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Software Requirements Specification (SRS)
Project Active Park Assist 2
Authors: Luke Kline, Robert Ramirez, Aojia Rui, Kyle Schmitz, Quinton Schwagle Customer: Eileen Davidson of Ford Motor Company Instructor: Dr. Cheng
1 Introduction
This document will specify the overall description, specific requirements, modeling requirements, and prototype models for the Active Park Assist system. This document is intended to specify:
- The perspective: how the product fits with the entire system of the vehicle.
- The function: what the product will be used for.
- User Characteristics: the type of customer and level of understanding of the system they should have in order to operate it.
- Constraints of the system.
- Assumptions about the uses of the product.
- Approportioning of Requirements: how the system relates to the customer- specified requirements.
- The specific requirements met by the system.
- Modeling requirements for the prototype.
- The prototype models.
- A description of how the system will run as described by how to run the prototype.
- Sample scenarios.
- References.
1.1 Purpose
This document is intended to give an in-depth view of the components, key elements and key functions of the Active Park Assist system. Components of the system will include radar sensors, object-detecting cameras, a Human-Machine Interface, and the Active Park Assist system. Key Elements will include the phases involved the execution of the system. Key functions are the tasks to be executed for the elements to communicate with each other. The system is developed to provide the Active Park Assist feature for automotive manufacturers to add to new automobiles. This document will provide a detailed outline
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 2 of the requirements of the software system for developers intending to implement the system.
1.2 Scope
Products to be developed include the component of the Human-Machine Interface that will send operational signals to the Active Park Assist, as well as the Active Park Assist system itself. The product will simplify the task of parking a vehicle for drivers. The software simplifies parking by completely automating the parking process of both parallel spaces and perpendicular spaces. For the vehicles that feature it, Active Park Assist is available as an on-board automation system to be used at the disposal of the driver.
1.3 Definitions, acronyms, and abbreviations
Following are terminology, acronyms, and abbreviation used throughout this document.
- The Driver is the person who is sitting in the seat behind the steering wheel and controls the vehicle.
- Active Park Assist (APA ) is the system to be designed and implemented.
- The Human Machine Interface (HMI) , is the interface which the Driver interacts with the Active Park Assist system.
- Sensor refers to a device that primarily detect distance between itself and an object.
- MPH is abbreviation for miles per hour.
- Signals are the network communication between HMI and APA.
1.4 Organization
Software Requirements Specification consists of 7 sections. Section 1 details the document and the project by which this document was created. The following sections form the specification. Section 2 gives the context of the system, constraints defining interfaces and behavior of the system are provided. A detailed description of the functionality of the system is given. Section 2 forms a depiction of the product in the context of its use. Section 3 is an integral part of the Active Park Assist System. The requirements of the product are listed in this section. Each requirement was used when defining the constraints and the functionality and is used in later sections. Section 4 provides models representing Active Park Assist. Sequence diagrams, a use case diagram, and the domain model diagram are included. Section 5 is the prototype. It is a representation of how the final product should interact with the Driver and its immediate observed environment. Section 6 has the references used in this document. Section 7 contains contact information for the project organizer.
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 4 When the parking process is completed, the APA system will put the vehicle in park, notifies the driver of the completion on the HMI and turn the APA system off. The system can be upgraded to obtain further functions, the upgrade message will only be displayed when the driver first turned on the vehicle and is in park. The upgrade will happen between midnight and 6 am, local time, and will be paused if the vehicle is turned on during this time. Constraints: System interfaces: The auto parking is mostly based on powertrain system, brake control system, steering control system and vehicle position system, any of these system’s failure will causes the APA system loses its primary function. User interfaces: The APA should only be accessed by the driver, any other person in the vehicle should not access the APA system during the APA operations. Hardware interfaces: The APA system will take control of the sensors/steering wheel/brake through the subsystems such as Sensor Control System/Steering Control System/Brake Control System. Software interfaces: The APA system interacts with the driver through the HMI, there will be buttons on the touch screen for the driver to either start detecting the parking spots or abort the parking process, etc. The HMI will display images during the parking process. Communication interfaces: There are no communication interfaces for APA system.
