scholarly journals Simulation on acceleration-deceleration characteristics of a hydraulic elevator with a variable displacement pump.

1988 ◽  
Vol 19 (4) ◽  
pp. 312-322
Author(s):  
Fumio FUJISAWA ◽  
Ichiro NAKAMURA
Keyword(s):  
Displacement Pump ◽  
Variable Displacement

Energy-saving design of variable-displacement bi-directional pump-controlled electrohydraulic system

2020 ◽  
pp. 095965182097389
Author(s):  
Samir Kumar Hati ◽  
Nimai Pada Mandal ◽  
Dipankar Sanyal
Keyword(s):  
Energy Saving ◽  
Absolute Error ◽  
Fast Response ◽  
Maximum Energy ◽  
Radial Clearance ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Axial Piston

Losses in control valves drag down the average overall efficiency of electrohydraulic systems to only about 22% from nearly 75% for standard pump-motor sets. For achieving higher energy efficiency in slower systems, direct pump control replacing fast-response valve control is being put in place through variable-speed motors. Despite the promise of a quicker response, displacement control of pumps has seen slower progress for exhibiting undesired oscillation with respect to the demand in some situations. Hence, a mechatronic simulation-based design is taken up here for a variable-displacement pump–controlled system directly feeding a double-acting single-rod cylinder. The most significant innovation centers on designing an axial-piston pump with an electrohydraulic compensator for bi-directional swashing. An accumulator is conceived to handle the flow difference in the two sides across the load piston. A solenoid-driven sequence valve with P control is proposed for charging the accumulator along with setting its initial gas pressure by a feedforward design. Simple proportional–integral–derivative control of the compensator valve is considered in this exploratory study. Appropriate setting of the gains and critical sizing of the compensator has been obtained through a detailed parametric study aiming low integral absolute error. A notable finding of the simulation is the achievement of the concurrent minimum integral absolute error of 3.8 mm s and the maximum energy saving of 516 kJ with respect to a fixed-displacement pump. This is predicted for the combination of the circumferential port width of 2 mm for the compensator valve and the radial clearance of 40 µm between each compensator cylinder and the paired piston.

Robust Nonlinear Control of a Novel Indexing Valve Plate Pump: Simulation Studies

2002 ◽  
Vol 124 (4) ◽  
pp. 613-616 ◽  
Author(s):  
X. Zhang ◽  
S. S. Nair ◽  
N. D. Manring
Keyword(s):  
Pressure Control ◽  
Plate Motion ◽  
Nonlinear Simulation ◽  
Response Characteristics ◽  
Model Free ◽  
Swash Plate ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Robust Adaptive ◽  
Improved Performance

A robust adaptive pressure control strategy is proposed for a novel indexing variable-displacement pump. In the proposed approach, parametric uncertainties and unmodeled dynamics are identified to the extent possible using a model free learning network and used to decouple the dynamics using physical insights derived from careful reduced order modeling. The swash plate motion control is then carefully designed to provide the desired pressure response characteristics showing improved performance with learning. The proposed control framework and designs are validated using a detailed nonlinear simulation model.

An Improved Alternative to the Three-Dimensional, Swash Plate Mechanism

1983 ◽  
Vol 105 (3) ◽  
pp. 468-470 ◽  
Author(s):  
T. E. Shoup ◽  
D. Chi
Keyword(s):  
Theoretical Analysis ◽  
Mechanism Design ◽  
Research Effort ◽  
Three Dimensional ◽  
Design Technique ◽  
Force Transmission ◽  
Swash Plate ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Crank Mechanism

This paper presents a theoretical analysis and a design technique for the use of a special type of adjustable spatial slider crank mechanism to replace the swash plate device commonly used as a variable displacement pump or compressor. This paper is an extension of a previous research effort utilizing the RSSP mechanism [7] and considers the influence of geometric proportions of a device on stroke size, velocity fluctuation, and force transmission effectiveness. The device is shown to have significant kinematic advantages over the traditional form of the swash plate mechanism. Design curves are presented and an example application is provided.

Simulation and Field Experiments With an Agricultural Tractor of a Robust Control for a Complete Fluid Power Circuit Using a New Electro-Hydraulic Pump: Part II—Control

2010 ◽  
Author(s):  
Pandeli Borodani ◽  
Davide Colombo ◽  
Marco Forestello ◽  
Patrizio Turco ◽  
Riccardo Morselli
Keyword(s):  
Field Experiments ◽  
Optimization Techniques ◽  
Point Of View ◽  
Hydraulic Pump ◽  
Power Circuit ◽  
Control Approach ◽  
New Device ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Energetic Point

The plant under control is the hydraulic circuit arranged by CNH in a prototype agriculture tractor of medium segment, where instead of the conventional main hydraulic pump, a new device electronically piloted, is installed. The main purpose is basically to obtain some advantages according to the energetic point of view, by means of an appropriate control structure, managing the electronic variable displacement pump. The frontier of the new systems requires the employment of the advanced control techniques, in order to assure the levels of precision, reliability, robustness demanded from systems. The control design methodology employed in the present case is based on robust H∞ optimization techniques, where robust stability properties are guaranteed in presence of unaccountable dynamics and other destabilizing factors. The effectiveness of the proposed control approach is tested on the demonstrative tractor realized from the CNH Agriculture at Modena plants, in all real conditions.

