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Technical Paper
2014-10-13
Chunshan Li, Guoying Chen, Changfu Zong
This paper presents a fault-tolerant control (FTC) approach for four-wheel independently driven and steered (4WID/4WIS) electric vehicles. An adaptive control-based passive fault-tolerant controller is designed to improve vehicle safety, performance and maneuverability when an actuator fault happens. The proposed fault tolerant control method consists of the following three parts: 1) a fault detection and diagnosis (FDD) module that monitors vehicle driving condition, detects and diagnoses actuator failures with the inequality constraints ; 2) a motion controller that computes the generalized forces/moments to track the desired vehicle motion using Model Predictive Control (MPC); 3) a reconfigurable control allocator that redistributes the generalized forces/moments to four wheels with equality constrained optimization. The FTC approach is based on the reconfigurable control allocation which reallocates the generalized forces/moments among healthy actuators once the actuator failures is detected.
Technical Paper
2014-09-28
Dongmei wu
With the promotion of electric vehicles, their stability control problem has become increasingly important. Four-wheel-drive electric vehicle can not only control the vehicle stability through hydraulic braking pressure regulation, but also through controlling the motor driving and braking force to generate yaw moment , which are different with the conventional vehicles. In addition, the hydraulic braking system of four-wheel-drive electric vehicle is Electro-Hydraulic Braking System (EHB), rather than the conventional hydraulic braking system. With EHB, the braking pressure in four wheel cylinders can be controlled independently and flexibly, rather than depending on the braking pedal. Besides, there are also several pressure sensors in EHB, which can supply the wheel cylinder pressure information, without the need for pressure estimation. As a result, the way to achieve stability control of four-wheel drive electric vehicle will be different with conventional vehicle. Currently, there are not many researches on the stability control of four-wheel-drive electric vehicle with EHB, and most of them are still at the stage of virtual simulation, lacking testing and applications in real system.
Technical Paper
2014-09-28
Alberto Boretti
Real driving cycles are characterized by a sequence of accelerations, cruises, decelerations and engine idling. Recovering the braking energy is the most effective way to reduce the propulsive energy supply by the thermal engine. The fuel energy saving may be much larger than the propulsive energy saving because the thermal engine energy supply may be cut where the engine operates less efficiently and because the thermal engine can be made smaller. The present paper discusses the state of the art of hydro-pneumatic driveline now becoming popular also for passenger cars and light duty vehicle applications.
Technical Paper
2014-09-28
Jongsung Kim, Chjhoon Jo, Yongsik kwon, Jae Seung Cheon, Soung Jun Park, Gab Bae Jeon, Jaehun Shim
Electro-Mechanical Brake (EMB) is the brake system that is actuated by the electrical energy and the motor rotation. It has similar design with Electro-Mechanical Parking Brake (EPB). It uses the gear multiplication structure for the enough torque and screw/nut mechanism for changing rotational movement to linear. The differences with EPB are screw/nut and motor type and some specification of the inner parts because the needed performance of the service braking like braking time is much higher than EPB, and usually EMB includes the force sensor for controlling the actuator and solenoid-lever structure for EPB function. The highly responsive and independent brake actuators lead to enhanced controllability which should result in not only better basic braking performance, but also improvements in various active braking functions such as integrated chassis control, driver assistance systems, or cooperative regenerative braking. Although the EMB system has the potential for numerous advantages and innovations in braking, it has yet to be successfully introduced in series production mainly due to safety and cost concerns.
Technical Paper
2014-09-28
Klaus Augsburg, Dzmitry Savitski, Lukas Heidrich, Valentin Ivanov
The presented study discusses design of brakes and brake control system for all-wheel drive electric vehicle equipped with individually controlled in-wheel motors (IWM). Initial part of the paper is dedicated to the analysis of different packaging of wheel brakes to be mounted together with IWM in the wheel hub. Special attention is given to the implementation of perimeter brake setup. Parameterization and design of specific perimeter brake configuration is introduced. The second part of the paper introduces advanced strategies for brake blending and ABS control. The proposed strategy of blending control realizes brake force distribution targeting the increase of regenerative braking with taking into account the limitations placed by the IWM operation. The ABS architecture is based on the direct slip controller. Its functionality will be illustrated with different case studies investigating the ABS braking with electric motors and hydraulic brake system. The particular attention is also given to the valuation of the brake comfort.
