Four-bar linkage prosthetic knee mechanisms

Radcliffe, Charles W.

doi:10.3109/03093649409164401

Cited by 145 publications

(94 citation statements)

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“…For the purpose of this study, the most critical functional requirement of the design was identified as enabling able-bodied kinematics and stability for walking at normal cadence. The biomechanical reason for enabling stability and able-bodied kinematics during normal cadence is well documented in literature [17,23,24] and was also articulated repeatedly by the Indian users in our survey, albeit not for biomechanical reasons [4]. Most users explicitly expressed the need for the prosthesis to help them look able-bodied.…”

Section: Primary Functional Requirement For Early Stagesupporting

confidence: 55%

“…By tuning the spring stiffness and damper friction coefficients to the prescribed values based on the weight of the person and weight of the prosthesis, it should be possible to closely replicate the desired knee moment for able-bodied kinematics. [23]. During early stance (Fig.…”

Section: Primary Functional Requirement For Early Stagementioning

confidence: 99%

“…For example, single-axis knee joints rely on voluntary control of hip musculature to resist flexion during early stance. Singleaxis locking knee joints such as International Committee of the Red Cross knee use a mechanical latch engaged by the user to provide extra stability, which leads to a stiff legged gait suited only for new amputees or low-activity elderly users who demand hyper-stability [5,23]. Polycentric mechanisms, using a four-bar mechanism or six-bar mechanism, rely on a moving instantaneous center of rotation to provide stability.…”

Section: Primary Functional Requirement For Early Stagementioning

confidence: 99%

“…Polycentric mechanisms, using a four-bar mechanism or six-bar mechanism, rely on a moving instantaneous center of rotation to provide stability. The instantaneous center of rotation starts off posterior to the GRF vector at the beginning of stance and moves anterior to the GRF vector just before toe-off enabling some late stance flexion [23]. The LCKnee, recently developed by Andrysek et al [13], uses an automatic stance locking mechanism to lock the knee during early stance and unlocks it during late stance to enable late-stance flexion for transition into swing.…”

Section: Primary Functional Requirement For Early Stagementioning

confidence: 99%

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Design and Preliminary Field Validation of a Fully Passive Prosthetic Knee Mechanism for Users With Transfemoral Amputation in India

Arelekatti

Winter

2018

Journal of Mechanisms and Robotics

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An estimated 230,000 above-knee amputees in India are currently in need of prosthetic devices, a majority of them facing severe socio-economic constraints. However, only a few passive prosthetic knee devices in the market have been designed for facilitation of normative gait kinematics and for meeting the specific daily life needs of above-knee amputees in the developing world. Based on the results of our past studies, this paper establishes a framework for designing a potentially low-cost, fully passive prosthetic knee device, which aims to facilitate able-bodied kinematics at a low metabolic cost. Based on a comprehensive set of functional requirements and biomechanical analysis from our past work, we present an early prototype mechanism for the prosthetic knee joint that is primarily focused on enabling able-bodied kinematics. The mechanism is implemented using two functional modules: an automatic early stance lock for stability and a differential friction damping system for late stance and swing control. For preliminary, qualitative validation of the knee mechanism, we carried out a field trial on four above-knee amputees in India, which showed satisfactory performance of the early stance lock. The prototype enabled smooth stance-to-swing transition by timely initiation of late stance flexion. Possible methods of incorporating an additional spring module for further refinement of the design are also discussed, which can enable flexion-extension during the early-stance phase of the gait cycle and potentially reduce the metabolic energy expenditure of the user further.

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Section: Primary Functional Requirement For Early Stagesupporting

confidence: 55%

Section: Primary Functional Requirement For Early Stagementioning

confidence: 99%

Section: Primary Functional Requirement For Early Stagementioning

confidence: 99%

Section: Primary Functional Requirement For Early Stagementioning

confidence: 99%

See 2 more Smart Citations

Design and Preliminary Field Validation of a Fully Passive Prosthetic Knee Mechanism for Users With Transfemoral Amputation in India

Arelekatti

Winter

2018

Journal of Mechanisms and Robotics

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“…The polycentric knee structure has the effect of shortening the length of the legs in the swing phase when walking, thus preventing foot drop and making it possible to walk in a manner that appears natural. Therefore, it is widely used for prosthesis or orthosis, and the torque applied to the hip joint can be managed efficiently depending on the location of the instantaneous center of rotation (ICR) for the ground reaction force [23]. As a result, a simple 1 DoF knee structure system does not take into account this anatomical knowledge, causing misalignment between the apparatus and the person, making the wearer feel uncomfortable, and causing loss of energy from the power source.…”

Section: Introductionmentioning

confidence: 99%

Design and Control of a Polycentric Knee Exoskeleton Using an Electro-Hydraulic Actuator

Lee

Song

et al. 2019

Sensors

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An exoskeleton robot helps the wearer with mechanical forces by identifying the wearer’s intentions and requires high energy efficiency, sufficient load capacity, and a comfortable fit. However, since it is difficult to implement complex anatomical movements of the human body, most exoskeleton robots are designed simply, unlike the anatomy of real humans. This forces the wearer to accept the robot’s stiffness entirely, and to use energy inefficiently from the power source. In this paper, a simple 1 degree of freedom (DoF) structure, which was mainly used in the knees of exoskeleton robots, was designed with a polycentric (multi-axial) structure to minimize the misalignment between wearer and robot, so that torque transfer could be carried out efficiently. In addition, the overall robot system was constructed by using an electro-hydraulic actuator (EHA) to solve the problems of the energy inefficiency of conventional hydraulic actuators and the low load capacity of conventional electric actuators. After the configuration of the hardware system, the sliding mode controller was designed to address the EHA nonlinear models and the uncertainty of the plant design. This was configured as Simulink for the first verification, and the experiment was conducted by applying it to the actual model to demonstrate the performance of the sliding mode control. In this process, an optical rotary encoder was used as the main feedback sensor of the controller. The proposed polycentric knee exoskeleton robot system using the EHA was able to reach the desired target value well despite the presence of many model uncertainties.

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Amputation in the Diabetic Foot

Pinzur

Schiff

2020

The Foot in Diabetes

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Four-bar linkage prosthetic knee mechanisms

Cited by 145 publications

References 0 publications

Design and Preliminary Field Validation of a Fully Passive Prosthetic Knee Mechanism for Users With Transfemoral Amputation in India

Design and Preliminary Field Validation of a Fully Passive Prosthetic Knee Mechanism for Users With Transfemoral Amputation in India

Design and Control of a Polycentric Knee Exoskeleton Using an Electro-Hydraulic Actuator

Amputation in the Diabetic Foot

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