F16: Titans

Project Title

Autonomous Navigating RC Car

Abstract

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Objectives & Introduction

Show list of your objectives. This section includes the high level details of your project. You can write about the various sensors or peripherals you used to get your project completed.

Track Progress in KanBan

• Titans Kanban Board

Team Members & Responsibilities

• Master Controller
  • Haroldo Filho
  • Urvashi Agrawal
• Motor Controller & I/O Module
  • Sant Prakash Soy
  • Saketh Sai Narayana
  • Kayalvizhi Rajagopal (LCD)
• GPS/Compass Module
  • Yang Thao (GPS)
  • Daamanmeet Paul (Compass)
• Sensors
  • Kayalvizhi Rajagopal
• Communication Bridge/Android App
  • Parth Pachchigar
  • Purvil Kamdar

Project Schedule

Legend: Motor & I/O Controller , Master Controller , Communication Bridge Controller, Geographical Controller, Sensor Controller , Team Goal

Week#	Start Date	End Date	Task	Status
1	09/13/2016	09/20/2016	Order Components and work distribution. Research on the type and model of sensors to use and order them. Research on components requirement based on past projects. Order motor controller related components: Traxxas RPM sensor, (Servo motor, DC motor and ESC)Included in traxxas RC car. Reverse engineering Traxxas ESC, signal receiver, and signal transmitter to learn about basic functionality of the car. Android Development Environment Setup. Map API fundamental study.	Completed
2	09/21/2016	09/27/2016	Set up git and wiki page Study the data sheet of sensor & prepare a high level design. Interface the sonic sensor to the sensor controller. Experiment and Research on voltage requirements for Servo and DC motor. Experiment and Research on PWM frequency requirements for DC and Servo motor. Experiment and Research on duty cycle required for controlling steer and speed of the car. Bluetooth BLE related android programming study and BLE protocol study.	Completed
3	09/28/2016	10/04/2016	Receive Components and distribute to group members. Interface all the front sensors and test the readings with different environment conditions. Interface the SJ One Board to car's ESC(Electronic Speed Controller) and servo motor and test research results. Decide on the CAN ids and the priorities of the CAN messaged for various nodes. Basic Android Application development, Intent passing, Finalize GUI template.	Completed
4	10/05/2016	10/11/2016	Agree on control system architecture, assign CAN node priorities and decide on communication paradigm between Master and Nodes. Prep for prototype. Stress test the sensors and design a filter so that reliable readings are sent to the master. Experiment and research on precision control of speed and steering using signals from SJ One board. Developing the framework for the I/O display and setting up SPI framework to read the CAN messages. Design the barebones basic functionality of the algorithm. Create a skeleton code. Controlling Bluetooth of Mobile Phone(i.e. Turn on, Connect), Connect Mobile phone with Bluetooth BLE module on SJOne.	Completed
5	10/12/2016	10/17/2016	Testing week for all nodes. Goal is for each node to have a basic interface to their sensors and actuators in place, where they are able to read data and manipulate control signals. For instance: sensors node should be reading distance, motors node should be able to generate motor speed control signals. Modify the necessary parts in the CAN.dbc file. Interface back sensor and test all the sensors together. Debug and fix any issues. Design software filter to filter CAN messages required for motor controller. Get readings from the RPM sensor. Read the CAN messages to display on the LCD connected to the SJ One board. Set up CAN communication between the sensor,motor and the master. Test for correct data transmission. Establishing basic communication between Android phone and SJOne Board.	Completed
6	10/18/2016	10/24/2016	Interface all nodes over Can bus and coordinate order and status message transfers between Master and Nodes. PCAN interface should be built to view & test CAN messages via Busmaster. Integrate sensors with other nodes via CAN and test the sensor values while the car is on the move. The master should have reliable data from sensors by now. Send signals to the motor controller from another CAN Node to control speed and steering using CAN interface. Creating necessary display messages and graphics related to the I/O modules. Design the algorithm to process the data received from the sensors and motors by the master. Integrate Google Map, Get Longitude and Latitude data from the position where Marker is placed, Get important data of other nodes from CAN bus.	Completed
7	10/25/2016	10/31/2016	Integrate all hardware to the RC car, including power supplies from batteries. Test self powered prototype with the goal of controlling forward, reverse, left and right with start/stop command from the phone app. Test & fix basic integration bugs. Integrating and testing motor & I/O controller with other nodes. Extend the algorithm to control the motors along with the obstacle information received from the sensors. Integrate bridge controller with other modules via CAN. Test & fix basic integration bugs.	Completed
8	11/1/2016	11/7/2016	Continue with hardware/software development & integration and complete first prototype of the collision avoidance feature. Design sensor mounts and 3D print them. Test and fine tune the algorithm developed so far for the first demo. Put multiple markers on Map and implement logic to find shortest route to destination and pass route information on CAN bus.	Completed
9	11/8/2016	11/14/2016	Integrate GPS coordinates from Android app into Master Node for autonomous feature. Mount the sensors and test for any dead band. Position them for maximum coverage. Obtain the data from the GPS and process the data to design the algorithm for navigation. Design and implement the kill switch to avoid the car from crashing. Integrate GPS coordinates from Android app into Master Node for autonomous feature. Testing and Bug fixing.	In Process
10	11/15/2016	11/21/2016	Integrate all nodes into one. Start testing car's autonomous driving capabilities with path following from GPS waypoints from Android app. Tune & optimize the sensor filter logic and the sensor mount as required. Integrate all the modules and test for the functionality. Save the data received from various modules into a log file for debugging purpose.	Not Started
11	11/22/2016	11/28/2016	Autonomous driving should be working by now. Focus on improving car's performance. Tweak all nodes to better performance, and fix last minutes bugs. Interface Head lights and turn them ON based on light sensor value. Include the headlights and the LCD on the car and display messages on them.	Not Started
12	11/22/2016	11/28/2016	Stress test the car with different environment scenarios. Improvise the algorithm and carry out stress testing and integration testing. Work on the modifications required and test previous hardware additions to the car.	Not Started
13	11/29/2016	Presentation date	Final touches to improve overall vehicle's robustness. Self-fixing nodes, reduce/eliminate unexpected behaviors and crashes. Integration and testing. Work to improvise on the algorithms and make sure individual modules work. Addition of any extra features and software development.	Not Started

