Obstacle Avoidance Robotic Vehicle

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Obstacle Avoidance Robotic Vehicle

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Abstract

• The main scope of project is to automatically
  changing the direction of robotic vehicle as
  required whenever any obstacle comes on its way.
• Here an ultrasonic sensor is used which detects
  the presence of any obstacle and sends the signal
  to microcontroller which changes the direction of
  the robot.

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Introduction

• This particular robotic device is a combination
  of both mechanical and electronics engineering.
• This system is made so that it can be used to
  detect and avoid obstacles successfully.
• This robot will be just like an electronic car
  that keeps on moving in straight line until
  something comes in its path thats when it
  decides to turns into some other direction so it
  successfully avoids the obstacle.

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Block diagram

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Working of circuit diagram

• The project proposes robotic vehicle that has an
  intelligence built in it such that it guides
  itself whenever an obstacle comes ahead of it.
• This robotic vehicle is built, using a
  microcontroller of 8051 family. An ultrasonic
  sensor is used to detect any obstacle ahead of it
  and sends a command to the microcontroller.
• Depending on the input signal received, the
  microcontroller redirects the robot to move in an
  alternate direction by actuating the motors
  interfaced to it through a motor driver IC.

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Hardware requirements

• POWER SUPPLY
• MICROCONTROLLER 8052
• ULTRASONIC SENSOR
• MOTOR DRIVER IC

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Power supply
Bridge rectifier
230 V AC 50 Hz
5v Regulator

5V DC
Filter(470µf)
12V step down transformer
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Micro controller

• 8K Bytes of In-System Programmable (ISP) Flash
  Memory.
• 4.0V to 5.5V Operating Range.
• Crystal Frequency 11.0592MHZ.
• Three-level Program Memory Lock.
• 256 x 8-bit Internal RAM.
• 32 Programmable I/O Lines.
• Three 16-bit Timer/Counters.

AT89S52
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Block diagram of MC

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MC components explanation

• ROM
• A code of 4K memory is incorporated as on-chip
  ROM in 8051.
• RAM
• The 8051 microcontroller is composed of 128 bytes
  of internal RAM.
• Interrupt Control
• An event which is used to suspend or halt the
  normal program execution for a temporary period
  of time in order to serve the request of another
  program or hardware device is called an
  interrupt.

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MC components explanation
Parallel Input/Output Ports PORT P0 When there
is no external memory present, this port acts as
a general purpose input/output port. PORT P1
This port is used for various interfacing
activities. PORT P2 This port can be used as a
general purpose port when there is no external
memory but when external memory is present it
works in conjunction with PORT PO as an address
bus. PORT P3 PORT P3 behaves as a dedicated
I/O port.

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MC components explanation

• Address Bus
• A bus is group of wires using which data transfer
  takes place from one location to another within a
  system.
• Timers and Counters
• Synchronization among internal operations can be
  achieved with the help of clock circuits which
  are responsible for generating clock pulses.
• Internal operations can be synchronized using
  clock circuits which produce clock pulses.

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Pin diagram of 8052

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8052 pin diagram explanation

• Port 0(p0.0 to p0.7)
• It is 8-bit bi-directional I/O port. It is bit/
  byte addressable. During external memory access,
  it functions as multiplexed data and low-order
  address bus AD0-AD7.
• Port 1 (p1.0 to p1.7)
• It is 8-bit bi-directional I/O port. When logic
  '1' is written into port latch then it works as
  input mode. It functions as simply I/O port and
  it does not have any alternative function.

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8052 pin diagram explanation

• Port 2 (p2.0 to p2.7)
• It is 8-bit bi-directional I/O port. It is bit/
  byte addressable.
• Port 3(p3.0 to port 3.7)
• It is 8-bit I/O port. In an alternating function
  each pins can be used as a special function I/O
  pin.
• RESET 
• It is active high I/P signal. It should be
  maintained high for at least two machine cycle
  while oscillator is running then 8051
  microcontroller resets.

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Ultrasonic sensor

• Ultrasonic sensors (also known as transceivers)
  work on a principle similar to radar or sonar
  which evaluate attributes of a target by
  interpreting the echoes from radio or sound waves
  respectively.
• Ultrasonic sensors generate high frequency sound
  waves and evaluate the echo which is received
  back by the sensor.

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Ultrasonic receiver

• Ultrasonic generators use piezoelectric materials
  such as zinc or lead zirconium tartrates or
  quartz crystal.
• The material thickness decides the resonant
  frequency when mounted and excited by electrodes
  attached on either side of it.
• The medical scanners used for abdomen or heart
  ultrasound are designed at 2.5 MHz In this
  circuit, a 40 kHz transducer is used for object
  detection in the air medium.

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Ultrasonic features

• Use for motion or distance sensing .
• Frequency 40kHz 1.0kHz.
• Aluminum case.
• Capacitance 2000Pf 20.
• Transmitter bandwidth 5.0kHz/100Db, sound
  pressure level.
• 112Db/40 1.0kHz

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Motor driver IC

• L293D is a dual H-bridge motor driver integrated
  circuit (IC).
• Motor drivers act as current amplifiers since
  they take a low-current control signal and
  provide a higher-current signal.
• This higher current signal is used to drive the
  motors.
• L293D contains two inbuilt H-bridge driver
  circuits. In its common mode of operation, two DC
  motors can be driven simultaneously, both in
  forward and reverse direction.

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Motor driver ic diagram

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Operation of motor driver

• L293D has 2 set of arrangements where one set has
  input 1, input 2, output 1 and output 2 and
  other set has input 3, input 4, output 3 and
  output 4, according to block diagram if pin no 2
  7 are high then pin no 3 6 are also high.
• If enable 1 and pin number 2 are high leaving
  pin number 7 as low then the motor rotates in
  forward direction.
• If enable 2 and pin number 10 are high leaving
  pin number 15 as low then the motor rotates in
  forward direction.

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Operation of motor driver

• If enable 1 and pin number 2 are low leaving pin
  number 7 as high then the motor rotates in
  reverse direction.
• If enable 2 and pin number 15 are high leaving
  pin number 10 as low then the motor rotates in
  forward direction.

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Operational diagram

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Software requirements

• Keil an ARM Company makes C compilers, macro
  assemblers, real-time kernels, debuggers,
  simulators, integrated environments, evaluation
  boards, and emulators for ARM7/ARM9/Cortex-M3,
  XC16x/C16x/ST10, 251, and 8051 MCU families.
• Compilers are programs used to convert a High
  Level Language to object code. Desktop compilers
  produce an output object code for the underlying
  microprocessor, but not for other
  microprocessors.

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Applications

• Obstacle Detection for a Mining Vehicle.
• Driverless vehicles running along beams.
• Obstacle detecting system for a motor vehicle.
• Autonomous cleaning robot.

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Future scope

• The future work includes the enhancement of the
  robot design so that it can compute area of a
  room and plot it on the computer.

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Conclusion

• It gives on an opportunity to test his mechanical
  and electronics and programming skills .
• Obstacle Avoidance Robotic Vehicle project also
  provides robot construction experience to
  beginners.
• This technology has application everywhere from
  industry to home appliances all that is required
  is to implement it correctly to get the best out
  of it.

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