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IJMERR 2023 Vol.12(3): 131-136
DOI: 10.18178/ijmerr.12.3.131-136

Design and Synthesis of the Gravity Compensator with a Non-zero Length Spring

Yang Zhang 1,2,3 and Vigen Arakelian 1,2*
1. LS2N/ECN UMR 6004, F-44321 Nantes, France
2. INSA-Rennes/Mecaproce, F-35708 Rennes, France
3. Productions Core Laboratory, Flanders Make, 8500 Kortrijk, Belgium
*Correspondence: vigen.arakelyan@insa-rennes.fr or vigen.arakelyan@ls2n.fr (V.A.)

Manuscript received November 30, 2022; revised February 6, 2023; accepted March 3, 2023.

Abstract—It is well known that conventional linear spring directly jointed with a rotating link cannot ensure a complete gravity balancing. In this case, the application of zero length springs is suggested. The zero length spring corresponds to a spring with special coils ensuring zero elastic force for zero length of the spring. This type of spring is often used in theoretical solutions or in academic studies but rarely in real robotic structures. The use of traditional linear springs leads to inclusion of the auxiliary mechanism. The associated mechanisms are different and each of them requires its study and improvement. The applied methods for their study are various. They depend on the structure of the auxiliary mechanism and locations of balancing forces. This paper deals with design and synthesis of the gravity compensator including an auxiliary two-link dyad added to the rotating link. The balancing spring is installed vertically at the base. The choice of a vertical installation is due not only to constructive practicality but also to the fact that the mass of the spring system does not affect the balancing conditions of the rotating link. The aim of the study is to propose an analytically tractable solution permitting to synthesize such link lengths of the additional dyad that will provide a more optimal generation of the balancing moment. The efficiency of the suggested mechanism design is illustrated via numerical simulations. It is shown that by using a non-zero length spring a quasi-perfect balancing has been achieved.

Keywords—gravity compensation, static balancing, mechanism synthesis, non-zero length spring, input torque cancellation

Cite: Yang Zhang and Vigen Arakelian, "Design and Synthesis of the Gravity Compensator with a Non-zero Length Spring," International Journal of Mechanical Engineering and Robotics Research, Vol. 12, No. 3, pp. 131-136, May 2023. 

Copyright © 2023 by the authors. This is an open access article distributed under the Creative Commons Attribution License (CC BY-NC-ND 4.0), which permits use, distribution and reproduction in any medium, provided that the article is properly cited, the use is non-commercial and no modifications or adaptations are made.