Use of nonlinear asymmetrical shock absorbers in multi-objective optimization of the suspension system in a variety of road excitations

2016 ◽  
Vol 231 (2) ◽  
pp. 372-387 ◽  
Author(s):  
Abolfazl Seifi ◽  
Reza Hassannejad ◽  
Mohammad Ali Hamed
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Low Cost ◽  
Suspension System ◽  
Objective Functions ◽  
Multi Objective Optimization ◽  
Vehicle Handling ◽  
Multi Objective ◽  
Shock Absorbers ◽  
The Impact

In this study, a new method to improve ride comfort, vehicle handling, and workspace was presented in multi-objective optimization using nonlinear asymmetrical dampers. The main aim of this research was to provide suitable passive suspension based on more efficiency and the low cost of the mentioned dampers. Using the model with five degrees of freedom, suspension system parameters were optimized under sinusoidal road excitation. The main functions of the suspension system were chosen as objective functions. In order to better illustrate the impact of each objective functions on the suspension parameters, at first two-objective and finally five-objective were considered in the optimization problem. The obtained results indicated that the optimized viscous coefficients for five-objective optimization lead to 3.58% increase in ride comfort, 0.74% in vehicle handling ability, and 2.20% in workspace changes for the average of forward and rear suspension.

scholarly journals Contribution to the development of methodology for assessing the impact of bus suspension system on fuel consumption and CO2 emission

2020 ◽  
pp. 168-168
Author(s):  
Dragan Sekulic ◽  
Ivan Ivkovic ◽  
Dusan Mladenovic ◽  
Davor Vujanovic
Keyword(s):  
Fuel Consumption ◽  
Co2 Emission ◽  
Degrees Of Freedom ◽  
Shock Absorber ◽  
Ride Comfort ◽  
Suspension System ◽  
Vertical Acceleration ◽  
Shock Absorbers ◽  
Parameter Values ◽  
The Impact

This paper analyzes the effects of intercity bus suspension system oscillatory parameters on driver's ride comfort and road damage. The analysis has been carried out through simulation by means of validated in-plane bus model with six degrees of freedom excited by real road roughness signal. Low root-mean-square values of the weighted vertical acceleration (less than 0.315 m/s2) have been achieved by shock-absorbers with lower damping coefficient and softer suspension system springs. Low values of dynamic load coefficient provide low shock-absorber damping and softer springs. However, low crest factor values for both axles are accomplished for high shock-absorber damping and softer springs in bus suspension system. Results from this analysis could be used as reference for selecting proper oscillatory parameter values when designing road-friendly bus suspension system which in turn would increase vehicle energy efficiency. Presented methods, results and analyzes are the part of wider methodology for assessing the impact of bus suspension system on fuel consumption and CO2 emission.

Multi-objective optimization of a hybrid electromagnetic suspension system for ride comfort, road holding and regenerated power

2016 ◽  
Vol 23 (5) ◽  
pp. 782-793 ◽  
Author(s):  
Mansour Ataei ◽  
Ehsan Asadi ◽  
Avesta Goodarzi ◽  
Amir Khajepour ◽  
Mir Behrad Khamesee
Keyword(s):  
Pareto Front ◽  
Ride Comfort ◽  
Optimization Method ◽  
Suspension System ◽  
Multi Objective Optimization ◽  
Damping Force ◽  
Nsga Ii ◽  
Electromagnetic Suspension ◽  
Multi Objective ◽  
Electromagnetic Component

This paper reports work on the optimization and performance evaluation of a hybrid electromagnetic suspension system equipped with a hybrid electromagnetic damper. The hybrid damper is configured to operate with hydraulic and electromagnetic components. The hydraulic component produces a large fail-safe baseline damping force, while the electromagnetic component adds energy regeneration and adaptability to the suspension. For analyzing the system, the electromagnetic component was modeled and integrated into a 2DOF quarter-car model. Three criteria were considered for evaluating the performance of the suspension system: ride comfort, road holding and regenerated power. Using the genetic algorithm multi-objective optimization (NSGA-II), the suspension design was optimized to improve the performance of the vehicle with respect to the selected criteria. The multi-objective optimization method provided a set of solutions called Pareto front in which all solutions are equally good and the selection of each one depends on conditions and needs. Among the given solutions in the Pareto front, a small number of cases, with different design purposes, were selected. The performances of the selected designs were compared with two reference systems: a conventional and a nonoptimized hybrid suspension system. The results show that the ride comfort and road holding qualities of the optimized hybrid system are improved, and the regenerated power is considerably increased.

