Performance Maps for a Bio-Inspired Robotic Condylar Hinge Joint

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Stuart C. Burgess ◽  
Appolinaire C. Etoundi
Keyword(s):  
Design Space ◽  
Three Dimensional ◽  
Design Parameters ◽  
Mean Square ◽  
Cruciate Ligaments ◽  
Range Of Movement ◽  
Mechanical Advantage ◽  
Human Knee ◽  
Hinge Joint ◽  
Human Knee Joint

This paper presents performance charts that map the design space of a bio-inspired robotic condylar hinge joint. The joint mimics the design of the human knee joint by copying the condylar surfaces of the femur and tibia and by copying the four-bar motion of the cruciate ligaments. Four aspects of performance are modeled: peak mechanical advantage, RMS (root mean square) mechanical advantage, RMS sliding ratio, and range of movement. The performance of the joint is dependent on the shape of the condylar surfaces and the geometry of the four-bar mechanism. The design space for the condylar hinge joint is large because the four-bar mechanism has a very large number of possible configurations. Also, it is not intuitive what values of design parameters give the best design. Performance graphs are presented that cover over 12,000 different geometries of the four-bar mechanism. The maps are presented on three-dimensional graphs that help designers visualize the limits of performance of the joint and visualize tradeoffs between individual aspects of performance. The maps show that each aspect of performance of the joint is very sensitive to the geometry of the four-bar mechanism. The trends in performance can be understood by analyzing the kinematics of the four-bar mechanism and the shape of the condylar surfaces.

A Bio-Inspired Condylar Hinge for Robotic Limbs

2013 ◽  
Vol 5 (3) ◽  
Author(s):  
Appolinaire C. Etoundi ◽  
Stuart C. Burgess ◽  
Ravi Vaidyanathan
Keyword(s):  
Knee Joint ◽  
Design Procedure ◽  
High Strength ◽  
Experimental Tests ◽  
Superior Performance ◽  
Mechanical Advantage ◽  
Human Knee ◽  
Hinge Joint ◽  
Cam Mechanism ◽  
Human Knee Joint

This paper presents a novel condylar hinge for robotic limbs which was inspired by the human knee joint. The ligaments in the human knee joint can be modeled as an inverted parallelogram four-bar mechanism. The knee joint also has a condylar cam mechanism between the femur and tibia bones. The bio-inspired joint mimics the four-bar mechanism and the cam mechanism of the human knee joint. The bio-inspired design has the same desirable features of a human knee joint including compactness, high mechanical advantage, high strength, high stiffness and locking in the upright position. These characteristics are important for robotic limbs where there are often tight space and mass limitations. A prototype hinge joint similar in size to the human knee joint has been designed and tested. Experimental tests have shown that the new condylar hinge joint has superior performance to a pin-jointed hinge in terms of mechanical advantage and stiffness. The prototype hinge has a mechanical advantage that is greater than a pin-jointed hinge by up to 35% which leads to a corresponding reduction in the peak force of the actuator of up to 35% for a squatting movement. The paper also presents a five-step design procedure to produce a combined inverted parallelogram mechanism with a cam mechanism.

Adaptive Geometry Representation of Turbine Vane Frames for Use in Optimization

2021 ◽  
Author(s):  
Sebastian F. Riebl ◽  
Christian Wakelam ◽  
Reinhard Niehuis
Keyword(s):  
Design Space ◽  
Cfd Simulation ◽  
A Priori ◽  
Three Dimensional ◽  
Optimization Method ◽  
Three Dimensions ◽  
Design Parameters ◽  
Adjustment Process ◽  
Turbine Vane ◽  
Integrated Concept

Abstract Turbine Vane Frames (TVF) are a way to realize more compact jet engine designs. Located between the high pressure turbine (HPT) and the low pressure turbine (LPT), they fulfill structural and aerodynamic tasks. When used as an integrated concept with splitters located between the structural load-bearing vanes, the TVF configuration contains more than one type of airfoil with sometimes pronouncedly different properties. This system of multidisciplinary demands and mixed blading poses an interesting opportunity for optimization. Within the scope of the present work, a full geometric parameterization of a TVF with splitters is presented. The parameterization is chosen as to minimize the number of parameters required to automatically and flexibly represent all blade types involved in a TVF row in all three dimensions. Typical blade design parameters are linked to the fourth order Bézier-curve controlled camber line-thickness parameterization. Based on conventional design rules, a procedure is presented, which sets the parameters within their permissible ranges according to the imposed constraints, using a proprietary developed code. The presented workflow relies on subsequent three dimensional geometry generation by transfer of the proposed parameter set to a commercially available CAD package. The interdependencies of parameters are discussed and their respective significance for the adjustment process is detailed. Furthermore, the capability of the chosen parameterization and adjustment process to rebuild an exemplary reference TVF geometry is demonstrated. The results are verified by comparing not only geometrical profile data, but also validated CFD simulation results between the rebuilt and original geometries. Measures taken to ensure the robustness of the method are highlighted and evaluated by exploring extremes in the permissible design space. Finally, the embedding of the proposed method within the framework of an automated, gradient free numerical optimization is discussed. Herein, implications of the proposed method on response surface modeling in combination with the optimization method are highlighted. The method promises to be an option for improvement of optimization efficiency in gradient free optimization of interdependent blade geometries, by a-priori excluding unsuitable blade combinations, yet keeping restrictions to the design space as limited as possible.

