Prototype Vehicle Research Articles

Comparison of experimental and finite element analysis results of a sheet metal prototype vehicle door hinge in X, Y and Z directions

In this study, the geometric differences which have a significant effect on the simulation results of the sheet metal prototype vehicle door hinge have been revealed. This geometric difference was examined by finite element simulations and experimental tests for the loads in the X, Y and Z directions specified in the UNECE R11 regulation. As a result, the curves of the finite element simulations and the experimental tests compared for each direction were examined and it was concluded that the compatible model with the experimental tests of the sheet metal prototype vehicle door hinge was 3D scan model. Keywords: Finite element simulation, UNECE R11 regulation, Vehicle door hinge, 3D scan, Cad model.

The test-bed research of a low power low-temperature PEM fuel cell

The article presents the results of testbed research of Horizon H-300 PEM Fuel Cell. It is a Polymer Electrolyte Membrane Fuel Cell (PEMFC) which reaches 300 Watt output power. It is a power source for hyper-light prototype vehicles taking part in the Shell Eco-Marathon competition. The aim of the research was to develop the load characteristics of a PEM type cell. The tests were carried out in a steady state of operation and included developing the characteristics of the output voltage concerning the load current. The current load was carried out by a programmable electronic load with the ability to accurately determine the load current. It also allows for measuring the output voltage. The tests were carried out in the load current range 0.2 - 7A, which is a significant range of the cell’s operating parameters which is used in the vehicle. During the tests, hydrogen consumption was also measured at individual points of the cell’s operation using a flow meter. This has also allowed the development of the characteristics of fuel consumption and power generated by the cell. The developed characteristics are presented in this article. A linear characteristic of power and fuel consumption in the function of the current loading on the cell was obtained for practically the whole range of the tested loads. Also, the specific fuel consumption is linearly dependent on the load power, and the lowest values (in the example the highest efficiency) were obtained at the lowest value of load power.

Automotive Architecture Topologies: Analysis for Safety-Critical Autonomous Vehicle Applications

Safety-critical systems such as Advanced Driving Assistance Systems and Autonomous Vehicles require redundancy to satisfy their safety requirements and to be classified as fail-operational. Introducing redundancy in a system with high data rates and processing requirements also has a great impact on architectural design decisions. The current self-driving vehicle prototypes do not use a standardized system architecture but base their design on existing vehicles and the available components. In this work, we provide a novel analysis framework that allows us to qualitatively and quantitatively evaluate an in-vehicle architecture topology and compare it with others. With this framework, we evaluate different variants of two common topologies: domain and zone-based architectures. Each topology is evaluated in terms of total cost, failure probability, total communication cable length, communication load distribution, and functional load distribution. We introduce redundancy in selected parts of the systems using our automated process provided in the framework, in a safety-oriented design process that enables the ISO26262 Automotive Safety Integrity Level decomposition technique. After every design step, the architecture is re-evaluated. The advantages and disadvantages of the different architecture variants are evaluated to guide the designer towards the choice of correct architecture, with a focus on the introduction of redundancy.

Efficient Local Navigation Approach for Autonomous Driving Vehicles

This paper presents an efficient and practical approach for a car navigation system (CVM-Car) based on the velocity space optimization paradigm. The method calculates the velocity control commands to keep the car in the lane while avoiding the obstacles detected by the proximity sensors. The car has to follow a road path consisting of a sequence of lanelets. This approach is a lower-level reactive control that combines the pure pursuit method to obtain a reference curvature and a reactive control algorithm that keeps the vehicle in the center of the lane' s free space while avoiding obstacles that can partially block it. CVM-Car formulates local obstacle avoidance as a constrained optimization problem in the velocity space of the car. In addition to the vehicle dynamics and obstacles constraints included by the curvature method, car-shape and non-holonomic restrictions are considered in the CVM-Car velocity space. The method has been applied to an autonomous vehicle prototype.

