Simulation and Implementation of ESC and Adaptive Front Lighting System for Automobiles

Transcription

1 Simulation and Implementation of ESC and Adaptive Front Lighting System for Automobiles Prateek Khurana 1, Navaid Zafar Rizvi 2, Rajat Arora 3 prateek.khurana31@gmail.com Abstract The use of Electronic Stability Control (ESC) in automobiles has become quite popular in the last decade and a number of research activities have been conducted for its further improvement. The use of these complex systems has reduced the number of accidents reported on highways and expressways around the world. The adaptive front lighting system has also undergone extensive research in the past decade and has proved very effective in increasing the stability of the vehicle while driving. A large part of literature available in this area enlightens about the effectiveness of ESC in situations where there is a risk of crash. In this paper, ESC and adaptive front lighting system have been implemented on a microcontroller to bring out the working of these complex systems. The model presented in this paper may be fabricated at a very low cost. It may also be incorporated in vehicles lacking this beneficial technology with minor modification. Keywords Electronic stability control; Vehicle Dynamics; Automobile engineering; PIC microcontroller. 1 School of ICT, Gautam Buddha University, Greater Noida, 2 School of ICT, Gautam Buddha University, Greater Noida, navaid@gbu.ac.in 3 School of ICT, Gautam Buddha University, Greater Noida,arora.rajat08@gmail.com Page 1

2 Introduction Electronic Stability Control (ESC) systems are very useful in situations where a driver loses traction while maneuvering an obstacle or drifting out of a corner. These systems are effective in reducing crashes, which involve only a single vehicle. ESC systems in such cases prevent the vehicle from turning over or colliding with another oncoming vehicle while driving at high speeds. It works by detecting the loss of traction and generating a control action upon this detection to stabilize the vehicle. In this way, the driver regains the control of the vehicle and a crash is prevented. European market was the first to witness the introduction of ESC in It was given as an optional safety accessory for passenger cars [1]. With the arrival of 21st century, leading automakers started giving ESC as standard safety feature in luxury cars. In the middle of 2006, adaptive front lighting system found its way in commercially produced cars [2]. In this system, the headlamps of the car turned with respect to the direction in which the car is turning. In this way, the person behind the steering wheel gets a better view of the road at night while taking a steep turn. The combination of both these technologies helps a lot in making cars safer and increasing their stability on road. Out of the many research activities conducted on the topic of ESC, most of them discuss about its effectiveness in reducing real life crashes. Many researchers have used Statistical tools for analysis to prove that this system can prevent crashes to large extent [3, 4 and 5]. The potency of the recently introduced Lane-Keeping ESC models has also been studied [6]. The limitations and possibilities of various complicated ESC systems have been analyzed [7]. An empirical study has also been carried out on this complex technology [8]. Few researchers have suggested the addition of Yaw Stability Control for vehicles in order to make ESC technology more effective [9]. Thus, it can be seen that most of the research activities in the past, discuss about the effectiveness of ESC in reducing crashes and preventing mishaps. ESC is a complex unit in itself and when installed in vehicles, it becomes difficult to understand its proper functioning. This is because a large number of sensors give inputs to this control unit, which then takes an action based upon these values. This action when triggered prevents the vehicle from slipping or loosing traction. In this paper, an attempt has been done to implement the complex ESC unit on an 8051 microcontroller along with adaptive front lighting system and a warning system. This depiction of the working of ESC brings out the proper functioning of the system. ESC systems usually employ a differential braking system to generate the control action. Different vendors for this same technology use different names and acronyms. In this system, depending upon the direction in which the car is losing traction, one of the four brakes is applied. Since brake pressure of each of the four tires of an automobile can be controlled, this system is called Differential Braking System. When the driver takes a steep turn or tries to maneuver an obstacle, two possibilities are there i.e. understeer and oversteer. These situations occur when the road is slippery or when the speed of vehicle is very high for that turn. In both the cases there is a risk of crash as the driver may bump into an oncoming vehicle or may be thrown out of the curvature of the road. This is where the ESC comes into picture and helps the driver to keep the vehicle on the intended trajectory. In oversteer situation the car turns more than required along the vertical axis passing through its center of gravity. To balance this effect, ESC applies brake pressure to the left front wheel of the car. This brake pressure generates a Page 2

3 counter effect and helps in bringing back the car to its normal trajectory. This situation is shown in Fig. 1 where the wheel on which the brake pressure was applied by the ESC has been highlighted. Figure 1: Working of ESC in an Oversteer Situation Figure 2: Working of ESC in an Understeer Situation In case of understeer, the vehicle does not turn to the extent that it should and is not able to cope up with the curvature of the road. The ESC in this case applies brake pressure to the right back wheel of the vehicle to generate a clockwise effect along the center of gravity of vehicle. This counter effect brings back the vehicle to its normal trajectory. This situation is shown in Fig. Page 3