Technical Paper
2014-09-28
Zhizhong Wang, Liangyao Yu, Yufeng Wang, Kaihui Wu, Jian Song, Ning Pan, Liangxu Ma
The Distributed Electro-hydraulic Braking System (DEHB) is a wet type brake-by-wire system for passenger vehicles, and is especially suitable for electric vehicles and hybrid electric vehicles. The basic DEHB comprises four independent brake actuators connected to four hydraulic brakes. The word ‘distributed’ refers to the distributed arrangement of the brake actuators on the vehicle. Each brake actuator comprises an electric motor to provide brake power, a mechanism to translate rotational motion of the motor shaft into translational motion of a piston. The piston moves back and forth in a cylinder under the control of the motor to push the brake fluid into the brake. In this way, braking pressure can be controlled by the motor. Like other brake-by-wire systems, brake pedal simulator and pedal sensors are also used in DEHB. Although the concept of DEHB traces back to 1990s, only a few research papers can be found. This paper gives a review and outlook on the design concepts of DEHB from the following three aspects. 1.
Technical Paper
2014-09-28
Lu Xiong, Bing Yuan, Songyun Xu, Xueling Guang
At the very beginning part, a detailed analysis on current status of electro-hydraulic brake system is carried out. By analyzing 28 electro-hydraulic brake systems, the paper provides a brief summarization on structural components of typical electro-hydraulic brake systems from the perspective of main functional units. Then a more in-depth analysis is conducted on the key functional units, particularly on Active pressure-building unit and Pedal simulation unit. For instance, in terms of Active pressure-building unit, electro-hydraulic brake system schemes can be divided into two categories according to active power sources: one is pump + high-pressure accumulator, the other electric motor+ reducing mechanism. Then author employs MK C1, the latest electro-hydraulic brake system launched by Continental AG, to illustrate its structural components and working principle. In the second part, the idea of dual-motor electro-hydraulic brake system is proposed. As a new solution, dual-motor electro-hydraulic brake system can actively simulate pedal feeling and merge pedal power (from the driver ) into braking power at the same time, which is a distinctive innovation compared to most current electro-hydraulic brake systems.
Technical Paper
2014-09-28
Michael Herbert Putz, Christian Wunsch, Markus Schiffer, Jure Peternel
With linear actuated brakes the actuation force (or actuation torque) rises linearly from 0 to the full actuation force at full braking, causing a very variable motor current. The electro-mechanical brake (EMB) of Vienna Engineering (VE) uses a highly non-linear mechanism to create the high pressing force of the pad. The advantage is that the pad moves very fast when the pad pressing force is low and moves slower with increasing pressing force. This non-linear actuation means that the motor is always running at relatively constant load (although the pad pressing force changes highly), resulting in a motor that can be optimized for constant torque and constant rpm, reducing size and costs and increasing efficiency. The normal force in EMBs is often controlled by observing mechanical deformation to conclude to stress or force, commonly using strain gauges. It causes costs of the gauge itself and attaching them to e.g. the caliper and a sensitive amplifier. The full gauge equipment goes into the safety-related brake control system.
Technical Paper
2014-09-28
Liang Zhou, Chuqi Su
In this paper,a strategy for recovery of braking energy in HEV with EMB is proposed, which is less limited to the performance of the 42V vehicle power supply, compared with the conventional recycling strategy without EMB. In the traditional HEV with 42V vehicle power supply, recovery of braking energy is mainly recycled to the 42V battery, directly. As charging current is too large, or charging time is too long can damage the battery, 42V battery is difficult to recycle braking energy effectively ,especially in complex urban condition with vehicle braking frequently and rapidly. But in HEV with EMB,the recovery transfers to the motor of EMB directly, which is utilized dynamically in the process of vehicle braking. Excess electricity transfers to the energy storage unit if the generator is performing a voltage higher than the required voltage of EMB brake motor, otherwise, the energy storage unit to supplement electricity. The kinetic energy of the HEV turned into electrical energy to EMB timely,rather than being stored statically in this process.
