F13: Line Following Robot - Revision history

Preet: /* Project Source Code */

2013-12-07T05:05:14Z

‎Project Source Code

Proj user4: /* References Used */

2013-12-06T01:48:27Z

‎References Used

Proj user4: /* Grading Criteria */

2013-12-06T01:42:17Z

‎Grading Criteria

Proj user4: /* References */

2013-12-06T01:40:24Z

‎References

Proj user4: /* Conclusion */

2013-12-06T01:29:31Z

‎Conclusion

Proj user4: /* Testing & Technical Challenges */

2013-12-06T01:27:22Z

‎Testing & Technical Challenges

Proj user4: /* Dual Serial Motor Controller */

2013-12-06T01:21:38Z

‎Dual Serial Motor Controller

Proj user4: /* Reflectance Sensor Array */

2013-12-06T01:21:19Z

‎Reflectance Sensor Array

Proj user4: /* Implementation */

2013-12-06T01:16:21Z

‎Implementation

Proj user4: /* Testing & Technical Challenges */

2013-12-05T02:58:59Z

‎Testing & Technical Challenges

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 === Project Source Code ===
-Send me your zipped source code and I will upload this to SourceForge and link it for you.
+*  [https://sourceforge.net/projects/sjsu/files/CmpE240_LM_F2013/ Sourceforge link for source code]
 == References ==

← Older revision		Revision as of 01:48, 6 December 2013
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	* [https://www.youtube.com/watch?v=GkbOJSvhCgU Video Tutorial for Crimping PCB Interconnect Cables]		* [https://www.youtube.com/watch?v=GkbOJSvhCgU Video Tutorial for Crimping PCB Interconnect Cables]
		+
		+	* [http://www.socialledge.com/sjsu/index.php?title=Bit_Structures Bit Structures Tutorial]

← Older revision		Revision as of 01:42, 6 December 2013
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−	~~=== Grading Criteria ===~~
−	~~<font color="green">~~
−	* How well is Software & Hardware Design described?
−	* How well can this report be used to reproduce this project?
−	* Code Quality
−	* Overall Report Quality:
−	** Software Block Diagrams
−	** Hardware Block Diagrams
−	**: Schematic Quality
−	** Quality of technical challenges and solutions adopted.
−	~~</font>~~
−
	== Line Following Robot ==		== Line Following Robot ==

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 == References ==
 === Acknowledgement ===
-Any acknowledgement that you may wish to provide can be included here.
+* Professor Kang
 === References Used ===
 * [http://www.nxp.com/documents/user_manual/UM10360.pdf LPC1758 User Manual]
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 * [https://www.youtube.com/watch?v=GkbOJSvhCgU Video Tutorial for Crimping PCB Interconnect Cables]

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 == Conclusion ==
-Conclude your project here.  You can recap your testing and problems.  You should address the "so what" part here to indicate what you ultimately learnt from this project.  How has this project increased your knowledge?
+The Line Following Robot project was a challenging and rewarding experience.  It provided the opportunity to apply and expand upon the knowledge taught by Professor Kang during the CmpE 240 course.  In particular, the knowledge gained included how a Reflectance Sensor Array uses infrared LEDs and phototransistors to provide reflectivity measurements, how a GPIO pin can be used as a very simple ADC with one bit resolution, how to communicate with peripherals, such as the Dual Serial Motor Controller, using the UART serial communication interface protocol, how pulse width modulation is used to control motors, and how to use a microcontroller to develop a simple embedded system.
 === Project Video ===

