Software for Fluid Power Technology

Introduction

        This review is intended to inform the reader about HyPneu, its origins, and its capabilities to contribute to the fluid power industry. HyPneu was first introduced to the public in 1993. HyPneu was developed by a team of individuals that have a total of over 150 years of combined technical and programming experience in the power and motion control industry. Among BarDyne, Inc.'s many resources is a valuable research archive that extends over 50 years, a vast variety of technical advisors in the industry, and an intimate understanding of standard engineering practices. This knowledge base, which has roots traced back to the Fluid Power Research Center (FPRC) at Oklahoma State University (OSU) directed by Dr. E. C. Fitch, provides the foundation for the HyPneu software and has been verified time and time again by tests, ran in BarDyne, Inc.'s testing laboratory as well as in other real world applications. This unique background is unmatched in the industry. BarDyne, Inc. has also used this wealth of experience and research to write a series of companion books to the HyPneu software. This series of books is a set of design handbooks written for a range of readers from those beginning to learn about fluid power design and control to experts in the field. The books are filled with analytical information as well as detailed examples and problem sets which make it ideal to use for a company training session or the classroom. HyPneu has a vast worldwide customer base that includes industries from all sectors such as aerospace, automotive, petroleum, construction, agricultural, and many more. HyPneu is a truly versatile tool for designing and developing power and motion control systems.

HyPneu

    The HyPneu software was created to be a practical and powerfully versatile virtual laboratory. HyPneu software uses standard ISO symbols in all of the circuit diagram icons and will support all engineering drawing sizes A through E or from A0 to A4. This facilitates a clean design data transition between the analytical designer and the manufacturer of the system that eliminates mistakes that might occur in the design process. Another feature of HyPneu is the ability to automatically determine the step size of a simulation application. One of the most painstaking tasks in running engineering simulations is determining the appropriate step size for the simulation. The HyPneu software has eliminated this step in the simulation process for the user by automatically determining the optimal step size needed to achieve the desired level of accuracy. This allows for faster and more accurate simulations so that the user may test each iteration of a design concept in a short amount of time. HyPneu is also versatile in the fact that it supports US Customized, Practical SI, SI, and English units. Since the software automatically converts units for the user, error is minimized when calculating conversion factors. Furthermore, HyPneu animates operation logic and state parameter status using a color coded circuit. This animation feature offers the user an opportunity to spot any operational malfunction that may occur at the design stage.
    HyPneu provides over 450 component icons with associated mathematical models. In addition, HyPneu allows users to define and create mathematical models for their own component icons. This gives HyPneu the needed flexibility to adapt to the ever changing fluid power industry. Each time a component is created in HyPneu, the user then names the component and enters all specification data needed. Information can typically be found from the manufacturer's data sheet, the experimental data, or the theoretical analysis. Once this is completed the component will be saved in HyPneu's component library, which allows the user to reuse the component again without having to redefine the specification data. This same principle is also used when defining different types of fluid in HyPneu. Each time the user creates a circuit diagram that is analyzed with a new fluid they may enter the parameters for the fluid and populate the data to the database for future use.
    As discussed above, HyPneu is a powerful tool for the analysis and design of hydraulic and pneumatic systems, but it is also simple to use. There are six basic steps to follow when running a HyPneu simulation which is outlined below:

HyPneu Features

    System designing is like putting a puzzle together. Using HyPneu, the vast majority of the puzzle pieces are modeled, validated, and ready to use. The building blocks available to the user through HyPneu make the task of system design straightforward as well as comprehensive. Creative designs can be stored to form the basis for future use. HyPneu is capable of simulating hydraulic, pneumatic, mechanical, and control systems, either individually or together. Figure 2 shows the HyPneu simulation setup and results of a regenerative hydraulic system.

    When dealing with the analysis of pneumatic systems though, the analysis may be especially difficult due to the highly compressible characteristics of the medium. HyPneu handles these complexities using built in gas theories and practical component models. Figure 3 shows the HyPneu simulation setup and results of a car air suspension system.

