INTELLIGENT BRAKING SYSTEM

Transcription

1 INTELLIGENT BRAKING SYSTEM A.H. Ingle 1,Shubham Gat 2, Sawan Kumar 3 1 Asso. Prof. and Head of department of Mechanical Engineering, S.R.P.C.E.Nagpur, anilingle75@gmail.com 2 Student of Mechanical Engg. Department, S.R.P.C.E.Nagpur, gatshubham@gmail.com 3 Student of Mechanical Engg. Department, S.R.P.C.E.Nagpur, golu6036@gmail.com ABSTRACT Accidents have become a serious concern in today s scenario. The rate of accidents are at an all time high currently. Thus there are different kinds of safety systems available for vehicles like ABS, EBD etc. All these systems consist of different sensors that constantly monitors the different parameters associated with the safe braking of the vehicle. In this system author proposes the use of ultrasonic sensors, hall sensors etc. to control the speed of the vehicle of the vehicle and apply the brakes automatically. This system consists of ultrasonic wave emitter provided on the front position of a vehicle and emits ultrasonic wave in frontward direction. An ultrasonic receiver also mounted at the front receives the reflected ultrasonic signal. The time required for the wave to strike the obstacle and to return back to the receiver gives the distance of the obstacle in front of the vehicle. The hall sensor constantly monitors the speed of the vehicle. These two information signals are fed to the microcontroller and then the microcontroller calculates the safe braking distance and applies the brakes automatically depending upon the safe braking distance. Keywords: Hall sensor, Ultrasonic sensor, Microcontroller, Pneumatic valve, Pneumatic cylinder INTRODUCTION Breaking system is an extremely important component of a vehicle which ensures the safety of the vehicle and its occupants. In this era of multitasking people tend to divede their attention while driving on their mobile phones etc. This neglect on the part of the driver is one of the most common causes of road accidents that lead to thousands of casualties every year. So the purpose of our project is to develop a system that can apply the brakes automatically as soon as it senses any obstacle within a predefined distance. The braking system employs pneumatic cylinder and control valves to actuate the different sensors/components used in the braking system, the braking circuit and its working. The sensors included are hall sensor, ultrasonic distance measurement sensor, micro-controller. These sensors are integrated in a logical manner so as to achieve the desired braking effect. This project is designed to develop a new system that can solve this problem where drivers may not brake manually but the vehicles can stop automatically due to obstacles. The main target for this project is, cars can run automatic braking due to obstacles when the sensor senses the obstacles. The braking circuit function is to brake the car automatically after received signal from the sensor. The primary objective of this paper is to develop a safety car braking system using ultrasonic sensor and to design a vehicle with less human attention to the driving. Accidents occur due to technical problem within the vehicle or due to mistake of driver. Sometimes the drivers lose control over the vehicle and sometimes accident occurs due to rash driving. When the drivers come to know that vehicle is going to collide they become nervous and they don t apply the brakes. Majority of the accidents occur

2 this way.the system designed will prevent such accidents. It keeps track of any vehicles in front. It will continuously keep the track of the distance between the two vehicles. When two come dangerously close the microprocessor in the system activates the brakes and it will stop the vehicle. 2. LITERATURE REVIEW The existing approaches in preventing accidents are: 2.1 Audi The full version of the system (Pre-Sense Plus) works in four phases. In the first phase, the system provides warning of an impending accident, while the hazard warning lights are activated, the side windows and sunroof are closed and the front seat belts are tensioned. In the second phase, the warning is followed by light braking, strong enough to win the driver's attention. The third phase initiates autonomous partial braking at a rate of 3 m/s². The fourth phase decelerates the car at 5 m/s² followed by automatic deceleration at full braking power, roughly half a second before projected impact. A second system, called (Pre-Sense Rear), is designed to reduce the consequences of rear-end collisions. The sunroof and windows are closed and seat belts are prepared for impact. The optional memory seats are moved forward to protect the car's occupants. 2.2 Ford Ford's Collision Warning with Brake Support was introduced in 2009 on the Lincoln MKS and MKT and the Ford Taurus. This system provides a warning through a Head Up Display that visually resembles brake lamps. If the driver does not react, the system precharges the brakes and increases the brake assist sensitivity to maximize driver braking performance. Ford demonstrated its Obstacle Avoidance technology relying on a mix of sensors, including a camera tucked behind the rearview mirror, to scan the road for vehicles and pedestrians and steer away if the driver does not take any action. 2.3 Honda Honda's Collision Mitigation Brake System (CMBS, although originally introduced with the initials CMS) introduced in 2003 on the inspire and later in acura, Honda's luxury brand in Canada and the United States, uses a radar-based system to monitor the situation ahead and provide automatic braking if the driver does not react to a warning in the instrument cluster and a tightening of the seat belts. The Honda system was the world's first production system to provide automatic braking. The 2003 Honda system also incorporated an "E-Pretension", which worked in conjunction with the CMBS system with electric motors on the seat belts. When activated, the CMBS has three warning stages. The first warning stage includes audible and visual warnings to brake. If ignored, the second stage would include the E-Pretension's tugging on the shoulder portion of the seat belt two to three times as an additional tactile warning to the driver to take action. The third stage, in which the CMBS predicts that a collision is unavoidable, includes full seat belt slack take up by the E-

