Semi-active control of ambulance stretcher system based on parallel mechanism with MR dampers and perturbation analysis

Gao, Xiang; Niu, Junchuan; Liu, Zhihui; Tian, Junrui

doi:10.1007/s10999-019-09444-2

Cited by 10 publications

(8 citation statements)

References 18 publications

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“…The dynamic equation of the proposed multi-dimensional isolator could be yielded by the Lagrange approach with damping coefficient. 22 Through deducing, the dynamic equation of the proposed isolator is given bywhere X=[xp,yp,zp,θ]bold-italicT and M=diag(mp,mp,mp,Iy) are displacement and inertia matrices of the moving platform, respectively, mp is the mass of the moving platform, Iy is the moment inertia around y axis, K=Gdiag(k)bold-italicGbold-italicT is the stiffness matrix, k is spring stiffness, bold-italicCe=Gdiag(ce)bold-italicGbold-italicT is the damping matrix, G=bold-italicJ−T is the force Jacobian matrix, and …”

Section: Model Of the Vibration Isolatormentioning

confidence: 99%

“…Defined coupled excitations are in horizontal, longitudinal, vertical, and roll directions. The uncertain values in manufacturing and assembling process affect the Jacobian matrix of the isolator 22 ; furthermore, the mass of facilities is not always the same, and stiffness and damping coefficient do not obey linear rules strictly. Taking uncertain values into account, the actual mass, stiffness, and damping coefficient can be illustrated as follows, respectivelywhere ωm, ωk, and ωc are uncertain ratios of mass, stiffness, and damping coefficient, respectively, defining ωm=ωk=ωc=10% in the following simulation.…”

Section: Semi-active Robust Optimal Control Of the Isolatormentioning

confidence: 99%

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Grey relation analysis of natural frequency and semi-active robust optimal control of a multi-dimensional isolator based on parallel mechanism and magneto-rheological damper

Gao

Niu

Jia

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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For isolating multi-dimensional vibrations experienced by precise facilities carried on a vehicle, a novel isolator is proposed based on 2-RPC/2-SPC parallel mechanism with magneto-rheological dampers. Kinematics and dynamics of the isolator are analyzed by geometrics and the Lagrange method. Grey relation analysis approach is conducted to determine the contributions of geometric parameters on natural frequency conveniently. Through analysis, the first order natural frequency of the isolator is affected by the length of the fixed platform most significantly. Due to manufacturing and assembling errors which could not be avoided in the isolator, robust optimal control algorithm is conducted to ensure control effect and robustness of the isolator at the same time. The gain of robust optimal control algorithm is obtained by deducing and solving linear matrix inequality. Compared to passive control, velocity root mean square values of robust optimal semi-active control decreased obviously in horizontal, longitudinal, vertical, and roll directions.

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Section: Model Of the Vibration Isolatormentioning

confidence: 99%

Section: Semi-active Robust Optimal Control Of the Isolatormentioning

confidence: 99%

Grey relation analysis of natural frequency and semi-active robust optimal control of a multi-dimensional isolator based on parallel mechanism and magneto-rheological damper

Gao

Niu

Jia

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…For the parallel mechanism, the motivation of kinematic analysis is obtaining inverse Jacobian matrix. The inverse Jacobian matrix is illustrated as follows (Gao et al, 2019)where Di is given by…”

Section: Kinematics and Dynamics Of The Stretchermentioning

confidence: 99%

“…The isolator could weaken the vibrations in rolling, pitch, and vertical directions effectively. Gao et al (2019) improved a 4-PUU parallel mechanism as the vibration isolation device of the ambulance stretcher, by installing springs and MR dampers on active joints. The vibrations were significantly attenuated in horizontal, longitudinal, vertical, and pitch directions.…”

Section: Introductionmentioning

confidence: 99%

Influence characteristics of electrical parameters and vibration isolation properties of the stretcher system based on parallel mechanism and self-powered magneto-rheological damper

Gao

Niu

Liu

et al. 2019

Journal of Vibration and Control

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For reducing multidimensional vibrations endured by supine patients on ambulances, a new ambulance stretcher composed of parallel mechanism and self-powered magneto-rheological damper is introduced. The main thrust of this work is to investigate the vibration isolation capability and energy conversion efficiency of the proposed stretcher with changes in electrical parameters. First, the kinematic and dynamic equations are deduced by geometry and Lagrange approach, respectively. Subsequently, the circuit model of self-powered magneto-rheological damper is created. The frequency response function is derived by Kirchhoff’s law, which indicates the electrical power utilization rate. Then, the vibration isolation capability of the self-powered stretcher system is analyzed with changes in electrical parameters. Compared with passive control, the vibration isolation capability of the self-powered stretcher is improved significantly in horizontal, longitudinal, vertical, and pitch directions. The first two resonance peaks of displacement response are insensitive to changes in electrical parameters in all directions. Last, the energy conversion efficiency of the self-powered stretcher is discussed. Decreasing resistance and inductance could improve energy conversion efficiency significantly.

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“…Chae et al designed a semiactive vibration reduction system for vehicle-mounted stretchers, which used MR dampers as the actuator and realized the vibration isolation control through sliding mode variable structure semiactive control. Gao et al [32] improved a 4-PUU parallel mechanism as a vehicle stretcher, took MR damper as the output force device, and adopted the LQR method combined with Hrovat algorithm to study the semiactive control and vibration isolation performance of the system. Wang et al [33] studied the ultralow-frequency vibration isolation in the process of neonatal transport through theory and experiment.…”

Section: Introductionmentioning

confidence: 99%

Design and Research of Semiactive Quasi‐Zero Stiffness Vibration Isolation System for Vehicles

Feng

Zhao

2021

Shock and Vibration

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The vehicle-mounted equipment is easy to be disturbed by external vibration excitations during transportation, which is harmful to the measurement accuracy and performance of the equipment. Aiming at the vibration isolation of the vehicle-mounted equipment, a semiactively controlled quasi-zero stiffness (QZS) vibration isolator with positive and negative stiffness is proposed. The vertical spring is paralleled with a magnetorheological (MR) damper, and the semiactive on-off control scheme is adopted to control the vibration. The analytical expression of the isolator’s displacement transmissibility is derived via the averaging method. Then, the vibration isolation performance under different road excitations and different driving speeds is simulated and compared with the uncontrolled passive QZS vibration isolator. In addition, the mechanical structure of the semiactive QZS isolator is designed and manufactured, and the test system is built by LabVIEW software and PXI embedded system. The isolation effect of the semiactive QZS isolator is verified through test data. It is found that the proposed semiactive QZS isolator shows excellent vibration isolation performance under various road excitations, while the passive QZS isolator is effective only under harmonic excitations. The vertical acceleration of vehicle-mounted device can be decreased over 70% after isolation, and the vibration isolation effect is remarkable. The design idea and research results of the semiactive QZS isolator may provide theoretical guidance and engineering reference for vibration isolation.

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Semi-active control of ambulance stretcher system based on parallel mechanism with MR dampers and perturbation analysis

Cited by 10 publications

References 18 publications

Grey relation analysis of natural frequency and semi-active robust optimal control of a multi-dimensional isolator based on parallel mechanism and magneto-rheological damper

Grey relation analysis of natural frequency and semi-active robust optimal control of a multi-dimensional isolator based on parallel mechanism and magneto-rheological damper

Influence characteristics of electrical parameters and vibration isolation properties of the stretcher system based on parallel mechanism and self-powered magneto-rheological damper

Design and Research of Semiactive Quasi‐Zero Stiffness Vibration Isolation System for Vehicles

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