Thermal Analysis

    The ability to predict the temperature of circulating fluid at any point in a system, along with the temperature of the components in a fluid power circuit at the design stage, is crucial to service assurance. Temperature that is either too low or too high will potentially cause excessive performance degradation and component malfunction. HyPneu can directly perform dynamic and steady state thermal analysis using any hydraulic/pneumatic circuit created schematically. In addition, HyPneu can evaluate pressure and flow in a fluid power system and assess the temperature profile of the fluid and components under any work cycle. Furthermore, with a bank of various heat exchanger models available, HyPneu thermal analysis becomes an effective tool in sizing a heat exchanger for applications. Figure 4 shows the HyPneu simulation setup and results of a machine with reciprocating loading conditions.

    In many systems, frequency analysis is a significant design consideration. HyPneu provides two modules to simulate system dynamics in frequency domain. They are the Frequency Response Analysis (FRA) and Frequency Power Analysis (FPA). With HyPneu’s graphical approach, it is no longer necessary to perform time-consuming, complicated, and even impractical mathematical model derivation for frequency analysis. The FRA is mainly to address the system response to a controlled signal or random system disturbances. The FRA generates a Bode diagram from a given system schematic for design analysis. On the other hand, the FPA is to identify sources of noise and vibration using the Power Spectral Density (PSD) technique. Since the minimization of vibration and noise in the operation of a fluid power system is a very critical design and maintenance goal, the FPA becomes an important tool in system diagnosis and trouble shooting. Figure 5 shows the HyPneu simulation setup and results of a quarter car suspension system while Fig. 6 shows a hydraulic motor experiencing both internal and external disturbances.

Environmental climate control systems are widely used in many applications including in airplanes, automobiles, labs, residential buildings, etc. Environmental climate control systems encompass four major areas when performing analysis, these areas are hydraulic, pneumatic, thermal, and control systems. HyPneu provides all the basic components needed to construct and model an environmental climate control system for dynamic simulations. These components include air cycle machines (ACM), vapor compression machines (VCM), heat exchangers, fans, orifices, and piping distribution models. HyPneu can be used to analyze flow distribution, temperature control, and sizing of system components to satisfy application requirements.

   HyPneu Universal Simulation Platform

    HyPneu provides users with a universal platform when analyzing a design, creating a co-simulation environment for the simulation needs. In today's world, programs typically cover a specific realm of expertise due to the comprehensive data we now have available in the world of engineering. Although HyPneu is generally used to analyze dynamic hydraulic and pneumatic simulations, it is capable of incorporating other programs that are designed for specialized needs to better assist the user in the analysis process. HyPneu has been designed to link with other CAE and/or motion control simulation programs via HyPneu Linx. HyPneu Linx module allows users to seamlessly link with third-party programs under the Simulink environment via a Simulink S-Function block. HyPneu also allows users to employ the powerful HyPneu Client/Server module to interface with other software or hardware directly. Programs such as RecurDyn, ADAMS, ChemCAD, etc. are examples of programs that HyPneu can directly communicate with when running a simulation via HyPneu Client/Server module. The infrastructure within HyPneu is designed to function effectively as either a client or a server. This feature permits co-simulation using the strong points of several programs to implement simulation. Co-simulation can be accomplished by following one of the three approaches:

1. Software-to-Software
2. Software in Parallel with Hardware
3. Hardware in the Loop

    The Software-to-Software approach allows the user to interface communication directly between software programs for improving simulation speed and accuracy. The Software in Parallel with Hardware challenges both software (model) and hardware (machine) simultaneously with a given command or disturbance for in-situ diagnosis and control compensation. Finally, the Hardware in the Loop employs software to simulate the complex physical system behavior while exchanging data with critical hardware components for rapid prototype evaluation and optimization. This capability makes HyPneu a universal platform in today's engineering simulation program world. It integrates a wide variety of specialized programs in the goal to better simulate the process in which the user needs to analyze. Figure 7 illustrates a co-simulation of HyPneu and Recurdyne to analyze the motion dynamic of an excavator.