Optimization and Stiffness Performance Analysis for 3-DOF Spatial and Spherical Parallel Mechanisms

2016 ◽  
Author(s):  
Dan Zhang ◽  
Bin Wei
Keyword(s):  
Performance Analysis ◽  
Degrees Of Freedom ◽  
General Procedure ◽  
Kinematic Model ◽  
Optimization Methods ◽  
Parallel Mechanisms ◽  
Objective Functions ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Workspace Optimization

This paper focuses on the optimization and stiffness performance analysis of three kinds of three degrees of freedom (DOF) spatial and spherical parallel mechanisms. Firstly, the kinematic model and the Jacobian matrix for the 3-DOF parallel mechanisms are established and solved, and the objective functions for stiffness and workspace optimization are formed; secondly, by using stiffness and workspace as objective functions and applying different multi-objective optimization methods, the general procedure for the multi-objective optimization problem for the parallel mechanisms are established. Finally, the correspondence and the differences between several stiffness models are compared and illustrated.

Multi-Objective Optimization of Road Vehicle Passive Suspensions With Inerter

2016 ◽  
Author(s):  
Kesavan Ramakrishnan ◽  
Liunan Yang ◽  
Federico Maria Ballo ◽  
Massimiliano Gobbi ◽  
Giampiero Mastinu
Keyword(s):  
Ride Comfort ◽  
Damping Ratio ◽  
Spring Stiffness ◽  
Objective Functions ◽  
Multi Objective Optimization ◽  
Suspension Spring ◽  
Multi Objective ◽  
Working Space ◽  
Design Variables ◽  
Equivalent Mass

The influence of inerter on the performance of passive suspension systems is studied by comparing six different suspension architectures using a simplified quarter-car model. The suspension architectures can have one or two springs, damper, and inerter. Ride comfort, road holding, and working space are considered as the objective functions, while the suspension spring stiffness, damping ratio, and inerter equivalent mass are taken as the design variables for the multi-objective optimization. The Pareto-optimal solutions are computed and compared in the objective functions domain. The results confirm that specific inerter architectures provide advantages when all the design variables are varied. The inerter benefits are more evident in all the considered architectures, when the suspension spring stiffness is kept constant.

Design and optimization of a semi-active suspension system for a two-wheeled vehicle using a full multibody model

2016 ◽  
Vol 231 (4) ◽  
pp. 630-646 ◽  
Author(s):  
A Khadr ◽  
A Houidi ◽  
L Romdhane
Keyword(s):  
Ride Comfort ◽  
Optimization Procedure ◽  
Active Suspension ◽  
Suspension System ◽  
Multi Objective Optimization ◽  
Nsga Ii ◽  
Passive Suspension ◽  
Multi Objective ◽  
Wheeled Vehicle ◽  
Passive Suspension System

This paper focuses on the design and the optimization of a semi-active suspension system used in a full dynamic model of a two-wheeled vehicle. The two-wheeled vehicle is considered as a multibody system. The equations of motion are obtained by applying an approach used widely in the robotic modeling field. Two basic strategies, called the continuous skyhook and the modified skyhook, are used to control the semi-active suspension system. Using the developed model, a multi-objective optimization procedure, based on Genetic Algorithms (NSGA-II), is proposed. The objective is to optimize the parameters of the two control laws of the semi-active suspension systems, in order to improve the ride comfort and the safety. To study the effectiveness of this approach, the results of the optimization are used in different simulations and the results are compared with those obtained from a simulation of a two-wheeled vehicle equipped with a passive suspension system. The results show that both control strategies of the semi-active suspension system give an improvement compared to the passive suspension system. Moreover, the multi-objective optimization results show that the simplified law “Modified Skyhook” ensures a higher ride safety, whereas the “Continuous Skyhook” is more effective in obtaining a higher level of ride comfort.

