software requirements specification (srs) project lane

Lane Management System 1

Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) have

been made by Betty H.C. Cheng, Michigan State University (chengb at chengb.cse.msu.edu)

Software Requirements Specification (SRS)

Project Lane Management System

Authors: Adam Pruim, Curtis Notarantonio, Jacob Heisey, Qiuning Ren, Matt Chebowski

Customer: Dr. S Ramesh, General Motors

Instructor: Dr. Cheng, Michigan State University

1 Introduction

This section provides a project scope and an overview of everything included in this

document. Also, the purpose of this project is outlined, and a list of all abbreviations and

definitions is provided.

1.1 Purpose

The purpose of this Software Requirements Specification (SRS) document is to provide a

detailed description of the functionalities of the Lane Management System (LMS). This

document covers each of the system’s intended features, as well as offers a preliminary

glimpse of the system’s User Interface (UI). The document also covers hardware,

software, and other technical dependencies.

This document is intended for the customer, Dr. Ramesh with General Motors, as well as

the course instructor, Dr. Cheng. Readers interested in a brief overview of the system

should focus on the rest of section 1, as well as section 2 of the document.

1.2 Scope

The product to be produced is titled Lane Management System. The Lane Management

System is representative of features that are implemented in next generation vehicles. The

application domain of the LMS is an embedded system for automotive systems. The LMS

is composed of two components. First the system has hardware that consists of 3 cameras

which will be placed on the left, center and right of the front of the vehicle. A toggle

switch for the system also exists inside the vehicle, allowing the driver to activate and

deactivate the system. Second the system has software which allows various components

of the system to communicate and respond accordingly to corresponding conditions and

scenarios the user may face. The LMS is also composed of several subsystem elements,

listed below:

● Camera Sensing Subsystem: captures images on the sides of vehicle and sends to

the image processing unit for lane marker detection

● Image Processing Subsystem: processes the raw images coming from the camera

and identifies the lane marker




● Vehicle State Estimation system: a set of sensors that periodically determines the

speed, steering angle, and road curvature

● Path Prediction Subsystem: a mathematical data processing subsystem which

receives information from the image processing and vehicle state estimation

subsystems and tries to predict the path of the vehicle in order to detect, warn, and

correct any potential lane violations

● User Interface Subsystem: the driver and LMS exchange control and data

information through this system

● Supervisory Control Subsystems: control all other subsystems, decides when to

enable and disable other subsystems, and possibly provide diagnostic information

The main objective of this system is to improve the safety of both the main driver and

drivers that are outside of this system (drivers that are not in the vehicle, but share the

road with the primary user) by ensuring the car remains inside of the lane. Our goal is to

develop a system that improves the safety of the driver, but also gives the driver complete

control of the system and the entire vehicle. The benefits we aim to provide with this

system include the following:

● Improve driver safety

● Improve safety of other drivers who share the road with the primary driver

● Give the user the ability to have complete control over the LMS and therefore the

entire vehicle. The LMS will not override the control of the driver.

● Provide both an audible and visual warning should the driver unintentionally

leave their lane

● Provide steering correction should the driver unintentionally leave their lane. This

corrective action should only occur after a warning is issued

1.3 Definitions, acronyms, and abbreviations

This section gives definitions of terms and acronyms that will be used in this document.

Definitions:

● Lane Management System – Driver assistance system that can detect lanes and

compute the relative position of the vehicle. Can take over control from the driver

to position the vehicle within a lane. The lane keeping system, lane departure

warning system, and lane centering system are components of this system.

● Lane Keeping System – Intervenes and sends commands to steer and adjust the

position of the vehicle

● Lane Departure Warning System – Makes use of lane sensing feature and issues

warnings to the driver when the vehicle leaves a lane

● Lane Centering System – Detects lane markings to compute appropriate center of

lane position

● CANbus - The network inside of the car that allows different systems in the car to

communicate.

