MECHATRONICS

1.INTRODUCTION:

 Automobiles need high degree of safety to protect the occupants and their property. When the driver applies force on the brake pedal the magnitude is sensed by the pressure transducer which in turn sends the actuating signals to microprocessor. We have also incorporated artificial intelligence. Logic gates for backup-circuit for safety and shift current for shifting the power pack from generating mode to braking mode and vice-versa to generator power.

 The scope of E.P.M. braking system is very high due to the following reasons:

v  HIGH EFFECIENCY

v  ROLLING STOP

v  INSTANT STOP

v  ADDITIONAL POWER GENERATION

v  NO WEAR AND TEAR

v  HIGH DEGREE OF SAFTEY

            In our universe nothing is permanent; the only permanent aspect is technology. In our machine oriented world no particular field can strive on its own, so merging of all the major technological sciences becomes inevitable to cater needs of the Human Race. A field thus evolved is ‘MECHATRONICS’.

2.WHAT IS MECHATRONICS?

            Mechatronics is concerned with the blending of mechanical electronics & software fields. So the mechanical system, motor heads and gigabytes go hand in hand. As the saying goes “Necessity is the mother of invention”, locomotion was first on feet, animals, then by wagons powered by horses, then horses were replaced by horse power produced by the engines which went at roaring speeds, their safety was a big concern, so the stoppers namely the brakes were developed for the safety of the occupants and the vehicles.

            Brakes are one of the most important control components of the vehicle. They                              

            2

are required to stop the vehicles at the smallest distance and this is achieved by   converting the kinetic energy of the wheels into heat energy, which is dissipated into the atmosphere.

To provide a cutting edge upon the conventional braking systems, we have come up with a new concept of E.P.M.Braking. This will result in high safety standard which will minimize the damage to life and property.  

The main parts of E.P.M.Braking system are:

v  POWER PACK

v  MICROPROCESSOR

v  PRESSURE TRANSDUCER

v  CAPACITOR

v  D.C. POWER SUPPLY

v  LOGIC CIRCUITS

2.1 POWER PACK:

                     This unit is specially designed for E.P.M.Braking. This consists of armature wiring on the dead and live axle, surrounded by permanent magnet made of samarium cobalt with desired air gap. The armature is wound round with room temperature super conducting materials like carbon fibers and its composites. The whole setup is placed inside the casing. Sensors are placed inside the casing to sense the braking action. Power pack is incorporated with shift circuit for conversion of system from braking mode to generating mode or vice versa.

2.2 MICROPROCESSOR:

            This being the heart of the E.P.M.Braking transmits a pulsating D.C. supply to armature, which is directly proportional to the intensity of signals from the

3

pressure transducer via brake pedal. This also monitors the RPM and the rotation of the wheels. Microprocessor controls the mode of operation of the power pack.

2.3 PRESSURE TRANSDUCER:

            This is a piezo-electric crystal. When the force is applied on the pressure transducer via brake pedal, this sends actuating signals from the pressure transducer which is directly proportional to the force applied on the brake pedal.

POWER PACK

3.FUNCTIONAL OUTLOOK:

            When the vehicle is moving at a desired velocity, if there is any interference in the path there arises the need for braking, while braking the wheels, should not skid as the driver looses the control of the vehicle. A good braking system should have a rolling stop, so that the driver can handle vehicle easily. When the driver applies force on the brake pedal, which is in contact with the pressure transducer or the piezo-electric crystal, it sends actuating signals to the microprocessor, which shifts the power pack from generator mode to braking mode.

            The microprocessor is programmed in such a way that the frequency of constant D.C. pulse discharged from the capacitor is directly proportional to the

4

 intensity of   actuating signals from the pressure transducer. This pulsating D.C. is send to the armature of the power pack, which is fitted to both the axles. This is sensed by the microprocessor through the sensors. The torque is sufficient to bring the vehicle to a rolling stop within a short distance since we apply only pulsating D.C., there is neither sliding nor skidding of the wheels.   

When the vehicle is operated in the reverse gear the sensors in the power pack senses the direction and communicates to the microprocessor, so that the pulsating D.C. supplied to the armature is in the reverse direction. Another important aspect of this braking system is that the power pack also acts as a generator. When there are no actuating signals from the pressure transducer the logic circuit shifts the power pack from the braking mode to the generator mode. The power produced by the generator mode is fed to D.C. power source.

4.SHIFTING LOGIC:

            When the power pack is operating in the generator mode power is produced. After crossing the critical speed, to prevent the over loading of the engine is in the uphill condition, we have designed a simple logic circuit, which consists of a zener diode, XOR-GATE, NOT-GATE, power transistor and current limiting resistors.

             When the velocity of the vehicle increases, power produced also increases. The power produced is fed to a zener diode through a current limiting resistor R1. when the voltage from the power pack exceeds the critical voltage of the zener diode , it overcomes the brake down voltage and the A.D.C.(Analog to Digital Converter) sends a signal to the X-OR gate to pin1. Pin2 of this gate is connected to the pressure transducer through a A.D.C. When there is no braking there is no signal

5

to pin2. As the logic of X-OR gate when the input is ‘1’ and ‘0’ the output is ‘1’, this is fed to a NOT gate which gives an output of ‘0’. The power transducer receives the signal and it is triggered to connect the power pack to the battery for charging. If the brakes are applied pin2 of the x-OR gate receives signal from pressure transducer hence the output of X-OR gate is ‘0’ and NOT gate output is ‘1’, this closes the transistor circuit and it shifts the power pack from generator mode to braking mode. 

7

5.SAFETY BACKUP:

            In the case, if the microprocessor fails, the output from the microprocessor is ‘0’, this signal ‘0’ is send to the pin3 of X-OR gate. Pin4 of the X-OR gate receives signal’1’ from the pressure transducer and the output of the X-OR gate is ‘1’, this triggers the micro controller to discharge the current from the capacitor to the power pack. This is only a constant D.C. supply not a pulsating one. This brings the vehicle to a sudden stop.

6.INCORPORATION OF ARTIFICIAL INTELLIGENCE:

            A C.C.D.(charged couple device) camera captures the image of the surface in which the vehicle is moving. The image is in the form of pixels. A matrix of pixels is taken and the resultant brightness is found out. Similarly the resultant for all the matrix of pixels is obtained. Using a comparator circuit the resultant is matched with the resultant of template images, which are already stored in memory.

Process & Graphs

Classification of the images and training of the comparator is taken care by A.N.N. (Artificial Neural Networks). With the help of V.C.O (Voltage Control Oscillator) the signals are feed into the main circuit i.e. the voltage signals are converted into

8

frequency depending upon the intensity of actuating signals from the pressure transducer and also from the V.C.O. the square wave pattern is generated. If we want a vehicle to come to a sudden stop the lag time of square wave is reduced. While deceleration the lag time is increased as per the rate of deceleration.    

7.HIGHLIGHTS OF E.P.M. BRAKING SYSTEM:

v  High efficiency

v  Rolling stop

v  High degree of safety

v  No wear and tear

v  Very high response

v  Additional power generation

8.CONCLUSION:

            The above ideas may seem to be impossible; not in mere future considering the safety of the passengers this method of braking system plays an important role. By incorporating this type of braking system there is no need of extra arrangement. The wear and tear of the brake system and the tyre is less. Apart from this advantage there is generation of additional power for the source. This also increases the efficiency of the engine.

9.References :

Electrical Technology by   B.L.Thereja

Basic Electronics by V.K.Mehata

Mechatronics by W.Bolten

     www.searchengine.com

     www.sae.org.com

     www.scienceofspeed.com