F12: Self-Driving GPS Following Car - Revision history

Preet: /* Project Source Code */

2013-02-04T22:03:44Z

‎Project Source Code

Caleb f12: /* Project Video */

2012-12-19T03:56:51Z

‎Project Video

Caleb f12: /* Project Video */

2012-12-19T02:47:59Z

‎Project Video

Caleb f12: /* Project Video */

2012-12-19T02:47:11Z

‎Project Video

Caleb f12: /* Hardware Interface */

2012-12-17T21:18:49Z

‎Hardware Interface

Caleb f12 at 21:12, 17 December 2012

2012-12-17T21:12:06Z

Caleb f12: /* Software Design */

2012-12-17T21:06:12Z

‎Software Design

Caleb f12: /* References */

2012-12-17T21:03:51Z

‎References

Caleb f12: /* Implementation */

2012-12-17T20:40:35Z

‎Implementation

Caleb f12: /* Hardware Design */

2012-12-17T20:39:23Z

‎Hardware Design

@@ Line 673: / Line 673: @@
 === Project Source Code ===
-Send me your zipped source code and I will upload this to SourceForge and link it for you.
+*  [http://sourceforge.net/projects/sjsuf12/files Project source code is available at SourceForge]
 == References ==

@@ Line 670: / Line 670: @@
 === Project Video ===
-[http://www.youtube.com/watch?v=Hx27m01OdYs Demonstration Video: Obstacle Avoidance]<BR/>
+[http://www.youtube.com/watch?v=wbpIZfiJ0zk Demonstration Video]<BR/>
 === Project Source Code ===

@@ Line 670: / Line 670: @@
 === Project Video ===
-[http://www.youtube.com/watch?v=Hx27m01OdYs CmpE146 F12 T7 Demonstration Video: Obstacle Avoidance]<BR/>
+[http://www.youtube.com/watch?v=Hx27m01OdYs Demonstration Video: Obstacle Avoidance]<BR/>
-[http://www.youtube.com/watch?v=QqenlpdfwVE CmpE146 F12 T7 Demonstration Video: Drive To GPS Destination]
+[http://www.youtube.com/watch?v=QqenlpdfwVE Demonstration Video: Drive To GPS Destination]
 === Project Source Code ===

@@ Line 670: / Line 670: @@
 === Project Video ===
-Upload a video of your project and post the link here.
+[http://www.youtube.com/watch?v=Hx27m01OdYs CmpE146 F12 T7 Demonstration Video: Obstacle Avoidance]<BR/>
 === Project Source Code ===

@@ Line 477: / Line 477: @@
 <table class="wikitable">
-<th>Inputs</th> <th></th> <th></th> <th>Motor Action</th> <th></th>
+<th>Enable</th> <th>Dir1</th> <th>Dir2</th> <th>Direction Motor</th> <th>Steering Motor</th>
 <tr>