Acronyms:

● SRS – Software Requirements Specification

● LMS – Lane Management System




● LKS – Lane Keeping System

● LDWS – Lane Departure Warning System

● LCS – Lane Centering Systems

● GM – General Motors

● SW – Software

● HW - Hardware

● CANbus - Controller Area Network Bus

1.4 Organization

This document is divided into six remaining sections. Section 2 provides an overview of

the system, and outlines the product perspective, product functions, user characteristics,

constraints, assumptions and dependencies and apportioning of requirements. Section 3

provides an enumerated list of specific requirements for this system. Section 4 describes

any modeling requirements necessary to the system, including use-cases and various

diagrams intended to give an overview of how the system is intended to function. Section

5 focuses on the system prototype, including instructions for how to run the prototype,

and an example scenario which can be applied to the prototype. Section 6 lists all

references used throughout this document, and Section 7 provides a point of contact for

further information regarding this document and/or project.The structure of this

document can be seen below:

2 Overall Description

This section covers the function and constraints of the LMS. It provides context for the

system and presents the goals of its functionality. Restrictions, on both the user and the

system, are enumerated. It also explores possible futures for the LMS.

2.1 Product Perspective

LMS is an autonomous feature, meaning that the LMS functions without any driver input

and allows the car to independently make steering correction in order to maintain its lane.

The LMS uses the three cameras mounted on the exterior of the vehicle and the Image

Processing subsystem to determine lane boundaries. Unintentional lane drift is

determined by torque sensors on the steering wheel. Should the vehicle drift and the

torque applied by the driver lies below a preset threshold, the LMS will issue an audio

warning. The LMS interacts with the steering wheel to make adjustments and keep the

vehicle in its lane. The LMS is focused on safety and will not operate if it does not have

enough information to find lane boundaries. The user interface allows the driver to

customize the degree of deviation of the LMS (sensitivity to a lane departure), and the

volume of audio warnings issued by the LMS. Visual warnings would be displayed on

the dash and audio warnings will be played through the speakers.

2.2 Product Functions

The function of LMS is to ensure a vehicle will hold its lane, by exerting torque on the

steering column when lane boundaries can be accurately established and the vehicle is




traveling faster than twenty miles per hour. It is intended to provide convenience and

safety to its users by preventing accidents that may occur when a car drifts out of its lane.

LMS will not interfere with the driver's ability to operate their vehicle as they normally

would when they interact with the steering wheel.

2.3 User Characteristics

Users of the system are expected to have a valid driver's license and proper faculties to

operate a motorized vehicle. They should also be introduced and familiar with the audio

warnings the system generates and the method involved in turning the system off.

2.4 Constraints

The Lane Management System is constrained by the control and safety of the driver. That

is, the LMS will not make rapid steering corrections that could endanger the driver, and

the LMS is not allowed to override the driver’s direct action to make steering

adjustments.

The functionality of the LMS is also constrained by speed and data provided via the

cameras on the vehicle. The LMS will not operate while the car is moving at a speed less

than twenty miles per hour. If the LMS is unable to find lane barriers or the center of the

lane via the images processed from the Image Processing Subsystem, the LMS will issue

a visual alert to the driver and will shut down. A system shutdown will not interfere with

the driver in any way, and the driver will continue on without use of the LMS.

2.5 Assumptions and Dependencies

The LMS relies on the cameras, speedometer, and torque sensor functioning properly and

would shut down if that were not the case. The algorithms to find the center of the lane

and the lane boundaries must be implemented correctly. It is only intended to work on

roadways where lane markings are visible and with a driver that is capable of operating a

vehicle. In weather conditions where the road markings are no longer visible the system

would shut down.

2.6 Apportioning of Requirements

In the future the LMS could be integrated into a fully autonomous vehicle system and use

its features to allow driverless cars to stay within road lanes. These autonomous features

could include, but are not limited to, blind spot detection, active park assist, and adaptive

cruise control. The algorithms used to find the center of the lane and other properties of

the roadway could be refined to make information more accurate. Accuracy is measured

car positioning and response time to situations on the road. Information gathered from

this system could be shared with other systems in the car.