Technical Paper
2014-09-28
Mandeep Singh Walia, Magnus Karlsson, Lars Hakansson, Gaurav Chopra
Mandeep Singh Walia An analysis method to study the potentials in recovering the brake energy from Volvo articulated haulers has been developed. The study is made to find out how and where possible hybrid solutions can be used. The method is based on the mapping of the peak brake power, brake energy and engine energy. The method was developed using adequate signals collected on haulers at three different customer sites. A conceptual study was also carried out concerning the brake energy to understand the actual amount of brake energy that may be stored in the Energy storage systems (ESS). The results indicate that the analysis method developed can map the brake energy generated and also provide an overview of the actual amount of brake energy that can be accumulated in the ESS, which can also guide in an effective selection of the ESS for a particular work site.
Technical Paper
2014-09-28
Kyung-Jung Lee, Jae-Min Kwon, Jae Seung Cheon, Hyun-Sik Ahn
X-by-wire technology replaces mechanical connections with electrical signals, and is indispensable for realizing an intelligent vehicle. The technology has many advantages including reduction of parts, increase in design degree-of-freedom, and safety increase. Especially, the Brake-by-Wire (BBW) system consists of electromechanical actuators and communication networks, instead of conventional hydraulic or electrohydraulic devices, has emerged as a new and promising vehicular braking control scheme. It offers enhanced safety and comfort, cuts off cost associated with manufacturing and maintenance, and eliminates environmental concerns caused by hydraulic systems. The BBW system has recently invoked a lot of interest for both industry and academia worldwide. The FlexRay is an automotive network communications protocol built to be a deterministic, fault-tolerant bus system. It was developed by the FlexRay Consortium as a conjunction with the leading automotive manufacturers. The FlexRay is a new time-triggered communication system for high-performance in-vehicle applications.
Technical Paper
2014-09-28
Ning Pan, Liangyao Yu, Zhizhong Wang, Liangxu Ma, Jian Song, Yongsheng Zhang, Wenruo Wei
With the purpose of individual wheel cylinder pressure regulation and independent of engine vacuum, Brake-by-wire (BBW) systems are suitable for electric vehicles and hybrid electric vehicles. BBW system has been developed in recent years. Electro-Hydraulic Brake (EHB) system is the first step towards BBW system. Various EHB systems have been proposed by researchers. A typical design includes a high pressure accumulator to supply pressure source and pulse width modulated (PWM) solenoid valves to regulate the brake pressure, such as the product of Bosch and Toyota. The electrically driven booster system uses motor to boost driver brake input, such as the system proposed by Mobis. Continental Teves proposed an EHB system with modified ESC hydraulic unit and electric vacuum pump. This paper proposes a new compact EHB system, arming at decreasing the size and cost without compromise of performance. There are there sections in this paper, the first section of which is system configuration and basic operation principles, the second section is the hydraulic pressure control algorithm to regulate the cylinder pressure, and the last section shows the simulation study to verify the performance of the new proposed EHB and its pressure control algorithm.
Technical Paper
2014-09-28
Liangxu Ma, Liangyao Yu, Xuhui Liu, Zhizhong Wang, Ning Pan
The paper is focused on the research of the automotive magneto-rheological brake system whose braking force comes from the shear stress of magneto-rheological fluid under the condition of magnetic field. The MRF brake is designed for a small-sized electric passenger car to replace a conventional hydraulic disc-type brake. The brake disk is immersed in the MRF whose yield stress changes as the applied magnetic field. The braking torque of this system can be linearly adjusted by the current in just a few milliseconds without the conventional vacuum booster. This system has a quick response and precise control performance with a low hysteresis. Besides, the system has adopted the original complicated structure to save space and cost. Nowadays, most of the related research of MRF is about the construction of the prototype and the realization of the brake force. However, due to a lack of optimal design and the understanding of MRF, the main research progress is only about the simulation and the braking effect of the prototype can hardly meet the requirement of the vehicle braking.