Parts List & Cost

Item#	Part Desciption	Vendor	Qty	Cost
1	RC Car - Traxxas 1/10 Slash 2WD	Amazon	1	$189.95
2	Traxxas 2872X 5000mAh 11.1V 3S 25C LiPo Battery	Amazon	1	$56.99
3	Traxxas 7600mAh 7.4V 2-Cell 25C LiPo Battery	Amazon	1	$70.99
4	Traxxas 2970 EZ-Peak Plus 4-Amp NiMH/LiPo Fast Charger	Amazon	1	$35.99
5	Bluetooth 4.0 BLE Bee Module (Dual Mode)	Robotshop	1	$19.50
6	4D systems 32u LCD	4D systems	1	$41.55
7	LV Maxsonar EZ0 Ultrasonic sensors	Robotshop	5	$124.75
8	Devantech SF05 Ultrasonic sensor	Provided by Preet	1	Free
9	Venus GPS with SMA connector	Amazon	1	$49.95
10	SMA Male Plug GPS Active Antenna	Amazon	1	$9.45
11	Wire wrapping board	Radio shack	1	$20.0
12	CAN tranceivers	Digikey	10	$10.0
13	SJOne Boards	Provided by Preet	5	$400.0

DBC File Implementation

• The following is the DBC file of the project.