Studying the Intact, ACL-Deficient and Reconstructed Human Knee Joint Using a Finite Element Model

2013 ◽  
Author(s):  
Achilles Vairis ◽  
Markos Petousis ◽  
George Stefanoudakis ◽  
Nectarios Vidakis ◽  
Betina Kandyla ◽  
...  
Keyword(s):  
Finite Element ◽  
Knee Joint ◽  
Cruciate Ligament ◽  
Three Dimensional ◽  
Element Model ◽  
Human Knee ◽  
Mechanical Responses ◽  
Human Knee Joint ◽  
Calculated Load ◽  
Anterior Cruciate

The human knee joint has a three dimensional geometry with multiple body articulations that produce complex mechanical responses under loads that occur in everyday life and sports activities. Knowledge of the complex mechanical interactions of these load bearing structures is of help when the treatment of relevant diseases is evaluated and assisting devices are designed. The anterior cruciate ligament in the knee connects the femur to the tibia and is often torn during a sudden twisting motion, resulting in knee instability. The objective of this work is to study the mechanical behavior of the human knee joint in typical everyday activities and evaluate the differences in its response for three different states, intact, injured and reconstructed knee. Three equivalent finite element models were developed. For the reconstructed model a novel repair device developed and patented by the authors was employed. For the verification of the developed models, static load cases presented in a previous modeling work were used. Mechanical stresses calculated for the load cases studied, were very close to results presented in previous experimentally verified work, in both load distribution and maximum calculated load values.

scholarly journals Relevance of the hyperelastic behavior of cruciate ligaments in the modeling of the human knee joint in sagittal plane

2015 ◽  
Author(s):  
Daniel Alejandro Ponce-Saldias ◽  
◽  
Daniel Martins ◽  
Carlos Rodrigo de Mello-Roesler ◽  
Otavio Teixeira-Pinto ◽  
...  
Keyword(s):  
Knee Joint ◽  
Sagittal Plane ◽  
Cruciate Ligaments ◽  
Human Knee ◽  
Human Knee Joint

The Contribution of the Cruciate Ligaments to the Load-Displacement Characteristics of the Human Knee Joint

1980 ◽  
Vol 102 (4) ◽  
pp. 277-283 ◽  
Author(s):  
R. L. Piziali ◽  
J. Rastegar ◽  
D. A. Nagel ◽  
D. J. Schurman
Keyword(s):  
Knee Joint ◽  
Soft Tissues ◽  
Lateral Load ◽  
Flexion Angle ◽  
Cruciate Ligaments ◽  
Significant Percentage ◽  
Human Knee ◽  
Human Knee Joint ◽  
Torsional Loads ◽  
Anterior Posterior

Human knee specimens were subjected to anterior-posterior, medial-lateral, varus-valgus, and torsional displacement tests. Loads were recorded for the intact joint and for the joint with all soft tissues cut except for the cruciate ligaments. The effect of condylar interference was determined for anterior-posterior, medial-lateral, and torsional displacements. The variation in load with flexion angle was considerable for medial-lateral (0–90-deg flexion) displacements, and less for varus-valgus (0–45-deg flexion) displacements. The cruciates were found to carry almost the entire anterior-posterior load; they carried a significant percentage of the medial-lateral load which varied considerably with flexion angle. A small, but not insignificant percentage of the varus-valgus load was carried by the cruciates and the variations with flexion angle were small. In torsion, the cruciates resisted only internal rotation. In the tested displacement ranges, condylar interference had a small effect on the medial-lateral load but did not affect anterior-posterior or torsional loads.

MEASUREMENT AND FITTING ON 3-D ARTICULAR SURFACES OF THE HUMAN KNEE JOINT

2002 ◽  
Vol 14 (04) ◽  
pp. 171-174
Author(s):  
XISHI WANG ◽  
LI-QUN ZHANG
Keyword(s):  
Knee Joint ◽  
Three Dimensional ◽  
Reconstruction Error ◽  
Reconstruction Procedure ◽  
Human Knee ◽  
Articular Surfaces ◽  
Human Knee Joint ◽  
Surface Measurements ◽  
Articulating Surface ◽  
Relative Analysis

In this study, the OptoTrak system was employed to collect the articulating surface measurements of the human knee for the femur, tibia and patella in three experimented specimens. Furthermore, a rigorous mathematical reconstruction procedure that estimates reconstruction error was completed by employed the relative analysis tools. The results show, the measurements for each session were able to reconstruct the three-dimensional calibration to a precision of 0.02mm. On the other word, the OptoTrak can be used to obtain the precise measurements of analytical surface of the human knee joint.

An Assessment of Village Drill Sustainability, With Recommendations

2017 ◽  
Author(s):  
Andrew T. Pack ◽  
Christopher A. Mattson
Keyword(s):  
Rural Areas ◽  
Design Space ◽  
Three Dimensional ◽  
Decision Makers ◽  
Random Sets ◽  
Design Parameters ◽  
Water Wells ◽  
Using Data ◽  
The Village ◽  
Drill Design

Sustainability is commonly broken into three categories: economic, environmental, and social. For products, there is a need for design tools that allow decision makers to handle the tradeoffs between each of these three pillars of sustainability. This paper simultaneously assesses all three pillars of sustainability for the Village Drill, a machine used to dig water wells in rural areas around the world. Using data and methods from Mattson et al. [1, 2] relationships are developed between the drill’s design parameters and key sustainability issues. These relationships are used to evaluate the sustainability of the current drill design as well as any alternatives. One million random sets of drill parameters are generated and the resulting drill alternatives are evaluated. A three-dimensional design space for the sustainability of the drill is found and recommendations are given with potential for improvements in each pillar of sustainability.

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