Technical Paper
2014-09-16
Evan Racine, Zachary Lammers, Street Barnett, John Murphy, Quinn Leland
Electromechanical Actuation System (EMAS) faces some major technological challenges before it could be fully adopted for primary flight control of aircraft, replacing conventional hydraulic actuation system. One of the challenges is the thermal management of EMAS. The working fluid in conventional hydraulic actuation system acts as a coolant while EMAS does not have a readily available heat sink. Another technical challenge facing EMAS for primary flight control is its highly dynamic demand on aircraft electric power system. Its high peak power demand and regenerative power pose a challenge to aircraft electric power generation and distribution system. The purpose of this study is to analyze EMAS’ transient and dynamic electrical and thermal energy flow under a simulated flight envelope and thermal environment. A laboratory test apparatus was set up to evaluate and characterize the energy flow of an EMA subjected to a simulated dynamic flight control surface load and thermal environment.
Technical Paper
2014-09-16
Christopher Ian Hill, Chris Gerada, Paolo Giangrande, Serhiy Bozhko
This paper presents the initial development of a Modelica Library for Electro-Mechanical Actuator system analysis. At present two main system components are described, these are the Power Electronic Converter and Electric Machine, although further components will be added. These models provide the user with the ability to simulate Electric Machine and Power Electronic Converter systems including physical effects, losses and fault conditions. Established modelling programs such as Saber and MATLAB SimPowerSytems are often unable to provide all the aspects required to accurately simulate real systems in an easy to use, flexible manner. Therefore this paper shows how Modelica has been used to create versatile models able to simulate many practical aspects such as Power Electronic Converter losses and Power Electronic Converter faults, Electric Machine losses and Electric Machine faults. Examples are included in order to demonstrate the use of these models within a variety of systems including an Electro-Mechanical Actuator.
Technical Paper
2014-09-16
Evgeni Ganev, William Warr
The more electric architecture (MEA) initiatives continue to be dominating trends in the aerospace industry, as they have for the last two decades. The commercial aircraft business is moving toward no-bleed air environmental control systems (ECS), variable-frequency (VF) and direct current (DC) power distribution buses, and electrical actuation. A typical example is the Boeing 787 platform. The next-generation Boeing and Airbus narrow-body airplanes will most likely use MEA. Some military aircraft already utilize MEA for both primary and secondary flight controls. Substantial progress has recently been made in replacing hydraulic and pneumatic systems with electric ones. These new aerospace and military trends have significantly increased electrical power-generation needs. The overall result has been a significant increase in the challenges to accommodate electrical equipment to the new platforms. This has led to increased operating voltages, and efforts to reduce system losses, weight, and volume.
Technical Paper
2014-09-16
Puvan Arumugam, Chris Gerada, Serhiy Bozhko, He Zhang, W.U.Nuwantha Fernando, Antonino La Rocca, Stephen Pickering
Aircraft platforms are presently being increasingly modernized due to the global effort towards having a more environmentally responsible transport network. Future aircraft platforms are expected to be more fuel efficient and also simpler to service and maintain. The way towards this goal has been identified as a move towards “more electric” systems by replacement of hydraulic and pneumatic sources of power with electrical counterparts. This can lead to an increased reliance on electrical power for a range of primary functions including actuation, de-icing, cabin air-conditioning and engine start. A more electric power generation system plays a key role in this technology and this paper focuses on the design of a starter/generator for such systems. One of the challenges often encountered in the design of a starter/generator for aero-engines is the need to satisfy the two fundamental functions, namely to energize the engines during start-up and to generate power during normal engine operation.
Technical Paper
2014-09-16
Prashant Vadgaonkar, Ullas Janardhan, Adishesha Sivaramasastry
Performance of Avionics systems is dictated by the timely availability and usage of critical health parameters. Various sensors are extensively used to acquire and communicate the desired parameters. In the Present day’s scenario, sensors are configured with wired approach. Number of sensors is growing due to automation, increasing the accuracy of intended Aircraft functions. Sensors are distributed all over the Aircraft and they are connected through wired network for signal processing and communicating. LRU’s which are integrating various sensors also use wired approach for communication. The Key driver for Airline operational cost is fuel. Fuel quantity is a direct function of weight. Weight of cables contributes significantly to the overall weight of the aircraft. Use of wired network approach poses challenges in terms of cable routing, stray capacitances, noise and mechanical structure. This paper describes various merits and demerits of wired sensors and their interface techniques.
