Nowadays validation of anti-lock braking systems（ABS） relies mainly on a large amount of road tests.An alternative means with higher efficiency is employing the hardware-in-the-loop simulation（HILS） system to subs...Nowadays validation of anti-lock braking systems（ABS） relies mainly on a large amount of road tests.An alternative means with higher efficiency is employing the hardware-in-the-loop simulation（HILS） system to substitute part of road tests for designing,testing,and tuning electronic control units（ECUs） of ABS.Most HILS systems for ABS use expensive digital signal processor hardware and special purpose software,and some fail-safe functions with regard to wheel speeds cannot be evaluated since artificial wheel speed signals are usually provided.In this paper,a low-cost ABS HILS test bench is developed and used for validating the anti-lock braking performance and tuning control parameters of ABS controllers.Another important merit of the proposed test bench is that it can comprehensively evaluate the fail-safe functions with regard to wheel speed signals since real tone rings and sensors are integrated in the bench.A 5-DOF vehicle model with consideration of longitudinal load transfer is used to calculate tire forces,wheel speeds and vehicle speed.Each of the four real-time wheel speed signal generators consists of a servo motor plus a ring gear,which has sufficient dynamic response ability to emulate the rapid changes of the wheel speeds under strict braking conditions of very slippery roads.The simulation of braking tests under different road adhesion coefficients using the HILS test bench is run,and results show that it can evaluate the anti-lock braking performance of ABS and partly the fail-safe functions.This HILS system can also be used in such applications as durability test,benchmarking and comparison between different ECUs.The test bench developed not only has a relatively low cost,but also can be used to validate the wheel speed-related ECU design and all its fail-safe functions,and a rapid testing and proving platform with a high efficiency for research and development of the automotive ABS is therefore provided.展开更多
Graphic processing units （GPUs） have been widely recognized as cost-efficient co-processors with acceptable size, weight, and power consumption. However, adopting GPUs in real-time systems is still challenging, due ...Graphic processing units （GPUs） have been widely recognized as cost-efficient co-processors with acceptable size, weight, and power consumption. However, adopting GPUs in real-time systems is still challenging, due to the lack in framework for real-time analysis. In order to guarantee real-time requirements while maintaining system utilization ~in modern heterogeneous systems, such as multicore multi-GPU systems, a novel suspension-based k-exclusion real-time locking protocol and the associated suspension-aware schedulability analysis are proposed. The proposed protocol provides a synchronization framework that enables multiple GPUs to be efficiently integrated in multicore real-time systems. Comparative evaluations show that the proposed methods improve upon the existing work in terms of schedulability.展开更多
Based on the vehicle-road dynamic model, the road characteristic parameter, which depends on different types of road surfaces, is introduced and a new method of road surface identification for automotive anti-lock bra...Based on the vehicle-road dynamic model, the road characteristic parameter, which depends on different types of road surfaces, is introduced and a new method of road surface identification for automotive anti-lock braking system (ABS) is proposed. According to the characteristics of vehicle-road dynamic model, a simple math resolution method of the model's factors is established. Only using the information of wheel speed, the vehicle reference velocity and the wheel slip ratio are estimated real-timely. And based on the wheel dynamic model, the road characteristic parameter is determined to identify the road surface for the determination of thresholds of ABS regulative parameters. With this new method, the road surface identification can be accurately obtained and calculation time is short that it can meet the ABS real time control need, and it also improves the performance of ABS.展开更多
In this paper the authors present an analysis and the implementation of microprocessor-baseddigital phase-locked loop speed control system for an induction motor which is actuated by aSPWM-GTR inverter.The system is c...In this paper the authors present an analysis and the implementation of microprocessor-baseddigital phase-locked loop speed control system for an induction motor which is actuated by aSPWM-GTR inverter.The system is controlled by a 16-bit single chip microprocessor.A new type of frequency and phase detector is presented in detail,An adaptive method isadopted in speed controller.A three mode control scheme is used.These techniques are very use-ful to the improvement of the dynamic behavior of digital AC motor drive system.Experimental results show that the system is of good stability,high precision and good dynam-ic performance.展开更多
