scholarly journals Design of cab seat suspension system for construction machinery based on negative stiffness structure

2021 ◽  
Vol 13 (8) ◽  
pp. 168781402110449
Author(s):  
Xin Liao ◽  
Xiaofei Du ◽  
Shaohua Li

In order to improve the vibration isolation performance of cab seat and ride comfort of the driver, a seat suspension structure of construction machinery cab is proposed based on negative stiffness structure (NSS) in this paper. The influences of different parameters of suspension system on dynamic stiffness are analyzed. The configuration parameter range of suspension system is obtained. Then, the nonlinear dynamic equation of the seat suspension system is established and the NSS optimization model is proposed. The vibration transmissibility characteristics of suspension structure are analyzed by different methods. The results show that the displacement and acceleration amplitude of optimized seat suspension system are obviously reduced, and the VDV and RMS in the vertical vibration direction for the seat are respectively decreased by 87% and 86%. The vibration transmissibility rate SEAT and the Ttrans are both decreased. Moreover, the peak frequencies of the vibration transmitted to the driver are not near the key frequency values which are easy to cause human discomfort. It indicates that the design of seat suspension system has no effect on the health condition of the driver after being vibrated. The advantages of vibration isolation performance of the designed NSS suspension system are demonstrated, improving the driver’s ride comfort and the working environment.

2021 ◽  
Vol 11 (15) ◽  
pp. 6928
Author(s):  
Xin Liao ◽  
Ning Zhang ◽  
Xiaofei Du ◽  
Wanjie Zhang

In this study, to improve the vibration isolation performance of a cab seat and the ride comfort of the driver, we propose a mathematical model for a seat suspension system of a construction machinery cab based on a negative stiffness structure (NSS). First, a static analysis of a seat suspension system is conducted and the different parameters and their influences on the dynamic stiffness are discussed. Thereby, the ideal configuration parameter range of the suspension system is obtained. Moreover, the nonlinear dynamic model of the designed seat suspension system is established. The frequency response and the stability are analyzed by using the HBM method and numerical simulation. The vibration transmissibility characteristics and vibration suppression effects of the seat suspension system are presented in detail. The results show that, as compared with a quasi-zero-stiffness system, the QZS-IE system has higher vibration suppression advantages under large excitation and small damping, as well as lower transmissibility and a wider vibration isolation frequency range. In addition, an inerter element with a larger mass ratio and relatively shorter distance ratio is better for vibration isolation performance of the QZS-IE system in a practical engineering application. The results of this study provide a scientific basis for the design and improvement of a seat suspension system.


Author(s):  
Hui Liu ◽  
Xiaojie Wang ◽  
Weida Wang ◽  
Changle Xiang

This paper proposes a torsion isolator with negative stiffness structures, which has low stiffness. The torsion isolator has been designed into disk structure, which is the installation position of the positive springs and negative stiffness structures. In this paper, the model of the torsion isolator is introduced firstly, and the nonlinear stiffness and torque are studied under different compression deformation of springs in negative stiffness structures. Then a two-degree-freedom equation of the torsional isolator is established and vibration transmissibility is obtained by using Harmonic Balance Method. Theoretical analysis results show that the isolator with negative stiffness structures has larger isolation frequency range than linear isolator. Finally, an initial experiment is completed. The experimental results show that the isolator has a good vibration isolation performance.


2013 ◽  
Vol 441 ◽  
pp. 580-583
Author(s):  
Gong Yu Pan ◽  
Xin Yang ◽  
You Yan

In order to solve the vibration problem of diesel engine powertrain assembly at its idle state, a six degree-of-freedom dynamics model of the powertrain mounting system is established and a optimization based on Adams/View is applied to simulation and analysis on the powertrain mounting system with energy decoupling method. The results show that the optimized repositioning mounts installation position can effectively improve decoupling rate in main vibration directions of mounting system. Based on this, the vibration transmissibility and acceleration response before and after optimization are simulated. The results show that the optimized engine mounting system makes a great improvement of vibration isolation performance.


Author(s):  
Georgios Papaioannou ◽  
Artemios Voutsinas ◽  
Dimitrios Koulocheris

A seat that provides good vibration isolation is of prime importance for passenger’s safety and health. The main conflict in seat suspensions implies that the increasing initial deformation of the system (increase in “static discomfort”) leads to better isolation of accelerations (increase in “dynamic comfort”). Many researchers have focused on overcoming or at least suppressing this conflict between load support capacity and vibration isolation by modeling new suspension systems, such as the so-called negative suspension systems. However, apart from the modeling of new suspension systems, optimization is an important part in designing a seat and finding the best compromise between these two objectives. Thus, in this work, four types of seat suspension systems with embedded negative stiffness elements are implemented and optimized in order to be benchmarked. Three of them have already been tested either in passenger or in an off-road vehicle seat. All the vibration isolators are optimized with genetic algorithms in respect to static and dynamic factors of ride comfort by applying constraints oriented to the objectives and the design of the structure. The optimization is implemented for two excitations, which correspond to a vehicle driving over road profiles of Classes A and B, and the common solutions are outlined.


