Research Papers

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

[+] Author and Article Information
Shawn R. Wilhelm

e-mail: Wilh0141@UMN.EDU

James D. Van de Ven

Assistant Professor
e-mail: vandeven@UMN.EDU
Department of Mechanical Engineering,
University of Minnesota,
Minneapolis, MN 55455

Contributed by the Mechanisms and Robotics Committee of ASME for publication in the JOURNAL OF MECHANISMS AND ROBOTICS. Manuscript received August 2, 2012; final manuscript received July 15, 2013; published online September 11, 2013. Assoc. Editor: Jian S Dai.

J. Mechanisms Robotics 5(4), 041008 (Sep 11, 2013) (8 pages) Paper No: JMR-12-1110; doi: 10.1115/1.4025122 History: Received August 02, 2012; Revised July 15, 2013

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.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.


Williamson, C., Zimmerman, J., and Ivantysynova, M., 2008, “Efficiency Study of an Excavator Hydraulic System Based on Displacement-Controlled Actuators,” Proceedings of the Bath/ASME Symposium on Fluid Power and Motion Control.
Li, P. Y., Loth, E., Simon, T. W., Van de Ven, J. D., and Crane, S. E., 2011, “Compressed Air Energy Storage for Offshore Wind Turbines,” International Fluid Power Exposition, Las Vegas, NV.
Ivantysyn, J., and Ivantysynova, M., 2001, Hydrostatic Pumps and Motors, Academic Books International, New Delhi.
Wieczorek, U., and Ivantysynova, M., 2002, “Computer Aided Optimization of Bearing and Sealing Gaps in Hydrostatic Machines—The Simulation Tool CASPAR,” Int. J. Fluid Power, 3(1), pp. 7–20.
Manring, N. D., 2003, “Valve-Plate Design for an Axial Piston Pump Operating at Low Displacements,” ASME J. Mech. Des., 125(1), pp. 200–205. [CrossRef]
Inaguma, Y., and Hibi, A., 2007, “Reduction of Friction Torque in Vane Pump by Smoothing Cam Ring Surface,” Proc. Inst. Mech. Eng., Part C: J. Mech. Eng. Sci., 221(5), pp. 527–534. [CrossRef]
Wang, S., 2012, “Improving the Volumetric Efficiency of the Axial Piston Pump,” ASME J. Mech. Des., 134, p. 111001. [CrossRef]
Grandall, D. R., 2010, “The Performance and Efficiency of Hydraulic Pumps and Motors,” MSc. thesis, The University of Minnesota, Minneapolis, MN.
Seeniraj, G. K., and Ivantysynova, M., “Impact of Valve Plate Design on Noise, Volumetric Efficiency and Control Effort in an Axial Piston Pump,” ASME 2006 International Mechanical Engineering Congress and Exposition, Fluid Power Systems and Technology, Chicago, IL, ASME Paper No. IMECE2006-15001, Nov. 5–10, New York, pp. 77–84.
Tao, D. C., and Krishnamoorthy, S., 1978, “Linkage Mechanism Adjustable for Variable Symmetrical Coupler Curves With a Double Point,” Mech. Mach. Theory, 13(6), pp. 585–591. [CrossRef]
Tao, D. C., and Krishnamoorthy, S., 1978, “Linkage Mechanism Adjustable for Variable Coupler Curves With Cusps,” Mech. Mach. Theory, 13(6), pp. 577–583. [CrossRef]
McGovern, J. F., and Sandor, G. N., 1973, “Kinematic Synthesis of Adjustable Mechanisms (Part 1: Function Generation),” ASME J. Eng. Ind., 95(2), pp. 417–422. [CrossRef]
McGovern, J. F., and Sandor, G. N., 1973, “Kinematic Synthesis of Adjustable Mechanisms (Part 2: Path Generation),” ASME J. Eng. Ind., 95(2), pp. 423–429. [CrossRef]
Handra-Luca, V., 1973, “The Study of Adjustable Oscillating Mechanisms,” ASME J. Eng. Ind., 95(3), pp. 677–680. [CrossRef]
Zhou, H., and Ting, K.-L., 2002, “Adjustable Slider-Crank Linkages for Multiple Path Generation,” Mech. Mach. Theory, 37(5), pp. 499–509. [CrossRef]
Xu, W., Lewis, D., Bronlund, J., and Morgenstern, M., 2008, “Mechanism, Design and Motion Control of a Linkage Chewing Device for Food Evaluation,” Mech. Mach. Theory, 43(3), pp. 376–389. [CrossRef]
Grenier, M., and Gosselin, C., “Kinematic Optimization of a Robotic Joint With Continuously Variable Transmission Ratio,” Proceedings of the ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Washington, DC, Aug. 28–31, ASME, New York, pp. 513–521.
Patel, S. R., and Patel, D., 2013, “Dynamic Analysis of Quick Return Mechanism Using MATLAB,” Int. J. Eng. Sci. Innovative Technol., 2(3), pp. 346–350.
Shyu, J. H., Chen, C. K., Yu, C. C., and Luo, Y. J., 2011, “Research and Development of an Adjustable Elliptical Exerciser,” Adv. Mater. Res., 308, pp. 2078–2083. [CrossRef]
Bai, L., Ge, W.-j., Chen, X.-h., and Meng, X.-y., “Hopping Capabilities of a Bio-Inspired and Mininally Actuated Hopping Robot,” 2011 International Conference on Proceedings of the Electronics, Communications and Control (ICECC), Zhejiang, China, Sept. 9–11, IEEE, New York, pp. 1485–1489.
Soong, R.-C., and Chang, S.-B., 2011, “Synthesis of Function-Generation Mechanisms Using Variable Length Driving Links,” Mech. Mach. Theory, 46(11), pp. 1696–1706. [CrossRef]
Anirban, G., and Amarnath, C., 2011, “Adjustable Mechanism for Walking Robots With Minimum Number of Actuators,” Chin. J. Mech. Eng., 24(5), p. 760.
Nelson, C. D., 1985, Variable Stroke Engine, U.S. Patent 4,517,931.
Pierce, J., 1914, Variable Stroke Mechanism, U.S. Patent 1,112,832.
Pouliot, H. N., Delameter, W. R., and Robinson, C. W., 1977, “A Variable Displacment Spark-Ignition Engine,” SAE Technical Paper No. 770114, SAE International.
Yamin, J. A. A., and Dado, M. H., 2004, “Performance Simulation of a Four-Stroke Engine With Variable Stroke-Length and Compression Ratio,” Appl. Energy, 77(4), pp. 447–463. [CrossRef]
Freudenstein, F., and Maki, E. R., 1981, “Variable Displacement Piston Engine,” U.S. Patent 4,270,495.
Freudenstein, F., and Maki, E., 1983 “Development of an Optimum Variable-Stroke Internal-Combustion Engine Mechanism From the Viewpoint of Kinematic Structure,” ASME J. Mech., Trans, and Automation, 105(2), pp. 259–266. [CrossRef]
Shoup, T. E., 1984, “The Design of an Adjustable, Three Dimensional Slider Crank Mechanism,” Mech. Mach. Theory, 19(1), pp. 107–111. [CrossRef]
Wilhelm, S., and Van de Ven, J. D., 2011, “Synthesis of a Variable Displacement Linkage for a Hydraulic Transformer,” Proceedings of the ASME 2011 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, IDETC/CIE 2011, August 28–31, 2011, Washington, DC, ASME, New York, p. 8.
Norton, R. L., 2008, Design of Machinery An Introduction to the Synthesis and Analysis of Mechanisms and Machines, McGraw-Hill, Boston, MA.
Sandor, G. N., and Erdman, A. G., 1984, Advanced Mechanism Design: Analysis and Sythesis, Prentice-Hall, Upper Saddle River, NJ.
Alt, V. H., 1932, “The Transmission Angle and Its Importance for the Design of Periodic Mechanisms,” Werstattstechnik, 26, pp. 61–64.


