Difference between revisions of "F17: Tata Nano"

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=== Hardware Design ===
 
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=== Software Design ===
 
=== Software Design ===

Revision as of 01:57, 16 December 2017

Contents

Grading Criteria

  • 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.

PAGE UNDER CONSTRUCTION

Tata Nano

Self-Navigation Vehicle Project

Abstract

Embedded system is a collection of hardware and software that are designed for a specific function that is a part of a larger system. Self driving car provides a challenge and opportunity to design a unique system that will solve a problem of getting from point A to point B. This project is focus on the industry standard and will go through a complete product lifecycle using the practice knowledge acquired in classroom with scrum methodology practiced by the team.

Key components of this self driving car are:

  • Android App interface with car
  • Obstacle detection and avoidance
  • Auto speed adjustment
  • GPS Navigation

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.

The self-driving car is considered a capstone of technical achievement for an embedded system. This project gives a very basic and essential experience in working with the core requirements for a working self-driving car. The project is subdivided into 5 modules:

  • Master Module - Mater Module is the center of all communication, it receives all the data from different modules and takes decisive action according to the data.
  • Sensor Module - Sensor Module is responsible for obstacle detection and updating the master controller with the distance values of the obstacle.
  • Motor Module - Motor Module is responsible for the driving and steering action of the car.
  • Geo Module - Geo Module is responsible for updating the Motor Controller about the direction motion.
  • Bridge Module - The android and communication bridge controller are responsible for establishing communication between the car and take Map checkpoints for the shortest route to the destination that the car must take.

CAN bus will be used as a communication bus between microcontrollers. Can Bus is a broadcast bus where all the controller will be listening to the incoming frames, CAN bus uses frames for data communication. Each module will have its unique ID called MsgID, the system startup is initiated with a START command sent to car from Android application. The path and destination are configured prior to START command. The car will navigate between the checkpoints by taking location feedback through a GPS system and using sensors for obstacles avoidance in the path of the car. IO systems present on the car give us information about the status of the car.

The Objectives of this project are:

  • All the modules must communicate with each other over the CAN bus.
  • The car must determine and avoid obstacles using LIDAR and ultrasonic sensors.
  • The car must interact with a Bluetooth mobile application, obtaining checkpoint and path data.
  • Car must be able to speed control based on the terrain.
  • The car must be able to gather location using GPS module and route towards the destination.
  • Provide module and sensor status using the LCD or LEDs.
  • Master must be able to determine the action required by data gathered through sensors and GPS.
System workflow

Team Members & Responsibilities

  • Master Controller
    • Shashank Iyer
    • Aditya Choudari
  • Geographical Controller
    • Kalki Kapoor
    • Aditya Deshmukh
  • Communication Bridge + Android Application + LCD
    • Ashish Lele
    • Shivam Chauhan
    • Venkat Raja
  • Motor and I/O Controller
    • Aditya Choudari
    • Manan Mehta
  • Sensor Controller
    • Pushpender Singh
    • Hugo Quiroz
  • Module Level Testing
    • Manan Mehta
    • Aditya Choudari