3 Specific Requirements

This section enumerates the specific functions of the pieces of the LMS system and

how the system interacts with itself.

1. Radio Screen will show system is active or inactive and has settings

1.1. When the LMS is active, there will be a visual icon that appears on the radio

screen

1.2. Shows the settings customization screen and allows user to adjust settings

1.3. An icon appears on the radio screen when a lane departure has been detected

2. Torque Sensor will detect the amount of torque on the wheel

2.1. Detects the amount of torque put on the wheel by the driver

2.2. Detects the amount of torque on the wheel generated by the system making a

correction

2.3. If there is torque detected on the wheel not created by the system and it is

above the torque threshold, the driver has control of the wheel, thus the

system is disabled

3. Three cameras will be mounted as follows

3.1. One camera will be located on the left side of the car in order to detect the

lane to the left of the car

3.2. One camera will be located on the right side of the car in order to detect the

lane to the right of the car

3.3. One camera will be on the front center of the vehicle will find center of

curvature of the lane

4. Warnings will be generated by the following conditions

4.1. Audio warning will sound if a lane departure is detected and corrective action

will be taken

4.2. Visual warning will be raised on the cluster and radio screen for when a lane

departure is detected

4.3. Audio indication will sound if the system is turned on or off

5. There will be an Enable/Disable Toggle Switch

5.1. Physical button on the steering wheel will allow the driver to enable and

disable the system

5.2. Driver will always be able to override the system by pressing this button to

disable the system

6. Settings Customization for the following parts of the system




6.1. Menu will be found on the radio screen

6.2. Allow the user to change the threshold allowed for the car to drift in the lane

6.2.1. User will be able to set the degree of deviation at either 1, 2, or 3, 1

being the smallest amount of deviation allowed and 3 being the largest

6.3. Volume of warnings can be changed here

7. Controller shall send and receive commands to all other systems

7.1. Communicates through the CAN bus

7.2. Indicate whether the system is active to all subsystems

7.3. Issue commands and retrieves data from the subsystems

7.4. Enable and disable the system

7.5. Disables the system if at least two of the camera feeds cannot sufficiently

detect the lane markings

8. Image Processor shall receive video feeds from the three cameras and send

information to the controller

8.1. Receives raw image data

8.2. Processes data to see if the lanes can be indicated or not

8.3. If the lane cannot be indicated from at least two of the cameras, sends a flag

to the controller to disable the system

9. Maintenance system will ensure system is functioning properly

9.1. System must be updated at the dealership

9.2. System diagnostic tools will be used to indicate if physical maintenance is

needed

9.3. Hardware is needed for system diagnostic tools

10. Safety and Security Requirements

10.1. If two of the camera feeds are sending the same information, the

information will be considered to have been tampered with and will shut

down

10.2. If the speed of the vehicle is under 20 mph, the system will never be active

10.3 The torque that is allowed to be applied to the wheel by the system will

have a threshold so it never creates a dangerous situation for the driver and

vehicle

10.4. If there is reduced visibility due to inclimate weather and the cameras

cannot decipher lane markings, the system will be disabled until the road

markings can be seen again.




4 Modeling Requirements

4.1 Class Diagram:

Class diagrams consist of the box which represent classes in our system. Inside the boxes

are attributes and operations. Attributes, located in the upper half of the box, represent the

names of variables in our system as well as the datatype of the respective variable.

Operations, located in the lower half of the box, represent functions that the class can

perform. In the LMS the controller is the conduit on which information flows and can

communicate with the CANBUS. It does not serve any function other than to pass

information to other systems and has flags to ensure the system is running properly. The

System On class will determine if the LMS is currently enabled or disabled with

information from itself and the controller. The Lane Keeping System determines if

corrective action could be taken and how much corrective action can be taken. The

Warning System provides the methods for warning the driver of the systems actions. The

Image Processor and Land Centering System work hand in hand to determine the lane

boundaries and detect when the car is leaving those boundaries.

