Road Profile Research Articles

Rollover stability analysis of liquid tank truck taking into account the road profiles

The rollover stability of the tank truck was quite poor compare with others due to the influence of the oscillating liquid inside the tank. In addition, it was also affected by road excitation during driving. Therefore, the paper presents the impact of the road profiles in turning and lane change maneuvers on the rollover stability characteristics of a liquid tank truck. Firstly, the study applies the quasi-static method and the roll model to built the dynamic model of a circular cross-section tank truck. After that, the Lagrange method and the D'Alembert's principle are used to set up the differential equations which are then used to investigate rollover stability of vehicle corresponding with each liquid level. The research used the value of the load transfer ratio (LTR), crest factor of LTR and the roll angle of suspension to evaluate vehicle stability in the time domain and the transfer function magnitude of LTR in the frequency domain. The simulation results had shown that the tank truck tends to a rollover phenomenon at the fluid level in tank of 50% and 75% (0.8m and 1.2m) when the vehicle ran survey road profiles in a steady state turning maneuver and in a lane change maneuver as there was not the road excitation. The research results can provide recommendations when operating liquid tank truck, developing control systems and warning of rollover.

Adaptive Integral Terminal Sliding Mode Control for the Nonlinear Active Vehicle Suspension System under External Disturbances and Uncertainties

Suspension system is one of the most effective vehicle components that play an essential role in the stability and comfort of the vehicle. The passive suspension can not fully meet a car's stability and comfort requirements. Instead, an active suspension system has been proposed to improve these challenges. Active suspension minimizes the vibrations entering the body using a closed-loop control system. To this end, in this research, an integral terminal sliding mode control (integral TSMC) for an active nonlinear car suspension system under external disturbances and uncertainties is designed. First, the integral TSMC is designed to deal with the uncertainties and the external disturbances in the system when the upper bound is known. Next, an adaptation law is recommended to estimate the upper bound of uncertainties and external disturbances. The results show that the proposed integral TSMC improves the convergence rate and tracking error of the closed-loop system. The stability of the nonlinear control system is investigated and proven using Lyapunov's stability theory. The numerical results indicate a good robust performance and stability for the proposed controller for the nonlinear suspension system with different road profiles in the presence of uncertainties and external disturbances. From the results, it can also be understood that important measures such as ride comfort, road holding, and mechanical structural limitations are met using the proposed approach.

A spatiotemporal datamining approach for road profile estimation using low-cost device

In this paper, we address the problem of the spatiotemporal data mining in the field of the road conditions estimation. We demonstrate that road condition estimation can be defined as a problem of dynamic discovering of different classes of road profile during training phase. We focus on the road profile classification from time series data collected by a low-cost inertial sensor embedded into smartphone devices. Data used in this work are composed of three datasets which treat real asphalt pavement problems. The first, called Asphalt-obstacle, address the identification problem of obstacles in the pavement where data are collected. The second, called Asphalt pavement-type, aims at identifying three types of pavements namely flexible pavement, cobblestone street and dirt roads. The third and final dataset, called Asphalt pavement-regularity, treat the pavement quality effect on the driver comfortability. In order to estimate the road conditions, we conduct an evaluation of four spatiotemporal algorithms which combine concepts from machine learning and data-driven. With uniform parameters setting and on-line implementation property, we find that Markov spatiotemporal dynamic model achieve the best average classification accuracy of 90.5%±0.01 in 4-class Asphalt obstacles, 84%±0.006 in 3-class Asphalt pavement-type and 94.9%±0.005 in 2-class Asphalt pavement-regularity.

A Novel Method for the Reconstruction of Road Profiles from Measured Vehicle Responses Based on the Kalman Filter Method

The estimation of the disturbance input acting on a vehicle from its given responses is an inverse problem. To overcome some of the issues related to ill-posed inverse problems, this work proposes a method of reconstructing the road roughness based on the Kalman filter method. A half-car model that considers both the vehicle and equipment is established, and the joint input-state estimation method is used to identify the road profile. The capabilities of this methodology in the presence of noise are numerically demonstrated. Moreover, to reduce the influence of the driving speed on the estimation results, a method of choosing the calculation frequency is proposed. A road vibration test is conducted to benchmark the proposed method.

