Validation of a calibration technique for 6-DOF instrumented spatial linkages

Transactions of the Canadian Society for Mechanical Engineering

Mundo

Danieli

2010

Self Cite

Six-degree-of-freedom instrumented spatial linkages are often used to measure anatomical joint motion for clinical studies or research applications in biomechanics. Their appropriate design is a fundamental issue to allow for accurate measurements and ease of application, and this mainly relies on addressing the kinematic analysis of the linkage. The aim of this paper is to integrate and extend past literature in the field by giving a generalized set of guidelines and ready-to-use mathematical relationships to approach the whole kinematic analysis of a general instrumented spatial linkage in a systematic way. The direct kinematics is formulated using common robotics formulation and, with reference to a specific linkage architecture, a geometrical approach is proposed to solve for the inverse kinematics in closed-form. Kinematic error analysis is addressed in a generalized way by using differential transformation theory, and it is then applied to the specific case under study. By the proper definition of a virtual joint, the inverse kinematics is used to estimate the static performance of the linkage over its specific task space.

“…the ISL resolution by definition. Experimental performance and results after calibration [34] also validate such estimated theoretical predictions.…”

Section: Computational Application and Numerical Validationsupporting

confidence: 66%

Section: Kinematic Error Analysismentioning

confidence: 99%

Kinematic Analysis and Performance Evaluation of 6r Instrumented Spatial Linkages

Transactions of the Canadian Society for Mechanical Engineering

Mundo

Danieli

2010

Self Cite

“…It is used to estimate the pose of its distal link (assumed to be rigidly connected to the tibia) relative to the proximal (assumed to be rigidly connected to the femur), so as to detect the envelope of knee motion. Its accuracy is estimated to be 0.183 ± 0.081 mm and 0.085 ± 0.036 deg after kinematic calibration and geometrical error compensation, as reported in Gatti and Danieli (2007). To mathematically describe the acquired knee motion, two orthogonal frames, {B} and {E}, are attached to the femur and tibia, respectively, as depicted in Figure 2a, and the transformation matrix T E B -describing the pose of frame {E} on the tibia relative to frame {B} on the femur-is estimated from the transducer readings and the linkage geometry through the direct kinematic model.…”

Section: Instrumented Spatial Linkagementioning

confidence: 81%

On the Estimate of the Two Dominant Axes of the Knee Using an Instrumented Spatial Linkage

Journal of Applied Biomechanics

2012

Self Cite

This article presents the validation of a technique to assess the appropriateness of a 2 degree-of-freedom model for the human knee, and, in which case, the dominant axes of flexion/extension and internal/external longitudinal rotation are estimated. The technique relies on the use of an instrumented spatial linkage for the accurate detection of passive knee kinematics, and it is based on the assumption that points on the longitudinal rotation axis describe nearly circular and planar trajectories, whereas the flexion/extension axis is perpendicular to those trajectories through their centers of rotation. By manually enforcing a tibia rotation while bending the knee in flexion, a standard optimization algorithm is used to estimate the approximate axis of longitudinal rotation, and the axis of flexion is estimated consequently. The proposed technique is validated through simulated data and experimentally applied on a 2 degree-of-freedom mechanical joint. A procedure is proposed to verify the fixed axes assumption for the knee model. The suggested methodology could be possibly valuable in understanding knee kinematics, and in particular for the design and implant of customized hinged external fixators, which have shown to be effective in knee dislocation treatment and rehabilitation.

“…The use of ISLs to measure three-dimensional human joints motion were effectively applied for either in vitro or in vivo studies (Lewandowski et al, 1997;Van Sint Jan et al, 2002), and also effectively used whenever direct fixation to bones is required (Gardner et al, 1996;Danieli et al, 2005a;Ishii et al, 1997), as an alternative approach to active robotic systems (Danieli et al, 2005b). Requirements for adequate measurements involve advanced calibration of the devices (Liu and Panjabi, 1996;Gatti et al, 2010;Gatti and Danieli, 2008;Sholukha et al, 2004;Gatti and Danieli, 2007). Several authors (Hollister et al, 1993;Roland et al, 2010;Gatti, 2012), presented and validated techniques to estimate and identify both the functional FE axis and the LR axis of the human knee.…”

Section: Knee Joint Axes Identificationmentioning

confidence: 99%

Hinged External Fixators for Knee Rehabilitation - Kinematic Concept of a Two Degree-of-Freedom System

Proceedings of the International Conference on Biomedical Electronics and Devices

Shweiki²,

Lupinacci

et al. 2014

Hinged external fixators are used in knee dislocation treatment, where they have shown their effectiveness. They are proposed as a technique to protect ligament reconstructions while allowing early postoperative rehabilitation. A hinged external fixator usually consists of two rigid links connected to each other by a revolute joint. Each link is then fixed to the femur and tibia, via direct pin fixation. A single-axis hinged external fixator thus well accommodates the main knee movement, i.e. the flexion and extension. This paper presents an investigation on the conceptual idea of a double-axis hinged external fixator for the human knee, which accommodates for both flexion-extension and longitudinal internal-external rotation of the tibia respect to the femur. The potential advantage of such a design is foreseen in the increasing range of motion in postoperative knee rehabilitation and a better accommodation of natural knee motion.