Application of a Magneto-rheological Damper and a Dynamic Absorber for a Suspension of a Working Machine Seat

Orečný, Martin; Segľa, Štefan; Huňady, Róbert; Ferková, Želmíra

doi:10.1016/j.proeng.2014.12.127

Cited by 14 publications

(6 citation statements)

References 11 publications

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“…In order to facilitate the vibration characteristics analysis of the convalescent-wheelchair system with DA, the convalescent-wheelchair system without DA is taken as a comparison object. Based on a typical commercially available wheelchair and the selection method of the DA [19], the values of the parameters for the convalescentwheelchair system is given in Table 1 [21]. e simulation condition is set as: u � 0.5∼2.5m/s, the C grade road with G q (n 0 ) � 256 × 10 −6 m −3 .…”

Section: Vibration Characteristics Comparisonmentioning

confidence: 99%

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Vibration Characteristics Analysis of Convalescent-Wheelchair Robots Equipped with Dynamic Absorbers

Wang

Zhao

et al. 2018

Shock and Vibration

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To provide a theoretical guidance for the vibration isolation design, the vibration responses characteristics for the convalescent-wheelchair robot with DA (dynamic absorber) undergoing the random road were revealed. Firstly, the vibration model of the convalescent-wheelchair system with DA was created. The frequency response functions of the road excitation velocity to the convalescent acceleration, the wheelchair body acceleration, and the tire dynamic deflection were deduced. Then, the numerical calculation method of the PSD (power spectral density) and the RMS (root mean square) responses were proposed. Thirdly, the vibration isolation performances of the wheelchair robot with DA and without DA were compared. Finally, the sensitivity analysis of the vibration responses to the mass ratios, the damping ratios, and the natural frequencies was carried out to reveal the effects of the parameters on the vibration responses. The results show that the DA can partly suppress the vibration of the convalescent and the wheelchair body, especially in the resonance area of the wheelchair body. However, the DA cannot successfully improve the tire contact behavior.

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Section: Vibration Characteristics Comparisonmentioning

confidence: 99%

“…eir users' vibration caused by the road excitation is mainly reduced by the tires and the cushion. e DA is a vibration reducing device connected to the vibration system by elastic and damping elements [19,20]. It occupies a small space and provides a cheap and effective way to attenuate the wheelchair robots vibration.…”

Section: Introductionmentioning

confidence: 99%

Vibration Characteristics Analysis of Convalescent-Wheelchair Robots Equipped with Dynamic Absorbers

Wang

Zhao

et al. 2018

Shock and Vibration

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“…The simulation step is set as ∆t = 0.001 s. Table 4 gives the values of the parameters for the human-wheelchair system. Based on the selection method of the DA [34,35], the DA mass m 0 was selected as the 10% of the wheelchair body mass m 1 . To make ω 0 = ω 1 , the DA stiffness K 0 was also selected as the 10% of the tire stiffness K 1 .…”

Section: The Time Domain Responsesmentioning

confidence: 99%

“…It occupies a small space, and provides a cheap and effective way to attenuate the shock and vibration of various vibration systems [34]. For example, Orečný et al introduced the DA to a working machine seat, and showed that the DA can effectively suppress the seat vibration [35]. However, there have been no related research reports on the use of dynamic absorbers in wheelchairs.…”

