Browse Topic: X-by-wire
ABSTRACT GS Engineering has developed technology to advance the sensory perception of autonomous systems. The Automatic Terrain Detection System (ATDS) is a technology that provides real time terrain detection. Vehicles deployed with ATDS have been able to yield improved mobility, automation of systems, and reduced fuel consumption. ATDS has been integrated into the MK23 MTVR, M1151 HMMWV for the ONR Predictive Adaptive Mobility (PAM) program, and into the Autonomous Ground Re-supply (AGR) by-wire kit for the Oshkosh Defense Palletized Load System (PLS). The ATDS is built upon proven sensors running integrated processing to replace or enhance existing vehicle systems. Citation: D. Subert, A. Diepen, K. Hubert, “Automatic Terrain Detection”, In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 13-15, 2019
The automotive PowerNet is in the middle of a major transformation. The main drivers are steadily increasing power demand, availability requirements, and complexity and cost. These factors result in a wide variety of possible future PowerNet topologies. The increasing power demand is, among other factors, caused by the progressive electrification of formerly mechanical components and a constantly increasing number of comfort and safety loads. This leads to a steady increase in installed electrical power. X-by-wire systems1 and autonomous driving functions result in higher availability requirements. As a result, the power supply of all safety-critical loads must always be kept sufficiently stable. To reduce costs and increase reliability, the car manufacturers aim to reduce the complexity of the PowerNet system, including the wiring harness and the controller network. The wiring harness e.g., is currently one of the most expensive parts of modern cars. These challenges are met with a
In an embedded world gone SOSA sensational, one might believe that centralized ATR-style OpenVPX systems are the best way to architect your next rugged system. While these chassis are routinely and successfully deployed on airborne, shipboard, and vetronics platforms, they are big, heavy, costly, and a real challenge to cool and connect. An alternate but equivalent rugged, deployable approach uses one or more small form factor chassis modules, distributed into any available space in the vehicle, interconnected via Apple® and Intel's® 40Gbps Thunderbolt™ 4, a commercial open standard that uses USB Type-C connectors with a single, thin bi-directional copper or fiber cable. With 4, 8, even 16 3U or 6U LRU (line replacement unit) boards inside an ATR chassis, 600 watts is on the low end of systems that can push well over 2,000 watts in a 200 square inch footprint or less. Assuming one can find the space for such a chassis in the vehicle or platform, there's also the issue of cooling it
If you accept that the oddball and odd-sized Journey never was a legit rival for the likes of the Honda CR-V, Toyota RAV4 and Ford Escape - and it wasn't - Stellantis' Dodge brand hasn't played in the compact SUV segment, one of the largest and most competitive in the U.S. That strategic gap is set to be filled by the 2023 Hornet, Dodge's performance-slanted attempt to peel out some sales volume from among the C-segment utilities that are typified by mundane and softly-tuned top-sellers. The Hornet's not just about having a little more engine power, either. Its platform is shared with the Alfa Romeo Tonale. Like Hornet, the Tonale slated to be in showrooms sometime in spring 2023 and incorporates chassis finery such as standard Koni-supplied Frequency Selective Damping (FSD) dampers. Specifically tuned, genuine by-wire braking (for the R/T trim) reduces curb weight by 9 lb. (4 kg) and improves steering feel via direct-action ratios from the electronic power steering; Stellantis claimed
Classic vehicle production had limitations in bringing the driving commands to the actuators for vehicle motion (engine, steering and braking). Steering columns, hydraulic tubes or steel cables needed to be placed between the driver and actuator. Change began with the introduction of e-gas systems. Mechanical cables were replaced by thin, electric signal wires. The technical solutions and legal standardizations for addressing the steering and braking systems, were not defined at this time. Today, OEMs are starting E/E-Architecture transformations for manifold reasons and now have the chance to remove the long hydraulic tubes for braking and the solid metal columns used for steering. X-by-wire is the way forward and allows for higher Autonomous Driving (AD) levels for automated driving vehicles. This offers new opportunities to design the vehicle in-cabin space. This paper will start with the introduction of x-by-wire technologies. It will cover the three aspects of the transformation
This document gives specific and measurable design requirements to be applied at a design review prior to tooling. The specification is formatted as a checklist to aid in its use. The requirements do not apply in all situations so engineering judgment must be used. This is a specification for design; applicable performance specifications (USCAR-2, etc.) must still be performed. Specific requirements in this document are grouped by component using a prefix as shown in Table 1 and are numbered by an item number following the prefix