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 09/12/2017 09/19/2017
  • Order Components and work distribution
  • Research on the type and model of sensors to use and order them
  • Research on the GPS and compass sensors
  • Research on components requirement based on past projects
  • Research various RC car models
 Completed
2 09/19/2017 09/26/2017
  • Set up git, slack channel, shared drive and wikipage
  • Distribute parts to sub-groups
  • Research various battery options especially NiMH and Li-Po batteries
  • Android Development Environment Setup
  • Research on various compatible bluetooth modules
 Completed
3 09/26/2017 10/03/2017
  • Discuss software architecture of each module
  • Study the data sheet of sensor & prepare a high-level design
  • Experiment and Research on voltage requirements and PWM requirements for Servo and DC motor
  • Experiment and Research on duty cycle required for controlling steer and speed of the car
 Completed
4 10/03/2017 10/10/2017
  • Agree on control system architecture
  • Design the mechanical structure of the car
  • Research and study various LCD modules
  • Start Basic Android Application development
  • Interface the ultrasound sensor with the SJone board
  • Research and study about LIDAR and its feasibility
  • Controlling Bluetooth of Mobile Phone(i.e. Turn on, Connect), Connect Mobile phone with Bluetooth BLE module on SJOne.
 Completed
5 10/10/2017 10/17/2017
  • Build the mechanical structure of the car
  • Integrate all hardware to the RC car, including power supplies from batteries.
  • Interface servo motor and ESC to the SJone board
  • Interface GPS and Compass sensor to the micrcontroller (Buy tilt compensation compass)
  • Basic testing of LIDAR sensor to get accustomed with its output
  • Build wrapper classes for steering and motor control
  • Android Application development Intent passing, Finalize GUI template.
  • Establishing basic communication between Android phone and SJOne Board.
  • Stress test the ultrasound 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.
  • Design the barebones basic functionality of the algorithm. Create a skeleton code.
  • Design software filter to filter CAN messages required for motor controller. (Push to later date/more signals to add for android app and LCD)
 Completed
6 10/17/2017 10/24/2017
  • Making tentative DBC file containing communication messages of the entire system
  • Mounted all boards on the car
  • 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.
  • Decide on the CAN ids and the priorities of the CAN messaged for various nodes.
  • Study and research about motor feedback RPM sensor.
  • Read the CAN messages to display on the LCD connected to the SJ One board. (To do)
  • Set up CAN communication between the sensor,motor and the master. Test for correct data transmission.
  • Interface LIDAR with SJone board
 Completed
7 10/24/2017 10/31/2017
  • Implement motors driven by sensor feedback functionality
  • Develop algorithm to retreive data from LIDAR on SJone according to obstacles.
  • Interface back sensor and test all the sensors together.
  • Debug and fix any issues.
  • Integrate sensors with other nodes via CAN
  • Test the sensor values while the car is on the move. (Testing done with static car)
  • 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.
 Completed
8 10/30/2017 11/7/2017
  • Implement motors driven by wheel feedback functionality
  • Integrate Hall effect sensor to determine motor RPM.
  • Develop algorithm to maintain same speed even on elevated paths.
  • Design sensor mounts and 3D print them.(To do)
  • 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
9 11/7/2017 11/14/2017
  • Mount all the sensors and test for any dead band and modify their positions for maximum coverage.
  • Integrate the fusion of LIDAR and Ultrasound sensor to get overall feedback from all the directions.
  • Develop algorithm to avoid obstacles and plan the car's further navigation path.
  • Complete final prototype of the obstacle avoidance feature.
  • Start development of android app.
 Completed
10 11/14/2017 11/21/2017
  • 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.
  • Integrate GPS coordinates from Android app into Master Node for the autonomous feature.
  • Start testing car's autonomous driving capabilities with path following from GPS waypoints from Android app.
  • 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 the autonomous feature. Testing and Bug fixing.
  • 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
11 11/21/2017 11/28/2017
  • Autonomous driving should be working by now. Focus on improving car's performance. Tweak all nodes to better performance, and fix last minutes bugs.
  • Put multiple markers on Map and implement logic to find the shortest route to destination and pass route information on CAN bus.
  • 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.
 Completed
12 11/28/2017 12/05/2017
  • 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.
  • Tune & optimize the sensor filter logic and the sensor mount as required.
  • Integrate all the modules and test for the complete autonomous functionality.
 Completed
13 12/05/2017 12/12/2017
  • Final touches to improve overall vehicle's robustness. Self-fixing nodes, reduce/eliminate unexpected behaviors and crashes.
  • Work to improvise on the algorithms and make sure individual modules work. Addition of any extra features and software development.
  • Save the data received from various modules into a log file for debugging purpose.
 Completed

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 Module HC-05 Amazon 1 $8.99
6 4D systems 32u LCD 4D systems 1 $73.70
7 LV Maxsonar EZ0 Ultrasonic sensors Robotshop 5 $124.75
8 LIDAR Sensor Robotshop 1 $190
9 Ultimate GPS breakout Adafruit 1 $49.95
10 CAN tranceivers Microchip Samples 10 Free
11 SJOne Boards Provided by Preet 5 $400.0

DBC File Link

https://gitlab.com/shivam5594/Autonomous-car/blob/embedded/common_dbc/243.dbc

Sensor Controller

Design & Implementation

Sensor controller is responsible for Obstacle Detection. This project is designed to use two sensor components, LIDAR, which is the state of the art sensing components that are being used by the self-driving car industry to map the objects in the vicinity of the vehicle. The other component is more traditional and tested approach for object detection, Ultrasound sensors. Employing the capabilities of these sensors gives and very robust sensing system for the self-driving car. This also ensures to cover the flaws of each system.

