The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform
Kenji Suzuki - One of the best experts on this subject based on the ideXlab platform.
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IROS - Unpowered Lower-Body Exoskeleton with Torso Lifting Mechanism for Supporting Sit-to-Stand Transitions
2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018Co-Authors: Diego Felipe Paez Granados, Hideki Kadone, Kenji SuzukiAbstract:In this paper, we propose the design of an exoskeleton with support at the knee joint and lower torso for sit-to-stand and stand-to-sit (STS) posture transitions; devised for users with spinal cord injury and other complete lower-body impairments. The STS transitions assistance is achieved through a power transfer mechanism that synchronizes knees and lumbar motion through a cable-Driven Pulley system. We analyze the human body dynamics in the posture transition with a rigid link model and the interaction interface with the exoskeleton through an impedance model for producing a passive system voluntarily controlled by natural motions of the upper body. Therefore, allowing the potential users to achieve STS transitions with their body residual capabilities without an external power source. Instead, transferring power from their upper-body to lower-body, herewith, controlling a passive energy storage. A prototype was constructed and evaluated with seven healthy subjects observing the proposed motion and muscle activity during the STS transitions. The results show a significant reduction in the muscle activity evaluated, at the erector spinae, gluteus maximus, and rectus femoris, with reductions between 30% to 50% at the $p level comparing STS transitions with and without the exoskeleton support. Concluding that the STS transitions support is feasible with the passive exoskeleton envisioned for applications in upright locomotion, STS training, and rehabilitation.
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Unpowered Lower-Body Exoskeleton with Torso Lifting Mechanism for Supporting Sit-to-Stand Transitions
2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018Co-Authors: Diego Felipe Paez Granados, Hideki Kadone, Kenji SuzukiAbstract:In this paper, we propose the design of an exoskeleton with support at the knee joint and lower torso for sit-to-stand and stand-to-sit (STS) posture transitions; devised for users with spinal cord injury and other complete lower-body impairments. The STS transitions assistance is achieved through a power transfer mechanism that synchronizes knees and lumbar motion through a cable-Driven Pulley system. We analyze the human body dynamics in the posture transition with a rigid link model and the interaction interface with the exoskeleton through an impedance model for producing a passive system voluntarily controlled by natural motions of the upper body. Therefore, allowing the potential users to achieve STS transitions with their body residual capabilities without an external power source. Instead, transferring power from their upper-body to lower-body, herewith, controlling a passive energy storage. A prototype was constructed and evaluated with seven healthy subjects observing the proposed motion and muscle activity during the STS transitions. The results show a significant reduction in the muscle activity evaluated, at the erector spinae, gluteus maximus and rectus femoris, with reductions between 30% to 50% at the p
Diego Felipe Paez Granados - One of the best experts on this subject based on the ideXlab platform.
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IROS - Unpowered Lower-Body Exoskeleton with Torso Lifting Mechanism for Supporting Sit-to-Stand Transitions
2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018Co-Authors: Diego Felipe Paez Granados, Hideki Kadone, Kenji SuzukiAbstract:In this paper, we propose the design of an exoskeleton with support at the knee joint and lower torso for sit-to-stand and stand-to-sit (STS) posture transitions; devised for users with spinal cord injury and other complete lower-body impairments. The STS transitions assistance is achieved through a power transfer mechanism that synchronizes knees and lumbar motion through a cable-Driven Pulley system. We analyze the human body dynamics in the posture transition with a rigid link model and the interaction interface with the exoskeleton through an impedance model for producing a passive system voluntarily controlled by natural motions of the upper body. Therefore, allowing the potential users to achieve STS transitions with their body residual capabilities without an external power source. Instead, transferring power from their upper-body to lower-body, herewith, controlling a passive energy storage. A prototype was constructed and evaluated with seven healthy subjects observing the proposed motion and muscle activity during the STS transitions. The results show a significant reduction in the muscle activity evaluated, at the erector spinae, gluteus maximus, and rectus femoris, with reductions between 30% to 50% at the $p level comparing STS transitions with and without the exoskeleton support. Concluding that the STS transitions support is feasible with the passive exoskeleton envisioned for applications in upright locomotion, STS training, and rehabilitation.