The problem of mechanical loads on pavement of roads in the cryolithic zone

By a process of field studies of roads in the cryolithic zone the main types of defects and destructions of asphalt concrete pavements related to mechanical load from vehicle wheels were identified. The dominant types of deformations that form in warm and cold seasons of the year, as well as factors causing them, were determined. It was found that, regardless of the temperature in any arbitrary transverse road profile, the load on the traffic rut from the car wheel has an impulse character. The frequency of the impulse action depends on the speed of the vehicle, the number of axles and the distance between the axles. The amplitude of impulses depends on the weight of the vehicle and the evenness of the pavement.The unsuitability of regulatory documentation on load calculation for practical application was proved.

Multi-Objective Optimisation of the Electric Wheelchair Ride Comfort and Road Holding Based on Jourdain’s Principle Model and Genetic Algorithm

Abstract The paper addresses the multi-body modelling of an electric wheelchair using Jourdain’s principle. First, a description of the adopted approach was presented. Next, the mathematical equations were developed to obtain the dynamic behaviour of the concerned system. The numerical computation was performed with MATLAB (matrix laboratory: a high performance language of technical computing) and validated by MBD (Multi-Body Dynamics) for Ansys, a professional multi-body dynamics simulation software powered by RecurDyn. Afterwards, the model was treated as an objective function included in genetic algorithm. The goal was to improve the ride quality and the road holding as well as the suspension workspace. The multi-objective optimisation aimed to reduce the Root-Mean-Square (RMS) of the seat’s vertical acceleration, the wheels load and the workspace modulus by varying the bodies’ masses, the spring-damper coefficients and the characteristics of the tires. Acceptable solutions were captured on the Pareto fronts, in contrast to the relatively considerable processing time involved in the use of a random road profile generated by the power spectral density (PSD). During the process, the compatibility and the efficiency of Jourdain’s equations were inspected.

Fuzzy control of active suspension system based on quarter car model

In this paper, the performance of model-free intelligent Fuzzy Controller analyzed with the model-based conventional controller concerning body displacement and body acceleration. The development of a mathematical model for active suspension is quite difficult which increases the difficulty of designing a model-based controller for active suspension. So, the model-free intelligent adaptive fuzzy controller has been proposed for active suspension. The Fuzzy Controller predicts and controls the performance of active suspension better than a conventional controller. The results obtained from the simulation of the road profile show that the proposed fuzzy control performs better than the conventional controller in terms of body displacement and body acceleration.

Road Profile Analysis Based on Elevation Map with LiDAR for Autonomous Driving

Road Profile Analysis Based on Elevation Map with LiDAR for Autonomous Driving

AN INVESTIGATION OF A TWO-STAGE ASYMMETRIC DAMPER’ EFFECT ON THE RIDE COMFORT OF AN INNER-CITY BUS BY USING 3-DOFS VEHICLE MODEL SUBJECTED TO RANDOM ROAD PROFILES

The effect of the asymmetric damper on the vertical acceleration of the driver’s body, suspension deflection and tire dynamic load were studied thoroughly in order to provide suggestions for choosing damping parameters while building a bus’s suspension system. The vehicle model with three DOFs exposed to random road profiles was employed to investigate the dynamic responses for both two cases of linear symmetric and two-stage asymmetric dampers. The investigation was carried out in the time domain by simulation, then the root-mean-square of oscillatory parameters was calculated and examined by using a program made in the MATLAB software. The results of the analysis show that a two-stage asymmetric damper ensures good oscillatory comfort of the driver but provides less handling stability of the bus when compared to a linear symmetric one.