4.2 Data Dictionary:

Element Name Description




Controller A class that describes the controller of

the system, everything in the system

sends commands through this class.

Attributes system_active: bool True if the system is active. False if

the system is disabled.

LaneIndicated: bool True if a lane is indicated. False if no

lane is indicated.

Operations

Relationships Sends and receives information from all other classes: Lane

Centering System, Lane Keeping System, System On, and Warning

System

UML

Extensions


Image Processor Processes images received from the

camera, detects lanes and lane

curvature.

Attributes feedC: bitmap The image feed for the center camera

feedL: bitmap The image feed for the left camera

feedR: bitmap The image feed for the right camera

feedC_active: bool If the center feed is active

feedL_active: bool If the left feed is active

feedR_active: bool If the right feed is active

Operations check_feed() Checks if the feeds are active

process_feed() Processes the data received from the

feeds

Relationships This class is a composition of the controller class. It receives raw

image data from the camera feeds, and then processes that data and




sets flags in the controller class. Also feeds info to the lane centering

system class.

UML

Extensions


Lane Centering System A class determines if the car is

centered in the lane or not.

Attributes curve_indicated : bool True if the lane currently has

curvature in it. False if there is no

curve indicated.

Lane_Markings : bool True if there are currently lane

markings found. False if lane

markings cannot be found.

image: bitmap image received from the image

processor class.

Operations Find_Center() Finds whether or not the car is

centered based on the image feeds

received from the image processor

class.

Relationships This class is a composition of the controller class. It receives info

from the image processor class and tells the controller class whether

or not car is centered in the lane.

UML

Extensions


Lane Keeping System A class that keeps the vehicle in the

lane.

Attributes torque : double the amount of torque applied on the

wheel

steering_angle : double the angle of the steering wheel




driver_override : bool If the driver has control of the wheel

Operations steer_correction() makes a steering correction

detect_driver() Detects if the driver has control of the

wheel or not, based on torque

Relationships This class is a composition of the controller class.

UML

Extensions


Warning System A class for any alert that occurs in the

system

Attributes volume : int level of volume of warnings

image : bitmap image of the warning icon

Operations visual_alert() makes a visual alert for the lane

departure

audio_warning() Makes an audio warning for a lane

departure

audio_indication() Makes an audio indication that the

LMS system has been turned on

Relationships The warning system is a composition of the controller class. The

controller class tells it what warnings to make

UML

Extensions


System On A class that indicates if the system is

enabled or disabled. If the speed is

less than 20mph the LMS will not

enable. If the LMS cannot detect a




lane the system will not enable. If the

driver has recently acted on the

steering wheel the system will not

enable.

Attributes system_Enabled : bool gives the current status of the LMS

(true = active, false = inactive)

speed : int current speed of the vehicle

Operations turn_on() turns the system on

turn_off() turns the system off

Relationships System on is a composite of the Controller and passes the current

status of the system along.

UML

Extensions

4.3 Use Case Diagram: Use case Diagram show the drivers interaction with the system and the interaction

between the system and itself in different scenarios:




Use Case: Lane Centering System

Actors: Driver

Description: The system is actively detecting and calculating the center of the lane

and the car's relationship to it. The Lane Centering System uses data

from both the Camera Sensing and Image Processing subsystems to

calculate the appropriate center of lane position.

Type: Primary

Includes: System Disabled

Extends: No Lane Markings, Lane Curvature exists, Intentional Lane Change,




Unintentional Lane Change

Cross-Refs: 3, 8.1, 8.2

Use cases: No Lane Markings, Lane Curvature exists, Intentional Lane Change,

Unintentional Lane Change

Use Case: Lane Keeping System

Actors: Driver

Description: The system detects the car is drifting and after a warning is issued

makes a corrective action. The Lane Keeping system intervenes and

sends commands to steer and adjust the position of the vehicle

accordingly as a means of accident prevention.