mentioning

confidence: 99%

Impact Responses and Parameters Sensitivity Analysis of Electric Wheelchairs

Wang

Zhao

et al. 2018

Electronics

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Featured Application: This work is specifically applied to wheelchairs. Abstract: The shock and vibration of electric wheelchairs undergoing road irregularities is inevitable. The road excitation causes the uneven magnetic gap of the motor, and the harmful vibration decreases the recovery rate of rehabilitation patients. To effectively suppress the shock and vibration, this paper introduces the DA (dynamic absorber) to the electric wheelchair. Firstly, a vibration model of the human-wheelchair system with the DA was created. The models of the road excitation for wheelchairs going up a step and going down a step were proposed, respectively. To reasonably evaluate the impact level of the human-wheelchair system undergoing the step-road transition, evaluation indexes were given. Moreover, the created vibration model and the road-step model were validated via tests. Then, to reveal the vibration suppression performance of the DA, the impact responses and the amplitude frequency characteristics were numerically simulated and compared. Finally, a sensitivity analysis of the impact responses to the tire static radius r and the characteristic parameters was carried out. The results show that the DA can effectively suppress the shock and vibration of the human-wheelchair system. Moreover, for the electric wheelchair going up a step and going down a step, there are some differences in the vibration behaviors.Electronics 2018, 7, 87 2 of 18 machine vision, pattern recognition, and human-machine interaction [10,11]. The price of intelligent wheelchairs is very high. It is difficult for ordinary families to afford them.In recent years, the enormous demand for wheelchairs has led to higher performance requirements [12]. How to effectively reduce the shock and vibration of electric wheelchairs has aroused a growing public attention [13][14][15]. When an electric wheelchair undergoes road irregularities, the shock and vibration of the human body and the wheelchair body are inevitable. The adverse effects of the shock and vibration caused by the road excitation mainly include four aspects. (1) The shock and vibration transmitted to the human body decrease the recovery rate of the patients. (2) The road excitation causes the uneven magnetic gap of the motor, resulting in the further deterioration of the vibration. (3) The intense shock causes a shorter working life of the wheelchair accessories, which include for instance, the mechanical parts, the motor, and the control hardware system. (4) The excessive vibration reduces the tire grounding safety.Various standards have been developed around the world to evaluate the performances of wheelchairs. The British standard 12183-2009 provides the requirements and the test methods of manual wheelchairs [16]. America instituted the standard ANSI/RESNA WC-1a-2009 for wheelchairs [17]. China instituted the standard GB/T 13800-2009 [18]. This standard is applicable for manual wheelchairs and electric wheelchairs. Generally speaking, the vibration acceleration of the human body is used to eva...

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“…In some studies, the three aforementioned control strategies have been compared. Orečný et al [39] reported that the idealized semi-active control of the seat vibration isolation is improved about 7% compared to the passive seat. Bouazara et al [40] performed a comparison between passive, semi-active and active vehicle models and concluded that the suspension is improved approximately 50% in the active and semi-active methods.…”

Section: Introductionmentioning

confidence: 99%

Design of optimum vibration absorbers for a bus vehicle to suppress unwanted vibrations against the harmonic and random road excitations

Rezazadeh

Moradi

2020

Scientia Iranica

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Unwanted vibrations of the vehicles are regarded as harmful threats to the human health from various biomechanical and psychophysical aspects. Road roughness has been considered as the main cause of unwanted vibrations in bus vehicles. Vertical seat vibrations have been found via simulation of a ten degree of freedom (10-DOF) model of an intercity bus vehicle under harmonic and random excitations caused by road roughness. To suppress undesirable vibrations, mass-spring-damper passive absorbers are proposed in a thirteen degrees of freedom (13-DOFs) model of the bus. By optimizing the characteristics of the embedded passive absorbers under each seat, and implementation of the designed absorbers, it is observed that the vertical displacement amplitudes in the frequency response of the seats are reduced especially near the bus resonant frequencies. In addition, the vertical displacement and acceleration amplitudes are decreased in the random excitation of the road roughness. According to the results, optimized mass-spring-damper absorbers are suggested as a practical solution to suppress the unwanted vibration effects in the bus vehicle.

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Application of a Magneto-rheological Damper and a Dynamic Absorber for a Suspension of a Working Machine Seat

Cited by 14 publications

References 11 publications

Vibration Characteristics Analysis of Convalescent-Wheelchair Robots Equipped with Dynamic Absorbers

Vibration Characteristics Analysis of Convalescent-Wheelchair Robots Equipped with Dynamic Absorbers

Impact Responses and Parameters Sensitivity Analysis of Electric Wheelchairs

Design of optimum vibration absorbers for a bus vehicle to suppress unwanted vibrations against the harmonic and random road excitations

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