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 ==== Line Following Robot System Test ====
-Describe testing here
+System test of the Line Following Robot involved testing the objectives of the project which include moving forward searching for a black line on a white surface, detect a black line on a white surface, and generate control commands to follow a detected black line.  This level of system test also presented the first opportunity to integrate and test the actual transmission of motor commands from the LPC1758 microcontroller to the Dual Serial Motor Controller because the infrastructure required to perform this testing was not in place until the assembly of the Line Following Robot was completed.  Previously, motor commands were simply looped back to the microcontroller and displayed to the Hercules terminal.  The system test of the Line Following Robot was performed by placing it on a line following course and observing its ability to meet the project objectives.  Further hardware and software changes were made as required based on the behavior of the Line Following Robot during its system test.
-Describe the challenges of your project.  What advise would you give yourself or someone else if your project can be started from scratch again?
+==== RSA Mounting Issue ====
-Make a smooth transition to testing section and described what it took to test your project.
+The preliminary mechanical design of the Line Following Robot involved mounting the Reflectance Sensor Array directly underneath the front of the lower chassis and routing the necessary wiring under the motors via right angle header connectors.  Unfortunately, the proximity of the twin motor gearbox to the ground and front of the lower chassis was not taken into account.  The placement of the twin motor gearbox prevented the planned mounting point from being used.  To resolve this issue, the universal metal joints were obtained to extend the mounting point of the Reflectance Sensor Array in front of the Line Following Robot and the right angle header connections were replaced with straight header connections.
-Include sub-sections that list out a problem and solution, such as:
+==== DSMC Configuration Issue ====
-=== Wifi Connection Issues ===
+==== DSMC Reset Issue ====
-Many wifi connection issues were encountered.  To solve this problem, a dedicated task was created to re-connect to wifi if the connection was ever lost.
+Two separate issues contributed to the Dual Serial Reset Controller reset issue.  These included the original selection of the pin used to provide reset control and the pull-down resistor value.  Because the Dual Serial Motor Controller is receive-only, the pin on the SJ One Board labeled as RXD2 was selected to be configured as a GPIO output, instead of the UART2 receive input, to drive the reset signal.  The RXD2 trace on the SJ One Board, however, contains a pull-up resistors and an active-low configured LED to indicate activity on the UART2 receive input.  The combination of pre-existing resistors and LED on the RXD2 line interfered with the pull-down resistor for the reset input of Dual Serial Motor Controller.  To overcome this problem, pin P1.22 which is designated as a general purpose pin on the SJ One Board was selected to drive the reset input of the Dual Serial Motor Controller.
 == Conclusion ==

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 ==== Dual Serial Motor Controller ====
-The Dual Serial Motor Controller accepts commands via its serial communication interface using a baud rate between 1200 and 19200 with eight data bits, no parity bit, and one stop bit.  Its serial interface is receive-only and automatically detects the baud rate.  The UART2 peripheral of the microcontroller is configured to transmit the generated motor commands to the Dual Serial Motor Controller at a baud rate of 9600.
+The Dual Serial Motor Controller (DSMC) accepts commands via its serial communication interface using a baud rate between 1200 and 19200 with eight data bits, no parity bit, and one stop bit.  Its serial interface is receive-only and automatically detects the baud rate.  The UART2 peripheral of the microcontroller is configured to transmit the generated motor commands to the Dual Serial Motor Controller at a baud rate of 9600.
 Upon receipt of a motor command, the Dual Serial Motor Controller adjusts its PWM motor control outputs to perform the commanded action.  The PWM motor control outputs operate at a frequency of 600 Hz and the voltage level is based on the input motor voltage supplied to the Dual Serial Motor Controller.  The PWM motor control outputs provide independent control of two brushed DC motors.  The independent control of the two motors allows the Line Following Robot to turn left or right using a ball caster as the third point of balance.

