donor Pool ◽  
Synthetic Control Method ◽  
The Mean ◽  
The Impact

AbstractIn some applications, researchers using the synthetic control method (SCM) to evaluate the effect of a policy may struggle to determine whether they have identified a “good match” between the control group and treated group. In this paper, we demonstrate the utility of the mean and maximum Absolute Standardized Mean Difference (ASMD) as a test of balance between a synthetic control unit and treated unit, and provide guidance on what constitutes a poor fit when using a synthetic control. We explore and compare other potential metrics using a simulation study. We provide an application of our proposed balance metric to the 2013 Los Angeles (LA) Firearm Study [9]. Using Uniform Crime Report data, we apply the SCM to obtain a counterfactual for the LA firearm-related crime rate based on a weighted combination of control units in a donor pool of cities. We use this counterfactual to estimate the effect of the LA Firearm Study intervention and explore the impact of changing the donor pool and pre-intervention duration period on resulting matches and estimated effects. We demonstrate how decision-making about the quality of a synthetic control can be improved by using ASMD. The mean and max ASMD clearly differentiate between poor matches and good matches. Researchers need better guidance on what is a meaningful imbalance between synthetic control and treated groups. In addition to the use of gap plots, the proposed balance metric can provide an objective way of determining fit.

The impact of highly permeable layer on hydraulic system in a coastal aquifer

2012 ◽  
pp. n/a-n/a ◽  
Author(s):  
Kue-Young Kim ◽  
Weon Shik Han ◽  
Eungyu Park
Keyword(s):  
Coastal Aquifer ◽  
Hydraulic System ◽  
Permeable Layer ◽  
The Impact

The Study of Underfill Epoxy Hardness in Reducing Curing Process Time for Flip Chip Packaging

2011 ◽  
Vol 462-463 ◽  
pp. 1194-1199
Author(s):  
Zainudin Kornain ◽  
Azman Jalar ◽  
Rozaidi Rashid ◽  
Shahrum Abdullah
Keyword(s):  
Thermal Expansion ◽  
Flip Chip ◽  
Ball Grid Array ◽  
Process Time ◽  
Curing Process ◽  
Curing Time ◽  
Hold Temperature ◽  
Flip Chip Packaging ◽  
Time Cycle ◽  
The Impact

Underfilling is the vital process to reduce the impact of the thermal stress that results from the mismatch in the co-efficient of thermal expansion (CTE) between the silicon chip and the substrate in Flip Chip Packaging. This paper reported the pattern of underfill’s hardness during curing process for large die Ceramic Flip Chip Ball Grid Array (FC-CBGA). A commercial amine based underfill epoxy was dispensed into HiCTE FC-CBGA and cured in curing oven under a new method of two-step curing profile. Nano-identation test was employed to investigate the hardness of underfill epoxy during curing steps. The result has shown the almost similar hardness of fillet area and centre of the package after cured which presented uniformity of curing states. The total curing time/cycle in production was potentially reduced due to no significant different of hardness after 60 min and 120 min during the period of second hold temperature.

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