英文外文文献

Applied Mechanics and Materials Vol. 109 (2012) pp 248-25Intelligent vehicle-mounted alcohol detection control systemKeywords: intelligent; alcohol detection; vehicle-mountedAbstract： The paper designed an intelligent vehicle-mounted alcohol detection control system, which is based on S3C2440 chip. The system tested the drivers response ability and eye-hand coordination in interactive way to determine whether the driver could control the vehicle. The system introduced psychology method innovatively. It can overcome the disadvantage of only depending on the gas alcohol concentration as the control basis, and enhance the applicability of the system.IntroductionDrink-driving has been a heavy topic, People hurts so much by traffic accident caused by drinking-driving and People takes various measures to curb drink driving phenomenon, There are some kinds of vehicle-mounted alcohol detection control system which are used to control drink-driving, those system use alcohol sensor which placed in the car detect the alcohol concentration and compare the alcohol concentration value with the set gas concentration value, then control the vehicle according to the result of comparison. They can reduce the drinking-driving behavior.But those system control the vehicle ignition by the gas alcohol content exist big disadvantage. Due to the difference physical condition of individual, the affection on people caused by alcohol is different. So the blood alcohol concentration (BAC) cannot fully reflect the impact of alcohol on peoples driving skills. Furthermore it is difficult to judge alcohol gas origin and measure the breath alcohol concentration (BrAC) accurately in the cars closed space with no surveillance.No matter how the alcohol sensor close to the driver, the gas which the sensor detected is still gas mixtures and BrAC cannot be detected accurately. Then the system control the car use the gas alcohol content exist big weakness. In addition those system cant distinguish the alcohol gas come from the drink driver from the alcohol gas come from copilot or other source of alcohol, Moreover those system unable to determine whether the driver want to coordinate with them.Based on the discussion upwards, a new intelligent vehicle-mounted alcohol detection control system is put forward in this paper. This system use the way of HumanComputer interaction and introduce the method of psychology. The method of psychology is used to test the drivers response ability and eye-hand coordination, then the system according the test result to control the vehicle, it overcome the weakness that using a gas alcohol concentration as reference points to control the vehicle. The system can perceive the inner environment by its sensors, and it will be more accurate and flexible to control drunk driving, and the test result shows that the system can work effectively.1 Hardware designThe figure 1 shows the Intelligent vehicle-mounted alcohol detection control system block diagram, the systems hardware mainly includes a process chip S3C2440,a large capacity memory, an alcohol sensor MQ-3，speed sensor, amplifier, A/D convertor. The process chip S3C2440 is developed with ARM920T core, 0.13m CMOS standard cells and a memory complier. Its low-power, simple, elegant and fully static design is particularly suitable for cost- and power-sensitive applications. It offers outstanding features with its CPU core, a 16/32-bit ARM920T RISC processor designed by advanced RISC machines, Ltd. The highest work frequency of the processor is 533 MHz and its address space reach 1 G. All kinds of interfaces and 8 channel 10bit A/D converter can satisfy the rapid response system and driving larger LCD screen. The MQ-3 sensor can be used range from alcohol content of gas 0.05mg/L to alcohol content of gas 10mg/L，and MQ-3 is sensitive to alcohol gas, selective and fast recovery, and the MQ-3 sensor is reliable, used with simple drive circuit. The system will use the MQ-3 alcohol sensors signal as a trigger signal, and then we can reduce the dependence of the system to the sensor. We just adjust two value of the sensor is accurate with the alcohol gas concentration, one is 0.0454mg/L correspond to BAC 10mg/100ml, the other is 0.3636mg/L correspond to 80mg/100ml, the former value used to exclude the uncertain value which is brought by the other gas. When the driver enters the vehicle the system detects the alcohol gas concentration. If the alcohol gas concentration is more than 0.0454mg/L, the system starts the test program. Which is used to determine whether the driver was drunk, when detecting alcohol gas concentration above 0.3636mg/L, the relay will be turn off and the system will watch the interfaces till the driver get out of the vehicle. The switch turns off when the driver set down, and turns on when the driver stand up. Speed sensor is used when the driver had drink and passes the test, the speed sensors signal feedback to the system. Relay and speed control circuit carry out the systems control signal. Touch-screen display message, provide interface for interaction with the driver. Electric fan accelerate air flow, it is helpful for the rapid detection of alcohol sensor. 