Hardware Design

Discuss your hardware design here. Show detailed schematics, and the interface here.

Hardware Interface

In this section, you can describe how your hardware communicates, such as which BUSes used. You can discuss your driver implementation here, such that the Software Design section is isolated to talk about high-level workings rather than the inner working of your project.

Lidar Sensor

Lidar Sensor is interfaced using a UART Protocol. As shown below the Lidar Sensor sends 5 bytes per data point over UART to the Sensor Controller. These 5 bytes include 1 byte for the quality of data, 2 bytes for the angle of reading, and 2 bytes for the distance of reading. The Sensor Board initiates the Lidar Sensor readings by sending a start command opcode. The Lidar Sensor responds by sending a start scan confirmation followed by continuous data readings.

Rplidar

Ultrasonic Sensor

LV‑MaxSonar‑EZ1 ultrasonic sensor by MaxBotix is used for a wide range object detection. Ultrasound sensors are configured as 2 ultrasound sensors in the front and one in the rear as the initial test configuration, this configuration helps to work in conjuncture with Lidar sensor mounted on the center of the car. The final project makes use of one ultrasound sensor that is dedicated for the detection of objects in the front of the car. LV‑MaxSonar‑EZ1 can detect objects from 0 inches to 254 inches, the object detected within 0-6 inches are provided with range information of 6 inches and the resolution is 1 inch. LV‑MaxSonar‑EZ1 provides three output formats pulse width output, analog output, and RS232 serial output. This project is using pulse width as the output from ultrasound sensors.

The following figure shows the pinout of the LV‑MaxSonar‑EZ1 ultrasonic sensor.

Sensor Pin Out
Pin Out description
  • Pin 1-BW- When BW pin is held high the TX output sends a pulse suitable for low noise chaining.(Not Used)
  • Pin 2-PW- This pin outputs a pulse width representation of range. The distance can be calculated using the scale factor of 147uS per inch.
  • Pin 3-AN- Outputs analog voltage with a scaling factor of (Vcc/512) per inch.(Not Used).
  • Pin 4-RX– This pin is internally pulled high. The LV-MaxSonar-EZ will continually measure range and output if RXdata is left unconnected or held high. If held low the sensor will stop ranging. Bring high for 20uS or more to command a range reading.
  • Pin 5-TX- When the *BW is open or held low, the TX output delivers asynchronous serial with an RS232 format.(Not Used)
  • Pin 6-+5V- Vcc – Operates on 2.5V - 5.5V. Recommended current capability of 3mA for 5V, and 2mA for 3V. Please reference page 4 for minimum operating voltage versus temperature information. Pin 7-GND- Return for the DC power supply.
  • GND- must be ripple and noise free for best operation.

Software Design

Show your software design. For example, if you are designing an MP3 Player, show the tasks that you are using, and what they are doing at a high level. Do not show the details of the code. For example, do not show exact code, but you may show psuedocode and fragments of code. Keep in mind that you are showing DESIGN of your software, not the inner workings of it.

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.

Testing & Technical Challanges

Motor & I/O Controller

The Motor and I/O controller board is responsible for control of the motors and relay information between the LCD and the rest of the System.Hence, the board could be divided into 2 parts, the motor control, and the LCD control. The motor control logic controls the steering and the speed of the vehicle using a servo and DC motor respectively based on the Car Control CAN message from the master. Based on other can messages from the Sensor Board, the Geo Board and the Android Board, the Motor and I/O board processes and communicates the information to the LCD display

Design & Implementation

The Servo and DC motor are controlled via PWM and hence initial work required finding out the required duty cycle values for desired motor frequency. Higher frequency gives us a better resolution and response from the motor but for this project, a frequency of 8Hz was ideal enough to attain the required speed of vehicle and response time of the steering of the vehicle. To find out the PWM values, we connected the RC receiver of the Traxxas Slash 2WD vehicle to an oscilloscope and varied the remote controller for forward and reverse movement as well as right and left movement of the car. PWM signals were observed on the CRO and as the controller trigger was varied, the duty cycle of the PWM signal on the CRO also varied.