This SAE standard establishes the minimum construction and performance requirements for a combination cable consisting of 11 conductors and two twisted pairs for use on trucks, trailers, and dollies for 12 VDC nominal applications in conjunction with SAE J2691 (15 pole connectors.) The cable includes both power and unjacketed SAE J1939-15 paired signal circuits along with dual ground wires to accommodate grounding requirements within the constraints of the SAE J2691 terminal capacity
As a new form of electric vehicle, Four-wheel-independent electric vehicle with X-By-Wire (XBW) inherits all the advantages of in-wheel motor drive electric vehicles. The vehicle steering system is liberated from traditional mechanical steering mechanism and forms an advanced vehicle with all- wheel independent driving, braking and steering. Compared with conventional vehicles, it has more controllable degrees of freedom. The design of the integrated vehicle dynamics control systems helps to achieve the steering, driving and braking coordinated control and improves the vehicle's handling stability. In order to solve the problem of lacking of vehicle state information in the integrated control, some methods are used to estimate the vehicle state of four-wheel-independent electric vehicles with XBW. In order to improve the estimation accuracy, unscented Kalman filter (UKF) is used to estimate the vehicle state variables in this paper. At the same time, simulations in several typical
Thin, segmented mirrors have been fabricated from monocrystalline silicon blocks. The material is economically viable, and is virtually free of internal stress because of its nearly perfect crystalline structure. The mirror surfaces will first be accurately figured and finished on thick silicon blocks, then sliced off at the desired thickness by wire electro-discharge machining. A finishing process has been conceived in which existing mirror-finishing processes are adapted to be capable of quickly and accurately figuring and finishing damage-free, segmented, monocrystalline silicon mirrors in a cost-efficient manner
Four-wheel independent control electric vehicle is a new type of x-by-wire EV with four wheels independent steering and four wheels independent drive/brake systems. In order to take full advantage of the vehicle's performance potential, this paper presents a novel integrated chassis control strategy. In the paper, the strategy is designed by the hierarchical control structure and divided into integrated control layer and allocation layer. By this method, the control logical can be modularized and simplified. In the integrated control layer, Model Prediction Control (MPC) is adopted to design the integrated control unit, which belongs to be a kind of local optimization algorithm with feedback correction features. Using this method could avoid the system performance degradation caused by the control model mismatch. The control allocation layer is to optimally distribute the vehicle control forces to the steering/driving/brake actuators on each wheel. In order to maximize the use of the
This paper proposed a novel fault-tolerant control method based on control allocation via dynamic constrained optimization for electric vehicles with XBW systems. The total vehicle control command is first derived based on interpretation on driver's intention as a set of desired vehicle body forces, which is further dynamically distributed to the control command of each actuator among vehicle four corners. A dynamic constrained optimization method is proposed with the cost function set to be a linear combination of multiple control objectives, such that the control allocation problem is transformed into a linear programming formulation. An analytical yet explicit solution is then derived, which not only provides a systematic approach in handling the actuation faults, but also is efficient and real-time feasible for in-vehicle implementation. The simulation results show that the proposed method is valid and effective in maintaining vehicle operation as expected even with faults
The automotive industry is replacing more and more hydraulic systems by electronic system. This not only reduces the weight of vehicles, but also has the potential for a large number of new features [1]. Such a change has led to researches on XbW(X-by-Wire) without the existing mechanical connection and hydraulic system, among which the study on BbW(Brake-by-Wire) in relation to brake devices proceeded to the point of EHB(Electro-Hydraulic-Brake) and then EMB(Electro-Mechanical-Brake). In replacement of existing CBS(Conventional Brake System) with EMB, various advantages such as improvement of response performance and easy combination with various brake applications including ABS and ESC have been found. In fact, however, the problem of fail-safe has remained. This study, therefore, is to develop the control strategy with which the vehicle's longitudinal and lateral motion can follow the driver's steering intention upon failure of one EMB actuator for braking in straight and corner. To
This SAE Aerospace Information Report (AIR) discusses the terminology, types, method of manufacture and chemistry of the fine wire meshes used for filtration of hydraulic, lubrication fuel systems, and similar applications. Information contained herein may be used for quality assurance testing to insure that a high performance filter grade wire mesh is acceptable for use in an aerospace application
