Experimental Vehicle Research Articles

Road Disturbance Estimation and Cloud-Aided Comfort-Based Route Planning.

This paper investigates a comfort-based route planner that considers both travel time and ride comfort. We first present a framework of simultaneous road profile estimation and anomaly detection with commonly available vehicle sensors. A jump-diffusion process-based state estimator is developed and used along with a multi-input observer for road profile estimation. The estimation framework is evaluated in an experimental test vehicle and promising performance is demonstrated. Second, three objective comfort metrics are developed based on factors such as travel time, road roughness, road anomaly, and intersection. A comfort-based route planning problem is then formulated with these metrics and an extended Dijkstra's algorithm is exploited to solve the problem. A cloud-based implementation of our comfort-based route planning approach is proposed to facilitate information access and fast computation. Finally, a real-world case study, comfort-based route planning from Ford Research and Innovation Center, Michigan to Ford Rouge Factory Tour, Michigan, is presented to illustrate the efficacy of the proposed route planning framework.

Personalized Driver Assistance for Signalized Intersections Using V2I Communication

Intersection crossing is a frequent driving maneuver in urban driving. Traffic lights and stop signs force the vehicles to stop and restart causing frustration to drivers. To help the driver in approaching and passing intersections, the vehicle can be equipped with an advanced driver assistance system (ADAS) that utilizes vehicle-to-infrastructure communication. As opposed to centralized traffic light optimization, the in-vehicle system uses information on traffic light location and timing to find an individual optimal driving pace, which is then conveyed to the driver. The conventional approach to the pace optimization problem is to consider such parameters as time of arrival, fuel consumption, and emissions. However, to be effective, the system should take into account another important factor—driver's preferences and driving characteristics to improve the acceptance of the system. In this paper, we propose a personalized pace optimization algorithm for approaching and passing signalized intersections that can be used in ADAS. It learns the personal driver's preferences and characteristics during the course of driving and uses this knowledge to calculate driving pace that improves fuel economy, reduces waiting time, and addresses the driver's preferences. We demonstrate the proposed methodology by comparing the system's recommendations for drivers with different preferences and driving styles. Drivers' features were extracted from data collected on an experimental vehicle. We utilize the drivers' profiles to find an optimal driving pace for a specified route for each particular driver. We validate the methodology by simulation to show fuel economy benefits of the generated speed profiles.

Safe driving envelopes for path tracking in autonomous vehicles

One approach to motion control of autonomous vehicles is to divide control between path planning and path tracking. This paper introduces an alternative control framework that integrates local path planning and path tracking using model predictive control (MPC). The controller plans trajectories, consisting of position and velocity states, that best follow a desired path while remaining within two safe envelopes. One envelope corresponds to conditions for stability and the other to obstacle avoidance. This enables the controller to safely and minimally deviate from a nominal path if necessary to avoid spinning out or colliding with an obstacle. A long prediction horizon allows action in the present to avoid a dangerous situation in the future. This motivates the use of a first-order hold discretization method that maintains model fidelity and computational feasibility. The controller is implemented in real-time on an experimental vehicle for several driving scenarios.

Intermediate experimental vehicle, ESA program aerodynamics–aerothermodynamics key technologies for spacecraft design and successful flight

With the aim of placing Europe among the world's space players in the strategic area of atmospheric re-entry, several studies on experimental vehicle concepts and improvements of critical re-entry technologies have paved the way for the flight of an experimental space craft.The successful flight of the Intermediate eXperimental Vehicle (IXV), under ESA's Future Launchers Preparatory Programme (FLPP), is definitively a significant step forward from the Atmospheric Reentry Demonstrator flight (1998), establishing Europe as a key player in this field.The IXV project objectives were the design, development, manufacture and ground and flight verification of an autonomous European lifting and aerodynamically controlled reentry system, which is highly flexible and maneuverable.The paper presents, the role of aerodynamics aerothermodynamics as part of the key technologies for designing an atmospheric re-entry spacecraft and securing a successful flight.

The IXV experience, from the mission conception to the flight results

The atmospheric re‐entry domain is a cornerstone of a wide range of space applications, ranging from reusable launcher stages developments, robotic planetary exploration, human space flight, to innovative applications such as reusable research platforms for in orbit validation of multiple space applications technologies.The Intermediate experimental Vehicle (IXV) is an advanced demonstrator which has performed in-flight experimentation of atmospheric re-entry enabling systems and technologies aspects, with significant advancements on Europe's previous flight experiences, consolidating Europe's autonomous position in the strategic field of atmospheric re-entry.The IXV mission objectives were the design, development, manufacturing, assembling and on-ground to in-flight verification of an autonomous European lifting and aerodynamically controlled reentry system, integrating critical re-entry technologies at system level. Among such critical technologies of interest, special attention was paid to aerodynamic and aerothermodynamics experimentation, including advanced instrumentation for aerothermodynamics phenomena investigations, thermal protections and hot-structures, guidance, navigation and flight control through combined jets and aerodynamic surfaces (i.e. flaps), in particular focusing on the technologies integration at system level for flight, successfully performed on February 11th, 2015.