Speed control of the vehicle was carried out using a Traxxas speed sensor and a bunch of magnets. Applying the priciples of a hall effect sensor, the magnets were attached to the inside of a wheel and the speed sensor was placed on the shaft of the back wheel. With every rotation, the magnets cut the field of the speed sensor giving a positive voltage to the SJone board. This positive voltage is accounted for and after neceassy calculations, we derive the speed of the vehicle.

The SJOne board communicates with the LCD display over UART using basic ASCII values that represent commands as well as information. The LCD graphics are preprogrammed into a MicroSD using the 4D systems workshop software and each graphical object conisists of ASCII commands to control it.

Hardware Design

The Motor and I/O controller system consists of the following modules to perform various functions as mentioned in the description section of the table

Parts in Motor and IO system
S.No Name Description Pin Number
1. SJOne Controller board with GPIO and PWM pins to control rest of the interfaces
2. ESC / DC motor Controls speed of vehicle
3. Servo Motor Controls direction of vehicle
4. Traxxas Speed sensor and magnets Senses rotation of motor/wheel of vehicle for speed control
5. LCD Displays vital information of the vehicle
6. LED lights Headlamps and signals various information abou the vehicle

Hardware Interface

Electronic Speed Controller (ESC)

The ESC is the interface inbetween the DC motor and SJOne board. The ESC enables speed control, protects the rest of the system from any back EMF and allows configuration of the motors in various Modes (Training/Race/Sport). The ESC has 2 connectors the first one is a 2 wire connector, black and red which is connected to the LiPo battery that powers the motors and the second if a connector of 3 wires. 2 wires (black and red) supply a 7V DC power stepped down from the 11V lipo battery to the motors. This 7V power is used to control the servo motor using the power distribution board designed for this porject. The 3rd wire (white) is an PWM input signal to the ESC from the SJOne controller that defines the speed of the motor.The ESC consists of a button to calibrate and turn on/off the ESC located on it.The ESC can be calibrated by following the steps mentioned ont the Traxxas website

ESC Pin Connection
S.No Wires on (ESC) Description Wire Color Code
1. (+)ve Connects to DC Motor (+)ve RED
2. (-)ve Connects to DC Motor (-)ve BLACK
3. (+)ve Connects to (+)ve of Battery RED
4. (-)ve Connects to (-)ve of Battery BLACK
5. PWM input PWM Signal From SJOne WHITE
6. (+)ve 7V power supply to power the servo RED
7. (-)ve Negetive terminal BLACK

DC Motor

The speed and direction of rotation of the motor (forward/backward) is controlled by the direction and amount of current that is supplied to the DC motor. In the figure below you can see the motor has 2 wires; one for positive(Red) and one for negative(Black). For the forward movement of the wheels the current flows from positive to negative, and for the reverse movement, the current flows from negative to positive. The speed is controlled by the amoutn of current it is fed from the ESC which is inturn controlled by the duty cycle of its PWM signal input.

DC Motor Pin Connection
S.No Wires on (ESC) Description Wire Color Code
1. (+)ve Positive Terminal RED
2. (-)ve Negetive terminal BLACK

Servo Motor

The direction the vehicle's front wheels turn is dependent on the servo motor in the vehicle. Based on various PWM signals, the servo steers the front wheels of the vehicle in the left and right direction. The servo has 3 wires of which one is for the PWM input signal whereas the other two are to power up the servo. We powered our servo motor using the 6v power supply from the battery elimination circuit present in the ESC so that a single switch to turn on and off both the servo and DC motor.