Method for calculating technical characteristics and parameters of movement of scale models of wheeled vehicles, ensuring the similarity of the processes during testing

Nowadays, when designing new vehicle models, there is a need to test certain solutions for the formation of a technical appearance both by simulation methods and on production samples. Full-scale road tests of vehicles make it possible to maintain full dynamic similarity during the experiment, but they can be carried out only after manufacturing of a vehicle prototype, which requires a lot of material costs. One of the ways to solve this problem is to create models that are a reduced copy of the designed vehicle. The main difficulty that appears when testing a scale model of vehicle is the need to accurately reproduce the conditions that occur when driving in real road conditions. The purpose of this paper is to find a relationship between the parameters of a production vehicle and a scale model for experimental development of algorithms for the dynamic stabilization of a wheeled vehicle. A method for calculating the technical characteristics and motion parameters of scale models for real full-scale wheeled vehicles while ensuring the similarity of the ongoing processes for scale models and for production vehicles is proposed on the basis of the theory of similarity. The main dependences for scale factors for force, kinematic and dimensional factors are obtained. The similarity of the occurring processes was confirmed by the methods of simulation modeling of the movement of a scale model and a full-scale wheeled vehicle.

Additive manufacturing for an urban vehicle prototype: re-design and sustainability implications

Additive Manufacturing (AM), allowing the layer-by-layer fabrication of products characterized by a shape complexity unobtainable with conventional manufacturing routes, has been widely recognized as a disruptive technology enabling the transition to the Industry 4.0. In this context, the design of a Portable Assisted Mobile Device (PAMD) prototype was considered as a case study. The best practices of the re-design for AM were applied to three of the main structural components, and the most sustainable manufacturing approach between AM processes and the conventional ones was identified with respect to cumulative energy demand, carbon dioxide emissions and costs. The paper aims to promote the debate concerning the correlation between design choices, process selection and sustainable product development.

Ground Segmentation Algorithm for Sloped Terrain and Sparse LiDAR Point Cloud

Distinguishing obstacles from ground is an essential step for common perception tasks such as object detection-and-tracking or occupancy grid maps. Typical approaches rely on plane fitting or local geometric features, but their performance is reduced in situations with sloped terrain or sparse data. Some works address these issues using Markov Random Fields and Belief Propagation, but these rely on local geometric features uniquely. This article presents a strategy for ground segmentation in LiDAR point clouds composed by two main steps: (i) First, an initial classification is performed dividing the points in small groups and analyzing geometric features between them. (ii) Then, this initial classification is used to model the surrounding ground height as a Markov Random Field, which is solved using the Loopy Belief Propagation algorithm. Points are finally classified comparing their height with the estimated ground height map. On one hand, using an initial estimation to model the Markov Random Field provides a better description of the scene than local geometric features commonly used alone. On the other hand, using a graph-based approach with message passing achieves better results than simpler filtering or enhancement techniques, since data propagation compensates sparse distributions of LiDAR point clouds. Experiments are conducted with two different sources of information: nuScenes’s public dataset and an autonomous vehicle prototype. The estimation results are analyzed with respect to other methods, showing a good performance in a variety of situations.

Energy and exergy analyses of experimental compressed air vehicle prototype with heating element

In this study, a new automobile powering system with compressed air is developed, built and tested. A working prototype for this pneumatic vehicle is developed at the Ontario Tech University, Oshawa, and its performance is investigated through energy and exergy efficiencies. The compressed air vehicle consists of a novel powering option integrated with a heating element prototype. The study introduces a new compressed air vehicle prototype with four air motors for powering the wheels. In addition, the compressed air exiting the motors is recovered for a second expansion to provide electrical power that heats the air before being recovered. A dynamometer is used for investigating the performance of the developed prototype. The energy efficiency for the prototype is found to be 59.5%. Also, the exergy efficiency is 51.0%. The prototype driving range is calculated to be 128 km with 300 litres of air at a pressure of 350 bars. The maximum shaft work generated is measured as 20.84 kW.

