Design of a Passive Gravity-Balanced Assistive Device for Sit-to-Stand Tasks

A sit-to-stand assist device can serve the needs of people suffering from muscle weakness due to age or disabilities that make sit-to-stand a difficult functional task. The objective of this paper is to design a passive gravity-balancing assist device for sit-to-stand motion. In our study, it has been shown that the contribution to the joint torques by the gravitational torque is dominant during sit-to-stand motion. On the basis of this result, a gravity balanced assistive device is proposed. This passive device uses a hybrid method to identify the center-of-mass of the system using auxiliary parallelograms first. Next, appropriate springs are connected to the device to make the total potential energy of the system due to the gravity and the springs constant during standing up. A demonstration prototype with the underlying principles was fabricated to test the feasibility of the proposed design. The prototype showed gravity balancing and was tested by the authors. This prototype will be modified appropriately for clinical testing.

[1]  Clément Gosselin,et al.  Static balancing of spatial parallel Platform mechanisms-revisited , 2000 .

[2]  Jorge Angeles,et al.  Fundamentals of Robotic Mechanical Systems: Theory, Methods, and Algorithms , 1995 .

[3]  A. Schultz,et al.  Biomechanical analyses of rising from a chair. , 1992, Journal of biomechanics.

[4]  J.E. Colgate,et al.  KineAssist: a robotic overground gait and balance training device , 2005, 9th International Conference on Rehabilitation Robotics, 2005. ICORR 2005..

[5]  D. A. Streit,et al.  Equilibrators for Planar Linkages , 1993 .

[6]  Josep Valls-Solé,et al.  Patterned electromyographic activity in the sit-to-stand movement , 1999, Clinical Neurophysiology.

[7]  Just L. Herder,et al.  Conceptual Design of a Passive Arm Orthosis , 2002 .

[8]  G Hendershot,et al.  Aging in the eighties: functional limitations of individuals age 65 years and over. , 1987 .

[9]  T Bajd,et al.  Standing-up of a healthy subject and a paraplegic patient. , 1982, Journal of biomechanics.

[10]  T. Rahman,et al.  A body-powered functional upper limb orthosis. , 2000, Journal of rehabilitation research and development.

[11]  Roderick Murray-Smith,et al.  Rehabilitation Robot Cell for Multimodal Standing-Up Motion Augmentation , 2005, Proceedings of the 2005 IEEE International Conference on Robotics and Automation.

[12]  Tadej Bajd,et al.  Robot assistive device for augmenting standing-up capabilities in impaired people , 2003, Proceedings 2003 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2003) (Cat. No.03CH37453).

[13]  S.K. Agrawal,et al.  Theory and design of an orthotic device for full or partial gravity-balancing of a human leg during motion , 2004, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[14]  Sunil K. Agrawal,et al.  Design and fabrication of an active gravity balanced planar mechanism using auxiliary parallelograms , 2001 .

[15]  Robertw . Mann,et al.  Mechanics of a constrained chair-rise. , 1991, Journal of biomechanics.

[16]  N de N Donaldson,et al.  FES standing: control by handle reactions of leg muscle stimulation (CHRELMS). , 1996, IEEE transactions on rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society.

[17]  Sunil Kumar Agrawal,et al.  A gravity balancing leg orthosis for robotic rehabilitation , 2004, IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA '04. 2004.

[18]  Tariq Rahman,et al.  A simple technique to passively gravity-balance articulated mechanisms , 1995 .

[19]  R Riener,et al.  Patient-driven control of FES-supported standing up: a simulation study. , 1998, IEEE transactions on rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society.

[20]  John T. McConville,et al.  Anthropometric source book. Volume 1: Anthropometry for designers , 1978 .

[21]  Robin Ficke.  Digest of Data on Persons with Disabilities. , 1992 .

[22]  Sunil K. Agrawal,et al.  On the Design of a Passive Orthosis to Gravity Balance Human Legs , 2005 .