Using a Redundant Planar Hip Exoskeleton to Reduce Human-Device Interface Forces

2017 ◽  
Author(s):  
David Schmitthenner ◽  
Samuel H. Shoemaker ◽  
Anne E. Martin
Keyword(s):  
Soft Tissue ◽  
Hip Joint ◽  
Degrees Of Freedom ◽  
Shear Forces ◽  
Dynamic Simulations ◽  
Lower Shear ◽  
Human Soft Tissue ◽  
Priority Method ◽  
Joint Center ◽  
Human Device

Robotic exoskeletons have the potential to improve gait rehabilitation. Currently, most exoskeletons use revolute joints that must be exactly aligned with the user’s joints to prevent uncomfortable shear forces at the human-device interface. This paper presents an alternative design for a planar hip exoskeleton based on a planar Stewart platform. In theory, this mechanism does not require exact knowledge of the human hip joint center of rotation to prevent large shear forces. The total human-device system has four degrees of freedom if the human soft tissue is neglected, which does complicate the control of the system compared to a rotational exoskeleton. To find a mapping between the desired human hip angle and the four actuated joints, the task priority method is used. To determine how well the proposed device can guide the hip through a step, dynamic simulations were conducted and compared to the results for a rotational exoskeleton. The compliance in the human soft tissue was included in the simulations because it can play a significant role in both the motion of the system and the human-device forces. Both the ideal case of exact hip joint alignment and the more likely case of hip joint misalignment were considered. In addition, the effects of differing levels of human effort were compared. In all cases, both exoskeletons were well able to guide the human hip in the desired motion. In addition, the novel exoskeleton has significantly lower shear forces at the thigh human-device connection point.

scholarly journals In-vivo quantification of dynamic hip joint center errors and soft tissue artifact

2016 ◽  
Vol 50 ◽  
pp. 246-251 ◽  
Author(s):  
Niccolo M. Fiorentino ◽  
Penny R. Atkins ◽  
Michael J. Kutschke ◽  
K. Bo Foreman ◽  
Andrew E. Anderson
Keyword(s):  
Soft Tissue ◽  
Hip Joint ◽  
Joint Center ◽  
Soft Tissue Artifact ◽  
Hip Joint Center

scholarly journals Dynamics of hip joint effusion after posterior soft tissue repair in total hip arthroplasty

2006 ◽  
Vol 30 (4) ◽  
pp. 233-236 ◽  
Author(s):  
Sarunas Tarasevicius ◽  
Uldis Kesteris ◽  
Romas Jonas Kalesinskas ◽  
Hans Wingstrand
Keyword(s):  
Soft Tissue ◽  
Total Hip Arthroplasty ◽  
Hip Joint ◽  
Hip Arthroplasty ◽  
Tissue Repair ◽  
Joint Effusion ◽  
Soft Tissue Repair ◽  
Total Hip ◽  
Posterior Soft Tissue

PO-1921 Radiosensitizing effect of Trabectidin on human soft tissue sarcoma cells

2021 ◽  
Vol 161 ◽  
pp. S1638-S1639
Author(s):  
M. Aquilano ◽  
G. Salvatore ◽  
M. Loi ◽  
D. Greto ◽  
E. Scoccimarro ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Soft Tissue Sarcoma ◽  
Radiosensitizing Effect ◽  
Human Soft Tissue ◽  
Sarcoma Cells

Evaluation of Anatomical and Functional Hip Joint Center Methods: The Effects of Activity Type, Gender, and Proximal Reference Segment

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
C. A. McGibbon ◽  
J. Fowler ◽  
S. Chase ◽  
K. Steeves ◽  
J. Landry ◽  
...  
Keyword(s):  
Hip Joint ◽  
Range Of Movement ◽  
Functional Methods ◽  
Reference Segment ◽  
Movement Type ◽  
And Gender ◽  
Joint Center ◽  
Chair Rise ◽  
Hip Joint Center