3 Pretension for more effective seat belt protection and automatic application of the brakes to lessen the severity of the predicted crash. The E-Pretension would also work to reduce seat belt slack whenever the brakes are applied and the brake assist system is activated. In late 2004, Honda developed an Intelligent Night Vision System, which highlights pedestrians in front of the vehicle by alerting the driver with an audible chime and visually displaying them via HUD. The system only works in temperatures below 30 degrees Celsius (86 Fahrenheit). This Intelligent Night Vision first appeared on the legend. 2.4Nissan Nissan's luxury brand in North America and Europe, infinite, offers a laser-based system in the US market, which pre-pressurizes the braking system so that maximum force can be applied early. Nissan is reportedly developing a new "magic bumper" system, which raises the accelerator pedal if it senses an impending collision. Once the driver lifts off the pedal, the system automatically applies the brakes. 2.5General Motors GM's collision alert system is featured in the 2012 GMC Terrain SUVs and uses a camera to provide warning when there is a vehicle ahead or there is a lane departure Cadillac ATS, XTS and SRX models featured automatic braking at low speeds (in heavy traffic or even in parking lots and driveways) when a collision is imminent Chevrolet Impala received the radar and camera based Crash imminent braking (Radar technology detects a possible crash threat and alerts the driver. If the driver does not appear to react quickly enough or doesn t react at all, this feature intervenes to apply the brakes in an effort to avoid the crash), Forward collision alert, Lane departure warning, Side blind zone alert (Using radar sensors on both sides of the vehicle, the system looks for other vehicles in the blind zone areas of the Impala and indicates their presence with LED-lit symbols in the outside mirrors), Rear cross traffic alert features. Drawbacks in the existing approaches: ABS can only help if the rider applies it in the right time manually and maintains the distance calculations. ABS has its own braking distance. Moreover many commuter bikes in India don t have the option of ABS because it s very expensive. Volvo s laser assisted braking could not work effectively in rainfall and snowfall season and laser is easily affected by atmospheric conditions. 3. PRINCIPAL COMPONENTS Ultrasonic ranging and detecting devices make use of high-frequency sound waves to detect the presence of an object and its range. These systems either measure the echo reflection of the sound waves from objects or detect the interruption of the sound beam as the objects pass between the transmitter and receiver. An ultrasonic sensor typically utilizes a transducer that produces an electrical output pulse in response to the received ultrasonic energy.the normal frequency range for hearing of humans is roughly around 20 to 20,000 hertz. Ultrasonic sound waves are the sound waves that are above the range of human hearing capability and, so have a frequency above 20,000 hertz. Any frequency which is above

4 20,000 hertz may be considered as ultrasonic. Most of the industrial processes, including almost all the sources of friction, create some ultrasonic noise. The ultrasonic transducer produces ultrasonic signals. These signals propagate through a sensing medium and the same transducer can be used to detect the returning signals. Ultrasonic sensors usually have a piezoelectric ceramic transducer that converts an excitation electrical signal into ultrasonic energy bursts. These energy bursts travel from the ultrasonic sensor, bounce off objects, and are returned towards the sensor as echoes. Transducers are the devices that convert electrical energy to mechanical energy, or vice versa. The transducer converts the received echoes into analog electrical signals that are outputs from the transducer. The piezoelectric effect refers to the voltage produced between surfaces of a solid dielectric (no conducting substance) when some mechanical stress is applied to it. On the other hand when a voltage is applied across certain surfaces of a solid that exhibits the piezoelectric effect, the solid undergoes a mechanical distortion. Such type of solids typically resonates within narrow frequency ranges. Piezoelectric materials are generally used in transducers. For example, they are used in phonograph cartridges, strain gauges, and microphones that produce an electrical output from a mechanical input. Also, they are used in earphones and ultrasonic transmitters that produce a mechanical output from an electrical inputs. 3.1 Ultrasonic sensor Ultrasonic sensor transmits ultrasonic waves from its sensor head and again receives the ultrasonic waves reflected from an obstacle. By measuring the length of time from the transmission to reception of the ultrasonic wave, it detects the distance and hence the position of the object. Fig. 1 Ultrasonic sensor Ultrasonic signals are like audible sound waves, except that the frequencies are much higher than them. Our ultrasonic transducers have piezoelectric crystals which resonate to a desired frequency and convert electric energy into acoustic energy and vice versa. The below illustration shows how sound waves, transmitted in a conical shape, are reflected from a target back to the transducer. Accordingly, an output signal is produced to perform some kind of indicating or control function. A certain minimum distance from the sensor is required to provide a time delay so that the "echoes" can be interpreted. Some variables which can affect the operation of ultrasonic sensing include, target surface angle, reflective surface roughness or changes in temperature or humidity. Targets can have any kind of reflective form. Ultrasonic Transmitter

