Design and Analysis of Driver Seat Suspension System

Abstract

Over the years, the vehicle driver has endured a great deal of agony and anguish as a result of poor road conditions or lengthier travel lengths that they must complete within a certain time limit. It is a misery to them that the standard or budget vehicles do not feature a good suspension system for their wellbeing. This research article demonstrates a unique design of scissor seat suspension for vehicles, as well as models for manufacturing and testing the system to eliminate low-frequency and high-amplitude vibrations that might cause health problems for vehicle drivers or passengers. Although scissor seat suspension is frequently utilized in commercial vehicles to reduce interior vibrations, a common optimization difficulty emerges because designs often involve a compromise between seat acceleration and suspension travel. The stiffness and damping characteristics of the scissor seat suspension are also investigated, and a simplified model of the scissor seat suspension is presented. The effect of damping force and mass on a human is investigated in preparation for future design and testing. The ideal vertical stiffness damping response is then cascaded into a performance-oriented model, and the design parameters are optimized with a multi-body kinematics model focused on the scissor seat suspension structure.

Introduction

I. INTRODUCTION

Seat suspension system is a necessity in all vehicles including commercial vehicles. In commercial vehicles the secondary suspension (seat, driver’s cabin) is responsible for the driver’s comfort. The fatigue caused by long termed vibrations to which the vehicle drivers are exposed, can be very severe spinal hernia, dislocation of the spinal disks, etc. In today’s world, considering the new technologies, Vehicle manufacturers have to focus on the safety and comfort of the vehicle drivers. After N-number of investigations it is observed that the driver is facing a lot of vibrations and discomfort while driving as they get tired out very quickly. The challenging task for us is the design of the suspension system. It is very essential to design reliable, safe, and convenient seats to eliminate road excitation, as it transmits vibrations to the Vehicle driver’s body, and it may cause some damaging effects on their health and efficiency. Vehicle drivers have faced a lot of vibrations from road surface unevenness. The outcomes for vehicle drivers are the following reasons such as lack of concentration, they may feel tiredness and reduction of the effectiveness of the work being conducted.

II. LITERATURE SURVEY

Jianqiang Yu et al. [1] proposed that under sinusoidal excitations, the MTS machine is utilized to measure dynamic damping characteristics. The backbone curve-based hysteretic model is chosen.

Xiu-Mei Du et al. [2] proposed that designs a simplified model of the semi-active scissors linkage seat suspension by analyzing its characteristics. And a robust state-feedback H∞ control is established by considering the system uncertainties. which helps in reduction of vibration.

Donghong Ning et al. [3] Member proposed that A continuously controllable electromagnetic damper (EMD) system, consisting of a permanent magnet synchronous motor (PMSM), a three-phase rectifier, a metal-oxide-semiconductor field-effect transistor (MOSFET) switch, and an external resistor, was employed in this study. To create a variable damping seat suspension, a commercial passive seat suspension was modified by removing the original damper and placing the variable damper in the center of the scissors structure.

Xinjie Zhang et al. [4] proposed that the foundation of scissor seat suspension optimization, control, and development is precisely obtaining the dynamics characteristics. The author went over the steps required in performing an analytical computation for the suspension system in detail.

The suggested scissor seat suspension multi-body dynamics model gives a precise dynamics characteristics description, which can be used for scissor seat suspension structure optimization and virtual product development, as demonstrated in this work.

Jianqiang Yu et al. [5] proposed the scissor suspension system should be self-powered, self-sensing, adaptable, and long-lasting. Magnetorheological fluid is employed in a damper controlled by an electromagnet to achieve this purpose.

Chunlei Wang et al. [6] proposed the hierarchical optimization on scissor seat suspension characteristic and its structure, providing a top-down methodology with the globally optimal and fast convergent solutions to compromise these design contradictions. In detail, a characteristic-oriented non-parametric dynamics model of the scissor seat suspension is formulated firstly via databases, describing its vertical dynamics accurately. Then, the ideal vertical stiffness-damping characteristic is cascaded via the characteristic-oriented model, and the structure parameters are optimized in accordance with a structure-oriented multi-body dynamic model of the scissor seat suspension. Eventually, the seat effective amplitude transmissibility factor, suspension travel and the CPU time for solving are evaluated.

Seung-Bokchoi et al. [7] proposed a magneto-rheological (MR) fluid damper was used to control the vibration of a semi-active seat suspension. which is built around the Bingham model of the MR fluid whose field-dependent damping force characteristics have been experimentally evaluated, and whose vibration control performances have been evaluated using hardware-in the-loop simulation.

Kiana Kia et al. [8] proposed that an active suspension seat may have the potential to reduce vertical and total WBV exposures in the future. However, none of the, including a vertical active suspension, multi-axial active suspension, and a static suspension-less seat, demonstrated any significant benefits on non-driving task performance, muscle activity, self-reported discomfort, or motion sickness measures in a simulated vehicle environment.