Pemodelan Suspensi Kendaraan Dalam Tinjauan Multi Derajat Kebebasan

The two most important parameters in vehicle vibration are the level of comfort and stability. To get the best value from that parameter, the vehicle suspension system is very important to reduce vibration due to road waves and keep the wheels attached to the road. This paper studied the effect of the type of suspension on the vibration of a one-wheeled vehicle in terms of comfort and stability. The type of suspension is related to the value of the spring stiffness and the damping. While the vehicle is modeled with one wheel in two degrees of freedom. The test is carried out by loading the vehicle including the mass of the vehicle and passengers for each type of suspension, namely soft, medium and hard. Vibration analysis was performed using Matlab Simulink to obtain the acceleration response and deflection response. The vibration response graph shows the comparison of the level of comfort and stability of the vehicle on the road profile modeled in step, impulse and sinusoidal functions. From the simulation results, it is found that the Soft and Medium Suspension can handle vibration very well, especially from the level of response speed for relatively flat roads. Meanwhile, the Hard type of suspension is very good at dampening vibrations for high bumpy roads.

Vibration Control of Semi-Active Suspension System using Modified Skyhook with Advanced Firefly Algorithm

The semi-active suspension (SAS) system is a partial suspension device used in the vehicle system to improve the ride comfort and road handling. Due to the high non-linearity of the road profile disturbances plus uncertainties derived from vehicle dynamics, a conventional Skyhook controller is not deemed enough for the vehicle system to improve the performance. A major problem of the implementation of the controller is to optimize a proper parameter as this is an important element in demanding a good controller response. An advanced Firefly Algorithm (AFA) integrated with the modified skyhook (MSky) is proposed to enhance the robustness of the system and thus able to improve the vehicle ride comfort. In this paper, the controller scheme to be known as MSky-AFA was validated via MATLAB simulation environment. A different optimizer based on the original firefly algorithm (FA) is also studied in order to compute the parameter of the MSky controller. This control scheme to be known as MSky-FA was evaluated and compared to the proposed MSky-AFA as well as the passive suspension control. The results clearly exhibit more superior and better response of the MSky-AFA in reducing the body acceleration and displacement amplitude in comparison to the MSky-FA and passive counterparts for a sinusoidal road profile condition.

Energy recovery from shock absorbers through a novel compact electro-hydraulic system architecture

Riding a road vehicle involves only 10-16% of the fuel energy to overcome the resistance from friction and air drag, while the rest contributes to a massive ecological and economic damage. From an energy balance point of view, a great amount of energy is dissipated as vibrations at the shock absorbers level. In this paper, a hydraulic regenerative shock absorber, able to recover and convert the vibration energy caused by road profiles is designed and manufactured by exploiting off-the-shelf components to reduce R&D costs, and its overall maximum efficiency is measured. The prototype is composed of a twin tube electronically controlled shock absorber and of an electro-hydraulic unit (also called regenerative valve) rigidly connected to it. The main relations ruling the dynamics of a regenerative damper are discussed and the main features of the regenerative valve are designed to comply with size, performance, and safety requirements. Parametric relations are illustrated and properly managed to justify the choice of a dedicated electric motor. Performances are assessed through simulations and experimental tests, while reliability is confirmed through a thermal analysis that reveals no thermal issues. The prototype reaches a maximum overall harvesting efficiency of 11.7% for an intermediate value of the external electric load at a 500mm/s rod speed and a maximum electric power in output of 75W for a high external electric load at 1000mm/s rod speed. Efficiency is strongly hindered at low values of rod speed because of predominant friction effects. It is also demonstrated the possibility to modify the damping curve by varying the electrical characteristics of the circuit connected to the electric machine. The compact design of the RSA, with a mass of only 5.8kg, allows its installation into the suspension of a B-class SUV with a minimum impact on the current damper structure.

