26-05-2012, 10:17 AM
Parallel Parking R/C Car
Parallel_Parking_RC_Car.pdf (Size: 224.49 KB / Downloads: 111)
Project Description
We as engineers may have thought about building a dream car. How is an
automated car possible? Well, it’s simple. At least the idea is. First, we need to make it
clear that we are not building a car. Furthermore, we are not saying we are going to make
a car that moves without a driver. We simply want to create a system that will help the car
to parallel park by itself.
This project is inspired by the new Lexus LS, which has a feature of self parallel
parking. Since it is too expensive to experiment with a real car, we sized down our object
of experiment to an RC car.
Using the microcontroller that we used in the previous term, Arduino, we control
the car. On the stripped down RC car, we attach a breadboard on top of it. The only parts
we used from the original RC car are the motors, the gears (to rotate the wheels) and the
wheels. Using the motor driver to control the motors based on the instructions sent by the
Arduino. Arduino simultaneously move the car forward while the IR sensor feed the
distance information to Arduino. The Arduino then keep moving the car forward until
some distance condition is met. If there is enough space to park and the conditions are
met, the car will start to self-park by using pre-defined movements. With this method, it
is possible to apply this system for different type of parking.
This project is designed with the view that future car does not require people to
actually drive it. With this in mind, this system would be able to assist the car in parallel
parking. And since this system only use one sensor and predefined movements to park the
car; we can apply this kind of system to any kind of parking.
3. System Level Block Diagram
Description:
9V Batteries
o Used to power up arduino and the motor driver.
Motor Driver
o Used to control the two motors: motor 1 and motor 2.
Arduino Microcontroller
o The brain of the project. The code that we wrote will be uploaded to this
microcontroller. This microcontroller will then control the motor driver based
on the inputs received from the IR sensor.
IR Sensor
o Used to detect distance, which is essential in positioning the car for parallel
parking.
Motor 1
o This motor will drive the RC Car forward or reverse, controlling the rear
wheels.
Motor 2
o This motor will function as the servo for the RC Car, controlling the front
wheels i.e. making the RC turn left or right.
4. Circuit Level Block Diagram
The measurements used for the descriptions bellow are assumed ideal conditions and not
mounted using a breadboard.
Arduino
The 9V and GND are connected to the positive and negative terminals of the 9V
battery respectively. This will power up Arduino.
The 5V is connected to the Vcc of the IR sensor and the pin 3 of the Motor Driver.
For the IR sensor, the 5V should provide the power for the IR to do the distance
measurement. As for Motor Driver, the 5V will provide the logic power supply
which will be used in determining the direction of the motors.
GND is also connected to the GND of the IR sensor and pin 2 of the Motor Driver
as depicted using black wires.
Analog pin 2 is connected to Vo of the IR sensor as depicted using yellow wires.
This pin will read in the values for distance reading done by the sensor.
Digital pin 11 is connected to the motor driver as the reset pin. The function of the
reset pin is to stop all the motors’ activities.
5
Digital pin 1 (TX) is connected to the motor driver as a mean to send instruction
to the motor driver. Using a specific format, we control the motor driver using
Arduino. The serial instruction sent through this pin enable us to control the
direction of both motors used in this experiment.
IR Sensor
Vcc is the input voltage for the IR sensor. This pin is connected to the 5V source
from the Arduino as depicted using red wires.
Vo is the output voltage from the IR sensor. The
output voltage is in analog which result will
vary depending on the distance of the object
with to the IR sensor. The output voltage is
expected to be varying from 0.7V to 2.6V
depending on the distance measured. As the
distance measured becomes larger, the output
voltage will decrease from 2.6V. The minimum
and maximum range this IR sensor can
measure is 10 cm and 24 cm respectively with
an error margin of 3 cm.
GND is connected to the GND of the Arduino.
This value should be absolute 0V.
Motor Driver
Pin 1 is used as motor supply. The possible input voltage for this pin ranges from
1.8V to 9V. In this case, we use 9V.
Pin 2 is the ground. We connect this to the GND of the 9V and the GND of the
Arduino.
Pin 3 is the logic supply. This pin should be connected to the 5V pin of Arduino.
This will drive the logic gates inside the Motor Driver.
Pin 4 is the serial control input. Using this pin, we control the logic of the motor
drivers in determining in what directions the motors should be. This pin is
connected to the Digital pin 1 of Arduino.