Type: Primary

Includes: System Disabled, Steering Correction

Extends: Unintentional Lane Change

Cross-Refs: 2, 8.3, 8.4, 7

Use cases: Unintentional Lane Change, Steering Correction




Use Case: Lane Departure Warning System

Actors: Driver

Description: This provides warnings to the driver using the car's interface to alert the

driver of a lane departure. The Lane Departure Warning System makes

use of the lane sensing feature and issues warnings to the driver when

the vehicle leaves a lane.

Type: Primary

Includes:

Extends: System Disabled, Unintentional Lane Change

Cross-Refs: 4, 1, 6

Use cases: Check Surroundings

Use Case: System Disabled

Actors: Driver

Description: This allows the driver or the car to disable the system in case of

malfunction or other factors. The system is by default enabled upon

vehicle start-up, and is active at speeds above 20mph. The driver can

disable the system should they choose to do so via the Enable/Disable

toggle button.

Type: Primary

Includes: LKS, LCS, Speed Threshold




Extends: LDWS

Cross-Refs: 5, 1.1

Use cases: Speed Threshold

Use Case: Unintentional Lane Change

Actors: Driver

Description: When the car moves from the center of the lane irregularly and is

flagged by the system. This use case is valid only when the system is

enabled and traveling at a speed greater than 20 mph. A distinction

between intentional and unintentional lane drift is made via the torque

sensors located on the steering wheel.

Type: Secondary

Includes: None

Extends: Lane Keeping System, Lane Departure Warning System, Lane

Centering System

Cross-Refs: 7, 4, 2

Use cases: Lane Keeping System, Lane Departure Warning System, Lane

Centering System

Use Case: Changing Lanes Intentionally

Actors: None




Description: The system automatically detects when the car is switching lanes

normally and takes no corrective action. The LMS distinguishes

between intentional and unintentional lane drift by the driver via the

torque sensor on the steering wheel of the vehicle.

Type: Secondary

Includes: None

Extends: Lane Centering System

Cross-Refs: 2, 5

Use cases: Lane Centering System

Use Case: Lane Curvature Exists

Actors: None

Description: The system detects when the road is curving and prepares to potentially

take corrective action. For this particular use case, the LMS makes use

of the Camera Sensing, Image Processing, and Vehicle State Estimation

subsystems to calculate and predict the curvature of the road in front of

the vehicle.

Type: Secondary

Includes: None


Cross-Refs: 8, 7

Use cases: Lane Keeping System, Lane Departure Warning System, Lane




Centering System

Use Case: No Lane Markings

Actors: Driver, Car

Description: When there are no visible lane markings to assess the center of the lane

the system automatically enters a disabled state as a means of preventing

inaccurate data readings that could potentially lead to an accident or put

the driver in danger.

Type: Secondary

Includes: None


Cross-Refs: 8.3, 8.4, 7, 5

Use cases: Lane Centering System

Use Case: Speed Threshold

Actors: None

Description: The system should only be active at a certain speed or higher. The

system is by default enabled upon vehicle start-up, but is only active at

speeds greater than 20 mph.

Type: Secondary

Includes: System Disabled

Extends: None




Cross-Refs: 5

Use cases: System Disabled

4.4 State Diagram: The following State diagram describes the movement of information and action

throughout the system while it is active:

4.5 Sequence Diagram:

4.5.1 Image processor & Lane Centering System:

When the driver pushes the button to turn on the whole system through System On, and

the System On will send system active signal to the Controller. Then the Controller will

turn on the camera. The Image Processor will receive images from the cameras and

process them, then check if all of the camera feeds work well and sends all camera feeds

and flags to the Lane Centering System. The LCS will find the center of the lane and send

all information to the Controller. If check feed fails, the Controller will send a make alert

signal to the Warning System, which will then disable the system and make audio alert.




4.5.2 Warning System:

When the driver pushes the button to turn on the whole system through System On, the

System On will send a system active command to the Controller. If the system is active,

the controller will send a make alert signal to Warning System. The Warning System will

return a system off signal and make alert to the driver.

