Optimal Seat Suspension Design Based on Minimum “Simulated Subjective Response”

1997 ◽  
Vol 119 (4) ◽  
pp. 409-416 ◽  
Author(s):  
Y. Wan ◽  
J. M. Schimmels
Keyword(s):  
Vibration Isolation ◽  
Optimization Procedure ◽  
Vertical Vibration ◽  
Whole Body ◽  
Subjective Response ◽  
Seat Suspension ◽  
Suspension Parameters ◽  
Sensitivity Standard ◽  
Selection Of

This work addresses a method for improving vertical whole body vibration isolation through optimal seat suspension design. The primary thrusts of this investigation are: (1) the development of a simple model that captures the essential dynamics of a seated human exposed to vertical vibration, (2) the selection and evaluation of several standards for assessing human sensitivity to vertical vibration, and (3) the determination of the seat suspension parameters that minimize these standards to yield optimal vibration isolation. Results show that the optimal seat and cushion damping coefficients depend very much on the selection of the vibration sensitivity standard and on the lower bound of the stiffnesses used in the constrained optimization procedure. In all cases, however, the optimal seat damping obtained here is significantly larger (by than a factor of 10) than that obtained using existing seat suspension design methods or from previous optimal suspension studies. This research also indicates that the existing means of assessing vibration in suspension design (ISO 7096) requires modification.

scholarly journals Improvement of Comfort in Suspension Seats with a Pneumatic Negative Stiffness System

Actuators ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 126
Author(s):  
Eduardo Palomares ◽  
Angel L. Morales ◽  
Antonio J. Nieto ◽  
Jose M. Chicharro ◽  
Publio Pintado
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Nonlinear Dynamic System ◽  
Negative Stiffness ◽  
Vehicle Model ◽  
Seat Suspension ◽  
Highly Nonlinear ◽  
Linear Actuators ◽  
Static Conditions

This paper presents a Negative Stiffness System (NSS) for vibration isolation and comfort improvement of vehicle seats, which enhances the performance of optimized traditional passive seat suspensions. The NSS is based on a set of two Pneumatic Linear Actuators (PLAs) added to a seat supported by a pneumatic spring. One end of each PLA is joined to the seat while the other end is joined to the vehicle frame. In static conditions, the PLAs remain horizontal, whereas in dynamic conditions, their vertical forces work against the pneumatic spring, reducing the overall dynamic stiffness and improving passenger comfort. The paper presents a stability analysis of the highly nonlinear dynamic system, as well as the numerical determination of the optimum PLA pressure for a given passenger mass that maximises comfort without instabilities. Finally, the performance of the proposed NSS is compared to that of a traditionally optimized passive seat suspension via simulations of an eight-degree-of-freedom vehicle model traversing several road profiles and speed bumps. Comfort improvements between 10% and 35% are found in all tests considered.

A new electric wheel and optimization on its suspension parameters

2020 ◽  
Vol 234 (12) ◽  
pp. 2759-2770
Author(s):  
Lingsheng Meng ◽  
Yuanji Zou ◽  
Yudi Qin ◽  
Zhichao Hou
Keyword(s):  
Vibration Isolation ◽  
Power Transmission ◽  
Optimal Solution ◽  
Vertical Vibration ◽  
Vehicle Body ◽  
Full Potential ◽  
Negative Effects ◽  
Vehicle Performance ◽  
Suspension Parameters ◽  
Motor Vibration

Hub-driven technology with its many advantages has become a potential transformation technology in the automotive industry. In order to inhibit the negative effects of the in-wheel motor, a new electric wheel configuration was presented with two-stage suspensions, and optimization was conducted for the suspension parameters. With the specially introduced flexible transmission elements and motor suspension, the electric wheel is capable of achieving power transmission and vertical vibration isolation simultaneously. A quarter-vehicle model was established, and vehicle performance-related indices were defined to evaluate the applicability of the new electric wheel. An optimization problem was then constructed for suspension parameters, where constraint conditions were derived according to vehicle dynamics. The optimal solution was sought by a genetic algorithm, aiming at utilizing the full potential of the configuration. Simulations were carried out taking the optimal suspension parameters into account, and comparison was made with vehicles equipped with other electric wheel configurations in terms of these performance indices. The results show that the proposed electric wheel reduces motor vibration, and increases wheel dynamic load and vehicle body acceleration.