VERSION ""
NS_:
 NS_DESC_
 CM_
 BA_DEF_
 BA_
 VAL_
 CAT_DEF_
 CAT_
 FILTER
 BA_DEF_DEF_
 EV_DATA_
 ENVVAR_DATA_
 SGTYPE_
 SGTYPE_VAL_
 BA_DEF_SGTYPE_
 BA_SGTYPE_
 SIG_TYPE_REF_
 VAL_TABLE_
 SIG_GROUP_
 SIG_VALTYPE_
 SIGTYPE_VALTYPE_
 BO_TX_BU_
 BA_DEF_REL_
 BA_REL_
 BA_DEF_DEF_REL_
 BU_SG_REL_
 BU_EV_REL_
 BU_BO_REL_
 SG_MUL_VAL_
BS_:

BU_: DBG MASTER GPS MOTOR SENSOR APP

BO_ 1 APP_START_STOP: 1 APP
 SG_ APP_START_STOP_cmd : 0|8@1+ (1,0) [0|0] "COMMAND" MASTER

BO_ 16 SENSOR_DATA: 3 SENSOR 
 SG_ SENSOR_left_sensor : 0|8@1+ (1,0) [0|0] "Inches" MASTER,APP 
 SG_ SENSOR_middle_sensor : 8|8@1+ (1,0) [0|0] "Inches" MASTER,APP 
 SG_ SENSOR_right_sensor : 16|8@1+ (1,0) [0|0] "Inches" MASTER,APP

BO_ 32 MASTER_HB: 2 MASTER 
 SG_ MASTER_SPEED_cmd : 0|8@1+ (1,0) [0|0] "" SENSOR,MOTOR,GPS,APP
 SG_ MASTER_STEER_cmd : 8|8@1+ (1,0) [0|0] "" SENSOR,MOTOR,GPS,APP

BO_ 65 GPS_Data: 8 GPS
 SG_ GPS_READOUT_valid_bit : 0|1@1+ (1,0) [0|1] "" MASTER,MOTOR,APP
 SG_ GPS_READOUT_read_counter : 1|6@1+ (1,0) [0|60] "" MASTER,MOTOR,APP
 SG_ GPS_READOUT_latitude : 7|28@1+ (0.000001,-90.000000) [-90|90] "" MASTER,MOTOR,APP
 SG_ GPS_READOUT_longitude : 35|29@1+ (0.000001,-180.000000) [-180|180] "" MASTER,MOTOR,APP

BO_ 66 COMPASS_Data: 2 GPS
 SG_ COMPASS_Heading : 0|9@1+ (1,0) [0|0] "Degree" MASTER,APP,MOTOR 

BO_ 67 GEO_Header: 3 GPS
 SG_ GPS_ANGLE_degree : 0|12@1+ (0.1,-180) [-180.0|180.0] "Degree" MASTER,MOTOR,APP
 SG_ GPS_DISTANCE_meter : 12|12@1+ (0.1,0) [0.0|400.0] "Meters" MASTER,MOTOR,APP

BO_ 48 MOTOR_STATUS: 3 MOTOR
 SG_ MOTOR_STATUS_speed_mph : 0|16@1+ (0.001,0) [0|0] "mph" MASTER,APP,MOTOR

CM_ BU_ MASTER "The master controller driving the car";
CM_ BU_ MOTOR "The motor controller of the car";
CM_ BU_ SENSOR "The sensor controller of the car";
CM_ BU_ APP "The communication bridge controller of car";
CM_ BU_ GPS "GPS and compass controller of the car";
CM_ BO_ 100 "Sync message used to synchronize the controllers";
BA_DEF_ "BusType" STRING ;
BA_DEF_ BO_ "GenMsgCycleTime" INT 0 0;
BA_DEF_ SG_ "FieldType" STRING ;
BA_DEF_DEF_ "BusType" "CAN";
BA_DEF_DEF_ "FieldType" "";
BA_DEF_DEF_ "GenMsgCycleTime" 0;
BA_ "GenMsgCycleTime" BO_ 32 100;
BA_ "GenMsgCycleTime" BO_ 16 100;
BA_ "GenMsgCycleTime" BO_ 48 100;
BA_ "GenMsgCycleTime" BO_ 65 100;
BA_ "GenMsgCycleTime" BO_ 66 100;

Sensor Controller

Design & Implementation

The main purpose of the sensor controller is Obstacle avoidance and one of the straight forward way to achieve the goal is to use an Ultrasonic sensor.

