Biomimetic Design of a Single DOF Stephenson III Leg Mechanism

Batayneh, Wafa; Al-Araidah, Omar; Malkawi, Salaheddin

doi:10.5539/mer.v3n2p43

Cited by 15 publications

(9 citation statements)

References 12 publications

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“…However, the relative foot stride is notably small. This concept was developed by the authors in [19] towards minimizing the number of links, and a six-link leg mechanism for a biped robot was synthesized. Unfortunately, they used prismatic joints, and the foot stride is small as well.…”

Section: Introductionmentioning

confidence: 99%

Multicriteria Optimization of Lower Limb Exoskeleton Mechanism

Ibrayev,

Ibrayeva,

Rakhmatulina

et al. 2023

Applied Sciences

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Typical leg exoskeletons employ open-loop kinematic chains with motors placed directly on movable joints; while this design offers flexibility, it leads to increased costs and heightened control complexity due to the high number of degrees of freedom. The use of heavy servo-motors to handle torque in active joints results in complex and bulky designs, as highlighted in the existing literature. In this analytical study, we introduced a novel synthesis method with analytical solutions provided for synthesizing the lower-limb exoskeleton. Furthermore, we proposed a mathematical model of multicriteria optimization; as a result, we obtained several lower-limb exoskeleton mechanisms comprising only six links, well-suited to the human anatomical structure, exhibit superior trajectory accuracy, efficient force transmission, satisfactory step height, and having internal transfer segment of the foot.

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Section: Introductionmentioning

confidence: 99%

Multicriteria Optimization of Lower Limb Exoskeleton Mechanism

Ibrayev,

Ibrayeva,

Rakhmatulina

et al. 2023

Applied Sciences

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“…The six-bar performs in a manner that is similar to the four-bar, but has extra design variables that can be used to improve the performance of the mechanism, typically supplying amplification or subtler control over forces and/or displacements. Several recent examples of using the six-bar to provide such design refinement include a furniture hinge mechanism [2], an adjustable mechanical forming press [3], a biomimetic leg mechanism [4], a body guidance mechanism [5], a hand rehabilitation robot [6], and a compact bellow globe valve design [7]. When locking the motion of the ankle, a human pedaling a bicycle is seen as a four-bar loop, with the thigh as a rocking input, the cnemis, or lower leg, as the coupler, and the crank connecting to sprocket and chain as the fully rotating output.…”

Section: Introductionmentioning

confidence: 99%

Six-Bar Linkage Models of a Recumbent Tricycle Mechanism to Increase Power Throughput in FES Cycling

et al. 2022

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This paper presents the kinematic and static analysis of two mechanisms to improve power throughput for persons with tetra- or paraplegia pedaling a performance tricycle via FES. FES, or functional electrical stimulation, activates muscles by passing small electrical currents through the muscle creating a contraction. The use of FES can build muscle in patients, relieve soreness, and promote cardiovascular health. Compared to an able-bodied rider, a cyclist stimulated via FES produces an order of magnitude less power creating some notable pedaling difficulties especially pertaining to inactive zones. An inactive zone occurs when the leg position is unable to produce enough power to propel the tricycle via muscle stimulation. An inactive zone is typically present when one leg is fully bent and the other leg is fully extended. Altering the motion of a cyclist’s legs relative to the crank position can potentially reduce inactive zones and increase power throughput. Some recently marketed bicycles showcase pedal mechanisms utilizing alternate leg motions. This work considers performance tricycle designs based on the Stephenson III and Watt II six-bar mechanisms where the legs define two of the system’s links. The architecture based on the Stephenson III is referred to throughout as the CDT due to the legs’ push acting to coupler-drive the four-bar component of the system. The architecture based on the Watt II is referred to throughout as the CRT due to the legs’ push acting to drive the rocker link of the four-bar component of the system. The unmodified or traditional recumbent tricycle (TRT) provides a benchmarks by which the designs proposed herein may be evaluated. Using knee and hip torques and angular velocities consistent with a previous study, this numerical study using a quasi-static power model of the CRT suggests a roughly 50% increase and the CDT suggests roughly a doubling in average crank power, respectively, for a typical FES cyclist.

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“…Six-bar linkage also forms the basis of extending linkages used for magnifying displacements or forces. Various applications of six-bar linkages include a hand rehabilitation robot based on the Watt II linkage [7], leg mechanism based on the Stephenson III linkage [8], body guidance mechanism based on the Watt I linkage [9], and a furniture hinge mechanism based on the Watt I configuration [10].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of Six-Bar Linkage Application to Bellow Globe Valve for Compact Design

et al. 2018

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Bellow sealing in valves provides the characteristic of no emission sealing by extending or compressing within the elastic limit to operate the valve. To keep the motion of the bellow within the elastic limit, a long length of bellow is required, which increases the length of the shaft and height of the valve. Increased height restricts valve usage, especially for large sizes, due to the limited platform space. This study presents the application of a six-bar linkage to operating mechanism by replacing the reciprocating shaft in an attempt to reduce the height of the valve. The mechanism produced aims to reduce the input displacement while maintaining the output displacement in order to reduce the required bellow length. Graphical synthesis of the mechanism was carried out using Autodesk Inventor. The designed mechanism was then subjected to analysis using a simulation tool for the position, force, and flow analysis. The prototype valve with the application of the new mechanism was manufactured using additive manufacturing, which was later used for experimental testing. Application of the mechanism to the bellow valve reduced the required input by 75%, which as a result, reduced the height of the valve up to 50%. The force analysis depicted that the force required to operate the mechanism was approximately eight times higher than the conventional design. Flow analysis of the valve showed that the introduction of the new mechanism had no effect on the flow efficiency of the valve and the flow coefficient of valve remained the same. Application of the six-bar linkage to the valve control mechanism made the design of the valve compact when compared to conventional design in terms of height, which makes it more suitable for use in industry.

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Biomimetic Design of a Single DOF Stephenson III Leg Mechanism

Cited by 15 publications

References 12 publications

Multicriteria Optimization of Lower Limb Exoskeleton Mechanism

Multicriteria Optimization of Lower Limb Exoskeleton Mechanism

Six-Bar Linkage Models of a Recumbent Tricycle Mechanism to Increase Power Throughput in FES Cycling

Experimental and Numerical Investigation of Six-Bar Linkage Application to Bellow Globe Valve for Compact Design

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