Optical Enhancement of Exoskeleton-Based Estimation of Glenohumeral Angles
In Robot-Assisted Rehabilitation (RAR) the accurate estimation of the patient limb joint angles is critical for assessing therapy efficacy. In RAR, the use of classic motion capture systems (MOCAPs) (e.g., optical and electromagnetic) to estimate the Glenohumeral (GH) joint angles is hindered by the...
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| Format: | Article |
| Language: | English |
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Wiley
2016-01-01
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| Series: | Applied Bionics and Biomechanics |
| Online Access: | http://dx.doi.org/10.1155/2016/5058171 |
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| author | Camilo Cortés Luis Unzueta Ana de los Reyes-Guzmán Oscar E. Ruiz Julián Flórez |
| author_facet | Camilo Cortés Luis Unzueta Ana de los Reyes-Guzmán Oscar E. Ruiz Julián Flórez |
| author_sort | Camilo Cortés |
| collection | DOAJ |
| description | In Robot-Assisted Rehabilitation (RAR) the accurate estimation of the patient limb joint angles is critical for assessing therapy efficacy. In RAR, the use of classic motion capture systems (MOCAPs) (e.g., optical and electromagnetic) to estimate the Glenohumeral (GH) joint angles is hindered by the exoskeleton body, which causes occlusions and magnetic disturbances. Moreover, the exoskeleton posture does not accurately reflect limb posture, as their kinematic models differ. To address the said limitations in posture estimation, we propose installing the cameras of an optical marker-based MOCAP in the rehabilitation exoskeleton. Then, the GH joint angles are estimated by combining the estimated marker poses and exoskeleton Forward Kinematics. Such hybrid system prevents problems related to marker occlusions, reduced camera detection volume, and imprecise joint angle estimation due to the kinematic mismatch of the patient and exoskeleton models. This paper presents the formulation, simulation, and accuracy quantification of the proposed method with simulated human movements. In addition, a sensitivity analysis of the method accuracy to marker position estimation errors, due to system calibration errors and marker drifts, has been carried out. The results show that, even with significant errors in the marker position estimation, method accuracy is adequate for RAR. |
| format | Article |
| id | doaj-art-b5bf9f6987c34dca89bfcde3d25a81a5 |
| institution | OA Journals |
| issn | 1176-2322 1754-2103 |
| language | English |
| publishDate | 2016-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Applied Bionics and Biomechanics |
| spelling | doaj-art-b5bf9f6987c34dca89bfcde3d25a81a52025-08-20T02:23:22ZengWileyApplied Bionics and Biomechanics1176-23221754-21032016-01-01201610.1155/2016/50581715058171Optical Enhancement of Exoskeleton-Based Estimation of Glenohumeral AnglesCamilo Cortés0Luis Unzueta1Ana de los Reyes-Guzmán2Oscar E. Ruiz3Julián Flórez4eHealth and Biomedical Applications, Vicomtech-IK4, Mikeletegi Pasealekua 57, 20009 San Sebastián, SpaineHealth and Biomedical Applications, Vicomtech-IK4, Mikeletegi Pasealekua 57, 20009 San Sebastián, SpainBiomechanics and Technical Aids Department, National Hospital for Spinal Cord Injury, SESCAM, Finca la Peraleda s/n, 45071 Toledo, SpainLaboratorio de CAD CAM CAE, Universidad EAFIT, Carrera 49 No. 7 Sur-50, 050022 Medellín, ColombiaeHealth and Biomedical Applications, Vicomtech-IK4, Mikeletegi Pasealekua 57, 20009 San Sebastián, SpainIn Robot-Assisted Rehabilitation (RAR) the accurate estimation of the patient limb joint angles is critical for assessing therapy efficacy. In RAR, the use of classic motion capture systems (MOCAPs) (e.g., optical and electromagnetic) to estimate the Glenohumeral (GH) joint angles is hindered by the exoskeleton body, which causes occlusions and magnetic disturbances. Moreover, the exoskeleton posture does not accurately reflect limb posture, as their kinematic models differ. To address the said limitations in posture estimation, we propose installing the cameras of an optical marker-based MOCAP in the rehabilitation exoskeleton. Then, the GH joint angles are estimated by combining the estimated marker poses and exoskeleton Forward Kinematics. Such hybrid system prevents problems related to marker occlusions, reduced camera detection volume, and imprecise joint angle estimation due to the kinematic mismatch of the patient and exoskeleton models. This paper presents the formulation, simulation, and accuracy quantification of the proposed method with simulated human movements. In addition, a sensitivity analysis of the method accuracy to marker position estimation errors, due to system calibration errors and marker drifts, has been carried out. The results show that, even with significant errors in the marker position estimation, method accuracy is adequate for RAR.http://dx.doi.org/10.1155/2016/5058171 |
| spellingShingle | Camilo Cortés Luis Unzueta Ana de los Reyes-Guzmán Oscar E. Ruiz Julián Flórez Optical Enhancement of Exoskeleton-Based Estimation of Glenohumeral Angles Applied Bionics and Biomechanics |
| title | Optical Enhancement of Exoskeleton-Based Estimation of Glenohumeral Angles |
| title_full | Optical Enhancement of Exoskeleton-Based Estimation of Glenohumeral Angles |
| title_fullStr | Optical Enhancement of Exoskeleton-Based Estimation of Glenohumeral Angles |
| title_full_unstemmed | Optical Enhancement of Exoskeleton-Based Estimation of Glenohumeral Angles |
| title_short | Optical Enhancement of Exoskeleton-Based Estimation of Glenohumeral Angles |
| title_sort | optical enhancement of exoskeleton based estimation of glenohumeral angles |
| url | http://dx.doi.org/10.1155/2016/5058171 |
| work_keys_str_mv | AT camilocortes opticalenhancementofexoskeletonbasedestimationofglenohumeralangles AT luisunzueta opticalenhancementofexoskeletonbasedestimationofglenohumeralangles AT anadelosreyesguzman opticalenhancementofexoskeletonbasedestimationofglenohumeralangles AT oscareruiz opticalenhancementofexoskeletonbasedestimationofglenohumeralangles AT julianflorez opticalenhancementofexoskeletonbasedestimationofglenohumeralangles |