Electrically Controlled Fixed-Displacement Pump, Variable-Displacement Motor Hydrostatic Transmission

2006 ◽  
Author(s):  
Michael A. Holland ◽  
Keith Harmeyer ◽  
John H. Lumkes
Keyword(s):  
Hydrostatic Transmission ◽  
Displacement Pump ◽  
Variable Displacement

Modeling and simulation of a hydrostatic transmission with variable-displacement pump

2000 ◽  
Vol 53 (4-6) ◽  
pp. 409-414 ◽  
Author(s):  
Andreas Kugi ◽  
Kurt Schlacher ◽  
Heinz Aitzetmüller ◽  
Gottfried Hirmann
Keyword(s):  
Modeling And Simulation ◽  
Hydrostatic Transmission ◽  
Displacement Pump ◽  
Variable Displacement

Review of Early Work on Digital Displacement® Hydrostatic Transmission Systems

2018 ◽  
Author(s):  
Niall Caldwell
Keyword(s):  
Time Domain ◽  
Lumped Parameter Model ◽  
Primary Control ◽  
Hydrostatic Transmission ◽  
Load Sensing ◽  
Lumped Parameter ◽  
Good Comparison ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Work Done

The paper describes the work done by the author (1) from 1999 to 2006 to develop the Digital Displacement Pump (DDP) and Pump/Motor (DDPM) and demonstrate the feasibility of off-highway vehicle applications. The link between DDPM capacity and the solenoid valve performance was identified. Magnetic geometry was improved by parametric FEA, then time-domain behavior was improved with a hybrid FEA/lumped-parameter model. Software improvements allowed variable speed and bidirectional operation, enabling the demonstration of the first Digital Displacement Transmission (DDT) systems on a vehicle, one featuring a load-sensing DDP and secondary control by DDPM displacement, and one featuring primary control by DDP displacement and a conventional axial motor. A time-domain simulation was created of the primary-controlled vehicle, which yielded good comparison to experimental results. The deterministic nature of the DDP lends itself to model-based system design methods, which have since been used to develop larger commercial systems. The first detailed analysis of DDP efficiency characteristics revealed profound differences to conventional variable displacement pumps, including exceptional part-load efficiency and the dominant effect of fluid compressibility. A peak overall efficiency of 97% was recorded for a DDP after analysis of loss sources prompted design improvement.

scholarly journals Experimental Validation of a Hydrostatic Transmission for Community Wind Turbines

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 376
Author(s):  
Biswaranjan Mohanty ◽  
Kim A. Stelson
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Pressure Control ◽  
Speed Ratio ◽  
Hydrostatic Transmission ◽  
Design Flexibility ◽  
Power Capture ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Hydrostatic Transmissions

Hydrostatic transmissions are commonly used in heavy-duty equipment for their design flexibility and superior power density. Compared to a conventional wind turbine transmission, a hydrostatic transmission (HST) is a lighter, more reliable, cheaper, continuously variable alternative for a wind turbine. In this paper, for the first time, a validated dynamical model and controlled experiment have been used to analyze the performance of a hydrostatic transmission with a fixed-displacement pump and a variable-displacement motor for community wind turbines. From the dynamics of the HST, a pressure control strategy is designed to maximize the power capture. A hardware-in-the-loop simulation is developed to experimentally validate the performance and efficiency of the HST drive train control in a 60 kW virtual wind turbine environment. The HST turbine is extensively evaluated under steady and time-varying wind on a state-of-the-art power regenerative hydrostatic dynamometer. The proposed controller tracks the optimal tip-speed ratio to maximize power capture.

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.

scholarly journals Modeling and Designing a Hydrostatic Transmission With a Fixed-Displacement Motor

1998 ◽  
Vol 120 (1) ◽  
pp. 45-49 ◽  
Author(s):  
N. D. Manring ◽  
G. R. Luecke
Keyword(s):  
Order System ◽  
Axial Piston Pump ◽  
Third Order ◽  
Stability Range ◽  
Hydrostatic Transmission ◽  
Control Gain ◽  
Variable Displacement ◽  
Linearized System ◽  
The Stability ◽  
Axial Piston

This study develops the dynamic equations that describe the behavior of a hydrostatic transmission utilizing a variable-displacement axial-piston pump with a fixed-displacement motor. In general, the system is noted to be a third-order system with dynamic contributions from the motor, the pressurized hose, and the pump. Using the Routh-Hurwitz criterion, the stability range of this linearized system is presented. Furthermore, a reasonable control-gain is discussed followed by comments regarding the dynamic response of the system as a whole. In particular, the varying of several parameters is shown to have distinct effects on the system rise-time, settling time, and maximum percent-overshoot.

scholarly journals Performance Improvement of a Hydraulic Active/Passive Heave Compensation Winch Using Semi Secondary Motor Control: Experimental and Numerical Verification

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2671
Author(s):  
Geir-Arne Moslått ◽  
Michael Rygaard Hansen ◽  
Damiano Padovani
Keyword(s):  
Performance Improvement ◽  
Experimental Validation ◽  
Control Method ◽  
Feedforward Control ◽  
State Of The Art ◽  
Numerical Verification ◽  
Stability Margins ◽  
Hydrostatic Transmission ◽  
Expected Performance ◽  
Variable Displacement

In this paper, a newly developed controller for active heave compensated offshore cranes is compared with state-of-the-art control methods. The comparison is divided into a numerical part on stability margins as well as operational windows and an experimental validation of the expected performance improvement based on a full-scale testing on site with a crane rated to 250 metric tons. Such a crane represents the typical target for the new control method using a combination of active and passive hydraulic actuation on the main winch. The active hydraulic actuation is a hydrostatic transmission with variable-displacement pumps and variable-displacement motors. The new controller employs feedforward control of the motors’ displacement so that the window of operation is increased and, simultaneously, oscillations in the system are markedly reduced.

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