CONTROL SYSTEM OPERATIONAL PROTOCOL FOR DUAL DC ELECTRIC MOTOR CONFIGURATION IN ELECTRIC VEHICLES

This paper is focused on the analysis of the performance of DC electric motor for electric vehicles (EV) in urban and intercity routes. The paper analyzes the different driving conditions in both types of routes reproducing the most current situations and how they influence the electric motor performance. The study is focused on a dual electric motor configuration, series and parallel, which equips an electric vehicle prototype, evaluating the power response using both configurations, and comparing results from any of the two types of DC electric motor. A control system is proposed to commute between series and parallel configuration depending on driving conditions and type of route to maximize the performance of the electric motor. Driving routes have been segmented into five categories, acceleration, deceleration, constant velocity, ascent and descent, as representative of any urban or intercity routes. A simulation process has been carried out to reproduce real driving conditions. The simulation has been applied considering the turning speed of the electric motor as the key parameter to decide which configuration should be selected. The results of the simulation process indicates that the control system selects the working configuration depending on the turning speed of the electric motor but also on the acceleration rate.

Energy and exergy analyses of experimental compressed air vehicle prototype with heating element

In this study, a new automobile powering system with compressed air is developed, built and tested. A working prototype for this pneumatic vehicle is developed at the Ontario Tech University, Oshawa, and its performance is investigated through energy and exergy efficiencies. The compressed air vehicle consists of a novel powering option integrated with a heating element prototype. The study introduces a new compressed air vehicle prototype with four air motors for powering the wheels. In addition, the compressed air exiting the motors is recovered for a second expansion to provide electrical power that heats the air before being recovered. A dynamometer is used for investigating the performance of the developed prototype. The energy efficiency for the prototype is found to be 59.5%. Also, the exergy efficiency is 51.0%. The prototype driving range is calculated to be 128 km with 300 litres of air at a pressure of 350 bars. The maximum shaft work generated is measured as 20.84 kW.

Effects of Magnet Type and Thickness on Outer Rotor Brushless Direct Current Motor Designed by Calculating the Required Motor Power for an Electric Vehicle Prototype

While electric vehicles are taking their place as today's transportation vehicles, big R&D investments are being made by automobile manufacturers. Outer and inner rotor motors are used for electric vehicles. Considering the fact that the transmission organs make the structure more complex, outer rotor motors come into prominence in applications requiring small power. This study includes the design of outer rotor brushless direct current motor for electric vehicle prototypes. In addition, the effects of magnet type and magnet thickness on the design were analyzed in detail. The effects of magnet type and magnet thickness selected in the design of outer brushless direct current motor can be observed from the results, especially effecting power and torque parameters.

Study, Development and Prototyping of a Novel Mild Hybrid Power Train for a City Car: Design of the Turbocharger

Within a large, state-funded, Italian National Project aimed to test the feasibility of an on-the-road prototype of a mild hybrid city vehicle, one of the tasks was to conceive, design and implement an innovative turbocharger that would allow for some energy recovery. The selected vehicle is propelled by a 3-cylinder, 998 cc turbocharged engine (the 66 kW Mitsubishi-Smart W451). The idea is to implement two types of energy recovery: one via the new turbocharger and one through a standard braking energy recovery (also known as KERS). The study of the former is the object of this paper. The proposed turbocharger configuration consists of mechanically separated, electrically coupled compressor and turbine, possibly mounting only slightly modified commercial equipment to reduce construction costs. This paper reports the results of the calculation of the behavior of the new turbocharging group across the entire engine operating range and describes the preliminary design of the unit. An accurate simulation of a mixed (urban and extra-urban) driving mission demonstrates that a net saving of about 5.6% can be attained by the installation of the novel turbocharger unit.

Two‐Dimensional Siloxene–Graphene Heterostructure‐Based High‐Performance Supercapacitor for Capturing Regenerative Braking Energy in Electric Vehicles

AbstractThe development of high‐performance electrodes that increase the energy density of supercapacitors (SCs) (without compromising their power density) and have a wide temperature tolerance is crucial for the application of SCs in electric vehicles. Recent research has focused on the preparation of multicomponent materials to form electrodes with enhanced electrochemical properties. Herein, a siloxene–graphene (rGO) heterostructure electrode‐based symmetric SC (SSC) is designed that delivers a high energy density (55.79 Wh kg−1) and maximum power density of 15 000 W kg−1. The fabricated siloxene–rGO SSC can operate over a wide temperature range from –15 to 80 °C, which makes them suitable for applications in automobiles. This study shows the practical applicability of siloxene–rGO SSC to drive an electric car as well as to capture the braking energy in a regenerative brake‐electric vehicle prototype. This work opens new directions for evaluating the use of siloxene–rGO SSC as suitable energy devices in electric vehicles.