IXV re-entry demonstrator: Mission overview, system challenges and flight reward

The Intermediate eXperimental Vehicle (IXV) is an advanced re-entry demonstrator vehicle aimed to perform in-flight experimentation of atmospheric re-entry enabling systems and technologies. The IXV integrates key technologies at the system level, with significant advancements on Europe's previous flying test-beds. The project builds on previous achievements at system and technology levels, and provides a unique and concrete way of establishing and consolidating Europe's autonomous position in the strategic field of atmospheric re-entry.The IXV mission and system objectives are the design, development, manufacturing, assembling and on-ground to in-flight verification of an autonomous European lifting and aerodynamically controlled reentry system, integrating critical re-entry technologies at system level. Among such critical technologies of interest, special attention is paid to aerodynamic and aerothermodynamics experimentation, including advanced instrumentation for aerothermodynamics phenomena investigations, thermal protections and hot-structures, guidance, navigation and flight control through combined jets and aerodynamic surfaces (i.e. flaps), in particular focusing on the technologies integration at system level for flight.Following the extensive detailed design, manufacturing, qualification, integration and testing of the flight segment and ground segment elements, IXV has performed a full successful flight on February 11th 2015. After the launch with the VEGA launcher form the CSG spaceport in French Guyana, IXV has performed a full nominal mission ending with a successful splashdown in the Pacific Ocean. During Flight Phase, the IXV space and ground segments worked perfectly, implementing the whole flight program in line with the commanded maneuvers and trajectory prediction, performing an overall flight of 34.400km including 7.600km with hot atmospheric re-entry in automatic guidance, concluding with successful precision landing at a distance of ~1km from the target, including the wind drift acting on the parachute from an altitude of 4.5km.

Effects and contrasts of silicon‐on‐insulator floating‐body and body‐contacted field‐effect transistors to the design of high‐performance antenna switches

A theoretical analysis and contrast of silicon-on-insulator (SOI) floating-body (FB) and body-contacted (BC) metal–oxide–semiconductor field-effect transistors (FETs) including insertion loss (IL), isolation, power handling capability as well as harmonics for radio frequency switches applications, are firstly developed in detail. From the presented investigation, lower IL and smaller chip size can be obtained using FB FETs, while the BC devices are beneficial to isolation and harmonics improvement. As an experimental vehicle for the presented analysis, the high-power single-pole eight-throw (SP8T) antenna switches for multi-mode multi-band applications, are fabricated in a partially depleted 0.18 μm SOI process based on FB and BC FETs, respectively. At 1.9 GHz, the tested IL, TR × 1 to TR × 3 isolation, and P −0.1 dB of the FB and BC SP8T switches are approximately 0.53/0.65 dB, 27.6/29.3 dB and 38.0/38.4 dBm. For the two cases, the second and third harmonics are −70.6/−75.5 and −60.4/−79.9 dBc, respectively, with a +33 dBm input power at 1.9 GHz. The experimental results strongly support the analysis that the FB FET is a preferred device in low loss or low throw-count switching design while the BC FET is a better selection in the applications that demand high power and low harmonic.

Dynamical and thermal qualification of the C–SiC nose for the IXV

The Intermediate experimental Vehicle (IXV) atmospheric re-entry demonstrator, developed within the FLPP (Future Launcher Preparatory Program) and funded by ESA, was aimed at developing a demonstration vehicle that gave Europe a unique opportunity to increase its knowledge in the field of advanced atmospheric re-entry technologies. Within this program, HERAKLES, Safran Group, was in charge of the TPS of the windward and nose assemblies of the vehicle, and has developed and manufactured SepcarbInox® Ceramic Matrix Composite (CMC) protection systems that provided a high temperature resistant nonablative outer mold line (OML) for enhanced aerodynamic control. A key component of this TPS is the nose assembly, which is one the most loaded part during re-entry.The paper describes the analysis activities that led to the qualification of the nose assembly, through two activities:•Dynamical behavior of the nose.•Thermal behavior of the noseFor both cases, the paper shows how FE models, compared with tests results, led to the understanding and simulation of the nose assembly behavior, allowing HERAKLES to confirm the design margins before flight.

