Effects of Spring Stiffness on Suspension Performances Using Full Vehicle Models

2018 ◽  
Author(s):  
M Hamed ◽  
M Elrawemi ◽  
F Gu ◽  
A D Ball
Keyword(s):  
Spring Stiffness ◽  
Full Vehicle ◽  
Suspension Performances

scholarly journals Control of Automotive Semi-Active MR Suspensions for In-Wheel Electric Vehicles

2020 ◽  
Vol 10 (13) ◽  
pp. 4522 ◽  
Author(s):  
Mauricio Anaya-Martinez ◽  
Jorge-de-J. Lozoya-Santos ◽  
L.C. Félix-Herrán ◽  
Juan-C. Tudon-Martinez ◽  
Ricardo-A. Ramirez-Mendoza ◽  
...  
Keyword(s):  
Internal Combustion Engine ◽  
Electric Vehicles ◽  
Combustion Engine ◽  
Control Strategies ◽  
Vertical Control ◽  
Suspension Systems ◽  
Full Vehicle ◽  
Active Suspension Systems ◽  
Resonance Frequencies ◽  
Suspension Performances

In this work, four different semi-active controllers for a quarter of vehicle and full vehicles are evaluated and compared when used in internal combustion engine (ICE) vehicles vs electric vehicles (EVs) with in-wheel motor configuration as a way to explore the use of semi-active suspension systems in this kind of EVs. First, the quarter of vehicle vertical dynamics is analyzed and then a full vehicle approach explores the effectiveness of the control strategies and the effects of the traction in the vertical Control performances. Aspects like the relation between traction and suspension performances, and the resonance frequencies are also discussed.

scholarly journals Reducing the metabolic energy of walking and running using an unpowered hip exoskeleton

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Tiancheng Zhou ◽  
Caihua Xiong ◽  
Juanjuan Zhang ◽  
Di Hu ◽  
Wenbin Chen ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Design Method ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Spring Stiffness ◽  
Spatiotemporal Parameters ◽  
The Common ◽  
Hip Flexion ◽  
Optimal Stiffness ◽  
Insight Into

Abstract Background Walking and running are the most common means of locomotion in human daily life. People have made advances in developing separate exoskeletons to reduce the metabolic rate of walking or running. However, the combined requirements of overcoming the fundamental biomechanical differences between the two gaits and minimizing the metabolic penalty of the exoskeleton mass make it challenging to develop an exoskeleton that can reduce the metabolic energy during both gaits. Here we show that the metabolic energy of both walking and running can be reduced by regulating the metabolic energy of hip flexion during the common energy consumption period of the two gaits using an unpowered hip exoskeleton. Methods We analyzed the metabolic rates, muscle activities and spatiotemporal parameters of 9 healthy subjects (mean ± s.t.d; 24.9 ± 3.7 years, 66.9 ± 8.7 kg, 1.76 ± 0.05 m) walking on a treadmill at a speed of 1.5 m s−1 and running at a speed of 2.5 m s−1 with different spring stiffnesses. After obtaining the optimal spring stiffness, we recruited the participants to walk and run with the assistance from a spring with optimal stiffness at different speeds to demonstrate the generality of the proposed approach. Results We found that the common optimal exoskeleton spring stiffness for walking and running was 83 Nm Rad−1, corresponding to 7.2% ± 1.2% (mean ± s.e.m, paired t-test p < 0.01) and 6.8% ± 1.0% (p < 0.01) metabolic reductions compared to walking and running without exoskeleton. The metabolic energy within the tested speed range can be reduced with the assistance except for low-speed walking (1.0 m s−1). Participants showed different changes in muscle activities with the assistance of the proposed exoskeleton. Conclusions This paper first demonstrates that the metabolic cost of walking and running can be reduced using an unpowered hip exoskeleton to regulate the metabolic energy of hip flexion. The design method based on analyzing the common energy consumption characteristics between gaits may inspire future exoskeletons that assist multiple gaits. The results of different changes in muscle activities provide new insight into human response to the same assistive principle for different gaits (walking and running).

Modelling and Validation of Full Vehicle Model based on a Novel Multibody Formulation

2019 ◽  
Author(s):  
Alberto Parra ◽  
Dionisio Cagigas ◽  
Asier Zubizarreta ◽  
Antonio Joaquin Rodriguez ◽  
Pablo Prieto
Keyword(s):  
Vehicle Model ◽  
Full Vehicle ◽  
Model Based

Load Distribution of Parallel Springs With Random Length and Stiffness

1987 ◽  
Vol 109 (4) ◽  
pp. 402-406 ◽  
Author(s):  
Go¨ran Gerbert ◽  
Jacques de Mare´
Keyword(s):  
Uniform Distribution ◽  
Load Distribution ◽  
Simple Formula ◽  
Mechanical Design ◽  
Numerical Results ◽  
Maximal Length ◽  
Major Influence ◽  
Length Variation ◽  
Spring Stiffness ◽  
Failure Risk

There are many applications in mechanical design where load distribution is modelled with parallel springs. Here random variation in spring length and spring stiffness is considered. Length variation is assumed to be the major influence and the case with uniform distribution is analyzed in detail. Small variations in spring stiffness are included. Numerical results are given. A simple formula is presented which gives the maximal length deviation as a function of the number of springs. The formula is based on a 10 percent failure risk which is a common number in practical mechanical design.

Transient Thermal Analysis for the Automotive Underhood and Underbody Components

2013 ◽  
Author(s):  
Yu Hsien Wu ◽  
Kumar Srinivasan ◽  
Steven Patterson ◽  
Emmanuel Bot
Keyword(s):  
Thermal Analysis ◽  
Thermal Management ◽  
Dissimilar Materials ◽  
Thermal Mass ◽  
New Approach ◽  
The Past ◽  
Full Vehicle ◽  
Development Cycle ◽  
Transient Thermal ◽  
Steady State Solutions

The transient thermal simulation is an important part of thermal management development for new vehicle architectures. Different techniques have been studied in the past to address this coupled conduction/convection/radiation problem. In order to fully capture the transient thermal behavior of various underhood and underbody components, it is also necessary to accurately model the thermal mass of each part and the thermal links between dissimilar materials. The paper will outline a new, efficient methodology for this type of thermal analysis that shows acceptable results for complex full vehicle thermal analysis without sacrificing accuracy. The methodology is based on approximating the transient convective field with intermittent steady state solutions. The paper will present results from this new approach and compare them with fully transient simulation results as well as experimental data. The new methodology can be optimized to significantly reduce simulation run times without sacrificing accuracy and to be more practical for application in the vehicle development cycle.

Durability Loads Prediction of Body-on-Frame Vehicles using Full Vehicle Simulations

2017 ◽  
Vol 10 (1) ◽  
pp. 13-24
Author(s):  
Nantu Roy ◽  
Christian Scheiblegger ◽  
Jos Darling ◽  
Peter Pfeffer
Keyword(s):  
Full Vehicle
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