Multi-Range Hydro-Mechanical Continuously Variable Transmission of Tractor

2009 ◽  
Vol 628-629 ◽  
pp. 167-172
Author(s):  
L.Y. Xu ◽  
Zhi Li Zhou ◽  
M.Z. Zhang ◽  
Y. Niu
Keyword(s):  
High Efficiency ◽  
Planetary Gear ◽  
Transmission Efficiency ◽  
Continuously Variable Transmission ◽  
Speed Range ◽  
Displacement Pump ◽  
Variable Transmission ◽  
Variable Displacement ◽  
Wide Speed Range ◽  
Ratio Transmission

In this paper, to improve the transmission ratio discontinuity problem during the gear shift process in the multi-gear fixed step ratio transmission of the tractors, a hydro-mechanical continuously variable transmission (HMCVT) for tractors is developed, which is composed of a single planetary gear differential train, a hydraulic transmission system consisted of the variable displacement pump (PV) and the fixed displacement motor (MF) and a multi-gear fixed step ratio transmission. Its stepless-speed-regulating characteristic, smooth range shifting condition and transmission efficiency are analyzed. The analytical results show that the tractors assembled with HMCVT can gain wide speed range and high transmission efficiency. There are eight high efficiency pure mechanical gears in the whole speed range, which is benefit to improve power and economic capabilities of vehicles.

scholarly journals Design and Validation of a Soft Switch for a Virtually Variable Displacement Pump

2017 ◽  
Vol 140 (6) ◽  
Author(s):  
Brandon K. Beckstrand ◽  
James D. Van de Ven
Keyword(s):  
Energy Loss ◽  
Soft Switching ◽  
Cycle Period ◽  
Soft Switch ◽  
Load Pressure ◽  
Locking Mechanism ◽  
Piston Displacement ◽  
Switch Mode ◽  
Displacement Pump ◽  
Variable Displacement

Switch-mode hydraulic control is a compact and theoretically efficient alternative to throttling valve control or variable displacement pump control. However, a significant source of energy loss in switch-mode circuits is due to throttling during valve transitions. Hydraulic soft switching was previously proposed as a method of reducing the throttling energy loss, by absorbing, in a small variable volume chamber, the flow that would normally be throttled across the transitioning high-speed valve. An active locking mechanism was previously proposed that overcomes the main challenge with soft switching, which is a lock mechanism that releases quickly and with precise timing. This prior work demonstrated a reduction in energy losses by 66% compared to a control circuit. In this paper, a numerical model is developed for a switch-mode virtually variable displacement pump (VVDP) circuit, utilizing the proposed soft switch. The model is then used as a means of designing a proof of concept prototype to validate the model. The prototype design includes methods for controlling the soft switch spring preload, travel distance, piston displacement required to unlock the soft switch, valve command duty cycle, switching cycle period, and load pressure. Testing demonstrated that the soft switch circuit performed as expected in a baseline condition. The operating region for this prototype was found to be quite narrow. However, the model does a good job of predicting the displacement of the soft switch.

Design and Testing of an Adjustable Linkage for a Variable Displacement Pump

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Shawn R. Wilhelm ◽  
James D. Van de Ven
Keyword(s):  
High Efficiency ◽  
Operating Conditions ◽  
The Novel ◽  
Hydraulic Pump ◽  
Low Friction ◽  
Transmission Angle ◽  
Displacement Pump ◽  
Order Of Magnitude ◽  
Variable Displacement ◽  
Design And Testing

A variable displacement hydraulic pump/motor with high efficiency at all operating conditions, including low displacement, is beneficial to multiple applications. Two major energy loss terms in conventional pumps are the friction and lubrication leakage in the kinematic joints. This paper presents the synthesis, analysis, and experimental validation of a variable displacement sixbar crank-rocker-slider mechanism that uses low friction pin joints instead of planar joints as seen in conventional variable pump/motor architectures. The novel linkage reaches true zero displacement with a constant top dead center position, further minimizing compressibility energy losses. The synthesis technique develops the range of motion for the base fourbar crank-rocker and creates a method of synthesizing the output slider dyad. It is shown that the mechanism can be optimized for minimum footprint and maximum stroke with a minimum base fourbar transmission angle of 30 deg and a resultant slider transmission angle of 52 deg. The synthesized linkage has a dimensionless stroke of 2.1 crank lengths with a variable timing ratio and velocity and acceleration profiles in the same order of magnitude as a comparable crank-slider mechanism. The kinematic and kinetic results from an experimental prototype linkage agree well with the model predictions.

Quadratic Programming to Optimize Energy Efficiency of Speed- and Displacement-Variable Pumps

2014 ◽  
Author(s):  
Johannes Willkomm ◽  
Matthias Wahler ◽  
Jürgen Weber
Keyword(s):  
Energy Efficiency ◽  
Energy Savings ◽  
Control Strategies ◽  
Quadratic Optimization Problem ◽  
Optimum Energy ◽  
Displacement Pump ◽  
Control Concept ◽  
Drive Speed ◽  
Variable Displacement ◽  
Dynamic Loss

Within the last years, speed-variable pump drives were investigated in numerous applications. In combination with a variable displacement pump, the volume flow and the drive speed can be decoupled. In this paper the resulting degree of freedom will be used to minimize the energy consumption of hydraulic processes by means of a novel model predictive control concept. A dynamic loss model of all drive components will be transformed to a mathematical quadratic optimization problem. The optimum use of the two control variables can achieve energy savings of up to 25% in comparison to known control strategies of speed-variable variable-displacement pumps. Especially in highly dynamic process cycles the proposed optimization guarantees optimum energy efficiency while known approaches become inefficient.

Sign in / Sign up

Export Citation Format

Share Document