當機械系統工作於不確定的環境時，需以控制系統來監控與環境的互動，確保接觸力保持在可接受的範圍內，不會造成破壞。本論文目標以被動式撓性定力機構來調控機械系統與不確定環境的接觸力，取代精密的控制系統，以降低成本、提高可靠度。本論文運用形狀最佳化方法來設計撓性定力機構，使機構在一定範圍內的輸入位移下保持固定的輸出力量。針對不同用途，分別提出三種對應的新型定力機構：可調式定力機構、定力嵌合扣件與定力遙軸順應性裝置。其中可調式定力機構用於調控機構軸向力，其具備力量調整功能，可依照需求調整輸出力量；定力嵌合扣件改良傳統嵌合扣件組裝，保持零件組裝扣持力，提昇產品可靠度；定力遙軸順應性裝置則可調控機構遠端之側向力，兼具遠端順應性與力量調控功能。三種定力機構皆採全撓性機構，一體成型之撓性機構具有零磨耗、無背隙及可微小化之優點，降低製造難度並增廣其運用領域。三種定力機構分別以模擬及實驗驗證其性能。最後，期望本論文設計的新型定力機構能應用於各種機械力量調控用途中。

Mechanical systems often require sophisticated sensors with computerized control to regulate forces when they interact with uncertain environments. This thesis presents constant-force mechanisms (CFM) to passively regulate the contact force of an end-effector for uncertain mechanical interactions. Since the use of sensors and control efforts are minimized, we expect the constant-force mechanisms to provide reliable and low-cost alternatives for mechanical systems. We use a shape optimal design formulation to find the configurations of CFMs and present three novel constant-force mechanisms for different applications. They are adjustable constant-force mechanism (ACFM), the constant-force snap-fit (CFS), and constant-force remote center compliance (CFRCC). The proposed ACFM can adjust the constant-force magnitude to adapt to different working environments. The CFS with constant gripping force improves the reliability of snap-fit assemblies. The CFRCC regulate lateral forces at the remote compliance center. Three mechanisms are all monolithic compliant mechanisms that have no frictional wear and are capable of miniaturization. The prototypes of these novel CFMs are validated by experiments. We expect the CFMs to be used in various force regulation applications.

[1] P. Alabuzhev, A. Gritchin, L. Kim, G. Migirenko, V. Chon, and P. Stepanov, 1989, Vibration Protecting and Measuring Systems with Quasi-Zero Stiffness, Hemisphere Publishing, New York.
[2] R. A. Ibrahim, 2008, “Recent advances in nonlinear passive vibration isolators,” Journal of Sound and Vibration, 314, pp. 371-452.
[3] W. Robertson, R. Wood, B. Cazzolato, and A. Zander, 2006, “Zero-stiffness magnetic springs for active vibration isolation,” Proceedings of the 6th International Symposium on Active Noise and Vibration Control, Adelaide, Australia.
[4] MinusK® http://www.minusk.com/
[5] J. L. Herder, 2005, “Development of a statically balanced arm support: Armon,” ICORR, Chicago, Illinois, USA, pp. 281-286.
[6] G. J. M. Tuijthof and J. L. Herder, 2000, “Design, actuation and control of an anthropomorphic robot arm,” Mechanism and Machine Theory, 35(7), pp. 945-962.
[7] R. H. Nathan, 1985, “A constant force generation mechanism,” ASME Journal of Mechanisms, Transmissions, and Automation in Design, 107(4), pp. 508-512.
[8] ATI Industrial Automation® http://www.ati-ia.com/
[9] VULCAN spring® http://www.vulcanspring.com/
[10] L. L. Howell and S. P. Magleby, 2006, “Substantially Constant-force Exercise Machine,” US Patent, 7060012, B2.
[11] I. Berliant, 2009, “Constant Force Rail Clamp,” US Patent, 7975811, B2.
[12] C. B. W. Pedersen, N. A. Fleck, and G. K. Ananthasuresh, 2006, “Design of a compliant mechanism to modify an actuator characteristic to deliver a constant output force,” ASME Journal of Mechanical Design, 128(5), pp. 1101-1112.
[13] J. C. Meaders and C. A. Mattson, 2010, “Optimization of near-constant force springs subject to mating uncertainty,“ Structural and Multidisciplinary Optimization, 41(1), pp. 1-15
[14] J. G. Jenuwine and A. Midha, 1994, “Synthesis of single-input and multiple-output port mechanisms with springs for specified energy absorption,” ASME Journal of Mechanical Design, 116(3), pp. 937-943.
[15] B. L. Weight, 2001, “Development and design of constant-force mechanisms,” Master’s thesis, Department of Mechanical Engineering, Brigham Young University, Provo, UT.