2.2 Product Functions
The APA system has the function of vehicle positioning, cruise control, and omnidirectional scanning. During the APA selected options, the APA system should have the function to locate parking spot based on the parking preferences, calculate parking trajectory of the vehicle, auto parking, cancel/abort the parking and detect obstacle or approaching pedestrians. At the software level, the APA system has the function to upgrade its controlling software and can also be interact with the driver through the HMI.
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 5
2.3 User Characteristics
The user of the APA system is the driver of the vehicle. Under the premise of having a driver's license, drivers need to have basic driving knowledge and basic understanding of electronic products. Also, the driver should have the ability to read the instruction on the owner’s manual. During the APA operation, the driver is required to pay attention to the surroundings of the vehicle and can react in time to cancel/pause the operation if needed.
2.4 Constraints
a) Regulatory policies
- Various state and federal laws regulating testing and functionality of the APA system. b) Hardware limitations (e.g., signal timing requirements)
- Sensors and cameras fit on the vehicle.
- Sensors and cameras are properly aligned. c) Interfaces to other applications
- Park Control Subsystem (PCS)
- Only able to accept driver’s input through HMI.
- Functions properly.
- Powertrain Management Subsystem (PMS)
- Given accurate PCS input to accelerate and select proper transmission gear to match the trajectory.
- HMI Subsystem
- Touch screen is responsive and accurate.
- Screen display is functioning properly.
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 7
- APA will notify the driver through the HMI, along with an audible beep, when a parking spot is found.
- The driver will verify the parking spot through the HMI after APA has found one. In the HMI, the trajectory of the vehicle will be displayed to the driver.
- APA will not start parking until the driver has accepted the action through the HMI.
- APA will take control of the vehicle when the driver has verified the parking spot.
- APA will shift the transmission between drive and reverse as needed to match the verified trajectory.
- APA will brake as needed to match the verified trajectory.
- APA will turn the steering wheel as necessary to meet the verified trajectory.
- Radar/cameras will be used during APA to prevent collisions.
- The driver may cancel APA by braking, obstructing the steering wheel, or by hitting ‘abort’ through the HMI.
- APA will turn off once the vehicle has parked successfully.
- If obstacles are detected in the parking trajectory (while APA is parking) APA will stop the vehicle, put the vehicle in park and turn itself off. It will leave a notification for the driver through the HMI of why the system was turned.
- APA must detect and track objects in all directions of the vehicle.
- Detectable obstacles include, but are not limited to: vehicles, trucks, motorcycles, mopeds, bicycles, scooters, pedestrians, traffic cones, shopping carts, wheelchairs.
- APA will include visual and audible prompts when the system is interrupted to alert the Driver.