HyPneu Magi

Another great feature of HyPneu is the subsidiary program Magi which is an engineer's ultimate toolbox for cutting edge solutions. Magi assists users in eliminating the drudgery of hydraulic and pneumatic design calculation, allowing the user to produce fast and accurate performance assessment. Complex operations can be visualized through component animation and versatile graphical data presentation. Magi gives the user unmatched calculating power and speed for achieving exceptional accuracy and productivity in the work place. The following calculators are some of many available with Magi:

• Fluid Viscosity Calculator
• Bulk Modulus Calculator
• Valve Flow Area Calculator
• Reynolds Number Calculator
• Cylinder Structural Integrity Analyzer
• Motor and Pump Performance Analyzer
• Tube Pressure Flow Calculator
• Unit Conversion Manager

    The Fluid Viscosity Calculator calculates the viscosity of a fluid at varying temperatures and pressures. This calculator allows users to graphically represent the viscosity of a fluid versus the operating temperature. These factors allow the user to select the most appropriate type of fluid to use in their application, testing, and simulation.
The Bulk Modulus Calculator calculates the effective bulk modulus of a fluid, which considers the bulk modulus of fluid, air and housing in its calculation. The information generated by the calculator will be plotted by Magi to produce a bulk modulus vs. percent of air in the liquid graph of the specified fluid. The Calculator will also calculate the effect of working temperature and pressure individually on a fluid's bulk modulus and allows you to plot these effects for design purposes.
    The Valve Flow Area Calculator calculates the flow area of different throttling devices, and then graphically represents the flow and its associated design parameters for easy valve sizing.
    The Reynolds Number Calculator calculates a fluid's Reynolds number of a flow stream. If the Reynolds number is known, the calculator can determine the hydraulic diameter, fluid velocity, or the kinematic viscosity.
    The Cylinder Structural Integrity Analyzer calculates the load that a cylinder can withstand before failure due to rod buckling. The values of these variables change with the way the cylinder is mounted. This analyzer will solve for any of these variables when all of the others have been entered. Magi will also graph the structural integrity of the cylinder so the user can predict what the critical load of the cylinder is at different lengths of the rod.
    The Motor and Pump Performance Analyzer evaluates and predicts the performance of any motor or pump at any condition possible using data supplied by the user. Using these values as well as other parameters specified by the user, the analyzer calculates the torque, flow rate, and overall efficiency at the specified conditions. The analyzer can graphically represent the efficiency of a motor or pump over a broad range of operating pressures and velocities
The Tube Pressure Flow Calculator calculates the pressure drop of, or flow rate in, a specific conduit. The calculator automatically determines the flow type (laminar or turbulent) in the calculation.
    The Unit Conversion Manager converts a variety of different units by selecting the initial units and the units to be converted to. The information gathered can be customized, then stored on a screen, and later printed off for the users’ convenience.

HyPneu's Companion Instructional Books

    BarDyne, Inc. provides a comprehensive book series that explores the theory and techniques of fluid power design, modeling, and simulation to support the HyPneu software. These books are vital in roles for educational purposes as well as training and understanding in industrial applications. Both educational and industrial worlds can benefit from the joint use of the HyPneu simulation program and the companion fluid power book series. The books encompass a vast amount of information that allows the reader to understand the concepts and ideas of how fluid power application truly works. Another great aspect of the companion book series is the descriptive questions that are available in one of the books. These questions consist of three sections: conceptual comprehension, design analysis, and computer simulation. The conceptual comprehension questions help train the reader's mind in understanding the general concepts of fluid power theories and definitions. The design analysis questions give the reader a chance to computationally solve problems using the concepts and equations discussed in the book series. The computer simulation questions give the reader an opportunity to apply computerized techniques, such as HyPneu, to gain experience in real-life design and problem solving skills through interactive use of the software's powerful simulation environment. A separate electronic copy of the solutions to all design analysis and computer simulation questions found in the book series are available, which is used as a reference guide to better comprehend the concepts and theories presented. These books will provide the reader with knowledge about fluid power that has never been coupled with the use of a fluid power simulation program such as HyPneu. The combination of the simulation program and book series has bridged the industrial and academic fields in the understanding of fluid power design, modeling, and simulation.

Summary

     HyPneu unleashes a new capability for fluid power and motion control design and application engineers to create and simulate system and/or component designs.  The companion book series with comprehensive problem and solution set provides a friendly interactive and self-learning environment to both industrial professionals and academic instructors and students.  The combination of the HyPneu and BarDyne book series establishes a powerful virtual laboratory for anyone from apprentices to experts to experience the most productive design analysis and learning environment.

References