WIP Standard
2014-07-09
To provide cross reference between test methods across the fiber optics industry.
Standard
2014-07-07
This ARP provides insights on how to perform a cost benefit analysis (CBA) to determine the return on investment that would result from implementing an integrated Health Management (HM) system on an air vehicle. The word “integrated” refers to the combination or “roll up” of sub-systems health management tools to create a platform centric system. The document describes the complexity of features that can be considered in the analysis, the different tools and approaches for conducting a CBA and differentiates between military and commercial applications. This document is intended to help those who might not necessarily have a deep technical understanding or familiarity with HM systems but want to either quantify or understand the economic benefits (i.e., the value proposition) that a HM system could provide. Prognostics is a capability within some HM systems that provides an estimation of remaining useful life (RUL) or time to failure and so Prognostic Health Management (PHM) is used where this predictive element exists.
Standard
2014-07-01
This SAE Aerospace Recommended Practice (ARP) is an application guide for fixed and variable displacement hydraulic motors. It provides details of the characteristics of fixed and variable displacement hydraulic motors, architectures, circuit designs, controls, and typical applications. The applications include airborne and defense vehicles with emphasis on high performance applications.
Magazine
2014-07-01
Global Viewpoints The latest strategies are investigated for vehicle development by automakers and major suppliers. Sports cars embrace array of green technology IMSA Tudor United SportsCar Championship promotes a variety of green technologies to link racing to the road. More gears, more challenges Many strategies, as well as key software and hardware aspects related to controllers, networks, sensors, and actuators, must be considered to keep automatic transmissions shifting smoothly as more gears are added to improve fuel economy. Advancing structural composites Industry experts address the opportunities and challenges involved with moving toward composite-intensive vehicles, including Nissan's effort to produce a high-volume, fully recyclable composite liftgate with low metal content.
Magazine
2014-06-05
Watching for ways to stand above the crowd Sensors monitor a broad range of parameters to help powertrain design teams add features and improve performance.
WIP Standard
2014-05-27
No scope available.
Technical Paper
2014-05-09
John O. Manyala, Todd W. Fritz
Electro-hydraulic actuated systems are widely used in industrial applications due to high torque density, higher speeds and wide bandwidth operation. However, the complexities and the parametric uncertainties of the hydraulic actuated systems pose challenges in establishing analytical mathematical models. Unlike electro-mechanical and pneumatic systems, the nonlinear dynamics due to dead band, hysteresis, nonlinear pressure flow relations, leakages and friction affects the pressure sensitivity and flow gain by altering the system's transient response, which can introduce asymmetric oscillatory behavior and a lag in the system response. The parametric uncertainties make it imperative to have condition monitoring with in-built diagnostics capability. Timely faults detection and isolation can help mitigate catastrophic failures. This paper presents a signal-based fault diagnostic scheme for a gearbox hydraulic actuator leakage detection using the wavelet transform. The novelty of the work is the development of a high fidelity leakage fault detection as low as 0.128 lit/min.
Standard
2014-04-24
This SAE Aerospace Recommended Practice (ARP) establishes software capability guidelines for computer controlled test equipment, hereinafter referred to as automatic test equipment (ATE), for testing hydraulic components. A typical ATE system is shown. The items herein have been selected as potential features which may or may not be applicable to a particular application. This document does not address software development requirements, qualification procedures, or hardware design requirements, but encourages users to refer to existing documents for guidance on such issues.
WIP Standard
2014-04-23
Generate an accompanying document to AS-6129 to define the verification method and criteria for all the requirements contained in AS-6129.
WIP Standard
2014-04-22
This SAE Aerospace Standard (AS) defines the editorial format and policies necessary for the publication of platform/subsystem Interface Control documents. The Common Interface Control Document Format Standard defines a common format for platform to subsystem interface documents to facilitate subsystem integration. This aerospace standard specifies the common technical data sections for the Common Interface Control Document Format down to the third header level for the majority of sub-sections. The Common Interface Control Document Format Aerospace Standard provides a structured document format in appendixes supported by example paragraphs, drawings, etc.
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