Accurate hip joint center (HJC) location is critical when studying hip joint biomechanics. The HJC is often determined from anatomical methods, but functional methods are becoming increasingly popular. Several studies have examined these methods using simulations and in vivo gait data, but none has studied high-range of motion activities, such a chair rise, nor has HJC prediction been compared between males and females. Furthermore, anterior superior iliac spine (ASIS) marker visibility during chair rise can be problematic, requiring a sacral cluster as an alternative proximal segment; but functional HJC has not been explored using this approach. For this study, the quality of HJC measurement was based on the joint gap error (JGE), which is the difference in global HJC between proximal and distal reference segments. The aims of the present study were to: (1) determine if JGE varies between pelvic and sacral referenced HJC for functional and anatomical methods, (2) investigate which functional calibration motion results in the lowest JGE and if the JGE varies depending on movement type (gait versus chair rise) and gender, and (3) assess whether the functional HJC calibration results in lower JGE than commonly used anatomical approaches and if it varies with movement type and gender. Data were collected on 39 healthy adults (19 males and 20 females) aged 14–50 yr old. Participants performed four hip “calibration” tests (arc, cross, star, and star-arc), as well as gait and chair rise (activities of daily living (ADL)). Two common anatomical methods were used to estimate HJC and were compared to HJC computed using a published functional method with the calibration motions above, when using pelvis or sacral cluster as the proximal reference. For ADL trials, functional methods resulted in lower JGE (12–19 mm) compared to anatomical methods (13–34 mm). It was also found that women had significantly higher JGE compared to men and JGE was significantly higher for chair rise compared to gait, across all methods. JGE for sacrum referenced HJC was consistently higher than for the pelvis, but only by 2.5 mm. The results indicate that dynamic hip range of movement and gender are significant factors in HJC quality. The findings also suggest that a rigid sacral cluster for HJC estimation is an acceptable alternative for relying solely on traditional pelvis markers.

scholarly journals Design and Production of Two-Piece Thyroid-Neck Phantom by the Concurrent Use of Epoxy Resin and Poly(Methyl Methacrylate) Soft Tissue Equivalent Materials

2018 ◽  
Vol 8 (2) ◽  
Author(s):  
M Karimi ◽  
H Mostaghimi ◽  
S. F Shams ◽  
A R Mehdizadeh
Keyword(s):  
Soft Tissue ◽  
Methyl Methacrylate ◽  
Epoxy Resin ◽  
Attenuation Coefficients ◽  
Poly Methyl Methacrylate ◽  
Tissue Equivalent ◽  
Concurrent Use ◽  
Human Soft Tissue ◽  
Mass Attenuation Coefficients ◽  
Mass Attenuation

The aim of this report is to present a new two-piece thyroid-neck phantom produced by the concurrent use of epoxy resin and poly(methyl methacrylate) (PMMA: plexiglass) soft tissue equivalent materials. Accordingly, mass attenuation coefficients of the epoxy resin and the plexiglass compounds were obtained from simulation (NIST XCOM 3.1) and measurements (practical dosimetry) and compared to those related to human soft tissue (ICRU 44). The thyroid-neck phantom and thyroid gland dimensions were derived from scientific references and the atlas of human anatomy, respectively. The thyroid phantom was designed by CATIA V5R16 software and produced by the epoxy resin compound by three-dimensional printer. Other organs were designed by ProNest software and made by the plexiglass sheets by CNC laser cutting machine. The mass attenuation coefficients for the epoxy resin (50 keV- 20 MeV) and the plexiglass (0-20 MeV) were comparable to human soft tissue (ICRU 44), all with standard relative deviation beneath 5%. In addition, the SPECT images indicated the similarity between human thyroid tissue and its phantom. In conclusion, this study proves the feasibility and reliability of epoxy resin application in the production of two-piece thyroid-neck phantom. This phantom can be applied in the calibration of gamma camera systems, dosimetry and gamma spectrometry in the nuclear medicine field.