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Unpowered Lower-Body Exoskeleton with Torso Lifting Mechanism for Supporting Sit-to-Stand Transitions
2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018Co-Authors: Diego Felipe Paez Granados, Hideki Kadone, Kenji SuzukiAbstract:In this paper, we propose the design of an exoskeleton with support at the knee joint and lower torso for sit-to-stand and stand-to-sit (STS) posture transitions; devised for users with spinal cord injury and other complete lower-body impairments. The STS transitions assistance is achieved through a power transfer mechanism that synchronizes knees and lumbar motion through a cable-Driven Pulley system. We analyze the human body dynamics in the posture transition with a rigid link model and the interaction interface with the exoskeleton through an impedance model for producing a passive system voluntarily controlled by natural motions of the upper body. Therefore, allowing the potential users to achieve STS transitions with their body residual capabilities without an external power source. Instead, transferring power from their upper-body to lower-body, herewith, controlling a passive energy storage. A prototype was constructed and evaluated with seven healthy subjects observing the proposed motion and muscle activity during the STS transitions. The results show a significant reduction in the muscle activity evaluated, at the erector spinae, gluteus maximus and rectus femoris, with reductions between 30% to 50% at the p
Robert G. Parker - One of the best experts on this subject based on the ideXlab platform.
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Piece-wise linear dynamic analysis of serpentine belt drives with a one-way clutch
Proceedings of the Institution of Mechanical Engineers Part C: Journal of Mechanical Engineering Science, 2008Co-Authors: Robert G. ParkerAbstract:A prototypical three-Pulley serpentine belt drive with belt bending stiffness is extended to include a one-way clutch in order to understand the non-linear dynamics of the system with the one-way clutch performance. The clutch is modelled based on the relative velocity of the Driven Pulley and its accessory. The clutch locks (engages) the Pulley and accessory for zero relative velocity and produces a positive inner clutch torque. Zero clutch torque initiates clutch disengagement, allowing unequal velocities of the two components. This model leads to a piece-wise linear system. The transition matrix is used to evaluate the system response in discrete time series for the two linear configurations, saving significant computational time. The system dynamics including response and dynamic tension drop are examined for varying excitation frequencies, inertia ratio of the Pulley and accessory, and external load. The investigation of vibration reduction because of the single-direction power transmission of the cl...
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Piece-Wise Linear Dynamic Analysis of Serpentine Belt Drives With a One-Way Clutch
Volume 7: 10th International Power Transmission and Gearing Conference, 2007Co-Authors: Robert G. ParkerAbstract:A prototypical three-Pulley serpentine belt drive with belt bending stiffness is extended to include a one-way clutch in order to understand the nonlinear dynamics of the system with the one-way clutch performance. The clutch is modeled based on the relative velocity of the Driven Pulley and its accessory. The clutch locks (engages) the Pulley and accessory for zero relative velocity and produces a positive inner clutch torque. Zero clutch torque initiates clutch disengagement, allowing unequal velocities of the two components. This model leads to a piece-wise linear system. The transition matrix is used to evaluate the system response in discrete time series for the two linear configurations, saving significant computation time. The system dynamics including response and dynamic tension drop are examined for varying excitation frequency, inertia ratio of the Pulley and accessory, and external load. The investigation of vibration reduction due to the single-direction power transmission of the clutch provides design guidelines in practice.Copyright © 2007 by ASME
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Microslip friction in flat belt drives
Proceedings of the Institution of Mechanical Engineers Part C: Journal of Mechanical Engineering Science, 2005Co-Authors: L Kong, Robert G. ParkerAbstract:AbstractThe microslip shear model of belt mechanics is extended to fully incorporate belt inertia effects and used to analyse the steady state of a two-Pulley drive. The belt is modelled as an axially moving string consisting of a tension-bearing member and a pliable elastomer envelope. Relative displacement between the tension-bearing member and the Pulley surfaces shears the elastomer envelope, transferring the friction from the Pulley surface to the tension-bearing member. The belt-Pulley contact arcs consist of adhesion and sliding zones. Static friction exists in the adhesion zones, whereas kinetic friction exists in the sliding zones. An iteration method involving one outer and two inner loops is proposed to find the steady mechanics, including the sliding and adhesion zones, belt-Pulley friction, and belt tension distribution. The outer loop iterates on the tight span tension similar to that used in published creep models. Two inner loops iterate on the tight span and Driven Pulley speeds respectiv...
