Abstract
This paper proposes gravity compensators for a 4-degree-of-freedom (4-DOF) humanlike manipulator. Eighteen springs (or 1-DOF gravity compensators) are required to achieve complete static balancing of a 4-DOF manipulator. Because locating 18 springs is impractical, incomplete gravity compensators are designed for practical implementation in this paper. Springs are selected using an objective function of the gravity compensation and design cost. The design cost indicates the complexity of the mechanisms. As a result, four- and two-spring designs are obtained. Optimizations of spring constants of the four- and two-spring designs are conducted for the objective function of gravity compensation. The torque ratios for the four-spring design are computed as [18.64%, 11.92%, 77.68%, 81.14%]. The torque ratios for the two-spring design are computed as [16.03%, 20.22%, 100.00%, 100.00%] and indicate that gravity compensation is made only at proximal joints to the base. Dynamic simulations are conducted, and simulation results show that the ratios of gravity compensation are achievable.
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References
H. Diken, Effect of mass balancing on the actuator torques of a manipulator, Mech. and Mach. Theory, 30 (4) (1995) 495–500.
Q. Lu, C. Ortega and O. Ma, Passive gravity compensation mechanisms: Technologies and applications, Recent Patents on Engineering, 5 (1) (2011) 32–44.
R. H. Nathan, A constant force generation mechanism, ASME Journal of Mechanisms, Transmissions and Automation in Design, 107 (4) (1985) 508–512.
N. Ulrich and V. Kumar, Passive mechanical gravity compensation for robot manipulator, Proc. of the 1991 IEEE Int. Conf. on Robotics and Automation, Sacramento, USA (1991) 1536–1541.
K. Koser, A cam mechanism for gravity-balancing, Mechanics Research Communications, 36 (4) (2009) 523–530.
T. Morita, F. Kuribara, Y. Shiozawa and S. Sugano, A novel mechanism design for gravity compensation in three dimensional space, Proc. of the 2003 IEEE/ASME Int. Conf. on Advanced Intelligent Mechatronics, Kobe, Japan (2003) 163–168.
G. J. Walsh, D. A. Streit and B. J. Gilmore, Spatial spring equilibrator theory, Mechanism and Machine Theory, 26 (2) (1991) 155–170.
R. Barents, M. Schenk, W. D. van Dorsser, B. M. Wisse and J. L. Herder, Spring-to-spring balancing as energy-free adjustment method in gravity equilibrators, Transactions of the ASME J. of Mechanical Design, 133 (2011) 061010–1-061010-10.
S. K. Agrawal and A. Fattah, Gravity-balancing of spatial robotic manipulators, Mechanism and Machine Theory, 39 (12) (2004) 1331–1344.
C. H. Cho, W. S. Lee, J. Y. Lee and S. C. Kang, A 2-dof gravity compensator with bevel gears, J. of Mechanical Science and Technology, 26 (2012) 2913–2919.
C. M. Gosselin and J. Wang, On the design of gravitycompensated six-degree-of-freedom parallel mechanisms, Proc. of the 1998 IEEE Int. Conf. on Robotics and Automation, Leuven, Belgium (1998) 2287–2294.
A. Russo, R. Sinatra and F. Xi, Static balancing of parallel robots, Mechanism and Machine Theory, 40 (2) (2005) 191–202.
B. van Ninhuijs, B. L. J. Gysen, J. W. Jansen and E. A. Lomonova, Multi-degree-of-freedom spherical permanent magnet gravity compensator for mobile arm support systems, Proc. of the 2013 IEEE Int. Electr. Mach. & Drives Conf. (IEMDC), Chicago, USA (2013) 1443–1449.
Y. Ono and T. Morita, An underactuated manipulation method using a mechanical gravity canceller, J. Rob. Mechatron, 16 (6) (2004) 563–569.
K. A. Wyrobek, E. H. Berger, H. F. M. V. Loos and J. K. Salisbury, Towards a personal robotics development platform: Rationale and design of an intrinsically safe personal robot, Proc. of the 2008 IEEE Int. Conf. on Robotics and Automation, Pasadena, USA (2009) 2165–2170.
C. H. Cho and S. C. Kang, Design of a static balancing mechanism for a serial manipulator with an unconstrained joint space using One-DOF gravity compensators, IEEE Trans. on Robotics, 30 (2) (2014) 421–431.
X.-S. Yang, Firefly algorithm, Lévy flights and global optimization, Research and Development in Intelligent Systems XXVI (2010) 209–218.
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Recommended by Associate Editor Kyoungchul Kong
Sang-Hyung Kim received the B.S. degree in Mechanical Engineering, Chosun University, Gwangju, Korea, in 2015. He is currently working toward the M.S. degree in Dept. of control & instruments. His current research interests are mechanism design and control of robotic systems.
Chang-Hyun Cho received the B.S. and M.S. degrees in Mechanical Engineering from Kyunghee University, Suwon, Korea, in 1997 and 1999, respectively, and a Ph.D. degree in the same discipline from Korea University, Seoul, Korea, in 2005. He was a member of the faculty of the Department of Control, Instruments, and Robotics, Chosun University, Kwangju, Korea, from 2008 to 2013. He joined the faculty of the Department of Mechanism and Systems, Chosun University, in 2014, and is currently an Associate Professor. His current research interests involve mechanism design and the control of robotic systems.
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Kim, SH., Cho, CH. Incomplete gravity compensator for a 4-DOF manipulator. J Mech Sci Technol 29, 4417–4426 (2015). https://doi.org/10.1007/s12206-015-0940-1
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DOI: https://doi.org/10.1007/s12206-015-0940-1