ISO 26262 is the actual standard for Functional Safety of automotive E/E (Electric/Electronic) systems. One of the challenges in the application of the standard is the distribution of safety related activities among the participants in the supply chain. In this paper, the concept of a Safety Element out of Context (SEooC) development will be analyzed showing its current problematic aspects and difficulties in implementing such an approach in a concrete typical automotive development flow with different participants (e.g. from OEM, tier 1 to semiconductor supplier) in the supply chain. The discussed aspects focus on the functional safety requirements of generic hardware and software development across the supply chain where the final integration of the developed element is not known at design time and therefore an assumption based mechanism shall be used. The inherent ambiguity deriving from such assumption based distribution of requirements also makes the responsibility allocation on
The automotive system domain are in increasing motivation with benefits by using the x-by-wire technologies, which employ new electronic devices to provide for automobile system more facilities during processes at development, production, usability and maintenance. Considering at automobile user domain point of view, the next generation of automobiles can give users more comfort, safety and flexibility. However, for the safety critical applications at automobiles have as requirements the use of distributed embedded systems and fault tolerance methodologies where in communication infrastructure need to offer fault-tolerance communication services. Several researches regards fault tolerance communication systems for automotive domain are now in progress and a strong convergence in use of the Flexray technology is noted for the automotive community. The Flexray is one of the communication systems that had been proposed and available at AUTOSAR standard. Flexray is a communication system
This paper is an overview of the current state (calendar year 2010) of in-vehicle multiplexing and what pertinent technologies are emerging. Usage and trends of in-vehicle networking protocols will be presented and categorized. The past few years have seen a large growth in the number and type of communication buses used in automobiles, trucks, construction equipment, and military, among others. Development continues even into boating and recreation vehicles. Areas for discussion will include SAE Class A, B, C, Diagnostics, SafetyBus, Mobile Media, Wireless, and X-by-Wire. All existing mainstream vehicular multiplex protocols (approximately 40) are categorized using the SAE convention as well as categories previously proposed by this author. Top contenders will be pointed out along with a discussion of the protocol in the best position to become the industry standard in each category
Future automobiles are required to support an increasing number of complex, distributed functions such as active safety and X-by-wire. Because of safety concerns and the need to deliver correct designs in a short time, system properties should be verified in advance on function models, by simulation or model checking. To ensure that the properties still hold for the final deployed system, the implementation of the models into tasks and communication messages should preserve properties of the model, or in general, its semantics. FlexRay offers the possibility of deterministic communication and can be used to define distributed implementations that are provably equivalent to synchronous reactive models like those created from Simulink. However, the low level communication layers and the FlexRay schedule must be carefully designed to ensure the preservation of communication flows and functional outputs. In this paper, we provide a discussion and an analysis of the aforementioned issues
This SAE Recommended Practice establishes limits for electrical circuits on motor vehicle safety glazing materials
This paper shows a realisation approach for functional safety considerations for X-by-Wire vehicles. The E/E architecture has been built up as a redundant highly-safety-critical multiapplication platform with access to all sensors and actuators (so called satellites) ensuring different safety integrity levels besides reliability. Such it will be possible to develop high-level control functions (HCFs) independently of the overall vehicle E/E architecture, redundancy and even data-flow. This means that herein an approach is shown of how to split the responsibility of safety and the development of intelligent vehicle control-functionality. The feasibility has been shown within the EC-funded project SPARC (www.sparc-eu.net). The paper focuses on the identification of functions being implemented in software to ensure safety. The detailed design of the mechanisms themselves will not be part of this paper