2 Systems working principleNormally, the driver gets in vehicle without drink, so this system designed to ensure rapid response capability as short as possible. When the driver opens the door from outside, the system act from standby into operation, heat alcohol sensor, start electric fan, disconnect the relay and lock vehicles. When driver open the vehicles door, the switch under the seat is off, the system will consider the driver is getting into the vehicle, when the switch is on, and vehicles door closed, it will be considered as the driver has entered the vehicle. When the door lock is closed, and the switch is on, the system will consider the driver is leaving the vehicle, the driver left seat, the switch turns off, and the vehicles door closed, then the system consider the driving leave the vehicle. Figure 2 is the work process of the system. When the driver entered the vehicle, the system wait for start the test program.3 Test program3.1 Design of test program Test program is the core of the system, its working principle was shown in Figure 3. When the system starts the test program, the voice prompts the driver not to drive after drinking and requires drivers to blow to the sensor. The system will compare the detected gas concentration of alcohol with the drivers alcohol gas concentration. If the former is lower than the latter, it indicates the driver didnt drink, the system closes the relay, the vehicle can start, then the system goes into standby state. If the former is not lower than the latter, it is considered to be the driver drinking, and then the system determine whether the alcohol concentration is more than alcohol concentration of gas of intoxication state, if more, the vehicle is not allowed to start. Only in the first case, the drivers response ability and eye-hand coordination are tested. Systems test methods borrow the ideas from methods to the responsiveness testing and hand-eye coordination tests in psychology.3.2 The implication to humans physical and psychological testingIt is shown that blood alcohol concentration has a direct impact on the drivers operation ability after researches. Testing to peoples physical and psychological in the enforcement process, mainly are in the following six ways: balance testing, pupil inspection, finger-nose testing, walking and turning writing and speaking tests and picking up coins experimental testing. These methods have the disadvantage of low accuracy, the lack of evidence and other reasons so that is not easy to use in law enforcement. But using the interaction testing of human physiological and psychological in the vehicle control method, and exert psychological impact can be applied to achieve better results.3.3 Test program executionSystem uses a touch-screen, which greatly facilitates the design of the system interface. When the system starts the testing program, first tests the response capabilities and hand-eye coordination, where imitate a sudden change of environment for the driver to react. when the Start is pressed, the program delayed a little time(limited to one second), change the screen background color, after changing start timing immediately, when the end is pressed, its the time to get the results as to determine whether the driver can drive. Normal response time is between 150ms and 400ms. The longer reaction time, the more dangerous driving, the system response time threshold will be limited to 500ms, if more than 500ms, the vehicle will be locked until the driver left. And then the system exit the test program, reset back to standby. If not more than system response time threshold, the system will test drivers ability as well as drivers reactions and hand-eye coordination, when the Start is pressed, three-color lights begin cycling, when light stops flashing cycle, the system starts timing. The system calculates the ending number based on the green light location, press the left once, middle twice, and three times the far right. When the end is pressed, the correct number of time is over. When the time results under limit and the pressing number are correct, the drivers can drive. It is assume that the number of need to press is n, the time interval the of press the button twice is x, the system sets correcting pressing time threshold is (500 + nx) ms. When x means 200ms, If testing time is more than (500ms + n * 200ms), the vehicle will be locked. The system will prompt the driver that the vehicle is locked. If the two tests are finished under a limited period of time, the system will prompt the driver that the highest speed has been limited. Until the driver left the vehicle, the system exits the test program, resets back to standby model.3.4 ConclusionsIntelligent vehicle-mounted alcohol detection control system controls the drinking drive from a new angle. It is more flexible, more interaction with the driver, more user-friendly than any other vehicle control system. The core of system is the test program, which gains drivers information through sensor, touch-screen, and then determine the drivers driving-related ability. An inadequacy of the system is that the system determines drivers responsiveness and hand-eye coordination in a short period of time when driver enters the vehicle but not in a long period of time, and the system ca