A suspension system with a variable roll centre for the improvement of vehicle handling characteristics

2001 ◽  
Vol 215 (6) ◽  
pp. 677-696 ◽  
Author(s):  
U Lee ◽  
C Han
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Suspension System ◽  
Lateral Acceleration ◽  
Vehicle Body ◽  
Control Input ◽  
Vehicle Handling ◽  
Body Side ◽  
Handling Characteristics ◽  
Suspension Geometry

In this paper, the improvement of vehicle handling characteristics using variable roll centre suspension (VRCS) is investigated. A vehicle with VRCS can improve stability and ride comfort by automatically controlling suspension geometry in accordance with the running conditions of the vehicle. To achieve this, a variable roll centre concept in the McPherson strut suspension system is suggested, while the two parts most sensitive for controlling the roll centre are suggested. One is between the vehicle body-side connecting portion of the lower arm and the vehicle body (control input, LCZ), and the other is between the vehicle body-side connecting portion of the strut and the vehicle body (control input, STY). Kinematic roll centre analysis, based on the analytic half-car model, shows that the use of two control inputs, LCZ and STY, can decrease migration of the roll centre and centre of gravity according to the side force. In order to quantify the relationship between roll centre and geometry control input and evaluate handling performance, a full vehicle model of 15 degrees of freedom (DOF) is constructed using multi-body dynamic analysis software, ADAMS. In step steering and double lane change manoeuvres, simulation results demonstrate that a vehicle with VRCS adjusts roll centre migration, and handling characteristics such as roll angle, lateral acceleration and yaw rate are much improved.

scholarly journals A New Approach to Group Multi-Objective Optimization under Imperfect Information and Its Application to Project Portfolio Optimization

2021 ◽  
Vol 11 (10) ◽  
pp. 4575
Author(s):  
Eduardo Fernández ◽  
Nelson Rangel-Valdez ◽  
Laura Cruz-Reyes ◽  
Claudia Gomez-Santillan
Keyword(s):  
Portfolio Optimization ◽  
Imperfect Information ◽  
Model Parameters ◽  
Final Decision ◽  
Project Portfolio ◽  
Objective Functions ◽  
Multi Objective Optimization ◽  
New Approach ◽  
Multi Objective ◽  
Group Member

This paper addresses group multi-objective optimization under a new perspective. For each point in the feasible decision set, satisfaction or dissatisfaction from each group member is determined by a multi-criteria ordinal classification approach, based on comparing solutions with a limiting boundary between classes “unsatisfactory” and “satisfactory”. The whole group satisfaction can be maximized, finding solutions as close as possible to the ideal consensus. The group moderator is in charge of making the final decision, finding the best compromise between the collective satisfaction and dissatisfaction. Imperfect information on values of objective functions, required and available resources, and decision model parameters are handled by using interval numbers. Two different kinds of multi-criteria decision models are considered: (i) an interval outranking approach and (ii) an interval weighted-sum value function. The proposal is more general than other approaches to group multi-objective optimization since (a) some (even all) objective values may be not the same for different DMs; (b) each group member may consider their own set of objective functions and constraints; (c) objective values may be imprecise or uncertain; (d) imperfect information on resources availability and requirements may be handled; (e) each group member may have their own perception about the availability of resources and the requirement of resources per activity. An important application of the new approach is collective multi-objective project portfolio optimization. This is illustrated by solving a real size group many-objective project portfolio optimization problem using evolutionary computation tools.

scholarly journals Braille Block Detection via Multi-Objective Optimization from an Egocentric Viewpoint

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2775
Author(s):  
Tsubasa Takano ◽  
Takumi Nakane ◽  
Takuya Akashi ◽  
Chao Zhang
Keyword(s):  
Optimization Problem ◽  
Line Pair ◽  
Objective Functions ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Optimization Framework ◽  
Visually Impaired People ◽  
Comprehensive Comparison ◽  
Basic Characteristics ◽  
Support Devices