5 Before transmitting the ultrasonic waves, there is an ultrasonic wave generator which generates an ultrasonic wave. In that part, there is timing instruction which generates an instruction signal for intermittently providing ultrasonic waves. This signal will be sent to an ultrasonic wave generator for generating ultrasonic waves based on the instruction signal from the timing instruction (transform electrical energy into sound wave). After the ultrasonic wave is produced, the ultrasonic transmitter transmits the ultrasonic waves towards a road surface to detect the obstacle. The range in which the obstacle detected is depends on the range of ultrasonic sensors used. Ultrasonic Receiver If the ultrasonic wave detects the obstacle, it will produce a reflected wave. An ultrasonic receiver is used for receiving the ultrasonic waves reflected from the road surface to generate a received signal. There is an ultrasonic transducer which will transform back the sound wave to electrical energy. This signal is amplified by an amplifier. The amplified signal is compared with a reference signal to detect components in the amplified signal due to obstacles on the road surface. The magnitude of the reference signal or the amplification factor of the amplifier is controlled to maintain a constant ratio between the averages of the reference signal. 3.2 Hall Sensor A Hall sensor is a transducer that varies its output voltage in response to changes in magnetic field density. Hall sensors are used for proximity switching, positioning, speed detection, and current sensing applications. In its simplest form, the sensor operates as an analogy transducer, directly returning a voltage. With a known magnetic field, its distance from the Hall plate can be determined. Using groups of sensors, the relative position of the magnet can be deduced. 3.3 MICROCONTROLLER The whole control of the system is in the hands of ATMEGA8-16PI microcontroller. A microcontroller is a computer on a chip. It is a type of microprocessor emphasizing self-sufficiency and cost effectiveness, in contrast to a general purpose microprocessor. 3.4 PNEUMATIC CYLINDER Pneumatic cylinders are mechanical devices which use the power of compressed gas to produced a force in a reciprocating linear motion. Like hydraulic cylinders, something forces a piston to move in the desired direction. The piston is a disc or cylinder, and the piston rod transfers the force it develops to the object to the moved. Engineers prefer to use pneumatic sometimes because they are quieter, cleaner, and do not require large amounts of space for fluid storage. 3.5 PNEUMATIC VAVLE Directional control vavles are one of the most fundamental parts in hydraulic machinery as well as pneumatic machinery. They allow fluid flow into different paths from one or more sources. They usually consist of a spool inside a cylinder which is mechanically or electrically controlled. The movement of the spool restricts or permits the flow, thus it controls the fluid flow. 4.SUMMARY One of the most important aspects that is considered while designing a vehicle is safety and the system provided to achieve that is the braking system. Today the braking system has

6 become so highly advanced that it does not even require the driver to apply the brakes but can still protect them from accidents. All the vehicle manufacturing companies have developed their own form of braking systems. But the basic principle behind each of these systems is same These braking systems convert signal from computers into brake pressure that actuates the braking in the vehicle. Although there are a lot of technologies available in the market but these are available in premium vehicles and are yet to be integrated with cheaper vehicles so that it is available to everybody. 5. CONCLUSION In the present work, a prototype of an ultrasonic distance measurement for stationary obstacle is obtained. And controlling the speed of vehicle accordingly to predetermined distance is shown. An ultrasonic sensor, cheaper and less demanding of hardware than other types of sensors presently used, such as the sensors based on computer vision or radar, is used to measure the distance between vehicle and the obstacle. The relative speed of the vehicle with respect to the obstacle is estimated using consecutive samples of the distance calculated. These two quantities are used by the control system to calculate the actions on both the accelerator and also the brake, thus to adjust the speed in order to maintain a safe distance to prevent accidents. As ultrasonic sensors can detect any kind of obstacle, this system can also prevent collision of the vehicle with pedestrians, or can at least reduce the injuries occurring. REFERENCES 1. G.V. Sairam, B. Suresh, CH SaiHemanth, K. Krishna sai, Intelligent Mechatronic Braking System,IJETAE,volume 3, Issue 4, April 2013, ISSN VallamkonduArun Kumar, SettyKalyan, Active Safety Braking System, JSSRP, volume 3, Issue 12, Dec. 2013, ISSN No Venkata Ramesh Mamilla and M.V. Mallikarjun, Control of Electro-Mechanical Brake with Electronic Control Unit, IJEER, volume 1, number 3, 2009, ISSN NO Dhanya K. R. and R. Jeyanthi, Automatic Braking System with Sensor Fusion Concept, IIEEES. 5. MilindS.Deotale, HrishikeshShivankar, Rohit More, Review on Intelligent Braking System, IJRITCC, VOLUME4, Issue 4, ISSN Firoz Syed, Suma lekha.p, Raja GopalReddy.Thiyyagura, Intelligent Mechatronic Braking System. 7. Niveditha.P.RandS.Gowri, Collision Warning System using Ultrasonic Sensors and Automatic Brake System, ACEEE. 8. ITETAE (ISSN , ISO 9001:2008) 9. HaiWang and Ronghong Xiao, Automatic car braking system, University of Gavle.