Balancing between dependability and cost-effectiveness is essential to promote X-by-Wire systems in the next decade. To achieve this goal, we have so far proposed a network centric architecture based on a concept of autonomous decentralized systems, where if one node fails, the remaining normal nodes autonomously execute a backup control to maintain the system's functionality, as well as a membership middleware indispensable to this architecture to ensure the consistency of the node status information among all nodes. In this work, we implemented membership middleware on a hardware and software platform equivalent to one assumed to be used in actual X-by-Wire systems. This paper describes the implementation details and performance evaluation result, and shows that membership middleware and a real-time critical application can coexist within one microcontroller
Embedded computing systems have become widely used in many areas. Great part of those systems has time constraints which are characterized as real-time embedded system. In nowadays, distributed computing has reached the automotive market, where some fieldbuses are already being used as communication platform. Some researches have presented different approaches in the real-time embedded communication system domain aiming to cover the growing demands of performance, predictability and reliability of emerging applications. Such requirements involve low latency, reduced jitter, time composability, fault-tolerance and support for future extensions. Particularly in the automotive industry where is considering the possibility of replacing the major part of mechanical and/or hydraulic systems by electronic “by-wire” systems, the importance of ensuring predictable behavior while also presenting some degree of flexibility plays a key role. Regarding to the flexibility, the FTT (Flexible Time
This SAE standard establishes the minimum construction and performance requirements for seven conductor 1/8-2/10-4/12 cable for use on trucks, trailers and converter dollies. Where appropriate, the standard refers to two types of cables, (Type F and S, described later in the standard), due to the variation in the performance demands of cables used in flexing and stationary applications. While the document’s title refers to ABS Power to differentiate the document from the SAE J1067 standard that it supersedes, the scope applies to both the primary green cable for powering ABS and lighting and the yellow auxiliary cable of the same construction
This SAE standard establishes the minimum construction and performance requirements for seven conductor 1/8-1/10-5/12 cable for use on trucks, trailers and converter dollies. Where appropriate, the standard refers to two types of cables, (Type F and S, described later in the standard), due to the variation in the performance demands of cables used in flexing and stationary applications
X-by-Wire systems are expected to enhance vehicle driving performance and safety. Regarding the dependable and cost-effective electronic platform for X-by-Wire systems, we have so far proposed a network centric architecture based on a concept of autonomous decentralized systems. In this architecture, in case a certain node fails, the remaining normal nodes autonomously execute a backup control to maintain the system function. Following the concept proposal, in this study, we have designed the middleware for cluster node status monitoring because it is essential to identify the failed node accurately to execute the autonomous backup control. The middleware has been implemented on the FlexRay-based prototype brake-by-wire system. This paper describes the features of the middleware indispensable to the network centric X-by-Wire systems
In this paper, the design and construction of a prototype Steer-by-Wire vehicle is described. The prototype vehicle has been built with fault tolerant X-by-Wire systems using a time triggered architecture. The Steer-by-Wire system consists of an electric rack actuator and electric feedback actuator. One of the main issues in the development by-Wire systems is its electronics based nature and consequently the difficulty to test and verify to such an extent that the results are sufficiently convincing that the complete system is working properly. Attention was paid to the design process, which was based on the V-model. This model allows for a development approach which is traceable and verifiable to such an extent that its proper and safe working can be proven more easily
A promising technology for active safety is “X-by-Wire”, where mechanical and electromechanical components are replaced by electronic functions. One of the reasons for this is to have more than the driver input in the command chain, and also include some degree of intervention by the control system in case the driver behaviour is likely to put the car at risk. The adoption of a small number of computing nodes is a clear trend in vehicle design. A wide range of functions that are now distributed in the form of separate modules will instead be integrated. This approach will overcome the physical constraints of electrical and mechanical components and the costs of many separate electronic modules with their own power supplies. However this new arrangement can introduce hazards if the software contains flaws, the nature of these flaws comes in two types: omission (failing to adhere to a requirement) and commission (doing something that should not be done at all, not observing timeliness or