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Mechanics and Sliding Friction in Belt Drives With Pulley Grooves
Journal of Mechanical Design, 2005Co-Authors: L Kong, Robert G. ParkerAbstract:The steady mechanics of a two-Pulley belt drive system are examined where the Pulley grooves, belt extension and wedging in the grooves, and the associated friction are considered. The belt is modeled as an axially moving string with the tangential and normal accelerations incorporated. The Pulley grooves generate two-dimensional radial and tangential friction forces whose undetermined direction depends on the relative speed between belt and Pulley along the contact arc. Different from single-Pulley analyses, the entry and exit points between the belt spans and Pulleys must be determined in the analysis due to the belt radial penetration into the Pulley grooves and the coupling of the driver and Driven Pulley solutions. A new computational technique is developed to find the steady mechanics of a V-belt drive. This allows system analysis, such as speed/ torque loss and maximum tension ratio. The governing boundary value problem (BVP) with undetermined boundaries is converted to a fixed boundary form solvable by a general-purpose BVP solver. Compared to flat belt drives or models that neglect radial friction, significant differences in the steady belt-Pulley mechanics arise in terms of belt radial penetration, free span contact points, tension, friction, and speed variations.
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Non-linear dynamics of a one-way clutch in belt–Pulley systems
Journal of Sound and Vibration, 2005Co-Authors: Robert G. ParkerAbstract:One-way clutches are frequently used in the serpentine belt accessory drives of automobiles and heavy vehicles. The clutch plays a role similar to a vibration absorber in order to reduce belt/Pulley vibration and noise and increase belt life. This paper analyzes a two-Pulley system where the Driven Pulley has a one-way clutch between the Pulley and accessory shaft that engages only for positive relative displacement between these components. The belt is modelled with linear springs that transmit torque from the driving Pulley to the accessory Pulley. The one-way clutch is modelled as a piecewise linear spring with discontinuous stiffness that separates the Driven Pulley into two degrees of freedom. The harmonic balance method combined with arclength continuation is employed to illustrate the non-linear dynamic behavior of the one-way clutch and determine the stable and unstable periodic solutions for given parameters. The results are confirmed by numerical integration and the bifurcation software AUTO. At the first primary resonance, most of the responses are aperiodic, including quasiperiodic and chaotic solutions. At the second primary resonance, the peak bends to the left with classical softening non-linearity because clutch disengagement decouples the Pulley and the accessory over portions of the response period. The dependence on clutch stiffness, excitation amplitude, and inertia ratio between the Pulley and accessory is studied to characterize the non-linear dynamics across a range of conditions.
Hideki Kadone - One of the best experts on this subject based on the ideXlab platform.
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IROS - Unpowered Lower-Body Exoskeleton with Torso Lifting Mechanism for Supporting Sit-to-Stand Transitions
2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018Co-Authors: Diego Felipe Paez Granados, Hideki Kadone, Kenji SuzukiAbstract:In this paper, we propose the design of an exoskeleton with support at the knee joint and lower torso for sit-to-stand and stand-to-sit (STS) posture transitions; devised for users with spinal cord injury and other complete lower-body impairments. The STS transitions assistance is achieved through a power transfer mechanism that synchronizes knees and lumbar motion through a cable-Driven Pulley system. We analyze the human body dynamics in the posture transition with a rigid link model and the interaction interface with the exoskeleton through an impedance model for producing a passive system voluntarily controlled by natural motions of the upper body. Therefore, allowing the potential users to achieve STS transitions with their body residual capabilities without an external power source. Instead, transferring power from their upper-body to lower-body, herewith, controlling a passive energy storage. A prototype was constructed and evaluated with seven healthy subjects observing the proposed motion and muscle activity during the STS transitions. The results show a significant reduction in the muscle activity evaluated, at the erector spinae, gluteus maximus, and rectus femoris, with reductions between 30% to 50% at the $p level comparing STS transitions with and without the exoskeleton support. Concluding that the STS transitions support is feasible with the passive exoskeleton envisioned for applications in upright locomotion, STS training, and rehabilitation.