Influence of balanced suspension on handling stability and ride comfort of off-road vehicle

Handing stability and ride comfort, basic indexes to evaluate vehicle performance, usually cannot be guaranteed simultaneously. Given the contradiction between the two indexes, a new type of suspension – balanced suspension, has attracted wide attentions for years. Balanced suspensions are a device that converts the movement of a wheel into force at the other wheels through a mechanical or hydraulic structure, which might improve ride comfort/handling stability while maintaining the handling stability/ride comfort. As the hydraulically interconnected suspension and hydro-pneumatic suspension show disadvantages of high cost and high installation space requirement, a specific balanced suspension which is connected through a mechanical structure is presented and thoroughly analyzed in this paper. The balanced suspension connects the front and rear suspension motion of the vehicle by means of the lever mechanical connection structure to obtain the comprehensive performance of enhanced vehicle’s ride comfort and handling stability. The half-vehicle mathematical model for ride comfort and the multi-body dynamics model for handling stability are established for the comparison and analysis of the dynamic performance of vehicle when the balanced suspension on and off. In addition, experimental tests of the modified vehicle prototypes when the balanced suspension on and off on the ride comfort and handling stability are conducted. Similar with the simulation results, experimental tests show that the handling stability is nearly unchanged while the ride comfort improves about 15.9% when the balanced suspension is on.

Fast Modelling and Identification of Hydraulic Brake Plants for Automotive Applications

Diffusion of electric and hybrid vehicles is accelerating the development of innovative braking technologies. Calibration of accurate models of a hydraulic brake plant involves availability of large amount of data whose acquisition is expensive and time consuming. Also, for some applications, such as vehicle simulators and hardware in the loop test rig, a real-time implementation is required. To avoid excessive computational loads, usage of simplified parametric models is almost mandatory. In this work, authors propose a simplified functional approach to identify and simulate the response of a generic hydraulic plant with a limited number of experimental tests. To reproduce complex nonlinear behaviours that are difficult to be reproduced with simplified models, piecewise transfer functions with scheduled poles are proposed. This innovative solution has been successfully applied for the identification of the brake plant of an existing vehicle, a Siemens prototype of instrumented vehicle called SimRod, demonstrating the feasibility of proposed method.

Driving Behavior Analysis of Intelligent Vehicle System for Lane Detection Using Vision-Sensor

Lane detection on the road is the most essential phase of existing advanced driver assistance systems (ADAS). In the current road scheme, the lanes are parallel tracks which are marked based on the different speed limit for the vehicles. Lane markings are defined as driving regions for the vehicles in order to avoid a collision. In an Intelligent Vehicle System (IVS), these markings are being identified by various massive computing techniques and sensor-based mechanisms like radar, LiDAR, and GPS and have high operational costs. However, vision-based detection methods are gaining popularity due to its low cost and better understanding capability of the scene. The proposed study follows computer vision and image processing techniques to examine and learn significant lane features. The approach demonstrates the practical and effective usage of the lane detection model (LDM). The LDM has been designed with a vehicle prototype using Raspberry Pi, which reveals the intelligent behavior against the detected lane lines. The model is less expensive and power-efficient, which confirms the operational capability of the proposed system under a heterogeneous environment.

Experimenting With Sensors of a Low-Cost Prototype of an Autonomous Vehicle

Autonomous vehicles are sought to be integral in smart cities. However, should those vehicles be equipped with high-cost sensors? Would the use of low-cost sensors on autonomous vehicles makes them effectively workable over a long period of time? The question of how effective low-cost sensors can be for the proper functionality of autonomous vehicles is addressed in this paper. We have built a small-size prototype of an autonomous vehicle, where low-cost sensors were employed. Then, we have done experimental tests on the vehicle and its sensors, with the features of object detection and response through collision avoidance, traffic lights detection and adequate response, lane detection and lane-keeping response, and end of route detection and stopping response. Our experimental results show that low-cost sensors perform well with carefully-prepared road conditions, but they can be a challenge for operation on real-world roads. Based on our testing experience and on the faced challenges, we share our findings as well as our recommendations with the research community. Therefore, this paper provides insights toward reliable and workable real-world low-cost autonomous vehicles.

