DESIGN AND FABRICATION OF INTELLIGENT ELECTROMAGNETIC BRAKING SYSTEM
ABSTRACT
A brake is device that uses friction, which is applied to the rotating axles or wheels to slow or stop a moving object. Friction brakes on vehicles store braking heat in the drum while braking then conduct it to the air gradually. When traveling downhill some vehicles can use their engines to brake. When the brake pedal is pushed the caliper containing piston pushes the pad towards the brake disc which slows the wheel down. On the drum brake it is also similar as the cylinder pushes the brake shoes towards the drum which also slows the wheel down. In this system we use a concept of electromagnetic system to engage the brake. Trams and trains use electromagnetic track brakes where the braking element is pressed by magnetic force to the rail. They are distinguished distinguished from mechanical track brakes, where the braking element is mechanically pressed on the rail. These electromagnetic are basically frictionless, because they do not require any contact between the disc and the braking element. The disc is connected to a shaft and the electromagnet is mounted on the frame. When electricity is applied to the coil a magnetic field is developed across the armature because of the current flowing across the coil and causes armature to get attracted towards the coil. As a result, it develops a torque and eventually the vehicle comes to rest.
This project studies the core of electromagnet and how it can be incorporated to commercial vehicles by controlling the current supplied to produce the required magnetic flux to stop or slow the vehicle.
Fig: Single pivot side-pull caliper brake
Fig: Rendering of a drum brake
LITERATURE REVIEW
#1
Investigation on Eddy Current Braking Systems Journal: Applied Mechanics and Materials (Volumes 592-594) Authors: G.L. Anantha Krishna and K.M. Sathish Kumar Review:
The changing magnetic field will induce eddy currents in the conductor. These currents will dissipate energy in the conductor and generate drag force. It is found that Aluminum is the best material as conductor compared to Copper and Zinc. It is also found that the larger thickness of disc, more number of turns of electromagnet and higher electrical conductivity of conductor influences
the
generation
of
greater
braking
torque.
Conventional braking system relies on adhesion force between rail and wheel. It is found that a brake built up from permanent magnet pieces that combine both magnetic rail brake and eddy current brake permits the most profitable braking action through the whole range of acceptable speeds. Permanent magnet eddy current brake uses Neodymium magnets. The analysis of permanent magnet eddy current shows that the parallel magnetized eddy current has the superior braking torque capability. In electrically controlled eddy current braking system resulted in highest braking torque.
#2
An Anti-Lock Braking Control System for a Hybrid Electromagnetic Brake-By-W ire System
Journal: Proceedings Conference
of
the
2004
American
Control
Authors: S. Anwar Review:
Anti-lock braking system (ABS) is a safety feature in automobile system which gives better control to the vehicle. It utilizes the wheel slip to control the wheel pressure using a set of valves and a pump in order to control the wheel braking system. Brake by wire is a hybrid vehicle which has hybrid actuators mounted on the front wheels. The data are taken such as vehicle mass, wheel inertia, etc., if the ABS command detects maximum available torque command from ABS controller, it estimates the maximum available torque for the eddy current brakes at a given wheel speed. If the ABS torque command is larger than the eddy current brake available torque, then the eddy current brake is commanded full excitation and if we use this system in under critical weather it gives better control to the wheels using this system.
#3
Fabrication of Electromagnetic Clutches and Braking System
Journal: ELK Asia pacific journals Authors: K.Saurabh, I.Ali Review:
Electromagnetic braking system basically uses application of magnetic flux to stop the vehicle. And in this clutch, are used to make and break the contact electromagnetically with the help of electromagnet which can be stopped and apply brakes at different clutches. A flywheel is used in this due to the rotation of the flywheel magnetic field is created thus is used to apply the brake. As magnetic flux increases, efficiency also increases which causes to brake properly and cope with the speed of the vehicle and if the speed decreases the magnetic field also decreases. We can use rectified power supply instead of constant power supply.
#4
Obstacle Avoidance With Ultrasonic Sensors
Journals: IEEE JOURNAL OF ROBOTICS AND AUTOMATION Authors: JOHANN BORENSTEIN AND YORAM KOREN Review:
The ultrasonic sensors are basically used to avoid the obstacles and to avoid collisions and physical damage. Ultrasonic sensors are used to detect the distance which is front of it by sending waves to it and that waves are reflected back to the sensor by this we can measure the distance. If this sensor is attached to the braking system we can avoid the collisions by detecting the distance and apply the brakes. We can make the braking system more responsive when the distance is less and the collisions occurrence is more during this time more force is applied to brake the vehicle and if the distance is far it is vice versa.
#5
Electromagnetic Braking System Using Eddy Current for Brake Disc of AL6061 AND AL7075 Journal: International Review of Mechanical Engineering Authors: M.Z.Baharom, M.Z.Nuawi, G.Priyandoko, S.M.Haris Review:
The behavior of electromagnetic braking using eddy current was studied. Started with preliminary study investigating 3 different materials of aluminum, copper and zinc to choose the best material as brake disc. It also looks on effects of increasing current induced into electromagnet. Aluminum performs better copper and zinc, and then the study continues using two different series of aluminum which are Al6061 and Al7075. A few parameters have been varied such as air-gap, brake disc thickness, number of electromagnet turns and voltage supplied to DC motor. For the purpose of recording speed (rpm) and time (s), an optical tachometer connected to PULSE analyzer has been used. Graphs presented to show the behavior and reaction of parameters involved, including the calculation of braking torque. From this study, it can be concluded that Al6061 has greater performance than Al7075 as the brake disc material. It also founded that the thicker the disc, small air-gap, large number of electromagnet turns and increasing the current induced will increase the performance of this electromagnetic braking . All parameters that have been studied show significant effects to be considered in developing electromagnetic braking to replace the conventional braking system.
#6
THE DESIGN OF EDDY-CURRENT MAGNET BRAKES Journal: Transactions of the Canadian Society for Mechanical
Engineering Authors: Der-Ming Ma, Jaw-Kuen Shiau Review:
The eddy-current is created by the relative motion between a magnet and a metal conductor. The current induces the reverse magnetic field and results in the deceleration of motion. The proposed mechanism implements this phenomenon in developing a braking system. The potential applications of the braking system can be a decelerating system to increase the safety of an elevator or any guided rail transportation system. To provide scientific investigation for industrial application of magnetic braking, this study presents four systematic engineering design scenarios to design a braking system. The constant magnetic field is the simplest and easiest design to implement. The optimal magnetic field distribution is obtained by minimizing the deceleration effort. The piecewise-constant magnetic field distribution offers a compromise between performance and magnetic field requirements. In the study, an experimental braking system using constant magnetic field is built to demonstrate the design procedure.