4 2. The wheel on which the brake pressure is applied by the ESC unit is highlighted. Thus, it can be seen that the use of ESC reduces the risk of crash and provides more stability and confidence to the driver behind the steering wheel. The activation of ESC when driver enters a steep bank or tries to maneuver an obstacle depends upon the input from the sensors. In this paper, the complexity of ESC has been simplified by implementing it on an 8051 microcontroller. An adaptive front lighting system and warning system are also interfaced with this microcontroller. Thus, the complete unit may be used to replace the current isolated units installed in a commercial vehicle. The detailed design and construction in this proposed approach is explained in next section. Section III discusses the working of this proposed module while in Section IV the results obtained from this setup are analyzed and presented. Design & Construction The previous work done to implement this technology used microcontrollers like PIC, externally interfaced analog to digital converters (ADCs), controller area network (CAN) bus and various types of sensors [10,11]. In this work, an 8051 microcontroller controller board (SM 8051) is used. This board is like a single chip computer. It accommodates many of the peripheral devices, that otherwise have to be externally interfaced such as the ADCs. Therefore, the proposed approach is more beneficial than the previous one in terms of the cost and size. The board has an on chip 8051 microcontroller (P89V51RD2) that operates at a voltage of 5V from 0 to 40 MHz s. It has a 64 kb flash memory with In-system and In-application programming (ISP and IAP). It also has a serial peripheral interface (SPI) and an enhanced universal asynchronous receiver/transmitter (UART). Two on chip ADCs are also there to analyze analog inputs along with four 8-bit input/output ports. The safety equipment presented here are divided into 4 modules. The first module consists of sensors that give input to the device to trigger a control action based upon these sensors. An angle sensor is used to measure the tilt angle of the steering wheel of the vehicle. Another angle sensor was used to measure the rotation of the vehicle along its center of gravity. It is used to detect the slip angle. Finally, a speed sensor is also used to measure the lateral speed and a pressure sensor measured the pressure with which the brakes were applied. All these sensors give analog outputs, which were converted into digital inputs by the ADCs and fed into the 8051 microcontroller. This module is depicted in Fig. 3. The second module represents the ESC. In this module four motors are interfaced with 4 output ports of the 8051 microcontroller. These motors are driven with the help of a motor driver IC (ULN2003). The four motors represents the four wheels of a vehicle and were triggered by the microcontroller when necessary. A block diagram as shown in Fig. 4 represents this module. Adaptive Front Lighting module is shown in Fig. 5. In this module an 8-bit LED section is interfaced with the 8051 microcontroller. LEDs L1 an L2, represent the left side lamps of the vehicle. On the other hand, LEDs L6 and L7 represent the right side lamps of the vehicle. Rest of the LEDs are considered as headlamps of the vehicle. Page 4

5 Figure 3: Module to Provide Inputs to the System The last module is used to generate a warning message for the driver to intimate him about the activation of ESC. In this module an LCD was interfaced with 8051 microcontroller on which caution message can be displayed. This module is shown in Fig. 6. Thus, all the four modules are made to work simultaneously to achieve the proper functioning of this safety unit. The detailed working of this equipment is explained in detail in next section. Figure 4: ESC Module with Four Interfaced Motors. Figure 5: Adaptive Front Lighting System Module Page 5

6 Figure 6: Module to provide warning message to the passenger Working The model discussed in the previous section performed the complete working of an ESC and Adaptive Front Lightning system. The 8051 microcontroller received the input parameters of ESC with the help of various sensors. The steering wheel angle sensor estimates the direction in which the driver intended to move the vehicle in order to maneuver an obstacle. The brake pedal sensor measures the force with which the brakes are applied in a situation of sudden risk of crash. The data from travel speed sensor and rotation angle sensor are received. The microcontroller has been programmed to take action based upon these input values. A program was written to calculate the slip angle in this case. The value of slip angle determined whether vehicle is understeering or oversteering. Mathematically, the slip angle is given as follow:- β = tan -1 ( V y / V x ) Where, Vy is the lateral velocity and Vx is the longitudinal velocity. In order to bring back the vehicle on its normal trajectory, the speed of one of the four motors is varied. Motors M1 and M2 represent the front wheels, whereas M3 and M4 represent the rear wheels. If the case of understeer is detected, the speed of the motor M3 is reduced. Similarly, if oversteer situation is detected, brake force is applied on motor M1. Thus, it may be seen that 8051 microcontroller may be programmed to take action, based upon the inputs. The working of adaptive front lightning system is based upon the input from steering wheel angle sensor. In this case, the LEDs representing the side lamps are activated according to the direction in which the vehicle is turning. Thus, the adaptive front lighting system improves the vision of the person sitting behind the steering wheel on blind turns or at nights. This system has been studied and researched in detail by various authors [12, 13 and 14]. Whenever the second module is activated, a warning message is issued to the driver. This notification is given in order to caution the driver. The 8051 microcontroller is programmed to do such task. This complete unit has been tested and analyzed for a number of different cases. The results obtained are summarized in the next section. Results Page 6