分布式锁是分布式存储系统的重要组件,锁协议的性能对系统整体的性能有关键性影响。远程直接内存访问(remote direct memory access,RDMA)是一种新兴的数据中心网络技术,它支持单边网络通信原语,可以降低系统CPU开销,同时具备低延迟、...分布式锁是分布式存储系统的重要组件,锁协议的性能对系统整体的性能有关键性影响。远程直接内存访问(remote direct memory access,RDMA)是一种新兴的数据中心网络技术,它支持单边网络通信原语,可以降低系统CPU开销,同时具备低延迟、高吞吐的性能特性,为设计高速分布式锁协议提供了新机遇。然而,设计基于RDMA的分布式锁协议面临诸多挑战。着重在保证高性能的前提下解决扩展性和公平性挑战,提出一种RDMA网络中的高性能分布式锁协议FeLock,它利用多种类型的RDMA网络通信原语,使客户端不仅能与服务端通信加解锁,还能与其他客户端直接通信以移交锁所有权,同时实现了高性能、公平性和性能的扩展性。具体地,为保证高性能,FeLock引入了节点粒度锁管理机制,缩减锁协议在关键路径上的网络往返次数。为实现扩展性,FeLock引入了轮转移交机制,将所有节点排成1个环,客户端按照其在环中的顺序依次移交锁的所有权。为实现公平性和避免客户端饥饿,FeLock引入了节点信用机制,限制节点连续加锁的次数,避免其他节点上的客户端无法加锁。实验显示,FeLock相比于现有单边RDMA锁协议(如DSLR)表现出相似或更高的性能,并且具有更好的公平性和扩展性。在3~120个客户端的环境下,FeLock的吞吐量是DSLR的1.01~7.51倍,公平性提升至多2.24倍。展开更多
基金supported by National Natural Science Foundation of China(Grant No.50908008)National Hi-tech Research and Development Program of China(863Program,Grant No.2009AA11Z216)
文摘Nowadays validation of anti-lock braking systems（ABS） relies mainly on a large amount of road tests.An alternative means with higher efficiency is employing the hardware-in-the-loop simulation（HILS） system to substitute part of road tests for designing,testing,and tuning electronic control units（ECUs） of ABS.Most HILS systems for ABS use expensive digital signal processor hardware and special purpose software,and some fail-safe functions with regard to wheel speeds cannot be evaluated since artificial wheel speed signals are usually provided.In this paper,a low-cost ABS HILS test bench is developed and used for validating the anti-lock braking performance and tuning control parameters of ABS controllers.Another important merit of the proposed test bench is that it can comprehensively evaluate the fail-safe functions with regard to wheel speed signals since real tone rings and sensors are integrated in the bench.A 5-DOF vehicle model with consideration of longitudinal load transfer is used to calculate tire forces,wheel speeds and vehicle speed.Each of the four real-time wheel speed signal generators consists of a servo motor plus a ring gear,which has sufficient dynamic response ability to emulate the rapid changes of the wheel speeds under strict braking conditions of very slippery roads.The simulation of braking tests under different road adhesion coefficients using the HILS test bench is run,and results show that it can evaluate the anti-lock braking performance of ABS and partly the fail-safe functions.This HILS system can also be used in such applications as durability test,benchmarking and comparison between different ECUs.The test bench developed not only has a relatively low cost,but also can be used to validate the wheel speed-related ECU design and all its fail-safe functions,and a rapid testing and proving platform with a high efficiency for research and development of the automotive ABS is therefore provided.
基金supported by the National Natural Science Foundation of China under Grant No.61003032/F020207
文摘Graphic processing units （GPUs） have been widely recognized as cost-efficient co-processors with acceptable size, weight, and power consumption. However, adopting GPUs in real-time systems is still challenging, due to the lack in framework for real-time analysis. In order to guarantee real-time requirements while maintaining system utilization ~in modern heterogeneous systems, such as multicore multi-GPU systems, a novel suspension-based k-exclusion real-time locking protocol and the associated suspension-aware schedulability analysis are proposed. The proposed protocol provides a synchronization framework that enables multiple GPUs to be efficiently integrated in multicore real-time systems. Comparative evaluations show that the proposed methods improve upon the existing work in terms of schedulability.
文摘Based on the vehicle-road dynamic model, the road characteristic parameter, which depends on different types of road surfaces, is introduced and a new method of road surface identification for automotive anti-lock braking system (ABS) is proposed. According to the characteristics of vehicle-road dynamic model, a simple math resolution method of the model's factors is established. Only using the information of wheel speed, the vehicle reference velocity and the wheel slip ratio are estimated real-timely. And based on the wheel dynamic model, the road characteristic parameter is determined to identify the road surface for the determination of thresholds of ABS regulative parameters. With this new method, the road surface identification can be accurately obtained and calculation time is short that it can meet the ABS real time control need, and it also improves the performance of ABS.
文摘In this paper the authors present an analysis and the implementation of microprocessor-baseddigital phase-locked loop speed control system for an induction motor which is actuated by aSPWM-GTR inverter.The system is controlled by a 16-bit single chip microprocessor.A new type of frequency and phase detector is presented in detail,An adaptive method isadopted in speed controller.A three mode control scheme is used.These techniques are very use-ful to the improvement of the dynamic behavior of digital AC motor drive system.Experimental results show that the system is of good stability,high precision and good dynam-ic performance.
文摘分布式锁是分布式存储系统的重要组件,锁协议的性能对系统整体的性能有关键性影响。远程直接内存访问(remote direct memory access,RDMA)是一种新兴的数据中心网络技术,它支持单边网络通信原语,可以降低系统CPU开销,同时具备低延迟、高吞吐的性能特性,为设计高速分布式锁协议提供了新机遇。然而,设计基于RDMA的分布式锁协议面临诸多挑战。着重在保证高性能的前提下解决扩展性和公平性挑战,提出一种RDMA网络中的高性能分布式锁协议FeLock,它利用多种类型的RDMA网络通信原语,使客户端不仅能与服务端通信加解锁,还能与其他客户端直接通信以移交锁所有权,同时实现了高性能、公平性和性能的扩展性。具体地,为保证高性能,FeLock引入了节点粒度锁管理机制,缩减锁协议在关键路径上的网络往返次数。为实现扩展性,FeLock引入了轮转移交机制,将所有节点排成1个环,客户端按照其在环中的顺序依次移交锁的所有权。为实现公平性和避免客户端饥饿,FeLock引入了节点信用机制,限制节点连续加锁的次数,避免其他节点上的客户端无法加锁。实验显示,FeLock相比于现有单边RDMA锁协议(如DSLR)表现出相似或更高的性能,并且具有更好的公平性和扩展性。在3~120个客户端的环境下,FeLock的吞吐量是DSLR的1.01~7.51倍,公平性提升至多2.24倍。