Development and flight qualification of the C–SiC thermal protection systems for the IXV

The Intermediate experimental Vehicle (IXV) atmospheric re-entry demonstrator, developed within the FLPP (Future Launcher Preparatory Programme) and funded by ESA, aimed at developing a demonstration vehicle that gave Europe a unique opportunity to increase its knowledge in the field of advanced atmospheric re-entry technologies. A key technology that has been demonstrated in real conditions through the flight of this ambitious vehicle is the thermal protection system (TPS) of the Vehicle. Within this programme, HERAKLES, Safran Group, has been in charge of the TPS of the windward and nose assemblies of the vehicle, and has developed and manufactured SepcarbInox® ceramic matrix composite (CMC) protection systems that provided a high temperature resistant non ablative outer mould line (OML) for enhanced aerodynamic control. The design and flight justification of these TPS has been achieved through extensive analysis and testing:●Mechanical, Dynamical and thermo-mechanical analysis.●Coupons and technological tests.●Sub-scale tests specifically made to assess the behaviour of the TPS during re-entry.●Full scale qualification tests that addresses the flight envelope of the vehicle:•Sine, Random and shock tests on nose and windward.•Thermal test of the nose.•Mechanical tests of nose and windward.This paper describes the Flight Model TPS design, as well as the development activities, tests and results that lead to the qualification of the nose and windward TPS assemblies.

Shared Steering Control Using Safe Envelopes for Obstacle Avoidance and Vehicle Stability

Steer-by-wire technology enables vehicle safety systems to share control with a driver through augmentation of the driver's steering commands. Advances in sensing technologies empower these systems further with real-time information about the surrounding environment. Leveraging these advancements in vehicle actuation and sensing, the authors present a shared control framework for obstacle avoidance and stability control using two safe driving envelopes. One of these envelopes is defined by the vehicle handling limits, whereas the other is defined by spatial limitations imposed by lane boundaries and obstacles. A model predictive control (MPC) scheme determines at each time step if the current driver command allows for a safe vehicle trajectory within these two envelopes, intervening only when such a trajectory does not exist. In this way, the controller shares control with the driver in a minimally invasive manner while avoiding obstacles and preventing loss of control. The optimal control problem underlying the controller is inherently nonconvex but is solved as a set of convex problems allowing for reliable real-time implementation. This approach is validated on an experimental vehicle working with human drivers to negotiate obstacles in a low friction environment.

Compact Representation of Dynamic Driving Environments for ADAS by Parametric Free Space and Dynamic Object Maps

We present a novel parametric representation of general dynamic driving environments. It is particularly suitable for near-future Advanced Driver Assistance Systems due to its compactness, inherent consistency between static and dynamic entities, suppression of irrelevant details, as well as its sensor-independent, real-time capable generation. By building upon a common occupancy grid map-based environment representation, cells belonging to dynamic objects are simultaneously extracted, classified, and tracked in an object-based manner via an Interacting-MultipleModel-Unscented-Kalman-Probabilistic-Data-Association (IMM-UK-PDA) filter and cleared from the grid. The remaining static environment grid is subsequently processed by methods from the image analysis domain, followed by an Information Filter-based contour tracking of relevant free space boundaries to create a spatiotemporally smooth compact Parametric Free Space (PFS) map. The PFS map represents the static part of the traffic scene with modest bandwidth requirements. The system runs in real time on an experimental vehicle equipped with an automotive radar and a stereo camera and is evaluated within real traffic environments.

Non-linear spacecraft component parameters identification based on experimental results and finite element modelling

The objective of the present paper is to describe a procedure to identify and model the non-linear behaviour of structural elements. The procedure herein applied can be divided into two main steps: the system identification and the finite element model updating. The application of the restoring force surface method as a strategy to characterize and identify localized non-linearities has been investigated. This method, which works in the time domain, has been chosen because it has ‘built-in’ characterization capabilities, it allows a direct non-parametric identification of non-linear single-degree-of-freedom systems and it can easily deal with sine-sweep excitations. Two different application examples are reported. At first, a numerical test case has been carried out to investigate the modelling techniques in the case of non-linear behaviour based on the presence of a free-play in the model. The second example concerns the flap of the Intermediate eXperimental Vehicle that successfully completed its 100-min mission on 11 February 2015. The flap was developed under the responsibility of Thales Alenia Space Italia, the prime contractor, which provided the experimental data needed to accomplish the investigation. The procedure here presented has been applied to the results of modal testing performed on the article. Once the non-linear parameters were identified, they were used to update the finite element model in order to prove its capability of predicting the flap behaviour for different load levels.

Keswa: An Uncovering

Keswa, Arabic for covering, is a public installation of folded digitally cut steel that evokes the image of Arab Gulf women by abstracting the stretch and flow of black fabric found in the abaya, or traditional black robe used to cover women's bodies in public. Two Saudi women, both architecture students, designed the piece and did the work of fabrication. Falling between the typology of the pavilion—a favored vehicle for architectural experimentation—and a piece of public art, Keswa invites the public to enter the space of the abaya, simultaneously venerating the garment and subverting its power to subordinate.