In this paper, we propose a method to detect Braille blocks from an egocentric viewpoint, which is a key part of many walking support devices for visually impaired people. Our main contribution is to cast this task as a multi-objective optimization problem and exploits both the geometric and the appearance features for detection. Specifically, two objective functions were designed under an evolutionary optimization framework with a line pair modeled as an individual (i.e., solution). Both of the objectives follow the basic characteristics of the Braille blocks, which aim to clarify the boundaries and estimate the likelihood of the Braille block surface. Our proposed method was assessed by an originally collected and annotated dataset under real scenarios. Both quantitative and qualitative experimental results show that the proposed method can detect Braille blocks under various environments. We also provide a comprehensive comparison of the detection performance with respect to different multi-objective optimization algorithms.

scholarly journals Research on Blank Optimization Design Based on Low-Carbon and Low-Cost Blank Process Route Optimization Model

2021 ◽  
Vol 13 (4) ◽  
pp. 1929
Author(s):  
Yongmao Xiao ◽  
Wei Yan ◽  
Ruping Wang ◽  
Zhigang Jiang ◽  
Ying Liu
Keyword(s):  
Optimization Model ◽  
Optimization Design ◽  
Design Method ◽  
Low Cost ◽  
Route Optimization ◽  
Low Carbon ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Blank Design ◽  
Process Route

The optimization of blank design is the key to the implementation of a green innovation strategy. The process of blank design determines more than 80% of resource consumption and environmental emissions during the blank processing. Unfortunately, the traditional blank design method based on function and quality is not suitable for today’s sustainable development concept. In order to solve this problem, a research method of blank design optimization based on a low-carbon and low-cost process route optimization is proposed. Aiming at the processing characteristics of complex box type blank parts, the concept of the workstep element is proposed to represent the characteristics of machining parts, a low-carbon and low-cost multi-objective optimization model is established, and relevant constraints are set up. In addition, an intelligent generation algorithm of a working step chain is proposed, and combined with a particle swarm optimization algorithm to solve the optimization model. Finally, the feasibility and practicability of the method are verified by taking the processing of the blank of an emulsion box as an example. The data comparison shows that the comprehensive performance of the low-carbon and low-cost multi-objective optimization is the best, which meets the requirements of low-carbon processing, low-cost, and sustainable production.

scholarly journals Multi-Objective Lightweight Optimization of Parameterized Suspension Components Based on NSGA-II Algorithm Coupling with Surrogate Model

Machines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 107
Author(s):  
Rongchao Jiang ◽  
Zhenchao Jin ◽  
Dawei Liu ◽  
Dengfeng Wang
Keyword(s):  
Ride Comfort ◽  
Lightweight Design ◽  
Dynamic Performance ◽  
Vehicle Dynamic ◽  
Multi Objective Optimization ◽  
Original Design ◽  
Dynamic Simulations ◽  
Nsga Ii ◽  
Torsion Beam ◽  
Multi Objective

In order to reduce the negative effect of lightweighting of suspension components on vehicle dynamic performance, the control arm and torsion beam widely used in front and rear suspensions were taken as research objects for studying the lightweight design method of suspension components. Mesh morphing technology was employed to define design variables. Meanwhile, the rigid–flexible coupling vehicle model with flexible control arm and torsion beam was built for vehicle dynamic simulations. The total weight of control arm and torsion beam was taken as optimization objective, as well as ride comfort and handling stability performance indexes. In addition, the fatigue life, stiffness, and modal frequency of control arm and torsion beam were taken as the constraints. Then, Kriging model and NSGA-II were adopted to perform the multi-objective optimization of control arm and torsion beam for determining the lightweight scheme. By comparing the optimized and original design, it indicates that the weight of the optimized control arm and torsion beam are reduced 0.505 kg and 1.189 kg, respectively, while structural performance and vehicle performance satisfy the design requirement. The proposed multi-objective optimization method achieves a remarkable mass reduction, and proves to be feasible and effective for lightweight design of suspension components.

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