scholarly journals The Effect of Soft Tissue on Detecting Hip Impingement

2017 ◽  
Vol 13 (18) ◽  
pp. 57
Author(s):  
Mahshid Yazdifar ◽  
Mohammadreza Yazdifar ◽  
Ebrahim Esat
Keyword(s):  
Soft Tissue ◽  
Hip Joint ◽  
Soft Tissues ◽  
Impingement Angle ◽  
Bone Contact ◽  
Specific Patient ◽  
Hip Impingement ◽  
Contact Kinematics ◽  
Impingement Zone ◽  
Centre Of Rotation

Hip impingement is a hip associated abnormality and it reduces the activity of those affected and also it can result in osteoarthritis. Current clinical methods in detecting hip impingement known as FADIR test. This is a manual method and relies heavily on surgeons experience and the method is prone to error. The use of computational programmes are known to be more accurate and reliable as the kinematic of contact can easily be studied using the digitised bones of the hip joint assuming that the impingement is determined by bone to bone contact kinematics. Current impingement studies assume that the kinematics of hip joint can be studied by assuming the centre of rotation is fixed for hip joint. For highly conforming joints this assumption is acceptable but for cases where conformity is poor the presence of soft tissue and soft tissue loading becomes very important. The important need in orthopaedics field is to develop a model without too much simplification. All previous work on detecting impingement has ignored the factor of soft tissue. In this paper for the first time the complete computational model of hip with soft tissue has been used to detect the impingement in a specific patient. In this paper the femur, acetabulum, cartilage and ligaments of specific patients were modelled in MIMICs using both MRI and CT scan. 3D hip models with and without soft tissues of normal hip, hip with impingement and hip with impingement after reshaping were modelled. The hip models were imported to detect impingement zone and impingement angle. Our results show that the soft tissue in hip model affects hip impingement angle and hip biomechanics. This finding also shows that, if the boundary condition is closer to the real hip, then the results of computer-aided program will be more reliable.

scholarly journals Jumping in frogs: assessing the design of the skeletal system by anatomically realistic modeling and forward dynamic simulation

2002 ◽  
Vol 205 (12) ◽  
pp. 1683-1702 ◽  
Author(s):  
William J. Kargo ◽  
Frank Nelson ◽  
Lawrence C. Rome
Keyword(s):  
Degrees Of Freedom ◽  
The Body ◽  
Joint Torque ◽  
Rotational Degree ◽  
Skeletal System ◽  
Dynamic Simulations ◽  
Inverse Dynamic ◽  
Maximal Distance ◽  
Out Of Plane ◽  
Rotational Degrees Of Freedom

SUMMARY Comparative musculoskeletal modeling represents a tool to understand better how motor system parameters are fine-tuned for specific behaviors. Frog jumping is a behavior in which the physical properties of the body and musculotendon actuators may have evolved specifically to extend the limits of performance. Little is known about how the joints of the frog contribute to and limit jumping performance. To address these issues, we developed a skeletal model of the frog Rana pipiens that contained realistic bones, joints and body-segment properties. We performed forward dynamic simulations of jumping to determine the minimal number of joint degrees of freedom required to produce maximal-distance jumps and to produce jumps of varied take-off angles. The forward dynamics of the models was driven with joint torque patterns determined from inverse dynamic analysis of jumping in experimental frogs. When the joints were constrained to rotate in the extension—flexion plane, the simulations produced short jumps with a fixed angle of take-off. We found that, to produce maximal-distance jumping,the skeletal system of the frog must minimally include a gimbal joint at the hip (three rotational degrees of freedom), a universal Hooke's joint at the knee (two rotational degrees of freedom) and pin joints at the ankle,tarsometatarsal, metatarsophalangeal and iliosacral joints (one rotational degree of freedom). One of the knee degrees of freedom represented a unique kinematic mechanism (internal rotation about the long axis of the tibiofibula)and played a crucial role in bringing the feet under the body so that maximal jump distances could be attained. Finally, the out-of-plane degrees of freedom were found to be essential to enable the frog to alter the angle of take-off and thereby permit flexible neuromotor control. The results of this study form a foundation upon which additional model subsystems (e.g. musculotendon and neural) can be added to test the integrative action of the neuromusculoskeletal system during frog jumping.

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