Advanced Temperature-Varied ECU Fingerprints for Source Identification and Intrusion Detection in Controller Area Networks

External wireless interfaces and the lack of security design of controller area network (CAN) standards make it vulnerable to CAN-targeting attacks. Unfortunately, various defense solutions have been proposed merely to detect CAN intrusion attacks, while only a few works are devoted to intrusion source identification. Demonstrated by our experimental studies, the most advanced IDS with intrusion source identification, which is based on the physical feature fingerprints of the in-vehicle Electronic Control Units (ECUs), will fail when the temperature changes. In this paper, we innovatively propose temperature-varied fingerprinting, called TVF, for CAN intrusion detection and intrusion source identification. Motivated by the remarkable observation that the physical feature of an ECU, i.e., its clock offset, changes linearly with the temperature of ECUs, the concept of temperature-varied fingerprints is proposed. Then, for a severe intrusion case, we provide an advanced TVF for further supplemented and expanded. The proposed advanced temperature-varied fingerprinting is implemented, and extensive performance evaluation experiments are conducted in both CAN bus prototype and real vehicles. The experimental results illustrate the effectiveness and performance of advanced TVF.

System, Design and Experimental Validation of Autonomous Vehicle in an Unconstrained Environment.

In recent years, technological advancements have made a promising impact on the development of autonomous vehicles. The evolution of electric vehicles, development of state-of-the-art sensors, and advances in artificial intelligence have provided necessary tools for the academia and industry to develop the prototypes of autonomous vehicles that enhance the road safety and traffic efficiency. The increase in the deployment of sensors for the autonomous vehicle, make it less cost-effective to be utilized by the consumer. This work focuses on the development of full-stack autonomous vehicle using the limited amount of sensors suite. The architecture aspect of the autonomous vehicle is categorized into four layers that include sensor layer, perception layer, planning layer and control layer. In the sensor layer, the integration of exteroceptive and proprioceptive sensors on the autonomous vehicle are presented. The perception of the environment in term localization and detection using exteroceptive sensors are included in the perception layer. In the planning layer, algorithms for mission and motion planning are illustrated by incorporating the route information, velocity replanning and obstacle avoidance. The control layer constitutes lateral and longitudinal control for the autonomous vehicle. For the verification of the proposed system, the autonomous vehicle is tested in an unconstrained environment. The experimentation results show the efficacy of each module, including localization, object detection, mission and motion planning, obstacle avoidance, velocity replanning, lateral and longitudinal control. Further, in order to demonstrate the experimental validation and the application aspect of the autonomous vehicle, the proposed system is tested as an autonomous taxi service.

A study on the filtration efficiency and regeneration capacity of the gasoline particulate filter

Gasoline particulate filters (GPF) are becoming a standard technology in gasoline engines because of the need for compliance with particulate matter (PM) emissions requirement. Generally, GPFs can be placed after a three-way catalysts (TWC) in the same can, or in a separate can downstream. As typical wall-flow filters, particulate matter is removed from the exhaust by physical filtration using a honeycomb structure similar to an emissions catalyst substrate but with the channels blocked at alternate ends. The goal of work was to the study the filtration efficiency and regeneration capacity of the GPF. Laboratory emission tests were carried out for one 2.0L gasoline turbo direct injection (GTDI) prototype vehicle according to the new World Harmonized Light Vehicle Test Cycle (WLTC). The data showed that the vehicle has a reliable and high GPF filtration efficiency to intercept the particulate pollution from the exhaust. Meanwhile, five 2.0L GTDI prototype cars from respective China stage 6 platforms were used for further study of soot accumulation and regeneration capacity. The results, in terms of modeled emissions in tests under real driving conditions of China cities (Nanjing and Hainan), showed that the heavy traffic road conditions lead to a low probability of soot regeneration. However, the GPF regeneration capacity of the test convoy was still adequate. In addition, the drive cycle exhibiting good road conditions with more aggressive driving behaviors offered a better regeneration environment due to the elevated GPF temperature and more frequent occurrence of deceleration fuel shut off (DFSO) creating an environment of excess oxygen content.