4 Modeling Requirements
Use Case Diagram
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 8
Use Case: Abort Parking Actors: None Description: An obstacle has been detected in the trajectory the vehicle was going to take to park the vehicle. APA will pause the parking process and alert the driver with the HMI that an obstacle has been detected. The driver will be allowed to either resume the parking process or abort the parking process with buttons in HMI. If the driver resumes the parking process and the obstacle is still detected, APA will abort the parking process. Type: Primary Includes: None Extends: None Cross-refs: 19 , 22, 23, 24, 25 Use cases: None
Use Case: Cancel Parking Actors: Driver Description: The driver can cancel the parking process manually by applying the brakes, turning the steering wheel or by pressing the “abort” button on the panel. The vehicle will stop and turn to “park” mode, along with turning off the APA system. Type: Primary Includes: None Extends: None Cross-refs: 2, 3, 2 0 , 25 Use cases: None
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 10 Use cases: 1, 2, 5
Use Case: Parking Successful Actors: Driver Description: APA has successfully parked the vehicle. After the vehicle has completed the parking process, APA will put the vehicle in park, notify the driver in the HMI that the system has completed the parking process and turn off the APA system. Control of the vehicle will return to the driver. Type: Primary Includes: None Extends: None Cross-refs: 21 Use cases: None
Use Case: Search for Parking Spot Actors: Obstacle Description: Having received a Boolean value for “parallel”, APA’s Searching is activated. The system searches for parallel parking spots given a true Boolean value, perpendicular parking for a false value. In this state the HMI displays a message directing the driver to drive 7mph or slower while it searches for a parking spot. Sensors and the cameras on the vehicle are then building maps of the parking spaces and checking if the vehicle could fit. Upon driving by a spot that the vehicle could park in, a message alert is made to the HMI asking the user to Verify the parking spot. During any operation the Driver is able hit Abort on the HMI to exit the APA completely. Additionally, they can hit Cancel on the HMI to go back and re-specify “right_side” and “parallel” options. Type: Primary Includes: None
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 11 Extends: Verify Parking Spot Cross-refs: 8, 9, 10, 11, 12 Use cases: 9
Use Case: Specify Parking Preference Actors: Driver Description: After the APA has been initiated and the parking options are presented to the driver, the driver will be able to select the options within the system if they wish to parallel park or perpendicular park. This will allow the cameras/sensors to focus on one side of the road for greater functionality. Type: Primary Includes: None Extends: None Cross-refs: 7 Use cases: 6
Use Case: Upgrade System Actors: Driver Description: Software upgrade will be displayed to the user in the HMI. This upgrade message will only appear when the driver has first turned on the vehicle and is in park. This message will never show up while the driver is driving the vehicle or reversing the vehicle, only when the driver has initially turned the vehicle on. If the driver verifies the software upgrade, the upgrade will happen between midnight and 6am, local time. If the vehicle is turned on during this time, the system will pause the upgrade request and continue with the upgrade the next day. Type: Secondary
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 13 Cross-refs: 2 , 3, 4 Use cases: None
Domain Model
Element Name Description ActiveParkAssist Control the parking of the vehicle. Attributes parallel:boolean If the driver wants to parallel park, this will be True. If the driver wants to perpendicular park, this will be False. vehicle_length:double Constant specifying the length of the vehicle. vehicle_width:double Constant specifying the width of the vehicle. Operations detectObstacle (parallel): map Scans specified area around the vehicle for a parking spot that would be acceptable to park in. Returns a 3D map of where the location is relative to the vehicle. Park (map): boolean Parks the vehicle based on the map that is provided. Success(): boolean Returns True if the vehicle was parked successfully without any incidents. Abort(): None Stops the vehicle, puts it in park, and disables ActiveParkAssist. ActivateAPA(): None System starts APA depending on the specifications the Driver has specified.
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 14 Relationships Has a 1 to 1 relationship with human machine interface. Uses 6 ultrasonic sensors and 2 cameras and also has a 1 to 1 relationship with the vehicle’s drive options. UML Extensions None. Element Name Description HumanMachineInterface Handles the interaction between driver and ActiveParkAssist Attributes parallel:boolean If the driver wants to parallel park, this will be True. If the driver wants to perpendicular park, this will be False. Operations ActivateHMI(): None Driver initiates the start of APA. Driver is asked what side of the street to park on and what kind of parking style they want. setParkSpecifications(parallel): boolean HMI communicates with APA to start the parking process based on the specifications the driver requested. Verify(message):boolean Driver accepts/declines the message. This message can be in regards to software upgrades or a message regrading whether they want to park in the spot that is found by APA. Cancel():None Driver cancels the APA, this gives control of the vehicle back to driver and stops APA. Upgrade():boolean Scans for a new version to upgrade, returns true if successful. DisplayMessage(message):None Based on the message passed, this will display in the HMI so the driver knows what is currently going on in the system. ObstacleResponse():boolean When an obstacle is found, the driver is asked whether they would like to abort the parking process or resume the parking process. Resume():None Signals to APA that the driver would like to resume the parking process. Relationships Has a 1 to 1 relationship with ActiveParkAssist. UML Extensions None.