Automakers have been pushing harder for the development of a safety-critical bus for the past years since there are many advantages of x-by-wire systems including steer-by-wire, brake-by-wire and throttle-by-wire. Such systems allow automakers to eliminate heavy hydraulic actuators and they offer the possibility of creating smarter and more efficient components that can be connected to a network bus. However, automakers and vendors know that a reliable, fault-tolerant bus is needed for such applications. Controller Area Network (CAN) buses, which are commonly used for powertrain and other automotive controls, are not considered reliable enough for drive-by-wire. The problem with CAN is that it is only event-based, so there is always a possibility that a message won't get through. For important applications, time-triggered architectures are needed because as time goes on, a slot for important messages is always assigned. In this paper, the performance evaluations of CAN, TTP and
X-by-Wire systems are expected to enhance vehicle driving performance and safety. This paper describes an electronic platform architecture for X-by-Wire systems that satisfies both cost-effectiveness and dependability. In the first part of this paper (Part 1), we have proposed a new electronic architecture based on a concept of autonomous decentralized systems. In the latter part (Part 2), the proposed architecture implementation to the actual vehicle control systems will be discussed. We clarify that, due to system level redundancy the proposed architecture provides, vehicle control systems can basically consist of low cost fail-silent nodes. Furthermore, for cost optimization, considering a tradeoff between hardware cost and fault detection coverage, we design a suitable hardware architecture for each node according to node function
The X-By-Wire (XBW) is one of the promising technologies for integrated vehicle dynamics control system for the next-generation. The system, in view of ECU architecture, combines multiple ECUs by a high-speed. In this, however, the failure of one ECU leads to system-wide failure. To avoid it, all the ECUs have to be fault tolerant, which is not a realistic solution in terms of cost. We propose a concept for a cost-effective and fault tolerant vehicle control architecture for real-time and scalable X-by-Wire systems. The concept is based on the Autonomous Decentralized Systems [1][2]. The features of the proposed concept are a shared data-field, self-operation, self-check, and self-backup. The proposed architecture will realize a fault-tolerant system without making all the subsystems fault-tolerant
The objective of this paper is to propose a new reliability analysis method for X-by-Wire systems, which includes both dynamic performance and static redundancy of the system, X-by-wire systems must meet not only reliability but also real-time requirements. In this context, we propose an integrated approach for evaluating both the performance in presence of perturbations - the Behavioural Reliability - and the evaluation of reliability based on classical failure rates of the components - the Static Reliability - of X-by-Wire systems. A example of quantification is given to illustrate the proposed method
The key-enabler for tomorrow's X-by-wire systems is the mastery of today's advanced active chassis control systems that are highly safety critical, distributed and complex. The only feasible way is to compose future X-by- wire systems with established and field approved functional management, components and infrastructure technologies, which are addressed in this paper
Many fault-tolerant mechanisms have been proposed by software and hardware designers based on the communication protocol to ensure Steer-by-Wire system safety. The objective of this paper is to evaluate the impact of two fault-tolerance services mainly used for X-by-Wire systems, Fail-Silent Electronic Control Units and Membership Agreement, as to X-by-Wire system dependability. By creating a Failure Model adapted to X-by-Wire systems and fault tolerance properties, we give an analytical method which quantifies the impact of Fail Silent Property on the probability of an undesired event, and the impact of Membership Agreement on the probability of vehicle immobilization
In future cars, mechanical and hydraulic components will be replaced by new electronic systems (x-by-wire). A failure of such a system constitutes a safety hazard for the passengers as well as for the environment of the car. Thus electronics and in particular software are taking over more responsibility and safety-critical tasks. To minimize the risk of failure in such systems safety standards are applied for their development. The safety standard IEC 61508 has been established for automotive electronic systems. At the same time, automatic code generation is increasingly being used for automotive software development. This is to cope with today's increasing requirements concerning cost reduction and time needed for ECU development combined with growing complexity. However, automatic code generation is hardly ever used today for the development of safety-critical systems. Reasons for this are the specific requirements on the code as well as inadequate experience in the development of
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