Surrogate-based modeling strategy for design optimization of passenger car suspension system

The dynamic response of a Low-Fidelity (LoFi) vehicle model exhibits a discrepancy when compared to a High-Fidelity (HiFi) vehicle model. HiFi model construction involves complex state-space equations, a high degree of freedom, and requires a huge quantity of early data to completely define this model. This causes a delay and makes the computation process less efficient. On the other hand, the LoFi model developed using simpler state-space equations is faster and computationally cheaper. However, the response accuracy of this model is lower than that of HiFi. Due to this competence mismatch, it constrains the ability and integration of LoFi model or HiFi model applications in vehicle dynamics research. In previous researches, the proposed surrogate model has been completely replaced any physics-based model for subsequent engineering applications once it has been generated. However, this model has limitation to perform fine tuning either on LoFi or HiFi models. The primary aim of this research was to formulate a surrogate-based modeling strategy by tuning LoFi model for optimizing the design of the passenger car suspension system. The study began with the development of HiFi and LoFi models in Matlab, and their performances were verified by comparing the results produced by MSC Adams software. The LoFi model was used to determine the overall relationship between the suspension system's main elements, namely spring stiffness (Ks) and damper rate (Cs), and the design criteria, namely Body Acceleration (BAcc), Dynamic Tire Load (DTL), and Suspension Workspace (SWS). Based on the Design Criteria Space (DCS) map and recommendations from the literature, the Design Objective Space (DOS) map for a passenger car suspension system was established. Following that, three approaches to formulating surrogate models were introduced, namely the Response-Based Approach (RBA), the Variable-Based Approach (VBA), and the Parameter-Based Approach (PBA). The VBA for the Quadratic Transformation Scheme (QTS) was found to be the most suitable for the proposed newly surrogate model. Next, the surrogate model was linked to an optimization strategy to tune the suspension elements. Finally, a single optimal solution was obtained using the Min-Max method. The optimal tuning for the suspension elements of the chosen passenger car was Ks = 12535.6 N/m and Cs= 1416.7 Ns/m which increased the BAcc by 12.6% but at the expense of DTL performance by 6.4%, and keeping the SWS below the 7 mm restriction. In conclusion, the proposed surrogate-based modeling strategy could be a potential tool for optimizing the design of a passenger car suspension system

Feasibility study of surrogate model for the application of vehicle suspension system

High-fidelity (HF) model always provides better performance in assessing vehicle suspension system design compared to low-fidelity (LF) model. However, HF model is computationally expensive. On the contrary, LF model, which depends on a few parameters allow the simulation of ’what-if’ problem run faster and the results potentially comparable with HF model. This research attempts to conduct feasibility study on LF model using the surrogate model for the application of vehicle suspension study. The surrogate models are classified into three types which are Response-Based (RB) model, Variable-Based (VB) model, and Parameter-Based (PB) model. Through three statistical metrics and graphical interpretation, the results show that VB model gave the most superior performance compared to RB model and PB model

vehicle dynamic model–driver model system: platform to evaluate car and human responses using double lane change circuit

Vehicle Dynamic Model–Driver Model (VDM-DM) system is developed to address the need to have a comprehensive system that can evaluate the performance of the car and the capability of the driver based on the planned trajectory. This is possible when VDM-DM system integrates the vehicle dynamic response with the driver model. The driver model determines the steer input from the geometrical properties of the intended path and this steer angle becomes the input for the vehicle dynamic response analysis. Finally, from the position of the car, the steer angle can be calculated. The position of the car will be then compared with the intended path and a new steer input can be determined by the driver model. Two case studies were carried out to demonstrate the application of the VDM-DM in evaluating the performance of the car and the capability of the driver using Double Lane Change (DLC) circuit. Based on the case studies, VDM-DM can be used as the tool to evaluate the performance of cars and capability of the drivers. This demonstrates that VDM-DM is capable to simulate the behavior of different drivers and hence, VDM-DM system has the potential to bring related road safety issue to the desktop

Stability Analysis of Disc Brake Squeal Considering Temperature Effect

Passenger cars have become one of the main transportations for people travelling from one place to another. Indeed, vehicle quietness and passenger comfort issues are a major concern. One of vehicle components that occasionally generate unwanted vibration and unpleasant noise is the brake system. Brake squeal noise is the most troublesome and irritant one to both car passenger and the environment, and is expensive to brakes and carmakers in terms of warranty costs. Brake squeal has been studied over 20 years ago through experimental, analytical and numerical methods in an attempt to understand, to predict and to prevent squeal occurrence. In recent years, the finite element (FE) method has become the preferred method due to inadequacy of experimental methods in predicting squeal at early stage in the design process. However, the drawbacks of the FE method are over-predictions and missing unstable modes in the squeal frequency range. This paper attempts to improve the drawbacks by considering temperature effect, which is typically neglected by many previous investigators. Prediction of disc brake squeal is performed using complex eigenvalue analysis that available in ABAQUS V6.4. In doing so, a validated and detailed 3-D finite element model of a real disc brake is used. Predicted results are then compared to those obtained in the experimental results with and without the effect of temperature

Applications of cubic motion curve

Cubic motion is a curve that is generated by the integration of Cubic Spline and dynamic of motion. Cubic spline will draw the curve, whilst the dynamic of motion will position the vertices. This embedded motion attribute to the curve will have an advantage to study related to motion of vehicle. The objective of the paper is to demonstrate the advantage of motion attribute in the curve. It is demonstrated by two case studies. The case studies are simulation of traffic flow system and study of vehicle dynamic respon

Strategies to integrate design process into TVET in conducting final year project

Ministry of Education (MOE) has imposed the final year project as a design-based project and the requirement to graduate with vocational diploma. Guideline for final year project becomes the basis to conduct the project executed based on Final Year Project I and II course. To have an effective and standardized teaching and learning (T&L) environment, design process should be implemented in technical and vocational education and training (TVET). Therefore, this paper proposes the strategies to integrate the design process in supervising, report writing, and assessing the final year project complying with the MOE guideline. The design process becomes the backbone due to its capability to sequence the design activities, integrate the various knowledge, and enhance the creativity towards the selection of the final design from a range of designs with their respective conflicting issues. The strategies include integration of the design process into the supervision, report writing, and assessing the course. These strategies will be implemented through workshop, feedback and student activities. Kolej Vokasional Kota Tinggi (KVKT) is selected to be the case study