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 16
State Diagram
States: Parking Specification: After the APA button is pressed, the driver is asked to specify how they want to park (parallel or perpendicular) and on what side of the road they would like to park on (left or right side). After this, the system will transition to start searching for a spot to park in. Searching for Spot: With the parking specifications from the driver, the system will know what side of the road scan and how the driver would like to park the vehicle. If a parking spot if found, the driver is asked to verify the spot. If the driver no longer wants to use APA, they can abort the system which will end the process. If the driver would like to go back to parking specifications to change their options, then they can return to parking specifications. Verify Spot: When a parking spot is found, the driver is asked to verify the parking spot. If the driver rejects the parking spot, the system returns to the searching for parking spot state. If the driver would like to halt the APA system, they can abort by tappinng the “Abort” button on the HMI. Park: Upon verification, APA can begin parking the vehicle. While the vehicle is being parked, if the system detects an obstacle in the path, the system will stop the vehicle and display a message to the driver. If the system successfully parks, the system will reach its final state. If the driver wants to abort the system at any time, they can abort by tapping the “Abort” button on the HMI. Obstacle in Path: When an obstacle is detected in the path of the vehicle, the system will stop the vehicle and ask the driver how they would like to proceed. The driver will have two options, abort or resume. Resume will presumably mean the driver no longer sees in
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 17 obstacle in the path and believes the vehicle can continue parking and go back to the park state. If the driver would like to abort, then the system will turn off and reach its end state.
Sequence Diagrams
Sequence diagram: Initiate Active Park Assist System The driver activates the HMI which will activate the APA system. Once activated, the APA system will start checking the status of all the sensors and cameras, if no camera or sensor fails, the APA system will go to the next stage that will let the driver give a parking preference, the APA system will be cancelled otherwise if any camera or sensor fails. Sequence diagram: Specify Parking Preferences When the driver is required to give a parking preference on the HMI, the HMI will give options to the driver, either perpendicular parking or parallel parking. Once the option is selected, the HMI will tell the APA system to start searching process. Sequence diagram: Search for Parking Spot
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 19 Sequence diagram: Cancel Parking In the case of Cancel Parking, the driver presses the Cancel button on the HMI, the HMI tells the APA system to abort this parking process. The APA system will apply the brake and shift the vehicle in park. The HMI will display the cancel message to the driver. Sequence diagram: Parking Successful The APA system successfully parks the vehicle in the right spot, the APA system will apply the brake and shift the vehicle in park. The HMI will display a message of successful parking to the driver. Sequence diagram: Upgrade System
Template based on IEEE Std 830-1998 for SRS. Modifications (content and ordering of information) 20 The APA system will check the upgrades itself. Once the APA system finds an available upgrade, it tells the HMI to let the driver verify the upgrade. The driver responds to the request and the HMI will tell the APA system to either apply the upgrade or not. Sequence diagram: Verify Parking Spot The driver will verify a parking spot after one has been found and then APA will begin the parking process. Sequence diagram: Verify Upgrade The driver will verify an upgrade to the system and then the system will begin to upgrade itself.
5 Prototype
5.1 How to Run Prototype
To run our prototype, the user must have a computer with internet access, a modern version of Chrome or Firefox, and JavaScript enabled. The prototype can be seen here (https://www.cse.msu.edu/~schmi703/Prototype/CSE- 435 - APA2-Prototype-master- ff9dfc67edfde2f14a3b07f46c026be0fdc940c4/CSE435-Prototype/), As the user progresses through the prototype, they will be presented with various screens that the user will see while they are parking the vehicle with Active Park Assist.