Sensor controller being the “eye” of the project, lot of thoughts were put into deciding the right sensor to serve the purpose of obstacle avoidance. Considering the factors of reliability and cost, Maxbotix EZ0 ultrasonic sensor is chosen to be left and right sensors. EZ ‘0’ model is selected because it has the widest beam coverage of all the Maxbotix EZ series sensor models. Devantech SF05 ultrasonic sensor is selected for the middle sensor. A different model is used for middle sensor because of its different frequency, which avoids interference between sensors.

The sensors are mounted and tested at different angles so that the front three sensors cover a wide area, without leaving any dead or uncovered region.

Hardware Design

The sensors are interfaced using Port 2 GPIO pins of the microcontroller. The sensors require 5V power supply, which was provided from the main board’s supply. The trigger input to the sensors and the PWM output are interfaced to the GPIO pins as shown below in table. The pins for each sensor are chosen in such a way that it would not tangle each other while physically connecting them on the main board. CAN 1 of the SJOne board is connected to the CAN bus of the car which is also shown in the table below.

Sensor Pin layout

Pin Name	Function
P2_0	Trigger for left sensor
P2_1	Echo for left sensor
P2_2	Trigger for middle sensor
P2_3	Echo for middle sensor
P2_4	Trigger for right sensor
P2_5	Echo for right sensor
P0_1	CAN Tx
P0_2	CAN Rx

3D Printing Design

Sensors are required to be placed at a minimum height of 18 cm from the ground and at a tilt of 5 degrees to avoid ground reflections. A proper mount is required to place them at adjustable angles and heights. Hence the mounts are 3D printed using the below 3D deigns. The heights are adjustable by adding mode standoffs and the angle is adjustable by using the bottom screws.

3D Design for Middle Sensor mount

3D Design for Middle Sensor mount

Hardware Interface

The sensors are interfaced using GPIO pins. CAN 1 of the sensor controller is interfaced to the CAN bus of the car. Below diagram shows the hardware interface between the micro controller, sensors and the CAN bus.

Software Design

Software is designed such that the no two sensors of same type/model close by will be triggered simultaneously, so as to avoid interference with each other. Since the left and right sensor are of the same model, they are triggered sequentially, every 50 ms. The Maxbotix sensors cannot be triggered faster than 49 ms because it takes the sensors a maximum of 49 ms to pull down the PWN pin low when there is no obstacle for 6 meters or 254 inches. If triggered sooner, the reflected waves from the sensor will interfere with the next sensor, giving unpredictable values. The middle sensor and the back sensor are triggered every 50 ms. Hence we get all 4 sensor readings in 100 ms. The triggering of sensors is handled in 1 ms task, but with the check to trigger only every 50 ms. Refer the below datasheets for timing information for triggering and detailed working of both sensor models.

Maxbotix EZ0: http://www.maxbotix.com/documents/LV-MaxSonar-EZ_Datasheet.pdf
Devantech SF05:https://www.robot-electronics.co.uk/htm/srf05tech.htm

Sensor triggering sequence

Implementation

Algorithm

1. Initialize the trigger pins as output and PWM pins as input
2. Configure the PWM pins for falling edge interrupt
3. Trigger left and middle and back sensor and start the timer for all three
4. Wait for echo from all of them
5. When echo is received, calculate the distance in inches using the below formula

                   Distance = (stop time – start time)/147

6. Trigger right and middle sensor and start the timer for both & repeat from step 4
7. Broadcast the sensor values on CAN bus

Below is the sample interrupt callback function(ISR) to calculate the distance of obstacle.

Sensor ISR Code Snippet

The flowcharts shown describes in detail on how each sensor is triggered and broadcasted over CAN every 100 ms.

Left Right sensor trigger flowchart

Middle sensor trigger flowchart

Back sensor trigger flowchart

CAN message broadcast in 100 ms task

Testing & Technical Challenges