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Unpowered Lower-Body Exoskeleton with Torso Lifting Mechanism for Supporting Sit-to-Stand Transitions
2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018Co-Authors: Diego Felipe Paez Granados, Hideki Kadone, Kenji SuzukiAbstract:In this paper, we propose the design of an exoskeleton with support at the knee joint and lower torso for sit-to-stand and stand-to-sit (STS) posture transitions; devised for users with spinal cord injury and other complete lower-body impairments. The STS transitions assistance is achieved through a power transfer mechanism that synchronizes knees and lumbar motion through a cable-Driven Pulley system. We analyze the human body dynamics in the posture transition with a rigid link model and the interaction interface with the exoskeleton through an impedance model for producing a passive system voluntarily controlled by natural motions of the upper body. Therefore, allowing the potential users to achieve STS transitions with their body residual capabilities without an external power source. Instead, transferring power from their upper-body to lower-body, herewith, controlling a passive energy storage. A prototype was constructed and evaluated with seven healthy subjects observing the proposed motion and muscle activity during the STS transitions. The results show a significant reduction in the muscle activity evaluated, at the erector spinae, gluteus maximus and rectus femoris, with reductions between 30% to 50% at the p
Hu Ding - One of the best experts on this subject based on the ideXlab platform.
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Vibration reduction effect of one-way clutch on belt-drive systems
European Journal of Mechanics A-solids, 2018Co-Authors: Hu Ding, Zhen Zhang, Li-qun ChenAbstract:Abstract In order to study the vibration reduction effect of the one-way clutch on belt-drive systems, especially on the transporting belt, an experimental platform is built. The strongest resonant areas of the midpoint of the transporting belt with and without the one-way clutch are compared. The experimental results clearly show the vibration reduction effect of the one-way clutch on the resonance of the belt-drive system. In order to determine the optimum vibration reduction parameters of the one-way clutch, a two-Pulley belt-drive dynamic model coupled is established. The commonalities between numerical simulation and experimental research are the inclusion of a translating belt, a driving Pulley, a Driven Pulley and an accessory Pulley. The difference is that there is no connection between the physical parameters of the numerical simulation and experimental studies. By establishing the relationship between the longitudinal vibration and transverse vibration of the translating belt spans, the coupled governing equations of the belt-drive system are derived to describe the coupling of the transverse vibration of the transporting belt and rotation of the Pulleys. The natural frequency of the belt is determined by using the amplitude spectrum of the free vibration response of the system. Numerical results illustrate that the two main parameters of the one-way clutch, the wrap spring and the pre-load have little effect on the natural vibration frequency of the belt. However, these two main parameters are very sensitive to the vibration reduction effect of the one-way clutch. Therefore, this study is very helpful to understand the optimal design of the one-way clutch.
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Periodic responses of a Pulley−belt system with one-way clutch under inertia excitation
Journal of Sound and Vibration, 2015Co-Authors: Hu DingAbstract:Abstract The stable steady-state periodic response of a two-Pulley belt drive system coupled with an accessory by a one-way clutch is presented. For the first time, the Pulley−belt system is studied under double excitations. Specifically, the dual excitations consist of harmonic motion of the driving Pulley and inertia excitation. The belt spans are modeled as axially moving viscoelastic beams by considering belt bending stiffness. Therefore, integro-partial-differential equations are derived for governing the transverse vibrations of the belt spans. Moreover, the transverse vibrations of the moving belt are coupled with the rotation vibrations of the Pulleys by nonlinear dynamic tension. For describing the unidirectional decoupling function of the one-way device, rotation vibrations of the Driven Pulley and accessory are modeled as coupled piecewise ordinary differential equations. In order to eliminate the influence of the boundary of the belt spans, the non-trivial equilibriums of the Pulley−belt system are numerically determined. Furthermore, A nonlinear piecewise discrete-continuous dynamical system is derived by introducing a coordinate transform. Coupled vibrations of the Pulley−belt system are investigated via the Galerkin truncation. The natural frequencies of the coupled vibrations are obtained by using the fast Fourier transform. Moreover, frequency−response curves are abstracted from time histories. Therefore, resonance areas of the belt spans, the Driven Pulley and the accessory are presented. Furthermore, validity of the Galerkin method is examined by comparing with the differential and integral quadrature methods (DQM & IQM). By comparing the results with and without one-way device, significant damping effect of clutch on the dynamic response is discovered. Furthermore, the effects of the intensity of the driving Pulley excitation and the inertia excitation are studied. Moreover, numerical results demonstrate that the two excitations interact on the steady-state response, as well as the damping effect of the one-way clutch.
