Design of an adjustable cam based constant force mechanism

Abstract A novel adjustable constant force mechanism (ACFM), which mainly consists of a linear spring and a cam mechanism (CM), has been proposed to passively regulate contact force. The CM is a linear negative stiffness mechanism and the constant force can be derived by paralleling the CM and the linear spring. To obtain the linear negative stiffness characteristic of the CM, the cam profile has been designed in detail. The magnitude of the constant force can be adjusted by preloading the linear spring. The mathematical model of the proposed ACFM, which doesn't contain complicated flexible members, is simple and accurate. To verify feasibility of the theoretical design procedure of the cam profile, a simulation of the ACFM has been carried out in virtual simulation software and the simulation results are consistent with the theoretical design procedure.

[1]  C. B. Allendoerfer,et al.  A Handbook On Curves And Their Properties , 1948 .

[2]  Chao-Chieh Lan,et al.  Distributed Shape Optimization of Compliant Mechanisms Using Intrinsic Functions , 2008 .

[3]  Takeshi Mizuno,et al.  Vibration Isolation System Using Negative Stiffness , 2003 .

[4]  Thomas Sugar,et al.  Compliant constant-force mechanism with a variable output for micro/macro applications , 2003, 2003 IEEE International Conference on Robotics and Automation (Cat. No.03CH37422).

[5]  Dung-An Wang,et al.  A constant-force bistable mechanism for force regulation and overload protection , 2011 .

[6]  I. C. Ugwuoke.  A Simplified Dynamic Model for Constant-Force Compression Spring , 2008 .

[7]  Just L. Herder,et al.  Negative Stiffness Building Blocks for Statically Balanced Compliant Mechanisms: Design and Testing , 2010 .

[8]  C. Seepersad,et al.  Design, fabrication, and evaluation of negative stiffness elements using SLS , 2012 .

[9]  G. Vassura,et al.  Design of a Single-Acting Constant-Force Actuator Based on Dielectric Elastomers , 2008 .

[10]  Chao-Chieh Lan,et al.  Generalized Shooting Method for Analyzing Compliant Mechanisms With Curved Members , 2006 .

[11]  Chao-Chieh Lan,et al.  Design of a constant-force snap-fit mechanism for minimal mating uncertainty , 2012 .

[12]  Christopher A. Mattson,et al.  Optimization of near-constant force springs subject to mating uncertainty , 2010 .

[13]  Larry L. Howell,et al.  Configuration Selection, Modeling, and Preliminary Testing in Support of Constant Force Electrical Connectors , 2007 .

[14]  Volkan Parlaktaş,et al.  Spatial compliant constant-force mechanism , 2013 .

[15]  Roderic S. Lakes,et al.  Extreme stiffness systems due to negative stiffness elements , 2004 .

[16]  M. Brennan,et al.  Optimization of a quasi-zero-stiffness isolator , 2007 .

[17]  M. S. Evans,et al.  Dynamic modeling of compliant constant-force compression mechanisms , 2003 .

[18]  Ikechukwu Celestine Ugwuoke.  Stability Analysis for Compliant Constant-Force Compression Mechanisms , 2009 .

[19]  Atsumi Ohtsuki,et al.  Analysis on Characteristics of a C-Shaped Constant-Force Spring with a Guide , 2001 .

[20]  Chao-Chieh Lan,et al.  An Adjustable Constant-Force Mechanism for Adaptive End-Effector Operations , 2012 .

[21]  G. K. Ananthasuresh,et al.  Design of a Compliant Mechanism to Modify an Actuator Characteristic to Deliver a Constant Output Force , 2006 .