[16] D. Nahar and T. G. Sugar, 2003, “Compliant constant-force mechanism with a variable output for micro/macro applications,” IEEE ICRA, Taipei, Taiwan, pp. 508-512.
[17] A. Carrella, M. J. Brennan, T. P. Waters, and K. Shin, 2008, “On the design of a high-static–low-dynamic stiffness isolator using linear mechanical springs and magnets,” Journal of Sound and Vibration, 315(3), pp. 712-720.
[18] Ü. Sönmez, 2007, “Introduction to compliant long dwell mechanism designs using buckling beams and arcs,” ASME Journal of Mechanical Design, 129(8), pp. 831-843.
[19] C. Boyle, L. L. Howell, S. P. Magleby, and M. S. Evans, 2003, “Dynamic modeling of compliant constant-force compression mechanisms,” Mechanism and Machine Theory, 38(12), pp. 1469-1487.
[20] N. Schmit and M. Okada, 2011, “Synthesis of a Non-Circular Cable Spool to Realize a Nonlinear Rotational Spring,” IROS, San Francisco, California, USA
[21] D. Salomon, 2006, Curves and Surfaces for Computer Graphics, Springer.
[22] C.-C. Lan and K. M. Lee, 2006, “Generalized Shooting Method for Analyzing Compliant Mechanisms with Curved Members,” ASME Journal of Mechanical Design, 128(4), pp. 765-775.
[23] S. Jung, T. C. Hsia, and R. G. Bonitz, 2004, “Force Tracking Impedance Control of Robot Manipulators under Unknown Environment,” IEEE Trans. Control Syst. Technol., 12(3), pp. 474-483.
[24] V. Mallapragada, D. Erol, and N. Sarkar, 2007, “A New Method of Force Control for Unknown Environments,” Int. J. Adv. Robot. Syst., 4(3), pp. 313-322.
[25] J. Qiu, J. H. Lang, and A. H. Slocum, 2004, “A Curved-Beam Bistable Mechanism,” IEEE Journal of Microelectromechanical Systems, 13(2), pp. 137-146
[26] Smalley® http://www.smalley.com/
[27] P. R. Bonenberger, 2005, The First Snap-Fit Handbook: Creating Attachments for Plastics Parts, Hanser Gardner Publications, Cincinnati, Ohio.
[28] AlliedSignal Corporation, 1997, Modulus Snap-Fit Design Manual, Allied-Signal Plastics, Morristown, New Jersey, USA.
[29] Jeff Raquet http://www.coe.uncc.edu/~jsraquet/java/ItsASnapApplet.html
[30] J. S. Oh, D. Q. Lewis, D. Lee, and G. A. Gabriele, 1999, “JAVA™ -Based Design Calculator for Integral Snap-Fits,” ASME DETC, Las Vegas, Nevada, USA.
[31] J. M. Brock and P. K. Wright, 2002, “Design Tool for Injection Molded Snap Fits in Consumer Products,” Journal of Manufacturing Systems, 21(1), pp. 32-39.
[32] Bayer MaterialScience® http://plastics.bayer.com/plastics/emea/en/home.jsp
[33] D. E. Whitney, 1982, “Quasi-static assembly of compliantly supported rigid parts,” J. Dyn. Syst. Measur. Contr., 104(1), pp. 65-77.
[34] S. Havlik, 1983, “A new elastic structure for a compliant robot wrist,” Robotica, 1(2), pp. 95-102.
[35] A. Fakri, A. Jutard, and G. Liegeois, 1984, “Passive compliant wrist with two rotation center for assembly robot,” International Conference on Assembly Automation, Paris, France, pp. 235-241.
[36] D. E. Whitney, 1986, “Remote center compliance,” Encycl. Robot. Contr., vol. 104, pp. 1316-1324.
[37] T. L. De Fazio, 1980, “Displacement-state monitoring for the Remote Center Compliance (RCC) - realization and application,” ISIR, Milan, Italy, pp. 559-569.
[38] D. E. Whitney and J. M. Rourke, 1986, “Mechanical behavior and design equations for elastomer shear pad remote center compliances,” J. Dyn. Syst. Measur. Contr., vol. 108, pp. 223-232.
[39] N. Ciblak and H. Lipkin, 2003, “Design and Analysis of Remote Center of Compliance Structures,” Journal of Robotic Systems, 20(8), pp. 415-427.
[40] G. Chen, D. L. Wilcox, and L. L. Howell, 2009, “Fully compliant double tensural tristable micromechanisms (DTTM),” Journal of Micromechanics and Microengineering, 19(2), 025011.
[41] D. L. Wilcox and L. L. Howell, 2005, “Double-tensural bistable mechanisms (DTBM) with on-chip actuation and spring-like post-bistable behavior,” ASME DETC, Long Beach, California, USA, pp. 537-546.