Applied Mechanics and Materials Online: 2011-10-24 ISSN: 1662-7482, Vols. 128-129, pp 898-903 doi:10.4028/www.scientific.net/amm.128-129.898 2012 Trans Tech Publications, Switzerland Hardware-in-loop Electronic Throttle System Based On Simulink Ning Chen 1,a,Pinchang Zhu 1,b 1 Zhejiang Institute of Mechanical & Electrical Engineering, Zhejing, Hangzhou, 310053 a frank_chan@139.com, b zhupinchang@126.com KeyWords: Electronic throttle, Simulink, Hardware-in-loop. Abstract: The structure and the principle of the electronic throttle control system(etcs) is elaborated. The electronic throttle(et) control model is built based on Matlab/Simulink, and the hardware-in-loop simulation on the ET model is processed. The result shows that the hardware-in-loop electronic throttle system have significant means on the automotive electronic teaching and design. Introduction The electronic control technology is widely used on automobile due to the problems of energy saving, environment protection and vehicle safety. And the automobile electronization marks the auto industrialization level of a country. China has already been the world's largest auto production and marketing kingdom since 2009. At the same time some proven techniques is introduced according to our country and the world famous auto factory's cooperation. However, because of the relatively backward industrial base, there is still a big gap in the automobile electronic technology development level compared with the developed countries. Therefore, it is necessary for us to focus on the automobile electronic technology research so as to transcend the advanced world level. For the traditional design method for the automobile electronic system, the computer algorithm is designed firstly, and the corresponding hardware assembly experiment is made afterwards. For this method, the design cycle is long, research and development is costly and the test is difficult. Considering the defects above, the hardware-in-the-loop simulation of automotive electronic control system design method is proposed which could be expressed in Figure 1. By using the hardware-in-the-loop simulation, it can be directly access the system and the control algorithm could be designed and validated. After the product design is finalized, it could be directly produced by just modify hardware and software of the system which would lead to more excellent products in relative short research time. Figure 1. The hardware-in-the-loop simulation design method All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, www.ttp.net. (#69814275, Pennsylvania State University, University Park, USA-18/09/16,14:11:15)
Applied Mechanics and Materials Vols. 128-129 899 1. ETCS composition and principle Throttle is an important control component for the engine. In order to improve the automobile dynamic property, ride, and reduce exhaust emission, the world's big carmakers introduced kinds of ETs and corresponding systems which have good control characteristic. The ETCS could precisely control the valve opening, this could not only improve fuel economy and reducing emissions but also obtain the satisfactory quick response and the control performance. On the other hand, the integration of the idle speed control, the cruise control and the vehicle stability control could be realized, and the system architecture is simplified. The ETCS consists of accelerator pedal position sensor, the ET body and the control unit which can be shown in figure 2. The accelerator pedal position sensor collects the pedal position signal which could reflect the driver s intention; the ET body is composed of the throttle positioning motor, the throttle position sensor, the throttle driver device and etc, which is the executive actuator for the throttle valve; The control unit makes the instructions for the throttle opening based on the working condition of the engine. Figure 2. ETCS composition When the driver controls the accelerator pedal, the position sensor produces certain voltage signal which would input throttle control unit. The signal is filtered at first for eliminating environmental noise, and then the basic demand of engine torque is calculated according to the current work pattern and the pedal mobile amount for analyzing driver s intention, later the basic expectation for the corresponding throttle Angle is obtained. Various sensor signals such as the engine speed, the gear position, the throttle position, the AC energy consumption are communicated with the throttle control unit with CAN bus which could calculate all the vehicle s torque demand. The best opening throttle would be obtained by compensating the throttle angle opening. After the drive circuit module receives the voltage signal, the best throttle opening position is achieved by control the throttle driver device. The throttle open degree signal feedbacks to throttle control unit and forms the closed loop. The electronic throttle control system diagram is shown in figure 3. Figure 3. The electronic throttle control system diagram The ET control strategy is mainly based on the engine torque requirements. However, it could also be used for the purpose of demand expansions for various aspects such as the acceleration slip regulation (ASR), the cruise control system (CCS), the idle speed control (ISC), the gear shifting control, the altitude compensation, etc.
