External fixation devices have proved to be effective for the reduction of long bone fractures. Parallel mechanisms exhibited suitable properties for this purpose. Mechanisms with three degrees of freedom (dof) are used which, however, can only provide an approximate solution since a correct fracture reduction requires a mechanism with six dof. This paper presents a new 6-dof external fixation device which comprises two serially connected 3-dof parallel mechanisms. They have the special feature to perform a planar motion and a spatial one that are complementary, which makes the device's closure equations decoupled. This property and the 6-dof device capability simplify the fracture reduction algorithms, relieve the surgeon of the problem to precisely position the broken bone segments to the fixation device, and greatly shorten the fracture reduction time. The inverse position analysis of the 6-dof device is reported. Finally, some design aspects are discussed in the paper.
A new decoupled 6-dof parallel mechanism for long bone fracture reduction
Di Gregorio R.;
2001
Abstract
External fixation devices have proved to be effective for the reduction of long bone fractures. Parallel mechanisms exhibited suitable properties for this purpose. Mechanisms with three degrees of freedom (dof) are used which, however, can only provide an approximate solution since a correct fracture reduction requires a mechanism with six dof. This paper presents a new 6-dof external fixation device which comprises two serially connected 3-dof parallel mechanisms. They have the special feature to perform a planar motion and a spatial one that are complementary, which makes the device's closure equations decoupled. This property and the 6-dof device capability simplify the fracture reduction algorithms, relieve the surgeon of the problem to precisely position the broken bone segments to the fixation device, and greatly shorten the fracture reduction time. The inverse position analysis of the 6-dof device is reported. Finally, some design aspects are discussed in the paper.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
