Development of a Low-cost Hardware-in-the-loop Simulation System as a Test Bench for Anti-lock Braking System

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.

MULTIPLE ELECTRONIC CONTROL UNITS CALIBRATION SYSTEM BASED ON EXPLICIT CALIBRATION PROTOCOL AND J1939 PROTOCOL

The rising number of electronic control units （ECUs） in vehicles and the decreasing time to market have led to the need for advanced methods of calibration. A multi-ECU calibration system was developed based on the explicit calibration protocol （XCP） and J1939 communication protocol to satisfy the need of calibrating multiple ECUs simultaneously. The messages in the controller area network （CAN） are defined in the J1939 protocol. Each CAN node can get its own calibration messages and information from other ECUs, and block other messages by qualifying the CAN messages with priority, source or destination address. The data field of the calibration message is designed with the XCP, with CAN acting as the transport layer. The calibration sessions are setup with the event-triggered XCP driver in the master node and the responding XCP driver in the slave nodes. Mirroring calibration variables from ROM to RAM enables the user to calibrate ECUs online. The application example shows that the multi-ECU calibration system can calibrate multiple ECUs simultaneously, and the main program can also accomplish its calculation and send commands to the actuators in time. By the multi-ECU calibration system, the calibration effort and time can be reduced and the variables in ECU can get a better match with the variables of other ECUs.

Hardware-in-the-Loop Research on the Electronic Control Unit for Diesel Engines

A hardware-in-the-loop simulating platform is developed to avoid designing defects caused by the complicated logical structure and multiple-functional buildup of the dectronic control unit（ECU）in modem diesel engines, and to diminish potential damages on components or human exposure to dangers in R＆D en- deavor. This plat-form consists of a computer installed with software Matlab/Simulink/RTW and dSPACE/ ControlDesk; a diesel engine ECU, and a dSPACE autobox which runs a real-time diesel engine model. A typical model of diesel engine with turbocharger and intercooler is presented. Based on this model our research is carried out with a real ECU to test its software control strategies. Results show that by using the diesel engine model downloaded inside, the hardware-in-the-loop platform can simulate diesel engine＇s working conditions and generate all kinds of sensor signals which ECU needs on a real-time basis. So the ECU control strategies can be validated and relevant parameters roughly calibrated.

APPLICATION OF CIRCUIT SIMULATION IN HARDWARE DESIGN FOR ELECTRONIC CONTROL HIGH PRESSURE COMMON-RAIL FUEL SYSTEM OF DIESEL ENGINE

By means of circuit simulation, hardware of electronic control unit （ECU） of high pressure common-rail electronic control fuel system for diesel engine is designed. According to the system requirements for hardware of ECU, signal-processing circuit of variable reluctance （VR） sensor, filter circuit for input signal, high voltage power circuit and driver and protection circuit of solenoid are simulated as emphases. Difficulties of wide scope of VR sensor output signal, efficiency of high voltage power and reliable and swift driver of solenoid are solved. The results of simulation show that the hardware meets the requirement of the fuel system. At the same time, circuit simulation can greatly increase quality of the design, alleviate design labor and shorten design time.

STRATEGY FOR DIESEL ROTARY ENGINE WITH COMMON RAIL INJECTION SYSTEM

A direct injection low compression ratios diesel rotary engine is designed and studied to find the appropriate application of the electronic controlled high pressure common rail injection system. Current development focuses on the applied fuel injection and ignition strategies, especially concerning the combustion configurations of injectors, ignition source, and combustion chamber. The prototype engine, equipped with Bosch common rail system and high performance electronic control unit （ECU）, is designed correspondingly. Studies show that the integration of a common rail injection system and the main and pilot duel injectors configurations, assisted with glow plug ignition device and flexible ECU, represents a promising approach to improve the potential of the low compression ratios diesel rotary engine. Currently the engine can run at 6 kr · min^-1 steadily and the power is about 68 kW/（4 kr ·min^- 1）.