The design and realisation of the IXV Mission Analysis and Flight Mechanics

The Intermediate eXperimental Vehicle (IXV) is a suborbital re-entry demonstrator successfully launched in February 2015 focusing on the in-flight demonstration of a lifting body system with active aerodynamic control surfaces. This paper presents an overview of the Mission Analysis and Flight Mechanics of the IXV vehicle, which comprises computation of the End-to-End (launch to splashdown) design trajectories, characterisation of the Entry Corridor, assessment of the Mission Performances through Monte Carlo campaigns, contribution to the aerodynamic database, analysis of the Visibility and link budget from Ground Stations and GPS, support to safety analyses (off nominal footprints), specification of the Centre of Gravity box, selection of the Angle of Attack trim line to be flown and characterisation of the Flying Qualities performances. An initial analysis and comparison with the raw flight data obtained during the flight will be discussed and first lessons learned derived.

The IXV vehicle model identification subsystem: Off-line estimation framework

The Intermediate eXperimental Vehicle (IXV) is an ESA re-entry technological platform built to verify in-flight the performance of critical re-entry technologies. The successful flight of the IXV provides the key elements to consolidate the knowledge necessary for the development of future European re-entry systems.The exploitation of in-flight data represents a cornerstone for this flying test bench. In this frame the IXV Vehicle Model Identification subsystem, VMI, represents those steps, techniques and algorithms that shall be applied to the collected data in order to improve the prediction capabilities for future design of re-entry vehicles and specifically to:●Improve IXV flight dynamics model.●Validate aerodynamic prediction methods based on Wind Tunnel Tests, WTT, and Computational Fluid Dynamics, CFD.●Validate the vehicle model identification process and tools.

Performance Testing of a Locomotive Engine Aftertreatment Pre-prototype in a Passenger Cars Chassis Dynamometer Laboratory

The aim of this work is the definition of a pilot test procedure to carry on the system testing and validation tests with a locomotive engine aftertreatment pre-prototype called ENSPIRIT system, developed in the framework of the FP7 European Project Eliminating NOx, SOx& Particulate in Rail Transportation. Here it is described the study, processing and definition of the test procedure. A study has been conducted investigating the legislation (both European and US EPA) dealing with emission standards and tests for locomotives, gathering the fundamental information to create a driving cycle, suitable for tests with passenger cars, taking into account the main features of the locomotive test cycle. The first version of the ENSPIRIT Driving Cycle (EDC) has been tested in laboratory with two 2.0 l diesel experimental vehicles in order to refine it to better reproduce the locomotive test procedure, in particular with respect to notches duration, speed and rpm increase. The refined and definitive version of the EDC has been tested as well and the obtained results are here reported. The developed EDC was then inserted in a pilot testing protocol whose aim is to determine, through the EDC laboratory execution, the ENSPIRIT pre-prototype effectiveness in reducing the emission of NOx > 75% and the emission of PM2.5 > 98%. This can be done comparing the emissions of the two experimental vehicles, deprived of all the emission abatement systems (DPF, EGR, Oxy cat), with and without the use of the ENSPIRIT pre-prototype.

Universal digital strain gauge measurement system of aeroelastic deformation development

This article presents description of the universal digital strain gauge system developed to measure the static and dynamic aeroelastic deformations of elasticity-scale models during the tests in aerodynamic tube and during in-flight tests of an experimental air vehicles. The main requirements for such devices are small size and possibility of operation in a wide temperature range. The article considers the dependence of zero offset from temperature. Functional diagram block and logic diagram of the build system are shown.

The Corrosion Performance Of Metals In An Experimental Biodiesel Vehicle Motor

ABSTRACTThe aim of this work was to assess the corrosion and degradation effects of a biofuel on metallic materials tested in an experimental internal combustion engine (ICE). Biodiesel is considered as an alternative fuel for diesel, for industrial applications ranging from boilers to ICE. The experimental vehicle motor, fitted with carbon steel, stainless steel, aluminum alloys and magnesium alloys was operated with local biodiesel. The corrosion performance was evaluated by gravimetric, chemical and electrochemical techniques, following the practices recommended in ASTM and NACE standards for corrosion testing. This work is the result of an international cooperation between the Institute of Engineering, Autonomous University of Baja California, Mexico and the Corrosion Research Center, Sami Shamoon College of Engineering, Israel. The characteristics and conditions of the ICE operated with biodiesel, and the results of the corrosion essays are presented, analyzed and discussed.

Experimental vehicle for human behavior signal processing

Experimental vehicle for human behavior signal processing

Aerodynamics and Flight Capability of a Supersonic Flight Experiment Vehicle

Aerodynamics and Flight Capability of a Supersonic Flight Experiment Vehicle