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 ==== Reflectance Sensor Array ====
-The Reflectance Sensor Array includes eight sensors.  Each of the eight sensors consists of an IR LED, a phototransistor, and a capacitor connected in series with the phototransistor.   To obtain a reflectivity reading from the Reflectance Sensor Array, the microcontroller GPIO pins connected to the sensor I/O pins are driven high to charge the capacitors.  Once the capacitors have been fully charged, the microcontroller switches its GPIO pins to inputs.  With the microcontroller GPIO pins switched to inputs, the capacitors begin discharging through the phototransistors at a rate based on the reflectivity of the surface illuminated by the IR LEDs.  After allowing an appropriate amount of time for the capacitors to discharge accordingly, the eight sensor I/O pins of the Reflectance Sensor Array are read by the microcontroller.
+The Reflectance Sensor Array (RSA) includes eight sensors.  Each of the eight sensors consists of an IR LED, a phototransistor, and a capacitor connected in series with the phototransistor.   To obtain a reflectivity reading from the Reflectance Sensor Array, the microcontroller GPIO pins connected to the sensor I/O pins are driven high to charge the capacitors.  Once the capacitors have been fully charged, the microcontroller switches its GPIO pins to inputs.  With the microcontroller GPIO pins switched to inputs, the capacitors begin discharging through the phototransistors at a rate based on the reflectivity of the surface illuminated by the IR LEDs.  After allowing an appropriate amount of time for the capacitors to discharge accordingly, the eight sensor I/O pins of the Reflectance Sensor Array are read by the microcontroller.
 A white surface has a high reflectivity and will turn the phototransistor on.  When the phototransistor is turned on, the capacitor in series with it will be allowed to discharge through the phototransistor.  With the capacitor discharged, a low voltage will be present at the sensor I/O pin and will be converted as a logical zero by the microcontroller.  In contrast, a black surface has a low reflectivity and will not turn the phototransistor on.  When the phototransistor is off, the capacitor in series with it will not be allowed to discharge through the phototransistor.  As a result, a high voltage will be present at the sensor I/O pin and will be converted as a logical high by the microcontroller.  Thus, sensors detecting a white surface will return a logical zero and sensors detecting a black surface will return a logical one when the microcontroller reads the Reflectance Sensor Array.

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 {|
 [[File:CmpE240_F13_LFR_displayRSA.jpg|480px|thumb|left|Software Flow Diagram for Display of Reflectance Sensor Array Data on the SJ One Board General Purpose LEDs]]
 |}
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 ==== Transmit Motor Command ====
-Once the selection of the movement command has been completed, the command is transferred to the Dual Serial Motor Controller in order to execute the desired steering action.  The transmission of the movement command is performed by the functions provided in the Dual Serial Motor Controller drivers.  After the movement command is transmit, the main loop concludes by updating the previous sensor data with the current sensor data for use in the next iteration of the loop.  The main loop then returns to the aforementioned 50 ms delay prior to obtaining the next Reflectance Sensor Array data reading.  The flow diagram below summarizes the steps performed by the software implementation of the Line Following Robot.
+Once the selection of the movement command has been completed, the command is transferred to the Dual Serial Motor Controller in order to execute the desired steering action.  The transmission of the movement command is performed by the functions provided in the Dual Serial Motor Controller drivers.  After the movement command is transmit, the main loop concludes by updating the previous sensor data with the current sensor data for use in the next iteration of the loop.  The main loop then returns to the aforementioned 50 ms delay prior to obtaining the next Reflectance Sensor Array data reading.
 == Testing & Technical Challenges ==

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 {|
-[[File:CmpE240_F13_LFR_2791.jpg|480px|thumb|left|Debug of the IR LED Reflectance Sensor Array and Dual Serial Motor Controller Drivers with the SJ One Board (LPC1758)]]
+[[File:CmpE240_F13_LFR_2791.jpg|480px|thumb|left|Reflectance Sensor Array Unit Test Setup]]
 |}
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 ==== RSA and DSMC System Test ====
-Describe testing here
+System test of the Reflectance Sensor Array and Dual Serial Motor Controller drivers was performed to integrate and test reading of the sensor array, processing the sensor data to select the appropriate movement command, and transmitting the selected movement command.  The test setup used for the integration and test of the Reflectance Sensor Array and Dual Serial Motor Controller drivers combined the setups of their individual unit tests.  The Reflectance Sensor Array was passed over a black line on a white surface, the movement command required to steer the center of the array over the black line was selected, the selected motor command was transmitted over the UART2 TXD2 pin and received on the UART3 RXD3 pin, and the received movement command was read from the UART3 receive FIFO.  Test results were verified by displaying the sensor reading, the selected movement command, and the received movement command read from the UART3 receive FIFO to the Hercules terminal.  The screenshot below provides a capture of the information displayed to the Hercules terminal during testing.
 ==== Line Following Robot System Test ====