Hydraulic Power System Analysis

The excitement and the glitz of mechatronics has shifted the engineering community’s attention away from fluid power systems in recent years. However, fluid power still remains advantageous in many applications compared to electrical or mechanical power transmission methods. Designers are left with few practical resources to help in the design and analysis of fluid power systems, especially when approaching fluid power for the first time. Helping you overcome these hurdles, Hydraulic Power System Analysis demonstrates modern computer-aided analytical techniques used to model nonlinear, dynamic fluid power systems. Following an overview of fluid power, the authors examine various relevant fluid properties, energy calculations, and steady state and dynamic analysis along with a review of automatic control theory. Turning to modeling, the next few chapters address valves and motors and then apply dynamic modeling to examples relating to pumps, hydrostatic transmissions, and valves. The book includes a unique chapter showing how to combine flow resistance equations with the differential equations governing dynamic system performance. The final chapter translates electrical circuit theory concepts to noise attenuation in fluid power systems. Illustrated with many equations, practical computer modeling examples, and exercises, Hydraulic Power System Analysis provides a much-needed modernization of dynamic modeling for fluid power systems using powerful computational tools.

Introduction What Is Fluid Power? A Brief History of Fluid Power Fluid Power Applications, Present and Future Advantages of Using Fluid Power Systems A Probable Future Development Properties of Fluids and Their Units Basic Properties of Fluids Compressibility of Liquids Steady State Modeling Rationale for Model Development Source of Equations Conservation of Flow and Energy Friction Losses in Pipes and Fittings Basic Component Equations Worked Examples Discussion Dynamic Modeling Development of Analytical Methods Software Options Dynamic Effects Worked Examples Modeling Hints and Tips Discussion Linear Systems Analysis Introduction Linear Systems The Laplace Transform Inversion, the Heaviside Expansion Method Stability Block Diagrams Spring-Mass-Damper Time Response to Unit Step Force Time Constant Frequency Response and Feedback Introduction Mathematics of Frequency Response Frequency Response Diagrams Using Frequency Response to Find Controller Gain Summary Valves and Their Uses Introduction Directional Control Valves Special Directional Control Valves, Regeneration Flapper Nozzle Valve Flow Control Elements Relief Valves Unloading Valve Pressure Reducing Valve Pressure Sequencing Valve Counterbalance Valve Flow Regulator Valve Pumps and Motors Configuration of Pumps and Motors Pump and Motor Analysis Leakage Form of Characteristic Curves Axial Piston Pumps and Motors Pressure During a Transition Torque Affected by Pressure Transition — Axial Piston Pump Torque and Flow Variation with Angle for Multicylinder Pumps Hydrostatic Transmissions Introduction Performance Envelope Hydrostatic Transmission Physical Features Hydrostatic Transmission Dynamic Analysis Pressure Regulating Valve Purpose of Valve Operation of Valve Mathematical Model of Valve Effect of Damping Valve Model Expansion Basic Valve Model Model Expansion An Assessment of Modeling Flow Division Introduction The Hydraulic Ohm Method Brief Review of DC Electrical Circuit Analysis Fluid Power Circuit Basic Relationships Consolidation of Fluid Power Resistances Application to Unsteady State Flow Conclusions Noise Control Introduction Discussion of Method Mathematical Model Effect of Entrained Air in Fluid Further Discussion of the Mathematical Model Other Methods of Noise Control Damping Methods Index