2021 ◽  
Vol 263 (3) ◽  
pp. 3011-3022
Author(s):  
Jing Bian ◽  
Xingjian Jing ◽  
Yishen Tian

Passive vibration isolation is always preferable in many engineering practices. To this aim, an innovative, compact, and passive vibration isolation mount is studied in this paper. The novel mount is adjustable to different payloads due to a special oblique and tunable stiffness mechanism, and of high vibration isolation performance with a wider quasi-zero-stiffness range due to the deliberate employment of negative stiffness of the X-shaped structure. The X-shaped structure has been well studied recently due to its excellent nonlinear stiffness and damping properties. In this study, by using of the negative stiffness property within the X-shaped structure, the X-shaped mount (X-mount) can have an obviously larger vibration displacement range which maintains the quasi-zero-stiffness property. A special oblique spring is thus introduced such that the overall equivalent stiffness can be much easily adjusted. Systematic parametric study is conducted to reveal the critical design parameters and their relationship with vibration isolation performance. A prototype and experimental validations are implemented to validate the theoretical results. It is believed that the X-mount would provide an innovative technical upgrade to many existing vibration isolation mounts in various engineering practices and it could also be the first prototyped mount which can offer adjustable quasi-zero stiffness conveniently.


2018 ◽  
Vol 14 (6) ◽  
pp. 155014771878237 ◽  
Author(s):  
Shuilong He ◽  
Binqiang Chen ◽  
Zhansi Jiang ◽  
Yanxue Wang ◽  
Fuyun Liu

Strong steering wheel jitter during idling states of the engine can seriously deteriorate the driving comfort as well as the driving safety. The powertrain suspension system can be considered as the only essential path for the transmission of vibrations from the engine to the vehicle cab. Its vibration isolation performance directly affects the severity of vibrations on the steering wheel. In this article, aiming at solving the problem of a certain type of commercial vehicle’s steering wheel with strong idle jitter at the idle state, the intrinsic characteristics and vibration isolation performances of the powertrain suspension system were studied in detail. A multi-sensor-based measurement strategy was utilized to evaluate the idle jitter severity of the steering wheel. In order to improve the indicators of the decoupling degree, the vibration transmissibility, and the resonant frequency distributions of the engine suspension system, an optimization model of engine suspension system was established. Parameters of the optimized suspension system were obtained by multi-objective particle swarm optimization. Finally, the effectiveness and feasibility of the optimization algorithm to solve the problem of the vehicle’s steering wheel jitter at idle states were verified through a test using multiple acceleration sensors, which has practical values in the engineering field.


2013 ◽  
Vol 471 ◽  
pp. 247-252
Author(s):  
Wajdi S. Aboud ◽  
Sallehuddin Mohamed Haris

The main goal of using mechatronic suspensions is to improve the ride comfort and handling performance. In this work, a robust linear controller for such a system was designed based on the μ synthesis method. The performance of a model two degree of freedom quarter car with parameter perturbations, subjected to road disturbances, was simulated and the time domain responses were analyzed. The simulation results indicate that the robust controller improved the vibration isolation performance of the mechatronic suspension system, despite the presence of parameter perturbations and exogenous disturbances. When compared to both LQG active control and to a passive suspension system, the μ synthesis controller also showed super or performance.


2011 ◽  
Vol 141 ◽  
pp. 364-369 ◽  
Author(s):  
Liang He ◽  
Si Hong Zhu ◽  
Hong Ling Zhu

Two kinds of full-float tractor cab suspension systems based on double crank mechanism and double rocking bar mechanism respectively for a power tractor safety cab was designed. CAD model of the tractor with cab was modeled by using Pro/E. The model was import into ADAMS, and virtual prototype of the tractor with cab suspension system was established. When stiffness and damping of tyres were set fixed, two kinds of suspension system were mounted to the cab. The vibration isolation performance of the two kinds of tractor cab suspension system was studied respectively when stiffness of cab suspension system changed from 20 N/mm to 200N/mm. Both harmonic excitation and a random road roughness excitation were applied vertically to the places where the tyres were mounted. The random road roughness excitation was simulated by using MATLAB/simulink. The simulation results showed that the comfort of the full-float tractor cab with suspension based on double rocking bar mechanism was better than the cab with suspension based on double crank bar mechanism. Therefore, the analysis results provided a basis for designing mechanism of full-float cab suspension system for power tractors.


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