900 Measuring Technology and Mechatronics Automation IV 2. The hardware-in-the-loop model The 9S12 microcontroller from the Feescale is chosen as the ET s ECU. All the input/output devices and control object is connected. The electronic throttle control algorithm is generated and downloaded to the 9S12 microcontroller by using the 9S12toolbox real-time hardware interface library. Then the ET hardware-in-the-loop simulation can be quickly realized. The ET hardware-in-the-loop model is shown in Figure 4. The A to D Converter Channel 1 is the signal from the accelerator pedal position sensor1 which is the system input signal; The A to D Converter Channel 0 is the signal from the Throttle position sensor1 which is the system feedback signal; The A to D Converter Channel 3 is the AC switch signal; The A to D Converter Channel 2 is the signal from the accelerator pedal position sensor2; the PWM-A is the signal from the No 1 position of the throttle positioning motor and the PWM-B is the signal from the No 2 position of the throttle positioning motor. Figure 4. The ET hardware-in-the-loop model 3. Control algorithm and debugging The ETCS adopts PID control method. The proportion(p), the integration(i)and the differentiation(d) is constituted as the control value by linear combination. The PID control system diagram is shown in Figure 5. Figure 5. The PID control system diagram Control deviation e(t) is defined as: e(t) = r(t) - y(t) (1)
Applied Mechanics and Materials Vols. 128-129 901 The PID control low is defined as: (2) Where, K p is the radio, T i is the integral time constant, and T d is the differential time constant. The K p reflect deviation proportion of the e(t) in the control system. The control system aims to minimize the system deviation. T i is mainly used to eliminate the static difference. Integral effect grade depends on the integral time constant T i. The bigger the T i is, the weaker the integral role is on the whole. It's the same in reverse. T d reacts the deviation trend of the signal, and introduce a modified signal in order to speed up the system action speed and reduce the system adjust cycle before the signal deviation changes too much. After elaborate debugging in Simulink, we established the simulation model for the ETCS system on the basis of PID control method. The ETCS PID control model is shown in Figure 6. Figure 6. The ETCS PID control model Transfer function determines that the system simulation is successful or not. Establishing the transfer function of electronic throttle needs to do a lot of assumptions, deductions, analysis and experiment. Relevant documents are used to fix its transfer function as follows: 4. Conclusion Using the hardware-in-the-loop simulation technology, the ET hardware-in-the-loop model is designed which is shown in Figure 4. Transfer function does not need to be considered because the controlled object (electronic throttle body) just in this system circuits. The controller which is designed with Simulink directly controls the ET body, thus the actual control effect could be (3)
902 Measuring Technology and Mechatronics Automation IV observed such as throttle sluggish and vibration phenomenon. If the control effect is not satisfied, the structure and the parameters of the controller could be adjusted until the prospective control effect is achieved. The figure 7 is the PID controller parameter adjustment interface, and the figure 8 is the system s actual response for the step signal when a group of control parameters is inputted. Figure 7. The PID controller parameter adjustment interface Figure 8. The system s actual response for certain step signal The controller which is debugged well could be considered to a actual controller prototypes. If the control effect is satisfied, embedded controller could be produced after certain modifications are made and the generated code can also be used directly. The ET controller development cycle could be greatly shorten and finally the controller s design is finalized. Practice shows that the hardware-in-the-loop simulation can improve efficiency and reduce the cost for the automotive electronic control system design. Also it can be introduced into the automobile electronic teaching, which has high application value for raising the high-skill person for the automotive electronic control system design Foundation item : Technology projects of education department, Zhejiang province(no. Y201018374)
Applied Mechanics and Materials Vols. 128-129 903 Brief introduction of authors: 1 Ning Chen(1974-),male,han ethnic,birth in Hangzhou Zhejiang,Zhejiang Institute of Mechanical & Electrical Engineering senior engineer,master degree,major in the electronic technology research 2 Pinchang Zhu(1981-),male,han ethnic,birth in Yiwu Zhejiang,Zhejiang Institute of Mechanical & Electrical Engineering engineer,master degree,major in the electronic technology, CAD/CAE research References: [1]Wei Pan,Jinghui Gao, Yahu Zhou etc. Hardware-in-loop Automobile ABS System Based On MATLAB/SIMULINK.[J]. CONTROL & AUTOMATION,2003 Vol.19 (No.12) [2]Dingyu Xue, Yangquan Chen etc. simulation technology and application Based on MATLAB /SIMULINK System [M]. Tsinghua University press,1999. [3]Jinzhu Zhang, Yi Zhang,Yumin Han etc. Design and simulation of Automobile electronic throttle control system [J]. HEILONGJIANG INSTITUTE OF TECHNOLOGY Journal. 2006(No.20) [4] Aldo Sorniotti,Mauro Velardocchia.Hardware-in-the-loop(HIL)Testing of Electronic Stability Program Commercial Hydraulic Units and Implementation of New Control Strategies.SAE, 2004-Ol-2770. [5] Guangzhao Luo,Weiguo Liu,Ke Song et a1.dspace based Permanent Magnet Motor HIL simulation and test bench.ieee International Conference ON Industrial Technology.2008:1-4. [6] Mauri M,Dezza F C,Marchegiani G.Hardware in the Loop(HIL)test bench for smal l scale Di stributed Generat ion systems.ieee International Symposium on Industrial Electronics,2008: 2177 2182.