7 The above implemented system has been rigorously tested for various input values. The tilt values of steering wheel angle sensor and rotational angle sensor have been varied for all possible cases. Similarly, different values of pressure are fed to the brake pedal pressure sensor. For all the input values, system works efficiently and generated the desired output. All these values are randomly varied and the corresponding action generated by the modules has been analyzed. The LCD display interfaced with 8051 microcontroller, generated the warning message whenever ESC module is activated. Fig. 7 and 8 show the two possible messages that are prompted on LCD display. Figure 7: LCD displaying ESC Terminated Message Figure 8: LCD displaying ESC Activated Message According to the programmed logic, ESC module is activated and the speed of one of the motor is varied. The interfacing of a steeper motor with 8051 microcontroller is shown in Fig. 9. The Adaptive front lightning system has also been comprehensively studied for all possible values of steering wheel angle sensor. When the vehicle is not turning, the headlamps represented by the center LEDs are switched on. This representation is shown in Fig. 10. The left and right side lamps are also activated based upon the values of the steering wheel angle sensor. Fig. 11 shows the condition when the driver intends to move the vehicle in right direction. In the case of vehicle moving to the left, the left side lamps are activated as shown in Fig. 12. Thus, it may be seen that both the Electronic stability control and Adaptive front lightning system works in a wellorganized and competent manner. Therefore, this complete unit may be used easily to replace the isolated safety units deployed in modern cars. Page 7

8 HCTL Open International Journal of Technology Innovations and Research (IJTIR) Figure 9: Interfacing of Stepper motor with 8051 Microcontroller Figure 10: LED module representing the Head Lamps of vehicle in ON state Figure 11: LED module representing the Head Lamps and Right Side Lamps of vehicle in ON state Page 8

9 Figure 12: LED module representing the Head Lamps and Left Side Lamps of vehicle in ON state Conclusion ESC has undergone a great deal of advancement, since its evolution in the year Due to the endless growth in technology, the complexity and cost of the system has significantly increased. This paper focused on the implementation of ESC along with the adaptive front lightning system in a more efficient manner. It successfully combined both these technologies into a single system and illustrated the detailed working of it. This whole system may be fabricated onto a single IC and can be installed in a four-wheel drive commercial vehicle with a brake force distribution system. Such a cost effective approach is essential for a country like India, where ESC is still not available in 75 % of its vehicles. This system significantly reduces the risk of crash and ensures better obstacle maneuvering. References [1] Høye, A. (2011). The effects of Electronic Stability Control (ESC) on crashes An update. Accident Analysis & Prevention, 43(3), [2] Ibrahim, Faroog. "Predictive adaptive front lighting integrated system." U.S. Patent Application 11/222,056, filed September 8, [3] Liebemann, E. K., Meder, K., Schuh, J., & Nenninger, G. (2004). Safety and performance enhancement: The Bosch electronic stability control (ESP). SAE Paper, 20004, [4] Ferguson, S. A. (2007). The effectiveness of electronic stability control in reducing realworld crashes: a literature review. Traffic injury prevention, 8(4), [5] Farmer, C. M. (2004). Effect of electronic stability control on automobile crash risk. Traffic Injury Prevention, 5(4), Page 9

10 [6] Lundahl, K., Olofsson, B., Berntorp, K., Åslund, J., & Nielsen, L. (2014). Towards Lane- Keeping Electronic Stability Control for Road-Vehicles. In 19th IFAC World Congress. [7] Piyabongkarn, D., Lew, J. Y., Rajamani, R., Grogg, J. A., & Yuan, Q. (2007). On the use of torque-biasing systems for electronic stability control: limitations and possibilities. Control Systems Technology, IEEE Transactions on, 15(3), [8] Erke, A. (2008). Effects of electronic stability control (ESC) on accidents: A review of empirical evidence. Accident Analysis & Prevention, 40(1), [9] Di Cairano, S., Tseng, H. E., Bernardini, D., & Bemporad, A. (2013). Vehicle yaw stability control by coordinated active front steering and differential braking in the tire sideslip angles domain. Control Systems Technology, IEEE Transactions on, 21(4), [10] Rajeswari, S. (2014). Drift and Front Lighting System in Self Propelled Vehicles Using Electronic Stability Control. Middle-East Journal of Scientific Research, 20(9), [11] Bhoi, B. K., Debnath, S., Das, S., & Kumar, A. (2012).Drift And Front Lighting System In Self Propelled Vehicles Using Electronic Stability Control, International Journal of Electrical and Electronic Engineering & Telecommunications, Vol.2(3),24-29 [12] Abdelnour, S., Dassanayake, M., Miller, R., Shannon, J., & Wrobel Jr, M. S. (2009). U.S. Patent No. 7,540,638. Washington, DC: U.S. Patent and Trademark Office. [13] Schmidt, C., Kalze, F. J., & Eichhorn, K. (2007). Adaptive front-lighting system in LED technology-initial steps and the future, No , SAE Technical Paper. [14] Higgins-Luthman, M. J., Ince, W. C., & Lu, Y. (2011). U.S. Patent No. 7,914,187. Washington, DC: U.S. Patent and Trademark Office. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( by the Authors. Licensed by HCTL Open, India. Page 10