Search for requirements for the width of pedestrian roads in the context of the classification of public space

Walking has long been the primary means of human transport. Nevertheless, in recent decades, the insufficient emphasis has been placed on it in the creation and renewal of public space. It focuses mainly on the needs of road transport, the volume of which is constantly growing enormously. It is only in recent years that the view begins to be re-evaluated and trends in the organization of public space gradually changed, as it is true that a larger supply generates a greater demand. Therefore, leading architects are gradually changing their approaches to the organization of public space and put humans, pedestrian transport, and its requirements first. In the Czech Republic, the trend is gradually changing, as it is worldwide. Walking again plays an important role in the creation of sustainable mobility plans for the cities of the Czech Republic. The main problems arise in the actual implementation of these ideas, as the legislative requirements are formulated only in general, unlike the requirements for road transport, which sets out the requirements for minimum road profiles in the context of design speed and traffic intensity in a given cross-section. These requirements are set out in Decree No. 501/2006 Coll. on general requirements for land use and also in CSN 73 6110 Design of local roads (CSN is Czech technical norm). However, such a categorization of requirements for pedestrian roads is not yet solved uniformly for the entire territory of the Czech Republic, even though CSN 73 6110 deals with sidewalks (functional group D roads). ). So far, this categorization is replaced only by seldom locally valid methodologies, manuals, or requirements and regulations in the town plans of individual cities. This paper aims to search for current approaches, legislative requirements, and approaches to addressing the width requirements for pedestrian roads in public space in the context of the classification of this area.

The method of kinematic excitation reconstruction based on measured suspension dynamic responses – experimental verification

The paper presents the method of kinematic road excitation reconstruction based on measured suspension dynamic responses and its reconstruction with use of estimated displacements of unsprung mass as a preliminary approximation of kinematic excitation and tracking control system with a PID controller that allows for faithful reconstruction of unsprung mass accelerations and, in turn, kinematic excitations. The authors performed an experimental verification of the method with use of one axle car trailer and measurements of road profile and acquiring signals of suspension dynamics responses. The signal processing methodology and obtained results are presented for random and determined excitations. The necessary requirements to use the method effectively were defined and its limitations were listed.

Self-tuning fuzzy logic control of quarter car and bridge interaction model

In this study, active suspension control of the interaction between the bridge can be modeled according to the Euler-Bernoulli beam theory, and the quarter car model with three degrees of freedom is studied. The active suspension system consists of a spring, damper, and linear actuator. The active suspension control is designed using classical PID and self-tuning fuzzy PID (STFPID) to reduce the vehicle body's disruptive effects. To determine the performance of the designed controllers, two different road profiles with the bridge oscillations caused by the bridge flexibility were considered as the disruptive effect of the vehicle. When the simulation results were examined in terms of passenger seat displacement and acceleration, the proposed STFPID method significantly increased road holding and ride comfort.

Estimating pavement roughness using a low-cost depth camera

ABSTRACT In a continuation of the Wyoming Technology Transfer Center (WYT2/LTAP) efforts to minimise the costs associated with the pavement condition assessment process, this study examined the capability of a low-cost depth camera (D435i) in measuring the International Roughness Index (IRI) as an indicator of pavement roughness. This study was performed on 48 pavement segments with various lengths and geometric features extracted from the Wyoming local roads database. A computer program was written specifically to control the camera, process the acquired data, and to return the final IRI values. The data was collected at posted speed limits. Noise reduction and hole filling techniques were applied to rectify the acquired depth data. It was found that a D435i depth camera can estimate the IRI of paved roads with a reasonable certainty compared to a standard profiler. The D435i depth camera can explain 83% of the variations in the actual IRI values measured using a standard road profiler. Statistical analysis showed no significant difference between both measurement methods at a 95% confidence level. The proposed approach has the potential to be a baseline for an inexpensive data collection system suitable for local agencies with limited budgets.

Vibration based pavement roughness monitoring system using vehicle dynamics and smartphone with estimated vehicle parameters