@@ Line 584: / Line 584: @@
 === Software Design ===
 The project was built on top of the FreeRTOS sample project with the UART, I2C, and ADC drivers included. Additional tasks were created to enable multitasking.
-=== Tasks ===
+==== Tasks ====
 The following tasks were used on the self-driving car:
 * Terminal Task
@@ Line 607: / Line 608: @@
 The tasks were created such that the GPS tasks have a higher priority than the rest. Since GPS data was stored into a buffer by UART, the data could not be allowed to collect or else by the time the car updates the coordinates, the data will already by outdated. The tasks were also designed with different sleep delays. The GPS tasks had no delay since they will automatically sleep when there is no data to read, while the sensors task had a delay of 75mS. The bare minimum allowed was 49mS, which was limited by the proximity sensors. Additional delay was added for safe measure to prevent reading echos. The navigation task was set to have a delay of 50mS. A delay less than the sensors was selected so that the worst case time before readjusting the motors to the driving conditions was 125mS. This would allow the car to have a faster reaction time.
-=== Shared Resources ===
+==== Shared Resources ====
 In order to allow data to be accessed by multiple tasks,  certain variables had to be made accessible globally. This was accomplished by using handles to the data. For the data that had to be updated simultaneously, such as GPS coordinates, a semaphore was used to lock the data. Integers that had to be shared were not required to be locked since the variables could be updated with a single instruction.
-=== GPS Data Handling ===
+==== GPS Data Handling ====
 The two GPS tasks processed GPS data identically. GPS data was received following the National Marine Electronics Association (NMEA) specifications. Since the only necessary information to read was latitude and longitude, sentences of type GGA were selected to be processed so that the coordinates could be stored for use in navigation.
 <BR/> <BR/>
 In the navigation task, computations had to be made to get from having two sets of GPS coordinates to knowing how to steer toward the destination. NMEA sentences store the coordinates in a degree-decimal minute format (DDDMM.MMMM). In order to make use of the coordinates for distance and bearing calculations, the coordinates have to be converted to decimal degree format (DDD.DDDD). Trigonometry can be used with the coordinates in decimal degree format to compute the distance and bearing necessary. But, the bearing computed is relative to the true north while the compass reading is relative to magnetic north. Since magnetic north is constantly changing depending on the geographical location, the difference, or magnetic declination, needs to be accounted for. The end result of all the computation is the target angle desired to be read on the compass, which indicates the direction of the destination.
-=== Obstacle Avoidance ===
+==== Obstacle Avoidance ====
 Obstacle avoidance was accomplished by using the distances read from the proximity sensors. The following flowchart shows the algorithm used to avoid obstacles. <BR/> <BR/>
 [[File:Cmpe146_F12_T7_Obstacle_Avoidance_Algorithm.jpg|center|frame|Obstacle Avoidance Algorithm]]
-== Hardware Implementation ==
+=== Hardware Implementation ===
 All of the components are interfaced through the SJOneboard which has a built-in LPC1758 Microcontroller. The three sonar sensors provide their data readings through ADC as voltage values, which are interpreted accordingly in software, based on their datasheet specifications. There are two motor controllers in the system, one for each motor in the car. The rear motor and its controller is manipulated with PWM, which enables for changes in speed. The PWM is connected to the enable pin in the motor controller to save battery and for better control of the motor. The front motor controller is always enabled since the motor is not used very often. Each motor controller has two direction pins, thus all four pins are connected to four GPIO ports on the main SJOne board. The last two components, the GPS and Compass are connected to the board through I2C and ADC, respectively.
 <BR/> <BR/>
@@ Line 631: / Line 632: @@
 [[File:CmpE146_F12_T7_Following Car Front View.jpg|center|frame| Following Car Front View]]
-== Software Implementation ==
+=== Software Implementation ===
-=== Terminal Task ===
+==== Terminal Task ====
 In order to simplify development, a configuration utility was used. The configuration utility allowed for calibrations to be made without reprogramming the microcontroller. This allowed for faster testing and calibration of the sensors, motor speed, and logging without having to rebuild every time. The configuration utility also allowed us to log sensor information in order to know the readings when the car was not connected directly to the terminal and it was in motion. The utility modifies the program variables directly in the flash memory with the use of specific terminal commands.
-=== XBee GPS and My GPS Tasks ===
+==== XBee GPS and My GPS Tasks ====
 All this task did was process the received GPS data from UART into a latitude and longitude coordinate. A NMEA sentence was verified to be valid by checking the checksum. Once the sentence was verified, the fields were parsed to get the coordinates.
-=== Sensors Task ===
+==== Sensors Task ====
 The sensors task used I2C to read compass data and ADC to read the proximity sensors. A compass reading was made by reading two bytes. A high byte register and low byte register was read and combined to create the reading. The data was then converted to the standard 360 degree format. Proximity sensor readings were made by reading the analog output from the sensor. The value was compared to the supply voltage to determine how much of the maximum range an object was at.
-=== Navigation Task ===
+==== Navigation Task ====
 In order to drive the car, the navigation task used sensor readings and navigation information to control the motor controllers. The motor controllers were controlled by using a PWM to set the motor speed and GPIO pins to set the motor directions. Speeds and directions were determined by checking distances from objects, whose thresholds could be configured. Objects at different thresholds would make the car react differently. When there were no obstacles, car would drive toward the destination by calculating the bearing needed to get from the starting GPS coordinate to the destination GPS coordinate. Under drive to destination condition, the car would steer to align its bearing with the required bearing and drive forward.
-=== Info Task ===
+==== Info Task ====
 The info task uses the configuration utility to determine what information to log and whether to log to the flash memory or just display it. Sensor readings and navigation information were all capable of being logged.

@@ Line 692: / Line 692: @@
 == References ==
-=== Acknowledgement ===
+=== Acknowledgements ===
-Any acknowledgement that you may wish to provide can be included here.
+Dr. Haluk Özemek<BR/>
 === References Used ===
-List any references used in project.
+Compute distance between coordinates: [http://stackoverflow.com/a/1416950]<BR/>
 === Appendix ===
-You can list the references you used.
+ZIP file: TODO

@@ Line 619: / Line 619: @@
 [[File:Cmpe146_F12_T7_Obstacle_Avoidance_Algorithm.jpg|center|frame|Obstacle Avoidance Algorithm]]
-=== Implementation ===
+== Hardware Implementation ==
-This section includes implementation, but again, not the details, just the high level.  For example, you can list the steps it takes to communicate over a sensor, or the steps needed to write a page of memory onto SPI Flash.  You can include sub-sections for each of your component implementation.
+All of the components are interfaced through the SJOneboard which has a built-in LPC1758 Microcontroller. The three sonar sensors provide their data readings through ADC as voltage values, which are interpreted accordingly in software, based on their datasheet specifications. There are two motor controllers in the system, one for each motor in the car. The rear motor and its controller is manipulated with PWM, which enables for changes in speed. The PWM is connected to the enable pin in the motor controller to save battery and for better control of the motor. The front motor controller is always enabled since the motor is not used very often. Each motor controller has two direction pins, thus all four pins are connected to four GPIO ports on the main SJOne board. The last two components, the GPS and Compass are connected to the board through I2C and ADC, respectively.
 == Testing & Technical Challenges ==

@@ Line 275: / Line 275: @@
 <center>
 [[File:Cmpe146_F12_T7_Leading_Car_Block_Diagram.png|center|frame|Leading Car Block Diagram]]
 </center>
@@ Line 295: / Line 294: @@
 <center>
 [[File:Cmpe146_F12_T7_Following_Car_Block_Diagram.png|center|frame|Following Car Block Diagram]]<BR/>
 </center>