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Steady-state responses of a belt-drive dynamical system under dual excitations
Acta Mechanica Sinica, 2015Co-Authors: Hu DingAbstract:The stable steady-state periodic responses of a belt-drive system with a one-way clutch are studied. For the first time, the dynamical system is investigated under dual excitations. The system is simultaneously excited by the firing pulsations of the engine and the harmonic motion of the foundation. Nonlinear discrete–continuous equations are derived for coupling the transverse vibration of the belt spans and the rotations of the driving and Driven Pulleys and the accessory Pulley. The nonlinear dynamics is studied under equal and multiple relations between the frequency of the firing pulsations and the frequency of the foundation motion. Furthermore, translating belt spans are modeled as axially moving strings. A set of nonlinear piecewise ordinary differential equations is achieved by using the Galerkin truncation. Under various relations between the excitation frequencies, the time histories of the dynamical system are numerically simulated based on the time discretization method. Furthermore, the stable steady-state periodic response curves are calculated based on the frequency sweep. Moreover, the convergence of the Galerkin truncation is examined. Numerical results demonstrate that the one-way clutch reduces the resonance amplitude of the rotations of the Driven Pulley and the accessory Pulley. On the other hand, numerical examples prove that the resonance areas of the belt spans are decreased by eliminating the torque-transmitting in the opposite direction. With the increasing amplitude of the foundation excitation, the damping effect of the one-way clutch will be reduced. Furthermore, as the amplitude of the firing pulsations of the engine increases, the jumping phenomena in steady-state response curves of the belt-drive system with or without a one-way clutch both occur.
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Steady-State Responses of Pulley-Belt Systems With a One-Way Clutch and Belt Bending Stiffness
Journal of Vibration and Acoustics, 2014Co-Authors: Hu Ding, Jean W. ZuAbstract:A nonlinear hybrid discrete-continuous dynamic model is established to analyze the steady-state response of a Pulley-belt system with a one-way clutch and belt bending stiffness. For the first time, the translating belt spans in Pulley-belt systems coupled with one-way clutches are modeled as axially moving viscoelastic beams. Moreover, the model considers the rotations of the driving Pulley, the Driven Pulley, and the accessory. The differential quadrature and integral quadrature methods are developed for space discretization of the nonlinear integropartial-differential equations in the dynamic model. Furthermore, the four-stage Runge–Kutta algorithm is employed for time discretization of the nonlinear piecewise ordinary differential equations. The time series are numerically calculated for the Driven Pulley, the accessory, and the translating belt spans. Based on the time series, the fast Fourier transform is used for obtaining the natural frequencies of the nonlinear vibration. The torque-transmitting directional behavior of the one-way clutch is revealed by the steady-state of the clutch torque in the primary resonances. The frequency-response curves of the translating belt, the Driven Pulley, and the accessory show that the one-way clutch reduces the resonance of the Pulley-belt system. Furthermore, the belt cross section's aspect ratio significantly affects the dynamic response.
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Effect of one-way clutch on the nonlinear vibration of belt-drive systems with a continuous belt model
Journal of Sound and Vibration, 2013Co-Authors: Hu Ding, Jean W. ZuAbstract:Abstract This study focuses on the nonlinear steady-state response of a belt-drive system with a one-way clutch. A dynamic model is established to describe the rotations of the driving Pulley, the Driven Pulley, and the accessory shaft. Moreover, the model considers the transverse vibration of the translating belt spans for the first time in belt-drive systems coupled with a one-way clutch. The excitation of the belt-drive system is derived from periodic fluctuation of the driving Pulley. In automotive systems, this kind of fluctuation is induced by the engine firing harmonic pulsations. The derived coupled discrete–continuous nonlinear equations consist of integro-partial-differential equations and piece-wise ordinary differential equations. Using the Galerkin truncation, a set of nonlinear ordinary differential equations is obtained from the integro-partial-differential equations. Applying the Runge–Kutta time discretization, the time histories of the dynamic response are numerically solved for the Driven Pulley and the accessory shaft and the translating belt spans. The resonance areas of the coupled belt-drive system are determined using the frequency sweep. The effects of the one-way clutch on the belt-drive system are studied by comparing the frequency–response curves of the translating belt with and without one-way clutch device. Furthermore, the results of 2-term and 4-term Galerkin truncation are compared to determine the numerical convergence. Moreover, parametric studies are conducted to understand the effects of the system parameters on the nonlinear steady-state response. It is concluded that one-way clutch not only decreases the resonance amplitude of the Driven Pulley and shaft's rotational vibration, but also reduces the resonance region of the belt's transverse vibration.