Due to the high cost associated with pavement roughness monitoring, researches are going on to develop new techniques of pavement monitoring which are cost effective, frequent and easily implementable. Conventionally, pavement monitoring is performed using road profilers consisting of laser and inertial sensors. Though these profilers provide measurements of high accuracy, the high operating cost of these devices makes it difficult to ensure regular pavement monitoring. With the development of technology, new researches are being performed for the development of low-cost pavement monitoring systems using ordinary vehicle and smartphones. However, in most of the studies, the effect of vehicle suspension system on pavement monitoring was not considered and also direct reconstruction of pavement profile was not performed to compute the International Roughness Index (IRI), widely used for pavement roughness monitoring system. Instead, some correlation based procedures have been followed for measurement of pavement roughness. In this paper, a vibration based method for monitoring of pavement condition is introduced using ordinary vehicle and smartphone as vibration sensors which includes calibration for vehicle suspension system. The whole process can be divided into two stages. The unknown dynamic parameters of the ordinary vehicle are identified first. The vehicle is driven over a speed bump of known dimension and vehicle vertical acceleration is recorded. State-space representation of the vehicle model with unknown parameters is performed and the parameters are estimated using Grey-Box model system identification technique. Secondly, a new pavement profile reconstruction technique is proposed based on inverse formulation of vehicle dynamics. The vertical acceleration of the vehicle with known parameters are collected by driving it over the pavement, the condition of which needs to be monitored. A new mathematical formulation of vehicle dynamics is developed and using the collected acceleration data, pavement profile is reconstructed. Further, International Roughness Index of the reconstructed pavement is calculated. Numerical simulations and field testing of the proposed method are performed for various pavement roughness conditions and vehicle speeds performed for determining its viability for pavement condition monitoring.

Effect of different seat angles on human subject while travelling by bus on Indian road conditions

Passenger seats are the most commonly used seats in the buses to provide comfort to the passengers during traveling from one place to another. During traveling by the road, the human body is subjected to vibrations that can be generated from so many sources such as wheel unbalances, road profiles, transmission, and auxiliary systems, aerodynamic loads and engines, etc. The generated vibrations are further transmitted to humans through the seat base and floor of the bus and cause discomfort. In this work, a FEM study was performed to investigate the effect of different seat backrest angles on the human subject during traveling on the passenger seats in the bus on Indian road conditions. A 3D CAD model of the human subject developed for the current study and also passenger seat with headrest has been modeled using reverse engineering with cushion material as synthetic rubber foam for seat pan and backrest. The current simulation study concludes that the minimum effect of transmissibility has been observed at 21° seat backrest angle.

Development and Simulation of 39 DOF Vehicle Model

In this study, a 39 degree-of-freedom mass-spring-damper model of a vehicle was developed. The model consists of 4 parts: wheels and suspensions, vehicle body, seats and passengers. A human model with 7 degrees of freedom was used to model the passengers. Equations of motion were obtained by drawing the free body diagram of each part. In order to solve the obtained equations of motion numerically, a model was created in the Simulink environment. To verify the accuracy of the outputs from the Simulink model, the script was written using the Python programming language. The developed model was tested by applying a road profile. Outputs from the Simulink model and test script are in agreement with each other and with the literature. Thanks to this study, the situations that affect passenger and driving comfort during vehicle design will be examined in detail with less experimentation.

Dynamic Vehicle and Rigid Road Interaction Analysis and Vibration Control of the Quarter Car Model Using Adaptive Neuro Fuzzy Algorithm

In this study 3-DOF quarter car model with the three bumps on the rigid road, the assumption has been modeled with the non-random irregularity. To reduce the excessive vibrations occurred on the vehicle body, an active suspension system with the linear actuator has been considered. Moreover, to control this actuator, an adaptive neuro-fuzzy algorithm is designed. The training and testing data of the ANFIS has been obtained from Proportional Integral Derivative (PID) control algorithm. After that the successful training process, a testing procedure has been applied to ANFIS for the measure of the adaptive neuro-fuzzy system with data that are not considered in the training process. Then, the performance of the ANFIS is compared by the PID algorithm and passive suspension system in terms of vehicle body vertical acceleration, vehicle body vertical displacement, and control force. The road model used in the study has been modeled according to non-random road profile mathematical formulation considering periodical and discrete road profile cases. In this formulation, one can easily determine the height, width, and number of the road defect with the series mathematical formulation. Consequently, with the results obtained from the presented study, it is proven that ANFIS is a very effective controlling algorithm to suppress vibration occurred on the vehicle body due to vehicle road interaction. Furthermore, the performance of the ANFIS has been tested with different parameters, for example, different number membership functions (MF), which used the fuzzification of the input parameters.