I.Maciejewski et al. [9] proposed an active vibration reduction system with a seated human body. A permanent magnet synchronous motor is developed to improve the vibration isolation properties of the horizontal seat suspension.

Jeong Ho Kim et al. [10] proposed that a new hybrid controller that combines three control schemes: fuzzy neural control, PI control, and sliding mode control Following the development of the mathematical model, the proposed controller is used to control the vibration of a vehicle seat suspension with a magneto-rheological (MR) damper. Both simulation and experiment show that the proposed controller can provide much better vibration control performance than conventional controllers with more robust stability.

Lixin Tu et al. [11] proposed that a magnetic spring with a negative stiffness is created by combining two columnar magnets in a specific arrangement. It can be used in semi-active seat suspension to reduce vibration on vehicle drivers. It reduces resonance frequency vibration during vertical excitation without compromising loading capacity and achieves excellent lowfrequency vibration suppression performance.

III. LITERATURE GAP

Referring to the studies conducted by the researchers around the globe, it was concluded that the need of a low-cost, highly effective seat suspension system is essential. In-depth investigation revealed that the components used to produce the desired operation in the case studies were sophisticated assemblies, rather than straightforward mechanical parts. Therefore, none of the other case studies that were presented shared the idea of using a simplified method to obtain the intended output.

IV. PROBLEM STATEMENT

Most of the vehicles have normal seats that are not able to isolate the low-frequency vibrations. It is fully identified that vertical vibration at lower frequencies is the most harmful vibration to the human body. However, in order to lower the vertical vibration acceleration, felt by the human body, a seat suspension system is required. Vehicle driver fatigue is typically caused by inadequate sleep, by working too many hours, or by driving while sick. This is one of the most dangerous impairments a vehicle driver can experience. Considering all these terms and factors the focus should be on the driver’s comfort so that the driver doesn’t feel restless very early.  Passive vibration control system where mechanical parts are utilized to damp undesired vibrations. The mechanical parts include spring, shock absorber, damper, etc. However, in order to lower the vertical vibration acceleration, felt by the human body, a seat suspension system is required. Vehicles are designed to carry a lot of weight on their axles, which effectively means that they need to have very stiff springs in their suspension. This makes for a very bouncy, harsh, uncomfortable ride, which can be fatiguing for a driver who has to deal with it all day long. “Chronic back pain” is often the result of a vehicle driver. Nearly, 59% of vehicle drivers experience low back pain.

To overcome these major problems, the need of a suspension seats system arises as the driver sit on a scissor-type frame that provides up-and-down travel to cushion the driver over speed breaker and also in uneven roads.

V. MATERIAL SELECTION

A. For Bell Cranks

Aluminium 6061 T6

 T6 temper 6061 has -

• Ultimate tensile strength of at least 290 MPa (42,000 psi)
• Yield strength of at least 240 MPa (35,000 psi).
• More typical values are 310 MPa (45 ksi) and 270 MPa (39 ksi), respectively.
• Young's modulus (E): 68.9 GPa (9,990 ksi)
• Elongation (ε) at break: 12–25%
• Density (ρ): 2.70 g/cm3
• Thermal conductivity (k): 151–202 W/(m•K).

1. Properties

a. Resistance to corrosion

b. A high value of hardness

c. Easy machinability

d. Rigidity and toughness

e. Light Weight with high yield strength

f. Good weld ability

B. For Pushrods and Mountings

AISI 4130 Chromoly Steel 19*1 mm

1. Mechanical Properties

2. Thermal Properties

Thermal conductivity (100°C) - 42.7 W/mk

Properties

a. Easy machinability

b. Good atmospheric corrosion resistance

c. Reasonable strength

d. High Strength to weight ratio

The spring damper system is an OEM part from DNM springs. The model used is Burner RCP- 2S with a stiffness(k)=140 pounds/inch.

IX. ACKNOWLEDGMENT

We would also like to show our gratitude to, Prof. Ms. Gayatri S. Patil (Asst. professor, department of Mechanical Engineering, KJ College of Engineering and Research Management, Pune, Maharashtra, India.) for sharing their pearls of wisdom with us during the course of this research. We are also immensely grateful to him for his comments on an earlier version of the manuscript, although any errors are our own and should not tarnish the reputations of these esteemed persons.

Conclusion

A seat suspension system is designed and analyzed to provide maximize seat quality and performance which reduce the driver’s stress during long operating drives A different topology is approached in this report to make the system more economically feasible and reliable at same time.

References

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Copyright

Copyright © 2023 Prathmesh Pawar, Prof. Gayatri S. Patil. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.