Development of CAN-Based Distributed Control System for Variable Rate Technology in Agricultural Machinery

The number of electronic devices connected to agricultural machinery is increasing to support new agricultural practices tasks related to the Precision Agriculture such as spatial variability mapping and Variable Rate Technology （VRT）. The Distributed Control System （DCS） is a suitable solution for decentralization of the data acquisition system and the Controller Area Network （CAN） is the major trend among the embedded communications protocols for agricultural machinery and vehicles. The application of soil correctives is a typical problem in Brazil. The efficiency of this correction process is highly dependent of the inputs way at soil and the occurrence of errors affects directly the agricultural yield. To handle this problem, this paper presents the development of a CAN-based distributed control system for a VRT system of soil corrective in agricultural machinery. The VRT system is composed by a tractor-implement that applies a desired rate of inputs according to the georeferenced prescription map of the farm field to support PA （Precision Agriculture）. The performance evaluation of the CAN-based VRT system was done by experimental tests and analyzing the CAN messages transmitted in the operation of the entire system. The results of the control error according to the necessity of agricultural application allow conclude that the developed VRT system is suitable for the agricultural productions reaching an acceptable response time and application error. The CAN-Based DCS solution applied in the VRT system reduced the complexity of the control system, easing the installation and maintenance. The use of VRT system allowed applying only the required inputs, increasing the efficiency operation and minimizing the environmental impact.

Advanced ECU Software Development Method for Fuel Cell Systems

The electronic control unit （ECU） in electrical powered hybrid and fuel cell vehicles is exceedingly complex. Rapid prototyping control is used to reduce development time and eliminate errors during software development. This paper describes a high-efficiency development method and a flexible tool chain suitable for various applications in automotive engineering. The control algorithm can be deployed directly from a Matlab/Simulink/Stateflow environment into the ECU hardware together with an OSEK real-time operating system （RTOS）. The system has been successfully used to develop a 20-kW fuel cell system ECU based on a Motorola PowerPC 555 （MPC555） microcontroller. The total software development time is greatly reduced and the code quality and reliability are greatly enhanced.

Efficient controller area network data compression for automobile apphcations

Controller area networks （CANs） have been designed for multiplexing communication between electronic control units （ECUs） in vehicles and many high-level industrial control applications. When a CAN bus is overloaded by a large number of ECUs connected to it, both the waiting time and the error probability of the data transmission are increased. Thus, it is desirable to reduce the CAN frame length, since the duration of data transmission is proportional to the frame length. In this paper, we present a CAN message compression method to reduce the CAN frame length. Experimental results indicate that CAN transmission data can be compressed by up to 81.06% with the proposed method. By using an embedded test board, we show that 64-bit engine management system （EMS） CAN data compression can be performed within 0.16 ms; consequently, the proposed algorithm can be successfully used in automobile applications.

Development of port fuel injected methanol(M85)-fuelled two-wheeler for sustainable transport

Due to increasingly stringent environmental pollution norms,there is a need for alternate combustion techniques and alternate fuels to keep up with changing trends.One of the viable solutions for India is the adaptation of methanol as a fuel for automotive sector.Therefore,in this study a functional two-wheeler prototype was developed,which uses M85(85%v/v methanol and 15%v/v gasoline)in an electronic control unit(ECU)controlled port fuel injected(PFI)engine.This study included comparative investigations of simulated on-road two-wheeler performance on chassis dynamometer using a gasoline-fuelled motorcycle with stock ECU vis-a-vis M85-fuelled motorcycle using recalibrated ECU.ECU recalibration exhibited that M85-fuelled vehicle was operated at relatively more advanced spark timing compared to baseline gasoline-fuelled vehicle.Performance results showed that M85-fuelled motorcycle produced relatively higher engine power and higher maximum vehicle speed compared to gasoline-fuelled motorcycle.Relatively superior acceleration characteristics(especially at higher speeds)of M85-fuelled motorcycle was another important finding of this study,indicating that M85 provided superior throttle response compared to gasoline.Comparative analysis of raw tailpipe emissions showed that modified M85-fuelled motorcycle emitted relatively higher hydrocarbon(HC),carbon monoxide(CO)and oxides of nitrogen(NO_x)emissions compared to stock gasoline-fuelled motorcycle.However,these emissions can be controlled by using adaptation of suitable after-treatment systems.