Maha Fluid Power Research Center
Center for Compact and Efficient Fluid Power
Global Fluid Power Society


Maha Fluid Power Research Center hosts cutting-edge research in hydraulics and fluid power. From computer modeling of pumps and motors, to experimental verification on real-world equipment, every aspect of fluid power and motion control is explored at Maha.

Multics: Multi-domain modeling of pumps and motors
Pump and motor novel designs
Noise control and acoustics
High efficiency hydraulic actuations
Electrification of fluid power systems
Advanced control systems: active vibration daming and traction
Fluid properties modeling and cavitation analysis
Condition monitoring in hydraulic systems
Machine learning applied to fluid power

Multics: Multi-domain modeling of Pumps & Motors

External gear pump simulation in Multics
Gerotor simulation in Multics

Multics is a cross-platform, multi-physics modeling software for positive displacement machines. It enables rapid design assessment and optimization.
Multics simulates the operation of hydraulic pumps/motors, combining multiple domains of study, such as:

  • Micromotions & deformations of internal parts
  • Power losses in lubricating films
  • Leakage flows and temperature
  • Fluid aeration & cavitation
  • Internal gear machine simulation in Multics
  • And more!

The software is highly configurable for different types of pumps and motors. The current presets include:

  • Axial Piston Machines (Multics CASPAR)
  • External Gear Machines
  • Internal Gear Machines
  • Gerotors

Check out the Multics Brochure for more information.

Axial piston pump simulation in Multics

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Pumps & Motor Novel Designs

Variable displacement gear machine: a unit that is usually fixed displacement converted to variable displacement

Maha has been contributing towards innovative designs in pumps and motors, to meet different technology trends:

  • New feature introduction
    Maha has worked on innovative design feautes to expand the range of applications in specific pump/motor designs, resulting in a variet of prototype developments
  • Energy efficiency improvement
    Researching better designs of pump/motor units to decrease losses due to heat and friction is an area in which Maha is doing significant work.
  • Optimal operating range expansion
    Through study of the limiting factors of unit operation, Maha develops and tests new solutions that can increase the envelope of conditions in which a pump/motor can run.
  • Micro-shaping on running surfaces of lubricating interfaces improves hydrodynamic effects and reduces friction
  • Noise emissions reduction
    Through increased understanding of unit noise sources from acoustics modeling and study, new solutions are being developed to reduce frequency emissions. See Noise Contol & Acoustics for more.
  • Pump electrification: ePump
    Maha is creating and validating designs for integrated electric-hydraulic machine prototypes. See Electrification of Fluid Power Systems for more.

Bimetallic piston design maintains high piston/cylinder interface efficiency over broader range of operating temperatures.

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Noise Control & Acoustics

Example of simulated gear pump pressure for modal analysis

Research activities in this area aim at understanding the sources of noise within hydraulic pumps and systems to provide solutions for quieter technology.

The analyses include all relevant domains of Fluid Borne Noise (FBN), Structure Borne Noise (SBN), and Airborne Noise (ABN). Activities mainly focus on positive displacement machines, where the in-house Multics simulation tool is used to replicate the measurements gathered from the Maha Sound Chamber.

Click Here to watch a more in-depth presentation on acoustics modeling at Maha.

Pressure ripple analysis on pump delivery systesm - transmission line effects

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High Efficiency Hydraulic Actuations

Ford F-150 hybrid hydrostatic Powersplit Transmission

Activities at Maha encompass drive cycle analysis application, to the formulation, simulation, and testing of novel solutions that improve energy efficiency.

Multi-chamber cylinder to minimize throttling losses in secondary control fluid power systems
New actuation technologies studies at Maha have included:

  • Pump displacement control (DC)
  • Hydraulic hybrids
  • Multi-pressure rail systems
  • Electronic load sensing
  • Independent metering actuation

Doubling the energy efficiency of the high-pressure hydraulic systems for tractors and implements via multi-pressure rail technology

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Electrification of Fluid Power Systems

Compact loader with working functions powered by Maha-designed EHA system. Energy consumption vs. baseline

This area of research relates to new concepts for fluid power systems and components suitable to electric-powered applications, such as battery operated vehicles.

Compared to conventional engine-driven systems, such applications require a more energy-efficient, compact, and integrated system that can meet the power characteristics of electric prime movers. Researchers at Maha are working at both the component level (integrated ePumps) and the system level (electro-hydraulic actuation, EHA).

Maha ePumps - Integrated electric machine and hydraulic machine based on external gear unit (left) and internal gear unit design with oil cooling (right)

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Active Vibration Damping & Traction Control

Active ride control circuit targeting implement motion to counter oscillations
Improvement results with implemented ride control solutions

This area of research aims at increasing the operator's comfort and machine controllability by proposing solutions for reducing machine vibrations. Several solutions for Active Ride Control have been proposed, which uses the working hydraulics with advanced electro-hydraulic control techniques.

Intelligent traction control systems have been developed for off-road vehicles to ease the operator effort and reduce tire wear. Considering the Maha mid-size wheel loader, introduced control strategies achieved wheel slip reduction up to 73%, fuel economy improvement up to 5%, and an increase in pushing force up to 60%.

Online tuning of traction slip-point for different mediums

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Fluid Property Modeling & Cavitation Analysis

Traction coefficient modeling and experiments considering asperity and thermal effects

Research on fluid properties of hydraulic fluids complements Maha's effort of formulating techniques for accurate modeling of hydraulic components and systems.
This area of research includes the following topics:

  • Modeling and experimentation of cavitation and aeration
  • Modeling properties of non-Newtonian fluids used in hydraulic components
  • Modeling fluid properties affecting friction in hydraulic components

Pump delivery pressure ripple with and without cavitation: simulation vs. experiments
EHL contact features in a Gerotor pump

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Condition Monitoring of Hydraulic Systems

Maha hydraulic crane unfolding with condition monitoring algorithm for counterbalance valves

Maha condition monitoring (CM) activites focus on both diagnostic and prognostic analyses of hydraulic control systems. Researchers have implemented a variety of CM algorithms and techniques in both simulation and on reference vehicles to monitor the health status of main hydraulic components.

Experimental work has included both specific fault detection and life percentage predictions. With concentration on applicability in mobile machinery, optimal sensor selection and signal processing has also been a primary area of research in creating CM solutions for effective real-time analysis.

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Machine Learning Applied to Fluid Power

Model and parameters of journal bearing for machine learning neural network to solve

Maha researchers use machine learning neural networks to speed up elastohydrodynamic lubrication (EHL) simulations. A convolutional neural network (CNN) was demonstrated to accurately predict the steady-state pressure distribution in a journal bearing, considering pressure deformation and cavitation.
Compared to the traditional numerical method, the proposed CNN is 250 times faster. Similar neural network approaches are being developed to implement in pump and motor kinematics and lubricating interface simulations.

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Maha Fluid Power Research Center
1500 Kepner Drive, Lafayette, IN 47905 USA
Phone: +1 (765) 496-6242