Servo Motor Pin Connection
S.No Pin No. (SJOne Board) Function Wire Color Code
1. PWM input PWM Signal WHITE
2. VCC 5 Volts RED
3. GND 0 volts BLACK

uLCD32-PTU

uLCD32-PTU by 4D systems has a 3.2" TFT LCD Display module. The module comes with a display resolution of 240x320 pixels. 4D Systems provides a programming cable based on UART for burning the LCD code to the module. The project is burnt to a uSD card which is used for display during booting of the LCD.

The following figure shows the programming cable and the pins of uLCD32-PTU.

LCD connections

Software Design

LCD DISPLAY

uLCD-32PTU communicates with the SJ1 board over UART. The steps taken for interfacing the LCD display with the SJ1 board are listed below:

  • Creating a project using Workshop 4 IDE and programming the LCD display
  1. After finalizing the design of the LCD's layout, a genie project was created using Workshop 4.
  2. The layout was split into different forms (pages) and appropriate buttons and gauges were added for display.
  3. uLCD-32PTU was programmed with the help of programming cable provided by 4D systems.
  • Programming SJ1 Board for LCD Display
  1. As raw data often cannot be displayed on the LCD directly, the values to be displayed had to be converted to appropriate byte-sized values.
  2. Communication with SJ1 board was established at the baud rate of 115200 bps.
  3. Commands for writing data and reading acknowledgment for various gauges were coded in the SJ1 board.


Implementation

Testing & Technical Challanges

Geographical Controller

Design & Implementation

Hardware Design

Hardware Interface

Software Design

Implementation

Testing & Technical Challanges

Communication Bridge Controller

This is a part of a project where different technologies meet. To make our project more understandable and easily accessible, we need some kind of user interface. Where a user or customer of the product can interact with the product easily and without knowing the technical complexity of it. We have decided to make an android application which communicates with the car and can show its current location, speed, heading direction etc. Here, we have discussed the design and implementation.

Design & Implementation

Main purpose of this is to exchange data using some wireless communication protocol. We had options like WiFi (UART to WiFi converter) or Bluetooth (UART to bluetooth converter). Here we made decision based on actual requirement and usability of that communication protocol. In case of WiFi it has advantages like long range, high speed and robust communication without loosing data packets. It can also connect to multiple devices at same time. Now, the actual requirement is to show useful data to user, where use is sitting inside a car(idle situation). Which doesn't require long range and multiple receivers like WiFi provides. So, we moved ahead with bluetooth which works fine and delivers everything we wanted.

we chose HC-05 module. It is a serial to Bluetooth converter with a very compact hardware design. On the other end, to make an android application we chose android studio, which is freely available by Google. It is a very intelligent software which helps programmer or developer like us who has little or no knowledge of java programming language, to develop a good piece of code with high code readability and re-usability.

Hardware Design

Bluetooth Module
Overview of hardware implementation

Hardware Interface

Connections with HC-05
Connections with SJOne

Software Design

Android application

Micro-controller end in freeRTOS

Implementation

Testing & Technical Challenges

Android application

Micro-controller end in freeRTOS

Master Controller

Design & Implementation

Hardware Design

Hardware Interface

Software Design

Implementation

Testing & Technical Challanges

Testing & Technical Challenges

Describe the challenges of your project. What advise would you give yourself or someone else if your project can be started from scratch again? Make a smooth transition to testing section and described what it took to test your project.

Include sub-sections that list out a problem and solution, such as:

LCD

  1. Problem: The SJ1 Board was rebooting frequently while sending data for all metrics at once.
Resolution: The metrics were split into different forms for display and the data belonging to the active form alone was sent.

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?

Project Video

Upload a video of your project and post the link here.

Project Source Code

References

Acknowledgement

Any acknowledgement that you may wish to provide can be included here.

References Used

  1. uLCD 32 PTU datasheet http://www.4dsystems.com.au/productpages/uLCD-32PTU/downloads/uLCD-32PTU_datasheet_R_2_1.pdf
  2. Workshop 4 user guide http://www.4dsystems.com.au/productpages/4D-Workshop-4-IDE/downloads/Workshop-4_userguide_R_2_1.pdf

Appendix

You can list the references you used.

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