Development of Automotive Collision Avoidance System Based on Intelli- gent Control

With the development of automotive industry, the traffic accident caused by automotive collision has become a social problem in the world. Aiming at improving the safety of automotives and reducing the collision accidents, an automotive collision avoidance system based on intelligence control is researched. As the control core, a 16-bit microcontroller receives the distance signal of the front car from ultrasonic distance measuring module, and controls a motor to realize the speed control of the vehicle. An infrared sensor is used to measure the car speed, and this signal is sent to the microcontroller to make the motor control more precise and stable. A small motor is installed at the car throttle, and the microcontroller controls this motor to adjust the opening of the throttle, thus avoiding human operator errors that the traditional mechanical throttle makes. The main modules of this intelligent control system have been developed; these modules include the PWM module, ECT module, PIT module, and PLL module. The intelligent throttle has been studied. The result shows that the system is reliable and has high-resolution control accuracy. Keyword: Automotive collision avoidance, intelligent control, ultrasonic signal infrared sensor, speed control. INTRODUCTION According to the Ministry of State Security of PRC, China State Security Bureau, 110000 people lose their lives because of traffic accidents in China each year, making China become one of the world leaders in terms of traffic accident-related deaths. Data was taken from the Transportation and Communities year book of China that road traffic death rate was increased by 95 percent from 1985 to 2005 (Barboza, 2011). How could this happen? What are the main causes of this and what could Chinese people do towards this? First here are two traffic accidents in China and the USA [1]. The form of road traffic safety is very grim in China. Statistics shows that the number of fatal traffic accidents in China of each year is nearly 100000, accounting for one point five percent of the total death toll. The seventh cause of death. The minutes died in under the wheel. Every minute, a person become disability because of traffic accidents. Each year, the economic losses caused by traffic accidents reach hundreds of billions. In recent years, along with the increasing of all kinds of vehicles, traffic accidents continue to occur. According to relevant statistics, China has 1.9% of the world’s automobile, and accounts for15% of the traffic accidents of the world, each year, the number killed in traffic accidents is more than 100000, in which is the highest in the world. Traffic accidents continue to occur, caused a great threat to people’s life and property safety and social order and stability, and has become a serious social problem. *Address correspondence to this author at the No. 1 Science and Technology 6 road, Xi’an, Shaanxi Province, 710065, China; E-mail: [email protected] Therefore, the safe driving cars will become one of the main causes for the stability of the family, The incidents in the real life have occurred when the car rear-end, he mistakenly stepped on the accelerator instead of the brake causing a fatal car crash and this tragedy event deeply touched my heart. With the development of the microcontroller’s electronic technology, you can make the car become more intelligent [2]. In China, most of vehicles are equipped with airbags and seat belts. However they are just Passive safety device,whose safety factor is not high. Aiming at enhance enhancing the positive safety of the vehicle, an intelligent collision avoidance system is developed. This system can detect the distance betweenfrom the front car distance and control the car speed automatically to avoid collision. The research is developed with low-cost, high performance, small footprint, high safety factor, market prospects, and it is with greater significance to promote China's actual level of the automotive industry. The system is characterized by the integration of software and hardware, low cost, high performance, small package, and high safety factor, which make it promising in the future market [5]. THE OVERALL BLOCK DIAGRAM OF THE SOFTWARE The overall block diagram of software design is as shown in Fig. (1): The core of this program is based on MC9S12xs128. When the ultrasonic signal triggers the interruption routine, the DC motor would be controlled accordingly. Program flow chart as shown in Fig. (2): Development of Automotive Collision Avoidance System The Open Automation and Control Systems Journal, 2015, Volume 7 779 Fig. (1). Software design diagram. Fig. (2). Software design flow. PWM MODULE PROGRAM The PWM has eight output channels, and each output channel can be independently output. Each output channel has a precise counter (calculated for calculatinges the pulse number), a cycle of control registers and two alternative clock sources. Each PWM output channel can modulate the waveform with the duty cycle range from 0 to 100% [7]. The Main Features of the PWM The PWM has eight independent output channels, and each output channel has a precise counter; PWM output enables each channel to be controlled by programming; The flip control for PWM output waveform can be achieved by programming; the cycle and pulse width can be double-buffered [3]. When the channel is turned off or PWM counter is 0, it can only work by changing the cycle and pulse width; 8 bytes or 16 bytes of channel protocol; there are four clock source options (A, SA, B, SB), which provide a wide range of frequencies [8]. Related Calculations 1) Calculate the clock The clock SA is generated by PWMSCLA register settings to the A clock frequency. Clock SA=Clock A/(2*PWMSCLA); The clock SB is generated by PWMSCLB register settings to B clock frequency. Clock SB = Clock B / (2*PWMSCLB); 2) Period calculation 780 The Open Automation and Control Systems Journal, 2015, Volume 7 Ling et al. 1When CAEx=0, that was left linear output: PWMx cycle=channel clock cycle * PWMPERx; 2When CAEx=1, namely, the center-aligned output: PWMx cycle=channel clock cycle*(2* PWMPERx); 3) Calculation of duty When PPOL=0: Duty=[(PWMPERxPWMDTYx)/PWMPERx]*100%; When PPOL=1: Duty=(PWMDTYx/ PWMPERx)*100% ; PWM Initialization Procedure PWME_PWME2=0x00; // Disable PWM PWMPRCLK=0x33; // 0011 0011 A=B=24M/8=3M PWMSCLA=150; // SA=A/2/150=10k WMSCLB=15; // SB=B/2/15 =100k PWMCLK_PCLK2=1; // PWM3-----SB PWMPOL_PPOL2=1; // Duty=High Time PWMCAE_CAE2=0; // Left-aligned PWMCTL=0x00; // no concatenation PWMPER2=100; // Frequency=SB/100=1K PPWMDTY2=0; // Duty cycle = duty PWME_PWME2=1; // Enable PWM