Design and evaluation of vibration reducing seat suspension based on negative stiffness structure

2020 ◽  
Vol 234 (21) ◽  
pp. 4171-4189
Author(s):  
Ehsan Davoodi ◽  
Pedram Safarpour ◽  
Mahdi Pourgholi ◽  
Mostafa Khazaee
Keyword(s):  
Design Procedure ◽  
Vertical Vibration ◽  
Negative Stiffness ◽  
Transfer Path ◽  
Seat Suspension ◽  
Suspension Parameters ◽  
Payload Capacity ◽  
Simulation Results ◽  
Iso 2631 ◽  
Isolation Performance

The vibration transmitted to helicopter aircrew is the main health risk, specifically at low excitation frequencies. In this paper, to improve the vibration environment for aircrew, a seat suspension using a negative stiffness structure has been proposed. The main feature of the proposed system is the negative stiffness structure along with a traditional positive stiffness structure. Here, the dynamic model of the proposed system is derived and the design procedure for the seat suspension parameters is presented in order to mitigate the vibration transmitted to occupant and at the same time preserving payload capacity of the system. Then, the vibration transmitted to seat as well as the transmissibility of the proposed system at the steady state are evaluated using ISO-2631 and conventional criteria. To verify the validity of the simulation results, the reproduced signal of the cabin floor of the Bell-412 helicopter is applied. Results reveal that the isolation performance of the proposed system based on the negative stiffness structure is well-suited so that the values of root mean square and vibration dose value for seat’s vertical vibration in this structure are 0.0789 and 0.1254, respectively. It showed an almost 90% reduction of amplitude with respect to the cabin floor’s vibration. Also, according to the ISO-2631 standard, the level of comfort is improved from uncomfortable to not uncomfortable that represents the promotion of riding quality and improvement of vibration environment for aircrew. As well as results display that the frequency spectrum of the cabin floor and the seat are similar to each other and actually frequency modulation does not happen in the vibration transfer path between the cabin floor and over the seat.

Integrated semi-active seat suspension for both longitudinal and vertical vibration isolation

2016 ◽  
Vol 28 (8) ◽  
pp. 1036-1049 ◽  
Author(s):  
Xian-Xu Bai ◽  
Peng Jiang ◽  
Li-Jun Qian
Keyword(s):  
Mathematical Model ◽  
Experimental Test ◽  
Vibration Isolation ◽  
Functional Integration ◽  
Mr Damper ◽  
Vertical Vibration ◽  
Suspension System ◽  
Switching Mechanism ◽  
Seat Suspension ◽  
The Mathematical Model

“Functional integration” is to integrate two or multiple systems or mechanisms that are independent with each other and to realize the two or multiple functions using only one actuation system. Maximization of engineering applications of actuation systems could be achieved through the use of the “functional integration” concept-based structural design. In this article, an integrated semi-active seat suspension, mainly composed of a switching mechanism, a transmission amplification mechanism, and a damping force- or torque-controllable rotary magnetorheological (MR) damper working in pure shear mode, for both longitudinal and vertical vibration attenuation, is proposed, designed, and fabricated. The switching mechanism employs the parallelogram frames as a motion guide which keeps the seat moving longitudinally and vertically. Both longitudinal and vertical motions are transformed into a reciprocating rotary motion that is transmitted to the rotary MR damper after an amplification by a gear mechanism. The torque generated by the MR damper can be tuned by adapting the applied current in real time, and hence, effective two-dimensional vibration control of the seat could be realized. The mathematical model of the semi-active seat suspension system is established, and vibration isolation performance of the system is simulated and analyzed. Based on the established experimental test rig, the prototype of the semi-active seat suspension system is tested, and the results of the mathematical model and the experimental test are compared.

DETERMINING THE DESALINATION UNIT COMPOSITION FOR COSTAL AREAS AND SMALL ISLANDS USE ANALYTIC HIERARCHY PROCESS

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Imam Setiadi ◽  
Dinda Rita K. Hartaja
Keyword(s):  
Analytic Hierarchy Process ◽  
Energy Demand ◽  
Pairwise Comparison ◽  
Small Islands ◽  
Ahp Method ◽  
Analytic Hierarchy ◽  
Comparison Research ◽  
Hierarchy Process ◽  
Selection Of

Selection of the appropriate composition desalination units can be done with a variety of method approaches, one of the method is the Analytic Hierarchy Process. In determining the desalination unit with AHP method to consider is setting a goal, an alternative criteria and pairwise comparison. Research for the determination of the exact composition of the desalination unit in order to achieve sustainable drinking water suppy in coastal areas and small islands has been conducted. The results of the study are as follows, the energy demand of 50.83%, operator costs of 26.64%, maintenance costs of 14.13% and chemical requirement 8.4%. For an alternative composition desalination unit of RO 10 m3 / day is the best alternative composition with value of 59.61%, the composition of the next alternative is RO 20 m3/ day of 30.40% and the last alternative of the desalination unit composition is RO 120 m3/ day of 09.99%.Key words : Desalination, Mukti Stage Flash Composition, AHP

Optimization of the selection of analysis methods for the determination of naturally occurring radionuclides

Kerntechnik ◽  
2008 ◽  
Vol 73 (3) ◽  
pp. 118-121
Author(s):  
T. Heinrich ◽  
L. Funke ◽  
M. Köhler ◽  
U.-K. Schkade ◽  
F. Ullrich ◽  
...  
Keyword(s):  
Naturally Occurring ◽  
Analysis Methods ◽  
Naturally Occurring Radionuclides ◽  
Selection Of
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