4.5.3 Lane Keeping System:

When the driver pushes the button to turn on the whole system through System On, the

System On will send an active signal to the Controller. If information from the Lane

Centering System indicates an unintentional drift, the Controller will activate the Lane

Keeping System. The Lane Keeping System does the steering correction and detects the

driver, then sends make correction signal to the Controller.




5 Prototype

The prototype shows the capability to enable and disable the system, the conditions by

which the visual warnings are flagged, and the settings which can be configured.

5.1 How to Run Prototype

The prototype is accessed through the internet. No internet connection would be required

in the final product. A web browser is required to view and interact with the prototype.

Additionally, it requires an internet connection to import jQuery, the Web Speech API

and for the user to access the prototype.

The jQuery library is the only dependency for this prototype. It also uses the Web Speech

API. It is written in HTML, CSS and jQuery. The prototype can be found at the following

location:

http://www.cse.msu.edu/~cse435/Projects/F2016/Groups/LANE1/web/prototype.html

5.2 Sample Scenarios

The user would like to observe the system behavior while the system is active and when a

driver unintentionally drifts into the left lane containing oncoming traffic. The user

begins by verifying the status of the system on the screen and in the warning bar. Both

will be green while the system is currently active (Figure 5.2.1)

http://www.cse.msu.edu/~cse435/Projects/F2016/Groups/LANE1/web/prototype.html




Figure 5.2.1

If the system is not active, the screen will display “System Inactive” with a red warning

bar. (Figure 5.2.2)

Figure 5.2.2

The system can be activated by clicking the toggle button. (Figure 5.2.3)

Figure 5.2.3

The type of lane change must be indicated by the user. (Figure 5.2.4) The options

available are intentional or unintentional.

Figure 5.2.4




The user may use the up and right or left arrows of the keyboard (↑, ←↑, or ↑→) to move the car forward or forward and to the left or right. In this case, since the user wants to observe the driver drifting into the left lane, they will simultaneously hold the up and left arrow keys.

The user can observe the vehicle moving into the left lane. (Figure 5.2.5) The warning

system will then be flagged and the audio and visual warning will be raised. The speaker

icon appears under the toggle button and the warning bar changes color to a bright red.

(Figure 5.2.6) An audio recording will also play the audio warning. (Figure 5.2.7)

Figure 5.2.5

Figure 5.2.6

Figure 5.2.7




The vehicle then makes the correction, returns to the center of the right lane and the

system returns to an active monitoring state with no warnings. (Figure 5.2.8)

Figure 5.2.8

Additionally, the user may apply different scenarios to the system. (Figure 5.2.9) All of

which, will temporarily suspend the system.

Figure 5.2.9




6 References

[1] Dr. Betty H.C. Cheng and Dr. S Ramesh, “GM-Lane_Management_System-v2”,

General Motors

[2] Dr. S Ramesh, “Client Question & Answer”, General Motors and Michigan State

University, October 2016

[3] Adam Prium, Matt Chebowski, Quining Ren, Curtis Notarantonio, Jacob Heisey,

“Lane 1 Website” http://www.cse.msu.edu/~cse435/Projects/F2016/Groups/LANE1/web/

[4] Lane Keeping Assist. (n.d.). Retrieved October 12, 2016, from

http://www.toyota-

global.com/innovation/safety_technology/safety_technology/technology_file/active/lka

.html

[5] Lane Departure Alert (LDA). (n.d.). Retrieved October 12, 2016, from http://www.toyota-global.com/innovation/safety_technology/safety_technology/technology_file/active/lda.html

7 Point of Contact

For further information regarding this document and project, please contact Prof. Betty

H.C. Cheng at Michigan State University (chengb at cse.msu.edu). All materials in this

document have been sanitized for proprietary data. The students and the instructor

gratefully acknowledge the participation of our industrial collaborators.

http://www.cse.msu.edu/~cse435/Projects/F2016/Groups/LANE1/web/

http://www.toyota-global.com/innovation/safety_technology/safety_technology/technology_file/active/lka.html





http://www.toyota-global.com/innovation/safety_technology/safety_technology/technology_file/active/lda.html



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