Grahic Jump Location
Fig. 1

Variable displacement linkage

Grahic Jump Location
Fig. 2

Base triangles for determining r1min and r1max

Grahic Jump Location
Fig. 3

Extended and overlapped extremes of fourbar linkage

Grahic Jump Location
Fig. 4

Variable ground pivot locations for extended case

Grahic Jump Location
Fig. 5

Configurations of variable linkage

Grahic Jump Location
Fig. 6

Associated triangle for determining θc and θr1min

Grahic Jump Location
Fig. 7

Variable linkage showing five-ground pivot positions between 0% and 100% displacement and the associated coupler curves

Grahic Jump Location
Fig. 8

Defining angle of axis of slide

Grahic Jump Location
Fig. 9

3D plot of stroke/footprint of case “a” linkage as a function of link lengths R3 and r4

Grahic Jump Location
Fig. 10

Sixbar vector loop diagram

Grahic Jump Location
Fig. 12

Piston acceleration

Grahic Jump Location
Fig. 13

Linkage timing ratio

Grahic Jump Location
Fig. 14

Prototype linkage cad model and rendering with labeled links

Grahic Jump Location
Fig. 15

Prototype variable displacement mechanism

Grahic Jump Location
Fig. 16

Experimental setup

Grahic Jump Location
Fig. 17

Input shaft velocity

Grahic Jump Location
Fig. 20

Piston acceleration




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In